/* v0.3 — spatial black / holographic learning system */
:root {
  color-scheme: dark;
  --bg: #020307;
  --bg-2: #050711;
  --surface: rgba(7, 10, 20, .46);
  --surface-solid: #080b13;
  --surface-2: rgba(18, 22, 36, .7);
  --line: rgba(177, 196, 255, .12);
  --line-strong: rgba(131, 92, 255, .58);
  --text: #f2f1f7;
  --muted: #9293a7;
  --cyan: #43d6ff;
  --green: #dfff24;
  --violet: #9147ff;
  --acid: #dfff24;
  --danger: #ff6a8a;
  --shadow: 0 34px 110px rgba(0, 0, 0, .62);
  font-family: "Arial Narrow", "Segoe UI Variable Display", "Segoe UI", "Microsoft YaHei UI", sans-serif;
}

html { overflow-x: clip; background: #020307; }
body { background: #020307; font-size: 16px; }

.topbar {
  border-bottom: 1px solid rgba(199, 203, 255, .08);
  background: rgba(2, 3, 8, .5);
  backdrop-filter: blur(16px) saturate(125%);
  -webkit-backdrop-filter: blur(16px) saturate(125%);
}

.brand-mark {
  border: 0;
  border-radius: 0;
  background: transparent;
  color: #fff;
  font-size: 22px;
  text-shadow: 0 0 22px rgba(145, 71, 255, .48);
}

.brand-mark span { color: var(--acid); }
.brand strong { font-size: 16px; }
.brand small { color: #77798b; letter-spacing: .19em; }

.top-actions { gap: clamp(13px, 2vw, 30px); }
.top-actions .pill-link,
.top-actions .icon-button {
  position: relative;
  width: auto;
  height: auto;
  min-height: 38px;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: #b7b7c6;
  backdrop-filter: none;
  cursor: pointer;
  font-size: 12px;
  letter-spacing: .06em;
  transition: color .25s ease, text-shadow .25s ease, translate .25s ease;
}

.top-actions .icon-button { min-width: 24px; }
.battery-icon {
  position: relative;
  width: 23px;
  height: 11px;
  display: inline-block;
  border: 1px solid currentColor;
  border-radius: 2px;
  color: #77798a;
}
.battery-icon::after {
  content: "";
  position: absolute;
  right: -4px;
  top: 3px;
  width: 2px;
  height: 5px;
  border-radius: 0 1px 1px 0;
  background: currentColor;
}
.battery-icon i {
  position: absolute;
  inset: 2px;
  width: 32%;
  background: currentColor;
  transition: width .25s ease, background .25s ease;
}
.eco-button.active .battery-icon {
  color: var(--acid);
  box-shadow: 0 0 12px rgba(223,255,36,.22);
}
.eco-button.active .battery-icon i { width: calc(100% - 4px); }
.top-actions .pill-link::after,
.top-actions .icon-button::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 3px;
  left: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--acid), transparent);
  scale: 0 1;
  transition: scale .3s cubic-bezier(.16, 1, .3, 1);
}

.top-actions .pill-link:hover,
.top-actions .icon-button:hover,
.top-actions .pill-link:focus-visible,
.top-actions .icon-button:focus-visible {
  color: #fff;
  text-shadow: 0 0 16px rgba(223, 255, 36, .3);
  translate: 0 -1px;
  outline: 0;
}

.top-actions .pill-link:hover::after,
.top-actions .icon-button:hover::after,
.top-actions .pill-link:focus-visible::after,
.top-actions .icon-button:focus-visible::after { scale: 1 1; }

/* Home — restrained smoke in a deep, scanned space. */
.home-page {
  overflow-x: hidden;
  background:
    radial-gradient(circle at 72% 18%, rgba(104, 44, 255, .09), transparent 30%),
    #020307;
}

.home-page .topbar { position: fixed; }
.home-page main { position: static; }
.home-page .site-footer,
.home-page .intro-strip,
.home-page .course-section { position: relative; z-index: 6; }

.home-page .hero {
  min-height: 760px;
  height: 100svh;
  background: transparent;
}

#fluid-canvas,
#home-space-canvas,
.fluid-fallback,
.home-page .hero-grid,
.depth-field {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
}

#home-space-canvas {
  z-index: 1;
  opacity: .86;
  pointer-events: none;
  mix-blend-mode: screen;
}
#fluid-canvas {
  z-index: 2;
  opacity: .74;
  pointer-events: none;
}

.home-scan-beams {
  position: fixed;
  z-index: 3;
  inset: 64px 0 0;
  overflow: hidden;
  pointer-events: none;
}
.home-scan-beams > i {
  position: absolute;
  top: -20vh;
  width: 1px;
  height: 85vh;
  background: linear-gradient(transparent, rgba(75,215,255,.55), rgba(223,255,36,.2), transparent);
  box-shadow: 0 0 18px rgba(75,215,255,.35);
  opacity: .35;
  animation: homeBeamDrift 9s ease-in-out infinite alternate;
}
.home-scan-beams > i:nth-child(1) { left: 18vw; }
.home-scan-beams > i:nth-child(2) { left: 58vw; animation-delay: -3s; animation-direction: alternate-reverse; }
.home-scan-beams > i:nth-child(3) { left: 86vw; animation-delay: -6s; }
.home-scan-beams > span {
  position: absolute;
  left: -20vw;
  top: 26vh;
  width: 140vw;
  height: 16vh;
  background: linear-gradient(transparent, rgba(65,211,255,.035), transparent);
  filter: blur(16px);
  transform: rotate(-7deg);
  animation: homeBandSweep 8s ease-in-out infinite alternate;
}
@keyframes homeBeamDrift {
  from { transform: translateX(-5vw) scaleY(.75); opacity: .18; }
  to { transform: translateX(7vw) scaleY(1.15); opacity: .58; }
}
@keyframes homeBandSweep {
  from { transform: translate3d(-8vw,-9vh,0) rotate(-7deg); opacity: .2; }
  to { transform: translate3d(9vw,22vh,0) rotate(-2deg); opacity: .75; }
}

.fluid-fallback {
  z-index: 0;
  filter: blur(20px);
  background:
    radial-gradient(ellipse at 62% 43%, rgba(123, 50, 255, .18), transparent 25%),
    radial-gradient(ellipse at 72% 46%, rgba(40, 111, 255, .12), transparent 31%),
    linear-gradient(120deg, #020307, #05030c 62%, #03050b);
}

.home-page .hero-grid {
  z-index: 4;
  opacity: .42;
  background-image:
    repeating-linear-gradient(0deg, rgba(175, 153, 255, .045) 0 1px, transparent 1px 5px),
    linear-gradient(90deg, rgba(223, 255, 36, .13) 1px, transparent 1px),
    linear-gradient(rgba(145, 71, 255, .07) 1px, transparent 1px);
  background-size: auto, 220px 100%, 100% 140px;
  mask-image: linear-gradient(90deg, #000, rgba(0,0,0,.9) 58%, transparent);
  pointer-events: none;
}

.depth-field { z-index: 3; overflow: hidden; pointer-events: none; }
.depth-field i {
  position: absolute;
  display: block;
  border-radius: 50%;
  mix-blend-mode: screen;
  will-change: translate, opacity;
}

.depth-field i:nth-child(1) {
  width: 42vw;
  height: 8vw;
  right: -7vw;
  top: 18vh;
  border-radius: 50%;
  background: rgba(102, 31, 255, .26);
  filter: blur(45px);
  animation: energyDrift 8s ease-in-out infinite alternate;
}

.depth-field i:nth-child(2) {
  width: 27vw;
  height: 27vw;
  right: 26vw;
  top: 39vh;
  background: radial-gradient(circle, rgba(118, 45, 255, .12), transparent 68%);
  filter: blur(34px);
  animation: energyDrift 11s ease-in-out -3s infinite alternate-reverse;
}

.depth-field i:nth-child(3) {
  width: 1px;
  height: 45vh;
  left: 11vw;
  top: 17vh;
  border-radius: 0;
  background: linear-gradient(transparent, var(--acid), transparent);
  box-shadow: 44vw 8vh 20px rgba(145,71,255,.55), 78vw -4vh 14px rgba(223,255,36,.35);
  opacity: .42;
}

@keyframes energyDrift {
  from { translate: -4vw -2vh; opacity: .42; scale: .85; }
  to { translate: 8vw 7vh; opacity: .82; scale: 1.15; }
}

.hero::before {
  content: "";
  position: absolute;
  z-index: 4;
  inset: 13vh 4vw 10vh;
  border: solid rgba(192, 255, 42, .09);
  border-width: 0 1px;
  pointer-events: none;
}

.hero::after {
  z-index: 4;
  height: 220px;
  background: linear-gradient(transparent, #020307);
}

.hero-copy {
  z-index: 6;
  width: min(780px, 78vw);
  margin-left: clamp(24px, 10vw, 170px);
}

.eyebrow,
.section-kicker {
  color: var(--acid);
  font-size: 11px;
  letter-spacing: .28em;
}

.eyebrow::before,
.section-kicker::before {
  content: "";
  display: inline-block;
  width: 52px;
  height: 2px;
  margin-right: 18px;
  vertical-align: middle;
  background: var(--acid);
  box-shadow: 0 0 14px rgba(223, 255, 36, .5);
}

.hero h1 {
  position: relative;
  isolation: isolate;
  max-width: 880px;
  font-size: clamp(65px, 9vw, 145px);
  line-height: .94;
  padding-block: .08em .03em;
  letter-spacing: -.075em;
  font-weight: 760;
  text-transform: uppercase;
  text-shadow: 0 24px 80px rgba(0,0,0,.7);
  animation: heroReveal .9s cubic-bezier(.16, 1, .3, 1) both;
}

.hero h1 span,
.hero h1 em {
  position: relative;
  display: inline-block;
}

.hero h1::after {
  content: none;
}

.hero h1 em {
  color: transparent;
  -webkit-text-stroke: 1px rgba(238, 236, 248, .88);
  background: linear-gradient(100deg, #ffffff 0%, #dfe8ff 30%, #9b64ff 62%, #c3f7ff 100%);
  background-size: 100% 100%;
  -webkit-background-clip: text;
  filter: drop-shadow(0 0 24px rgba(132, 61, 255, .38));
  text-transform: none;
  animation: none;
}

.hero h1 span:first-child {
  text-shadow:
    0 24px 80px rgba(0,0,0,.72),
    0 0 22px rgba(255,255,255,.08),
    -5px 0 0 rgba(67,214,255,.06),
    5px 0 0 rgba(145,71,255,.08);
}

@keyframes heroReveal {
  from { opacity: 0; translate: 0 42px; }
  to { opacity: 1; translate: 0; }
}

.hero-lead {
  max-width: 620px;
  color: #aaa9b8;
  font-size: clamp(17px, 1.45vw, 21px);
  line-height: 1.8;
}

.primary-button {
  min-height: 50px;
  padding: 0 23px;
  border: 1px solid var(--acid);
  border-radius: 2px 12px 2px 12px;
  background: rgba(10, 13, 16, .48);
  color: #f7ffcf;
  box-shadow: inset 0 0 24px rgba(223,255,36,.05), 0 0 30px rgba(223,255,36,.06);
  transition: translate .28s ease, background .28s ease, box-shadow .28s ease;
}

.primary-button:hover {
  translate: 0 -3px;
  background: rgba(173, 205, 23, .14);
  box-shadow: 0 0 38px rgba(223,255,36,.15);
}

.text-button { color: #a2a1b0; }
.hero-status,
.path-steps,
.track-heading {
  border-radius: 0;
  background: rgba(4, 5, 11, .4);
  backdrop-filter: blur(17px);
}

.hero-status { border-color: rgba(223,255,36,.14); }
.status-dot { background: var(--acid); box-shadow: 0 0 14px var(--acid); }
.status-meter i { background: linear-gradient(90deg, var(--violet), var(--acid)); }

.intro-strip { margin-top: 0; padding-top: 72px; }
.path-steps { border-color: rgba(143, 102, 255, .17); }
.path-steps b { -webkit-text-stroke-color: rgba(223, 255, 36, .48); }

.course-section {
  width: min(1420px, 95vw);
  margin-bottom: 180px;
}

.section-heading h2 {
  max-width: 760px;
  font-size: clamp(40px, 5.5vw, 78px);
  line-height: .95;
  letter-spacing: -.06em;
}

.track {
  --track-accent: var(--acid);
  position: relative;
  margin-top: 90px;
  isolation: isolate;
}
.track-violet { --track-accent: #9451ff; }
.track-ghost {
  position: absolute;
  z-index: -1;
  left: clamp(8px, 4vw, 70px);
  top: -112px;
  color: transparent;
  -webkit-text-stroke: 1px color-mix(in srgb, var(--track-accent), transparent 64%);
  background: linear-gradient(105deg, transparent 15%, color-mix(in srgb, var(--track-accent), transparent 75%) 42%, transparent 68%);
  background-size: 220% 100%;
  -webkit-background-clip: text;
  background-clip: text;
  font: 900 clamp(300px, 41vw, 650px)/.78 "Arial Narrow", "Segoe UI", sans-serif;
  letter-spacing: -.1em;
  text-shadow:
    0 0 26px color-mix(in srgb, var(--track-accent), transparent 80%),
    0 0 110px color-mix(in srgb, var(--track-accent), transparent 87%);
  opacity: .7;
  mix-blend-mode: screen;
  pointer-events: none;
  animation: trackGhostPulse 6s ease-in-out infinite alternate, trackGhostScan 4.8s linear infinite;
}
.track-ghost::after {
  content: attr(data-ghost);
  position: absolute;
  inset: 0;
  color: transparent;
  -webkit-text-stroke: 1px color-mix(in srgb, var(--track-accent), transparent 82%);
  text-shadow: 12px 0 24px color-mix(in srgb, var(--track-accent), transparent 84%);
  transform: translate(12px,8px);
  opacity: .65;
  animation: trackGhostEcho 3.2s steps(2,end) infinite;
}
@keyframes trackGhostPulse {
  from { filter: drop-shadow(0 0 0 transparent); transform: translateY(0); }
  to { filter: drop-shadow(0 0 24px color-mix(in srgb, var(--track-accent), transparent 75%)); transform: translateY(-8px); }
}
@keyframes trackGhostScan { to { background-position: -220% 0; } }
@keyframes trackGhostEcho {
  0%, 92%, 100% { clip-path: inset(0 0 0 0); translate: 0; }
  94% { clip-path: inset(18% 0 61% 0); translate: 11px -2px; }
  97% { clip-path: inset(63% 0 17% 0); translate: -8px 3px; }
}
.track-heading {
  padding: 16px 20px;
  border: 0;
  border-left: 2px solid var(--track-accent);
  border-bottom: 1px solid color-mix(in srgb, var(--track-accent), transparent 78%);
}

.track-letter {
  border: 0;
  border-radius: 0;
  color: var(--track-accent);
  font-size: 38px;
  text-shadow: 0 0 22px color-mix(in srgb, var(--track-accent), transparent 50%);
}

.track-heading h3 { color: var(--track-accent); }
.course-deck-viewport {
  position: relative;
  z-index: 1;
  width: 100%;
  padding-top: 128px;
  padding-bottom: 34px;
  overflow-x: auto;
  overflow-y: clip;
  scroll-padding-inline: 24px;
  scrollbar-width: thin;
  scrollbar-color: color-mix(in srgb, var(--track-accent), transparent 55%) transparent;
}

.course-deck {
  position: relative;
  min-width: 1180px;
  height: var(--deck-height, 455px);
  perspective: 1500px;
  transform-style: preserve-3d;
  contain: layout style;
}

.course-deck .course-card {
  position: absolute;
  inset: 0 auto auto 0;
  width: var(--card-width, 318px);
  height: 392px;
  min-height: 0;
  padding: 0;
  display: block;
  overflow: hidden;
  border: 1px solid color-mix(in srgb, var(--track-accent), transparent 68%);
  border-radius: 12px;
  background:
    linear-gradient(155deg, color-mix(in srgb, var(--track-accent), transparent 92%), transparent 44%),
    linear-gradient(145deg, #0f101b, #03050a);
  box-shadow: -18px 24px 52px rgba(0,0,0,.55);
  transform:
    translate3d(var(--deck-x, 0), var(--deck-y, 0), 0)
    rotate(var(--deck-tilt, 0deg))
    scale(var(--deck-scale, 1));
  transform-origin: 50% 105%;
  transition:
    transform .23s cubic-bezier(.2, .78, .2, 1),
    border-color .18s ease,
    box-shadow .22s ease;
  will-change: transform;
  backface-visibility: hidden;
  contain: layout paint style;
}

.home-reveal-ready .track:not(.is-revealed) .course-card {
  opacity: 0;
  translate: -72px 38px;
}
.home-reveal-ready .track.is-revealed .course-card {
  animation: dealCardIn .72s cubic-bezier(.16,1,.3,1) backwards;
  animation-delay: calc(var(--deal-index, 0) * 58ms);
}
@keyframes dealCardIn {
  0% { opacity: 0; translate: -72px 38px; filter: blur(5px) brightness(.7); }
  68% { opacity: 1; translate: 8px -4px; filter: blur(0) brightness(1.04); }
  100% { opacity: 1; translate: 0 0; filter: blur(0) brightness(1); }
}

.home-reveal-ready .scroll-reveal {
  opacity: 0;
  translate: 0 58px;
  transition: opacity .75s ease, translate .9s cubic-bezier(.16,1,.3,1);
}
.home-reveal-ready .scroll-reveal.is-revealed { opacity: 1; translate: 0; }
.home-reveal-ready .scroll-reveal:not(.is-revealed) .path-steps article,
.home-reveal-ready .scroll-reveal:not(.is-revealed) .section-heading > *,
.home-reveal-ready .scroll-reveal:not(.is-revealed) .review-copy > *,
.home-reveal-ready .scroll-reveal:not(.is-revealed) .review-progress-preview > * { opacity: 0; }
.home-reveal-ready .scroll-reveal.is-revealed .path-steps article,
.home-reveal-ready .scroll-reveal.is-revealed .section-heading > *,
.home-reveal-ready .scroll-reveal.is-revealed .review-copy > *,
.home-reveal-ready .scroll-reveal.is-revealed .review-progress-preview > * {
  animation: childRiseIn .7s cubic-bezier(.16,1,.3,1) backwards;
}
.home-reveal-ready .path-steps article:nth-child(2),
.home-reveal-ready .section-heading > *:nth-child(2),
.home-reveal-ready .review-copy > *:nth-child(2),
.home-reveal-ready .review-progress-preview > *:nth-child(2) { animation-delay: 90ms !important; }
.home-reveal-ready .path-steps article:nth-child(3),
.home-reveal-ready .review-copy > *:nth-child(3),
.home-reveal-ready .review-progress-preview > *:nth-child(3) { animation-delay: 180ms !important; }
.home-reveal-ready .review-copy > *:nth-child(4) { animation-delay: 270ms !important; }
@keyframes childRiseIn {
  from { opacity: 0; translate: 0 30px; filter: blur(4px); }
  to { opacity: 1; translate: 0; filter: blur(0); }
}

.course-deck .course-card::before {
  content: "";
  position: absolute;
  z-index: 3;
  inset: -25% -95%;
  border-radius: 0;
  background: linear-gradient(
    112deg,
    transparent 42%,
    rgba(255,255,255,.015) 46%,
    rgba(255,255,255,.16) 49.4%,
    rgba(255,255,255,.035) 52%,
    transparent 57%
  );
  transform: translateX(-34%);
  transition: transform .9s cubic-bezier(.16, 1, .3, 1);
  pointer-events: none;
}

.course-deck .course-card::after {
  inset: 0;
  width: auto;
  height: auto;
  right: auto;
  top: auto;
  border-radius: inherit;
  opacity: .18;
  background:
    radial-gradient(circle at 74% 16%, color-mix(in srgb, var(--track-accent), white 28%) 0 2%, transparent 27%),
    radial-gradient(circle at 88% 8%, color-mix(in srgb, var(--track-accent), transparent 72%), transparent 28%);
  filter: none;
  mix-blend-mode: screen;
  transition: opacity .22s ease;
}

.course-deck .course-card:hover,
.course-deck .course-card:focus-visible,
.course-deck .course-card.is-focused {
  border-color: color-mix(in srgb, var(--track-accent), transparent 30%);
  box-shadow: -19px 31px 66px rgba(0,0,0,.66), 0 0 30px color-mix(in srgb, var(--track-accent), transparent 89%);
  outline: 0;
}

.course-deck .course-card.is-focused::before { transform: translateX(34%); }
.course-card-grid {
  position: absolute;
  inset: 0;
  opacity: .34;
  background-image:
    linear-gradient(color-mix(in srgb, var(--track-accent), transparent 90%) 1px, transparent 1px),
    linear-gradient(90deg, color-mix(in srgb, var(--track-accent), transparent 93%) 1px, transparent 1px);
  background-size: 100% 26px, 26px 100%;
  mask-image: linear-gradient(180deg, #000, transparent 70%);
}

.course-card-top {
  position: relative;
  z-index: 2;
  height: 45px;
  padding: 0 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid color-mix(in srgb, var(--track-accent), transparent 78%);
  color: color-mix(in srgb, var(--track-accent), white 14%);
  font: 600 9px/1 ui-monospace, monospace;
  letter-spacing: .16em;
}

.course-card-body {
  position: relative;
  z-index: 2;
  height: calc(100% - 45px);
  margin: 0;
  padding: 20px 20px 18px;
  display: flex;
  flex-direction: column;
  opacity: .82;
  transform: none;
  transition: opacity .3s ease;
}

.course-card.is-focused .course-card-body { opacity: 1; }
.course-big-number {
  position: absolute;
  left: 14px;
  top: 82px;
  color: transparent;
  -webkit-text-stroke: 1px color-mix(in srgb, var(--track-accent), white 8%);
  font: 800 104px/.8 "Arial Narrow", "Segoe UI", sans-serif;
  letter-spacing: -.13em;
  opacity: .72;
  text-shadow: 0 0 28px color-mix(in srgb, var(--track-accent), transparent 84%);
}

.course-deck .course-title {
  margin-top: 85px;
  margin-left: 112px;
}
.course-deck .course-title h4 {
  max-width: 165px;
  margin: 16px 0 9px;
  font-size: 22px;
  line-height: 1.16;
  letter-spacing: -.035em;
}

.course-deck .course-title p {
  max-width: 220px;
  margin: 0;
  color: #767789;
  font-size: 9px;
  line-height: 1.5;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.course-status {
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--track-accent);
  font-size: 9px;
  letter-spacing: .16em;
}

.course-card-actions {
  margin-left: 112px;
  padding-top: 13px;
  border-top: 1px solid color-mix(in srgb, var(--track-accent), transparent 82%);
  color: var(--track-accent);
  font-size: 11px;
}

.course-card-actions b { font-size: 18px; font-weight: 400; transition: translate .25s ease; }
.course-card:hover .course-card-actions b { translate: 4px -4px; }

.review-section {
  position: relative;
  z-index: 6;
  width: min(1420px, 95vw);
  min-height: 560px;
  margin: 110px auto 170px;
  padding: clamp(55px, 7vw, 100px);
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(280px, .7fr);
  align-items: end;
  gap: 70px;
  overflow: hidden;
  border: solid rgba(145,71,255,.24);
  border-width: 1px 0;
  background:
    repeating-linear-gradient(0deg, rgba(145,71,255,.025) 0 1px, transparent 1px 6px),
    radial-gradient(circle at 76% 48%, rgba(122,45,255,.16), transparent 30%),
    rgba(3,4,10,.66);
}
.review-copy { position: relative; z-index: 2; }
.review-copy h2 {
  max-width: 850px;
  margin: 0;
  font-size: clamp(46px, 6vw, 88px);
  line-height: .94;
  letter-spacing: -.06em;
}
.review-copy > p:not(.section-kicker) {
  max-width: 650px;
  margin: 28px 0 34px;
  color: #b5b3c0;
  font-size: 18px;
  line-height: 1.8;
}
.review-progress-preview {
  position: relative;
  z-index: 2;
  display: grid;
  gap: 1px;
  background: rgba(145,71,255,.2);
}
.review-progress-preview span {
  min-height: 94px;
  padding: 20px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(4,5,12,.88);
}
.review-progress-preview b { color: var(--acid); font: 500 32px/1 ui-monospace,monospace; }
.review-progress-preview small { color: #858595; font-size: 9px; letter-spacing: .14em; }
.review-orbit { position: absolute; inset: 0; pointer-events: none; }
.review-orbit i {
  position: absolute;
  right: -9vw;
  top: -13vw;
  width: 47vw;
  height: 47vw;
  border: 1px solid rgba(145,71,255,.18);
  border-radius: 50%;
  box-shadow: 0 0 80px rgba(145,71,255,.12), inset 0 0 80px rgba(145,71,255,.08);
  animation: lessonOrbit 20s linear infinite;
}
.review-orbit i:nth-child(2) { right: 3vw; top: -1vw; width: 25vw; height: 25vw; animation-direction: reverse; }
.review-orbit span {
  position: absolute;
  right: 11vw;
  top: 70px;
  color: transparent;
  -webkit-text-stroke: 1px rgba(223,255,36,.32);
  font: 700 150px/1 serif;
}

.review-orbit span,
.review-progress-preview span:last-child b,
.final-review-glyph {
  color: transparent;
  -webkit-text-stroke: 1px rgba(157, 105, 255, .62);
  background: linear-gradient(105deg, #6e35ff 0%, #d7b8ff 24%, #63ddff 48%, #efff86 66%, #8a4dff 100%);
  background-size: 260% 100%;
  -webkit-background-clip: text;
  background-clip: text;
  filter: drop-shadow(0 0 16px rgba(123, 71, 255, .32));
  animation: infinityLightFlow 3.8s linear infinite;
}

@keyframes infinityLightFlow {
  from { background-position: 180% 50%; }
  to { background-position: -80% 50%; }
}

.review-page {
  position: relative;
  isolation: isolate;
  min-height: 100vh;
  overflow-x: hidden;
  background:
    radial-gradient(circle at 75% 8%, rgba(112,39,255,.13), transparent 27%),
    #04050b;
}
.review-page .topbar { position: fixed; z-index: 20; }
.review-fx-canvas {
  position: fixed;
  z-index: -2;
  inset: 0;
  width: 100vw;
  height: 100vh;
  opacity: .92;
  pointer-events: none;
  mix-blend-mode: screen;
}
.review-space {
  position: fixed;
  z-index: -3;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  perspective: 700px;
  background:
    radial-gradient(circle at 76% 16%, rgba(125,44,255,.28), transparent 24%),
    radial-gradient(circle at 18% 60%, rgba(50,77,255,.1), transparent 27%),
    linear-gradient(#03040a, #07030f 72%, #020307);
}
.review-space::before {
  content: "";
  position: absolute;
  right: -20vw;
  bottom: -63vh;
  left: -20vw;
  height: 106vh;
  border-top: 1px solid rgba(223,255,36,.18);
  background-image:
    linear-gradient(rgba(143,77,255,.16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(143,77,255,.16) 1px, transparent 1px);
  background-size: 64px 48px;
  transform: rotateX(67deg);
  transform-origin: center top;
  animation: reviewGridRun 5s linear infinite;
  mask-image: linear-gradient(180deg, transparent, #000 18%, #000 66%, transparent);
}
.review-space::after {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(0deg, transparent 0 4px, rgba(173,136,255,.026) 4px 5px);
  animation: reviewScanNoise .65s steps(2) infinite;
}
.review-space > i {
  position: absolute;
  width: 1px;
  height: 80vh;
  top: 8vh;
  background: linear-gradient(transparent, rgba(145,71,255,.65), rgba(223,255,36,.25), transparent);
  box-shadow: 0 0 22px rgba(145,71,255,.55);
  transform-origin: center;
  animation: reviewBeam 7s ease-in-out infinite alternate;
}
.review-space > i:nth-child(1) { left: 10vw; }
.review-space > i:nth-child(2) { left: 38vw; animation-delay: -2s; opacity: .5; }
.review-space > i:nth-child(3) { left: 70vw; animation-delay: -4s; }
.review-space > i:nth-child(4) { left: 91vw; animation-delay: -6s; opacity: .4; }
.review-horizon {
  position: absolute;
  right: -10vw;
  top: 14vh;
  width: 64vw;
  height: 64vw;
  border: 1px solid rgba(145,71,255,.23);
  border-radius: 50%;
  box-shadow:
    0 0 90px rgba(107,34,255,.18),
    inset 0 0 90px rgba(107,34,255,.12),
    0 0 0 7vw rgba(129,64,255,.018),
    0 0 0 14vw rgba(129,64,255,.012);
  animation: lessonOrbit 26s linear infinite;
}
.review-scan {
  position: absolute;
  top: -30vh;
  left: -10vw;
  width: 120vw;
  height: 24vh;
  background: linear-gradient(transparent, rgba(124,60,255,.09), rgba(223,255,36,.035), transparent);
  filter: blur(16px);
  animation: reviewSweep 8s cubic-bezier(.4,0,.2,1) infinite;
}
.review-cursor-field {
  position: fixed;
  z-index: 0;
  left: 0;
  top: 0;
  width: 420px;
  height: 420px;
  margin: -210px 0 0 -210px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(145,71,255,.12), rgba(91,45,255,.035) 37%, transparent 68%);
  filter: blur(8px);
  pointer-events: none;
  transition: opacity .2s;
}
@keyframes reviewGridRun { to { background-position: 0 48px, 64px 0; } }
@keyframes reviewScanNoise { 50% { opacity: .66; } }
@keyframes reviewBeam {
  from { transform: translateX(-3vw) scaleY(.72); opacity: .22; }
  to { transform: translateX(5vw) scaleY(1.08); opacity: .8; }
}
@keyframes reviewSweep {
  0%, 12% { transform: translateY(-20vh); opacity: 0; }
  30% { opacity: 1; }
  72%, 100% { transform: translateY(145vh); opacity: 0; }
}
.review-main {
  position: relative;
  z-index: 2;
  width: min(1420px, 94vw);
  margin: 0 auto;
  padding: 150px 0 150px;
}
.review-hero { position: relative; min-height: 680px; padding: 40px 0 100px; }
.review-hero h1 {
  margin: 0;
  font-size: clamp(72px, 10vw, 150px);
  line-height: .82;
  letter-spacing: -.075em;
  text-transform: uppercase;
  text-shadow: 0 30px 90px rgba(0,0,0,.72);
}
.review-hero h1 > span,
.review-hero h1 > em { display: block; }
.review-hero h1 em { color: transparent; -webkit-text-stroke: 1px #9f62ff; font-style: normal; }
.review-hero > p:last-of-type { max-width: 630px; margin-top: 36px; color: #b5b3c0; font-size: 19px; line-height: 1.8; }
.review-total {
  position: absolute;
  right: 4vw;
  bottom: 80px;
  display: flex;
  align-items: end;
  gap: 13px;
}
.review-total b { color: var(--acid); font: 500 90px/.8 ui-monospace,monospace; }
.review-total span { color: #8e8d9c; font: 500 22px/1 ui-monospace,monospace; }
.review-total small { margin-top: 8px; display: block; font: 9px/1.4 "Segoe UI",sans-serif; letter-spacing: .1em; }
.review-live-signal {
  position: absolute;
  right: 4vw;
  top: 80px;
  display: flex;
  align-items: center;
  gap: 10px;
  color: #858595;
  font: 9px/1 ui-monospace,monospace;
  letter-spacing: .14em;
}
.review-live-signal i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--acid);
  box-shadow: 0 0 0 0 rgba(223,255,36,.4);
  animation: reviewSignal 1.8s ease-out infinite;
}
@keyframes reviewSignal { 75%, 100% { box-shadow: 0 0 0 14px rgba(223,255,36,0); } }
.review-list-track { margin-top: 100px; }
.review-list-track > header {
  padding: 0 0 22px;
  display: grid;
  grid-template-columns: auto auto 1fr;
  align-items: end;
  gap: 18px;
  border-bottom: 1px solid rgba(145,71,255,.3);
}
.review-list-track > header strong { color: var(--acid); font: 500 58px/.8 ui-monospace,monospace; }
.review-list-track > header span { color: #aaa9b7; font-size: 10px; letter-spacing: .17em; }
.review-list-track > header i { height: 1px; background: linear-gradient(90deg, rgba(223,255,36,.45), transparent); }
.review-lesson-lists { display: grid; }
.review-lesson-list { border-bottom: 1px solid rgba(145,71,255,.22); }
.review-lesson-list > header {
  position: relative;
  min-height: 160px;
  padding: 26px 18px;
  display: grid;
  grid-template-columns: 100px 1fr auto;
  align-items: center;
  gap: 24px;
  overflow: hidden;
  background: linear-gradient(90deg, rgba(88,37,184,.12), rgba(5,6,13,.74) 72%);
}
.review-lesson-list > header::after {
  content: "";
  position: absolute;
  right: -80px;
  width: 310px;
  height: 310px;
  border: 1px solid rgba(145,71,255,.18);
  border-radius: 50%;
  box-shadow: inset 0 0 42px rgba(145,71,255,.12);
}
.review-lesson-list > header > b {
  color: transparent;
  -webkit-text-stroke: 1px rgba(223,255,36,.6);
  font: 800 76px/.8 "Arial Narrow","Segoe UI",sans-serif;
}
.review-lesson-list > header h2 { margin: 8px 0 0; font-size: clamp(28px,3vw,45px); letter-spacing: -.045em; }
.review-lesson-list > header small { color: #8e8d9d; font: 9px/1 ui-monospace,monospace; letter-spacing: .13em; }
.review-lesson-list > header > span { padding-right: 24px; color: var(--acid); font: 500 27px/1 ui-monospace,monospace; text-align: right; }
.review-lesson-list > header > span small { display: block; margin-top: 8px; }
.review-meter { height: 2px; margin-top: auto; background: #242633; }
.review-meter i { display: block; height: 100%; background: linear-gradient(90deg,var(--violet),var(--acid)); }
.review-lesson-list > header .review-meter { position: absolute; right: 0; bottom: 0; left: 0; }
.review-task-head,
.review-task-row {
  display: grid;
  grid-template-columns: 64px minmax(210px,1.25fr) minmax(170px,1fr) 112px 100px;
  align-items: center;
  gap: 18px;
}
.review-task-head {
  min-height: 44px;
  padding: 0 18px;
  border-bottom: 1px solid rgba(145,71,255,.15);
  color: #666878;
  font: 9px/1 ui-monospace,monospace;
  letter-spacing: .15em;
}
.review-task-row {
  --rx: 50%;
  --ry: 50%;
  position: relative;
  min-height: 110px;
  padding: 14px 18px;
  overflow: hidden;
  border-bottom: 1px solid rgba(150,128,218,.11);
  color: #d9d7e0;
  background: rgba(5,7,14,.7);
  transition: transform .32s cubic-bezier(.16,1,.3,1), background .25s, border-color .25s;
}
.review-task-row::before {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0;
  background: radial-gradient(circle 230px at var(--rx) var(--ry), rgba(147,78,255,.18), transparent 68%);
  transition: opacity .25s;
  pointer-events: none;
}
.review-task-row::after {
  content: "";
  position: absolute;
  left: 0;
  top: 16%;
  width: 2px;
  height: 68%;
  scale: 1 0;
  background: var(--acid);
  box-shadow: 0 0 16px var(--acid);
  transition: scale .3s ease;
}
.review-task-row:hover,
.review-task-row:focus-visible {
  z-index: 2;
  transform: translateX(12px);
  border-color: rgba(223,255,36,.28);
  background: rgba(14,11,28,.92);
  outline: 0;
}
.review-task-row:hover::before,
.review-task-row:focus-visible::before { opacity: 1; }
.review-task-row:hover::after,
.review-task-row:focus-visible::after { scale: 1 1; }
.review-task-row > b { color: #747586; font: 500 20px/1 ui-monospace,monospace; }
.review-task-title { min-width: 0; display: grid; gap: 7px; }
.review-task-title small { color: #756f8d; font: 9px/1 ui-monospace,monospace; }
.review-task-title strong { overflow: hidden; font-size: 19px; white-space: nowrap; text-overflow: ellipsis; }
.review-task-row:hover .review-task-title strong { color: #fff; text-shadow: 0 0 25px rgba(145,71,255,.5); }
.review-task-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.review-task-tags i {
  padding: 5px 8px;
  border: 1px solid rgba(145,71,255,.24);
  border-radius: 999px;
  color: #aaa8b7;
  background: rgba(105,47,203,.05);
  font: 10px/1 "Segoe UI",sans-serif;
  font-style: normal;
}
.review-task-difficulty { font: 600 10px/1 ui-monospace,monospace; letter-spacing: .08em; }
.review-task-difficulty.difficulty-very-easy { color: #8bd5ff; }
.review-task-difficulty.difficulty-easy { color: #b9ef87; }
.review-task-difficulty.difficulty-middle { color: #ffd16e; }
.review-task-difficulty.difficulty-hard { color: #ff718f; }
.review-task-state {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #8a8998;
  font: 10px/1 ui-monospace,monospace;
  letter-spacing: .08em;
}
.review-task-state i { width: 7px; height: 7px; border: 1px solid #656676; border-radius: 50%; }
.review-task-row.passed .review-task-state { color: var(--acid); }
.review-task-row.passed .review-task-state i { border-color: var(--acid); background: var(--acid); box-shadow: 0 0 11px rgba(223,255,36,.7); }
.review-planned-lesson {
  min-height: 76px;
  padding: 0 18px;
  display: grid;
  grid-template-columns: 64px 1fr auto;
  align-items: center;
  gap: 18px;
  border-bottom: 1px solid rgba(145,71,255,.1);
  background: rgba(4,5,11,.46);
}
.review-planned-lesson > b { color: transparent; -webkit-text-stroke: 1px rgba(145,71,255,.28); font: 700 32px/1 "Arial Narrow",sans-serif; }
.review-planned-lesson > span { display: flex; align-items: baseline; gap: 16px; }
.review-planned-lesson small { color: #555667; font: 8px/1 ui-monospace,monospace; }
.review-planned-lesson strong { color: #858594; font-size: 15px; font-weight: 500; }
.review-planned-lesson > i { color: #555666; font: 8px/1 ui-monospace,monospace; font-style: normal; letter-spacing: .1em; }

.review-lesson-accordion {
  border-bottom: 1px solid rgba(145,71,255,.16);
  background: rgba(4,5,11,.52);
}
.review-lesson-summary {
  position: relative;
  width: 100%;
  min-height: 116px;
  padding: 20px 18px;
  display: grid;
  grid-template-columns: 82px minmax(0,1fr) auto auto;
  align-items: center;
  gap: 22px;
  overflow: hidden;
  border: 0;
  background: linear-gradient(90deg, rgba(88,37,184,.09), rgba(5,6,13,.76) 72%);
  color: #d9d7e0;
  cursor: pointer;
  text-align: left;
  transition: min-height .42s cubic-bezier(.16,1,.3,1), background .3s, padding .42s cubic-bezier(.16,1,.3,1);
}
.review-lesson-summary::before {
  content: "";
  position: absolute;
  right: -115px;
  width: 300px;
  height: 300px;
  border: 1px solid rgba(145,71,255,.15);
  border-radius: 50%;
  box-shadow: inset 0 0 42px rgba(145,71,255,.09);
  transition: scale .6s cubic-bezier(.16,1,.3,1), opacity .3s;
}
.review-lesson-summary:hover,
.review-lesson-summary:focus-visible { background: linear-gradient(90deg, rgba(105,42,213,.18), rgba(7,8,17,.84) 72%); outline: 0; }
.review-lesson-summary:hover::before { scale: 1.12; }
.review-lesson-summary > b {
  color: transparent;
  -webkit-text-stroke: 1px rgba(223,255,36,.5);
  font: 800 58px/.8 "Arial Narrow","Segoe UI",sans-serif;
}
.review-summary-title { min-width: 0; display: grid; gap: 8px; }
.review-summary-title small { color: #767787; font: 9px/1 ui-monospace,monospace; letter-spacing: .13em; }
.review-summary-title strong { overflow: hidden; font-size: clamp(22px,2.4vw,34px); white-space: nowrap; text-overflow: ellipsis; }
.review-summary-progress { padding-right: 6px; color: var(--acid); font: 600 23px/1 ui-monospace,monospace; text-align: right; }
.review-summary-progress small { margin-top: 6px; display: block; color: #747584; font-size: 8px; letter-spacing: .12em; }
.review-lesson-summary > em {
  position: relative;
  z-index: 1;
  min-width: 125px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 9px;
  color: #858595;
  font: 700 8px/1 ui-monospace,monospace;
  font-style: normal;
  letter-spacing: .1em;
}
.review-lesson-summary > em i {
  width: 8px;
  height: 8px;
  border: solid currentColor;
  border-width: 0 1px 1px 0;
  transform: rotate(45deg) translateY(-2px);
  transition: transform .38s cubic-bezier(.16,1,.3,1), color .25s;
}
.review-lesson-accordion.is-open .review-lesson-summary > em { color: var(--acid); }
.review-lesson-accordion.is-open .review-lesson-summary > em i { transform: rotate(225deg) translate(-1px,-1px); }
.review-lesson-summary .review-meter { position: absolute; right: 0; bottom: 0; left: 0; margin: 0; }
.review-lesson-body {
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  transition: grid-template-rows .62s cubic-bezier(.16,1,.3,1), opacity .35s ease;
}
.review-lesson-body > div { min-height: 0; overflow: hidden; }
.review-lesson-accordion.is-open .review-lesson-body { grid-template-rows: 1fr; opacity: 1; }
.review-lesson-accordion.is-open .review-lesson-summary { min-height: 145px; padding-block: 28px; }
.review-lesson-accordion.planned .review-lesson-summary {
  min-height: 76px;
  grid-template-columns: 64px minmax(0,1fr) auto;
  filter: saturate(.45);
  cursor: default;
}
.review-lesson-accordion.planned .review-lesson-summary > b { font-size: 32px; -webkit-text-stroke-color: rgba(145,71,255,.3); }
.review-lesson-accordion.planned .review-summary-title { display: flex; align-items: baseline; gap: 16px; }
.review-lesson-accordion.planned .review-summary-title strong { color: #858594; font-size: 15px; font-weight: 500; }
.review-summary-planned { color: #555666; font: 8px/1 ui-monospace,monospace; letter-spacing: .1em; }
.review-task-difficulty { font-size: 13px; }
.final-review-row {
  position: relative;
  min-height: 300px;
  margin-top: 120px;
  padding: 55px 38px;
  display: grid;
  grid-template-columns: 120px 1fr auto;
  align-items: center;
  gap: 35px;
  overflow: hidden;
  border: solid rgba(223,255,36,.2);
  border-width: 1px 0;
  background: linear-gradient(90deg, rgba(223,255,36,.045), rgba(7,9,16,.78) 40%, rgba(145,71,255,.06));
}
.final-review-glyph { color: transparent; -webkit-text-stroke: 1px rgba(223,255,36,.42); font: 700 120px/.7 serif; text-shadow: 0 0 40px rgba(223,255,36,.12); }
.final-review-row small { color: var(--acid); letter-spacing: .18em; }
.final-review-row h2 { max-width: 760px; margin: 16px 0; font-size: clamp(38px,4vw,62px); line-height: .96; }
.final-review-row p { max-width: 650px; color: #aaa9b6; font-size: 16px; line-height: 1.8; }
.final-review-row > span { color: #777887; font: 10px/1 ui-monospace,monospace; letter-spacing: .14em; }
.final-challenge-lanes {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}
.final-challenge-card {
  position: relative;
  min-height: 280px;
  padding: 24px;
  display: grid;
  gap: 18px;
  overflow: hidden;
  border: 1px solid rgba(223,255,36,.22);
  border-radius: 22px 4px 22px 4px;
  background:
    radial-gradient(circle at 84% 12%, rgba(223,255,36,.13), transparent 27%),
    linear-gradient(145deg, rgba(10,13,22,.88), rgba(4,5,12,.96));
  color: #f0f1fa;
  text-decoration: none;
  transition: transform .26s cubic-bezier(.16,1,.3,1), border-color .24s ease, box-shadow .24s ease;
}
.final-challenge-card::before {
  content: "";
  position: absolute;
  inset: -40% -25%;
  background: linear-gradient(110deg, transparent 42%, rgba(255,255,255,.12), transparent 58%);
  transform: translateX(-45%);
  transition: transform .7s cubic-bezier(.16,1,.3,1);
}
.final-challenge-card:hover,
.final-challenge-card:focus-visible {
  transform: translateY(-6px);
  border-color: rgba(223,255,36,.52);
  box-shadow: 0 34px 90px rgba(0,0,0,.55), 0 0 36px rgba(223,255,36,.12);
  outline: 0;
}
.final-challenge-card:hover::before,
.final-challenge-card:focus-visible::before { transform: translateX(36%); }
.final-challenge-card.final-violet {
  border-color: rgba(145,71,255,.35);
  background:
    radial-gradient(circle at 84% 12%, rgba(145,71,255,.18), transparent 29%),
    linear-gradient(145deg, rgba(13,11,24,.9), rgba(4,5,12,.96));
}
.final-challenge-card header {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0,1fr) auto;
  gap: 8px 18px;
  align-items: start;
}
.final-challenge-card header small {
  grid-column: 1;
  color: var(--acid);
  font: 700 9px/1 ui-monospace, monospace;
}
.final-challenge-card.final-violet header small { color: #b687ff; }
.final-challenge-card header strong {
  grid-column: 1;
  font-size: clamp(24px, 2.6vw, 36px);
  line-height: 1;
}
.final-challenge-card header b {
  grid-row: 1 / span 2;
  grid-column: 2;
  color: transparent;
  -webkit-text-stroke: 1px rgba(255,255,255,.28);
  font: 900 clamp(58px, 7vw, 96px)/.75 "Arial Narrow","Segoe UI",sans-serif;
  letter-spacing: -.08em;
}
.final-challenge-card p {
  position: relative;
  z-index: 1;
  max-width: 640px;
  margin: 0;
  color: #b8b8c7;
  font-size: 15px;
  line-height: 1.7;
}
.final-challenge-meter {
  position: relative;
  z-index: 1;
  height: 28px;
  display: grid;
  align-items: center;
  border-top: 1px solid rgba(255,255,255,.1);
  border-bottom: 1px solid rgba(255,255,255,.1);
}
.final-challenge-meter i {
  height: 2px;
  background: linear-gradient(90deg, var(--acid), var(--cyan));
  box-shadow: 0 0 16px rgba(223,255,36,.24);
}
.final-challenge-meter span {
  position: absolute;
  right: 0;
  color: #8f91a4;
  font: 700 10px/1 ui-monospace, monospace;
}
.final-challenge-card ul {
  position: relative;
  z-index: 1;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
  list-style: none;
}
.final-challenge-card li {
  min-height: 50px;
  padding: 9px 10px;
  display: grid;
  grid-template-columns: 92px minmax(0,1fr) auto auto;
  align-items: center;
  gap: 12px;
  background: rgba(255,255,255,.035);
}
.final-challenge-card li > b { color: #85869a; font: 700 10px/1 ui-monospace, monospace; }
.final-challenge-card li strong { display: block; overflow: hidden; white-space: nowrap; text-overflow: ellipsis; font-size: 14px; }
.final-challenge-card li small { display: flex; flex-wrap: wrap; gap: 5px; margin-top: 5px; }
.final-challenge-card li small i {
  color: #87889b;
  font: 700 8px/1 ui-monospace, monospace;
  font-style: normal;
}
.final-challenge-card li em {
  color: var(--acid);
  font: 800 12px/1 ui-monospace, monospace;
  font-style: normal;
}
.final-challenge-card li em.difficulty-middle { color: #ffb86b; }
.final-challenge-card li mark {
  background: transparent;
  color: #777889;
  font: 800 9px/1 ui-monospace, monospace;
}
.final-challenge-card li.passed mark { color: #8fffbf; }

/* Lesson — a black void with readable holographic planes. */
.lesson-page {
  position: relative;
  isolation: isolate;
  overflow-x: hidden;
  background:
    radial-gradient(circle at 72% 7%, rgba(111, 46, 255, .12), transparent 25%),
    radial-gradient(circle at 14% 32%, rgba(34, 96, 192, .06), transparent 20%),
    #05060d;
}

.lesson-page::before,
.exercise-page::before {
  content: "";
  position: fixed;
  z-index: -1;
  inset: 0;
  background-image:
    radial-gradient(circle, rgba(219,225,255,.32) 0 1px, transparent 1.5px),
    linear-gradient(115deg, transparent 49.8%, rgba(139,82,255,.05) 50%, transparent 50.2%);
  background-size: 173px 173px, 380px 380px;
  background-position: 31px 17px, center;
  mask-image: radial-gradient(ellipse at center, #000, transparent 82%);
  opacity: .5;
  pointer-events: none;
}

.lesson-page::before {
  right: -18vw;
  bottom: -58vh;
  left: -18vw;
  top: auto;
  height: 108vh;
  opacity: .72;
  border-top: 1px solid rgba(145, 90, 255, .18);
  background-image:
    linear-gradient(rgba(127, 75, 224, .14) 1px, transparent 1px),
    linear-gradient(90deg, rgba(127, 75, 224, .14) 1px, transparent 1px);
  background-size: 64px 48px;
  background-position: center top;
  transform: perspective(700px) rotateX(66deg);
  transform-origin: center top;
  mask-image: linear-gradient(180deg, transparent, #000 18%, #000 72%, transparent);
}

.lesson-page::after {
  content: "";
  position: fixed;
  z-index: -1;
  inset: 0;
  background: repeating-linear-gradient(0deg, transparent 0 5px, rgba(126,92,255,.012) 5px 6px);
  pointer-events: none;
}

.lesson-page .topbar { background: rgba(1, 2, 7, .62); }
.lesson-progress {
  background: linear-gradient(90deg, var(--violet), var(--acid));
  box-shadow: 0 0 12px rgba(223,255,36,.4);
}

.lesson-hero {
  position: relative;
  min-height: 690px;
  grid-template-columns: minmax(0, 1fr);
  background:
    linear-gradient(90deg, rgba(3,4,11,.9), rgba(4,5,13,.42) 66%, rgba(3,4,11,.76)),
    radial-gradient(ellipse at 73% 44%, rgba(114, 40, 255, .25), transparent 32%);
}

#lesson-space-canvas {
  position: absolute;
  z-index: 0;
  inset: 68px 0 0;
  width: 100%;
  height: calc(100% - 68px);
  opacity: .95;
  pointer-events: none;
  mix-blend-mode: screen;
}

.lesson-hero::after {
  content: "";
  position: absolute;
  inset: 70px 3.5vw 30px;
  border: solid rgba(223,255,36,.08);
  border-width: 0 1px;
  background: repeating-linear-gradient(0deg, rgba(122,62,255,.025) 0 2px, transparent 2px 6px);
  pointer-events: none;
}

.lesson-hero-copy,
.lesson-preview { position: relative; z-index: 1; }
.lesson-hero-copy { z-index: 3; max-width: 900px; }
.lesson-hero-motion {
  position: absolute;
  z-index: 1;
  inset: 70px 0 0;
  overflow: hidden;
  pointer-events: none;
}
.lesson-data-scan {
  position: absolute;
  z-index: 2;
  inset: 70px 0 0;
  overflow: hidden;
  pointer-events: none;
  mask-image: linear-gradient(90deg, transparent 2%, #000 28%, #000 94%, transparent);
}
.lesson-data-scan i {
  position: absolute;
  top: -15%;
  left: 62%;
  width: 1px;
  height: 125%;
  background: linear-gradient(transparent, rgba(223,255,36,.7), rgba(145,71,255,.55), transparent);
  box-shadow: -31vw 12vh 18px rgba(145,71,255,.42), 18vw -4vh 22px rgba(223,255,36,.24);
  animation: lessonDataBeam 6.5s ease-in-out infinite alternate;
}
.lesson-data-scan span {
  position: absolute;
  left: 18vw;
  top: 28%;
  width: 88vw;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(145,71,255,.65), rgba(223,255,36,.28), transparent);
  box-shadow: 0 0 20px rgba(145,71,255,.35);
  animation: lessonDataSweep 5.2s ease-in-out infinite alternate;
}
@keyframes lessonDataBeam {
  from { transform: translateX(-10vw) rotate(5deg); opacity: .25; }
  to { transform: translateX(12vw) rotate(-4deg); opacity: .82; }
}
@keyframes lessonDataSweep {
  from { transform: translate3d(-12vw,-12vh,0) scaleX(.7); opacity: .18; }
  to { transform: translate3d(5vw,26vh,0) scaleX(1.08); opacity: .75; }
}
.lesson-hero-motion::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    repeating-linear-gradient(0deg, rgba(139,81,255,.035) 0 2px, transparent 2px 7px),
    linear-gradient(90deg, transparent, rgba(145,71,255,.06), transparent);
  mask-image: linear-gradient(90deg, transparent 5%, #000 28%, #000 90%, transparent);
}
.lesson-hero-motion i {
  position: absolute;
  display: block;
  border-radius: 50%;
  mix-blend-mode: screen;
  will-change: transform, opacity;
}
.lesson-hero-motion i:nth-child(1) {
  width: 72vw;
  height: 18vw;
  right: -18vw;
  top: 8vh;
  background: linear-gradient(90deg, transparent, rgba(116,39,255,.75), rgba(154,83,255,.18), transparent);
  filter: blur(34px);
  transform: rotate(-12deg);
  animation: lessonRibbonA 8s ease-in-out infinite alternate;
}
.lesson-hero-motion i:nth-child(2) {
  width: 42vw;
  height: 42vw;
  right: 6vw;
  top: -20vw;
  border: 2px solid rgba(143,76,255,.36);
  box-shadow: 0 0 70px rgba(120,46,255,.24), inset 0 0 70px rgba(120,46,255,.18);
  filter: blur(7px);
  animation: lessonOrbit 13s linear infinite;
}
.lesson-hero-motion i:nth-child(3) {
  width: 26vw;
  height: 8vw;
  left: 42%;
  bottom: 10%;
  background: rgba(79,44,255,.36);
  filter: blur(46px);
  animation: lessonRibbonB 10s ease-in-out -2s infinite alternate;
}
.lesson-hero-motion span {
  position: absolute;
  right: 8vw;
  top: 12vh;
  width: 1px;
  height: 50vh;
  background: linear-gradient(transparent, rgba(223,255,36,.5), transparent);
  box-shadow: -34vw 16vh 16px rgba(145,71,255,.4);
  opacity: .5;
}
@keyframes lessonRibbonA {
  from { transform: translate3d(-9vw,-4vh,0) rotate(-12deg) scale(.8); opacity: .36; }
  to { transform: translate3d(7vw,8vh,0) rotate(-6deg) scale(1.12); opacity: .9; }
}
@keyframes lessonRibbonB {
  from { transform: translate3d(-12vw,3vh,0) scale(.7); opacity: .25; }
  to { transform: translate3d(14vw,-7vh,0) scale(1.28); opacity: .72; }
}
@keyframes lessonOrbit { to { transform: rotate(360deg); } }
.lesson-label { color: var(--acid); }
.lesson-label i { background: var(--acid); box-shadow: 0 0 12px rgba(223,255,36,.5); }
.lesson-hero h1 {
  font-size: clamp(56px, 7.4vw, 108px);
  line-height: .87;
  font-weight: 760;
  text-transform: uppercase;
}

.lesson-hero h1 span {
  color: transparent;
  -webkit-text-stroke: 1px rgba(188, 183, 208, .55);
  font-weight: 700;
}

.lesson-hero h1 > span[data-translation] {
  color: #f2f1f7;
  -webkit-text-stroke: 0;
  text-shadow: 0 18px 65px rgba(0,0,0,.7);
}

.lesson-hero p { color: #aaa9b8; font-size: 18px; }
.lesson-preview {
  border: 1px solid rgba(145,71,255,.28);
  border-radius: 4px;
  background: rgba(6,7,13,.46);
  backdrop-filter: blur(14px);
  box-shadow: 0 38px 100px rgba(0,0,0,.68);
  transform: perspective(1000px) rotateY(-5deg) rotateX(1deg);
}

.lesson-preview img { border-radius: 2px; }
.lesson-preview span {
  border-radius: 2px;
  background: rgba(2,3,8,.78);
  color: var(--acid);
}

.lesson-layout {
  width: min(960px, calc(100vw - 300px));
  margin-inline: auto;
  transform: translateX(0);
  transition: transform .48s cubic-bezier(.16,1,.3,1);
}
.lesson-page.toc-proximity .lesson-layout { transform: translateX(110px); }
.lesson-module {
  margin-bottom: 190px;
  padding: 36px 0 10px;
  opacity: 1;
}

.lesson-module::before {
  content: "";
  position: absolute;
  top: 0;
  right: -9vw;
  left: -4vw;
  height: 1px;
  background: linear-gradient(90deg, var(--violet), rgba(145,71,255,.2) 44%, transparent);
  box-shadow: 0 0 20px rgba(145,71,255,.18);
}

.module-number { color: rgba(223,255,36,.5); }
.module-meta { color: var(--acid); }
.module-meta i { background: linear-gradient(90deg, rgba(223,255,36,.3), transparent); }
.lesson-module h2 {
  font-size: clamp(40px, 5vw, 65px);
  line-height: 1.04;
  letter-spacing: -.045em;
}

.module-lead {
  max-width: 920px;
  color: #bbb9c8;
  font-size: clamp(18px, 1.55vw, 21px);
  line-height: 1.9;
}

.content-grid { gap: 26px; margin: 38px 0; }
.concept-card {
  padding: 19px 22px 22px;
  border: 0;
  border-left: 1px solid rgba(145,71,255,.45);
  border-bottom: 1px solid rgba(145,71,255,.12);
  border-radius: 0;
  background: linear-gradient(100deg, rgba(113,45,255,.085), rgba(10,12,23,.3) 72%);
  backdrop-filter: none;
}

.concept-card h3 { color: #f0eff5; font-size: 18px; }
.concept-card p,
.concept-card li {
  color: #c1bfca;
  font-size: 15.5px;
  line-height: 1.85;
}

.lesson-code {
  position: relative;
  min-height: 120px;
  margin: 34px 0;
  padding: 0;
  display: grid;
  grid-template-columns: 60px minmax(0, 1fr);
  overflow: hidden;
  border: 1px solid rgba(93, 82, 139, .28);
  border-radius: 2px;
  background: #0a0e17;
  color: #d4d4d4;
  font: 17px/1.72 Consolas, "Cascadia Mono", "Cascadia Code", monospace;
}

.lesson-code-gutter {
  padding: 24px 10px 24px 0;
  border-right: 1px solid #1f2630;
  background: #080b12;
  color: #53697b;
  text-align: right;
  user-select: none;
}

.lesson-code-gutter span { display: block; height: 1.72em; }
.lesson-code pre {
  margin: 0;
  padding: 24px 28px 34px;
  overflow: auto;
  white-space: pre;
  font: inherit;
}
.lesson-page code,
.lesson-page pre,
.lesson-page .memory-cell,
.lesson-page .stream-char,
.lesson-page .bucket,
.lesson-page .diagram-node {
  font-family: Consolas, "Cascadia Mono", "Cascadia Code", "Microsoft YaHei Mono", monospace;
  font-variant-ligatures: none;
}

.lesson-code > small {
  position: absolute;
  right: 14px;
  top: 10px;
  color: #4fc1ff;
  font: 9px/1 ui-monospace, monospace;
}

.lesson-code::before { content: none; }
.interaction-shell {
  margin: 45px 0 28px;
  padding: 28px;
  border: solid rgba(145,71,255,.32);
  border-width: 1px 0;
  border-radius: 0;
  background: linear-gradient(115deg, rgba(91,36,190,.09), rgba(8,10,19,.54) 55%, rgba(223,255,36,.025));
  box-shadow: none;
  backdrop-filter: none;
}

.interaction-header h3 { font-size: 18px; }
.interaction-header p { font-size: 14px; line-height: 1.6; }
.interaction-header small { color: var(--acid); }
.interactive-stage {
  min-height: 270px;
  border: 1px solid rgba(156,143,217,.12);
  border-radius: 2px;
  background:
    repeating-linear-gradient(0deg, rgba(145,71,255,.018) 0 1px, transparent 1px 5px),
    rgba(7,9,17,.76);
}

.interaction-code-strip {
  width: min(100% - 48px, 920px);
  margin: 0;
  padding: 26px 30px;
  overflow-x: auto;
  border: 1px solid rgba(102, 198, 255, .2);
  background: #090d16;
  color: #d7e8f7;
  white-space: pre;
  font: clamp(15px, 1.55vw, 22px)/1.6 Consolas, "Cascadia Mono", "Cascadia Code", monospace;
}

.interaction-controls button,
.interaction-controls input {
  border-radius: 2px;
  background: rgba(13,15,25,.75);
  font-size: 14px;
}

.interaction-controls button.active { color: var(--acid); border-color: var(--acid); }
.outline-button {
  border: 0;
  border-bottom: 1px solid rgba(223,255,36,.5);
  border-radius: 0;
  color: var(--acid);
  font-size: 13px;
  letter-spacing: .05em;
}

.module-practice-link {
  position: relative;
  margin-top: 34px;
  padding: 22px 24px;
  display: grid;
  grid-template-columns: 220px 1fr auto;
  align-items: center;
  gap: 25px;
  border-top: 1px solid rgba(223,255,36,.2);
  border-bottom: 1px solid rgba(223,255,36,.08);
  background: linear-gradient(90deg, rgba(223,255,36,.035), transparent);
  transition: padding .35s cubic-bezier(.16,1,.3,1), background .3s ease;
}

.module-practice-link:hover {
  padding-right: 29px;
  padding-left: 29px;
  background: linear-gradient(90deg, rgba(223,255,36,.08), transparent 72%);
}

.module-practice-link > span:first-child { display: grid; gap: 7px; }
.module-practice-link small { color: var(--acid); font-size: 9px; letter-spacing: .18em; }
.module-practice-link strong { font: 500 18px/1 ui-monospace, monospace; }
.module-practice-link > span:nth-child(2) { color: #b0aeba; font-size: 16px; }
.module-practice-link i { color: var(--acid); font-size: 25px; font-style: normal; }

.inline-checkpoint {
  margin: 38px 0 28px;
  border: solid rgba(223,255,36,.2);
  border-width: 1px 0;
  background: linear-gradient(100deg, rgba(223,255,36,.04), rgba(145,71,255,.035) 65%, transparent);
}
.inline-checkpoint > summary {
  min-height: 84px;
  padding: 18px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  list-style: none;
  cursor: pointer;
}
.inline-checkpoint > summary::-webkit-details-marker { display: none; }
.inline-checkpoint > summary > span { display: grid; gap: 7px; }
.inline-checkpoint > summary small { color: var(--acid); font-size: 9px; letter-spacing: .18em; }
.inline-checkpoint > summary strong { font-size: 21px; }
.inline-checkpoint > summary i { color: #a9a8b5; font: 500 10px/1 ui-monospace, monospace; font-style: normal; letter-spacing: .11em; }
.inline-checkpoint[open] > summary { border-bottom: 1px solid rgba(223,255,36,.12); }
.inline-checkpoint[open] > summary i { color: var(--acid); }
.inline-checkpoint-body {
  padding: 30px;
  display: grid;
  grid-template-columns: minmax(260px, .72fr) minmax(0, 1.45fr);
  gap: 32px;
}
.inline-problem {
  padding-right: 30px;
  border-right: 1px solid rgba(145,71,255,.2);
}
.inline-problem > p { margin: 0 0 25px; color: #d0ced7; font-size: 16px; line-height: 1.8; }
.inline-problem dl { margin: 0; }
.inline-problem dl > div { padding: 14px 0; border-top: 1px solid rgba(151,142,194,.13); }
.inline-problem dt { margin-bottom: 7px; color: var(--acid); font: 600 9px/1 ui-monospace, monospace; letter-spacing: .14em; }
.inline-problem dd { margin: 0; color: #aaa9b6; font-size: 14px; line-height: 1.65; }
.inline-sample { margin-top: 12px; display: grid; grid-template-columns: 1fr; gap: 1px; background: rgba(145,71,255,.15); }
.inline-sample > div { min-width: 0; padding: 13px; background: #090c14; }
.inline-sample > div + div { border-top: 1px solid rgba(145,71,255,.18); }
.inline-sample b { color: #8c8b9a; font: 500 8px/1 ui-monospace, monospace; letter-spacing: .12em; }
.inline-sample pre { min-height: 44px; margin: 9px 0 0; overflow: auto; color: #d8f2e6; font-size: 12px; line-height: 1.55; }

.output-policy {
  display: block;
  margin-top: 8px;
  color: #a9c8dc;
  font-size: .78em;
  line-height: 1.55;
}
.inline-coding { min-width: 0; }
.inline-editor { min-height: 540px; height: 58vh; max-height: 680px; }
.inline-editor .code-editor-shell { height: 100%; }
.inline-actions { margin-top: 12px; display: flex; gap: 8px; }
.inline-actions button {
  min-height: 38px;
  padding: 0 14px;
  border: 1px solid rgba(151,142,194,.2);
  border-radius: 2px;
  background: rgba(15,17,27,.8);
  color: #c7c6cf;
  cursor: pointer;
  font-size: 12px;
}
.inline-actions button:hover { color: #fff; border-color: rgba(145,71,255,.55); }
.inline-actions .submit-button {
  margin-left: auto;
  border-color: rgba(223,255,36,.5);
  background: rgba(223,255,36,.08);
  color: #edff82;
}
.inline-results { margin-top: 10px; }

.quick-check-section {
  margin: 76px 0 34px;
  padding-top: 28px;
  border-top: 1px solid rgba(145,71,255,.22);
}
.quick-check-section > header {
  margin-bottom: 22px;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 20px;
}
.quick-check-section > header span {
  color: var(--acid);
  font: 700 10px/1 ui-monospace,monospace;
  letter-spacing: .2em;
}
.quick-check-section > header strong {
  color: #82818e;
  font-size: 13px;
  font-weight: 500;
}
.quick-check-grid {
  display: grid;
  grid-template-columns: repeat(2,minmax(0,1fr));
  gap: 14px;
}
.quick-check-card {
  min-width: 0;
  padding: 24px;
  border: 1px solid rgba(145,71,255,.22);
  background:
    linear-gradient(135deg, rgba(145,71,255,.055), transparent 45%),
    rgba(7,9,17,.74);
  transition: border-color .28s ease, background .28s ease, translate .28s ease;
}
.quick-check-card:hover {
  translate: 0 -2px;
  border-color: rgba(145,71,255,.48);
}
.quick-check-card.is-mastered { border-color: rgba(223,255,36,.32); }
.quick-check-meta {
  display: flex;
  justify-content: space-between;
  gap: 15px;
  color: #777b8c;
  font: 700 9px/1 ui-monospace,monospace;
  letter-spacing: .13em;
}
.quick-check-meta i { color: var(--acid); font-style: normal; }
.quick-check-card h3 {
  min-height: 58px;
  margin: 20px 0;
  color: #f0eef5;
  font-size: 18px;
  line-height: 1.55;
}
.quick-check-code {
  margin: 20px 0;
  font-size: 12px;
}
.quick-check-choices { display: grid; gap: 8px; }
.quick-check-choices button {
  min-height: 50px;
  padding: 10px 13px;
  display: grid;
  grid-template-columns: 28px minmax(0,1fr);
  align-items: center;
  gap: 10px;
  border: 1px solid rgba(124,138,165,.18);
  background: rgba(3,5,11,.66);
  color: #b7b8c4;
  text-align: left;
  cursor: pointer;
  transition: border-color .2s ease, color .2s ease, background .2s ease;
}
.quick-check-choices button:hover {
  border-color: rgba(145,71,255,.55);
  color: #fff;
}
.quick-check-choices button b {
  color: #8179a9;
  font: 700 11px/1 ui-monospace,monospace;
}
.quick-check-choices button.correct {
  border-color: rgba(121,224,151,.55);
  background: rgba(69,180,103,.09);
  color: #dcffe6;
}
.quick-check-choices button.wrong {
  border-color: rgba(255,106,138,.58);
  background: rgba(255,73,111,.075);
}
.quick-check-feedback {
  margin-top: 14px;
  padding: 16px 18px;
  border-left: 2px solid var(--acid);
  background: linear-gradient(90deg, rgba(223,255,36,.055), transparent);
}
.quick-check-feedback[hidden] { display: none; }
.quick-check-feedback b { color: var(--acid); font-size: 13px; }
.quick-check-feedback p { margin: 8px 0 0; color: #aaaab6; font-size: 14px; line-height: 1.65; }

.lesson-toc-zone { width: 94px; }
.lesson-toc {
  left: 16px;
  width: 330px;
  max-height: calc(100vh - 115px);
  padding: 15px 30px 15px 0;
  overflow: auto;
  transform: translate(-310px, -50%);
  border: 0;
  border-radius: 0;
  background: transparent;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  transition: transform .48s cubic-bezier(.16,1,.3,1);
  scrollbar-width: none;
}

.lesson-toc-zone:hover .lesson-toc,
.lesson-toc-zone:focus-within .lesson-toc,
.lesson-page.toc-proximity .lesson-toc { transform: translate(0, -50%); }

.lesson-toc a {
  padding: 8px 2px;
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 7px;
  border: 0;
  background: transparent;
  color: #75768a;
  font-size: 13px;
  line-height: 1.35;
  white-space: normal;
  transform-origin: left center;
  transition: padding .35s cubic-bezier(.16,1,.3,1), color .25s ease, transform .35s ease, text-shadow .25s ease;
}

.lesson-toc a b {
  color: #4f5060;
  font: 500 11px/1.5 ui-monospace, monospace;
}

.lesson-toc a:hover,
.lesson-toc a:focus-visible,
.lesson-toc a.is-hovered {
  padding-top: 13px;
  padding-bottom: 13px;
  color: #e8e6ef;
  transform: translateX(7px) scale(1.045);
  outline: 0;
}

.lesson-toc a.active {
  padding-top: 12px;
  padding-bottom: 12px;
  color: #fff;
  text-shadow: 0 0 18px rgba(145,71,255,.55);
}

.lesson-toc a.active b { color: var(--acid); }
.toc-tab { display: none !important; }
.lesson-page:not(.lesson-content-active) .lesson-toc-zone {
  pointer-events: none;
}
.lesson-page:not(.lesson-content-active) .lesson-toc {
  transform: translate(-340px, -50%) !important;
  opacity: 0;
}
.lesson-page:not(.lesson-content-active) .mobile-toc-button { display: none; }

/* Dedicated ACM practice workspace. */
.exercise-page {
  height: 100vh;
  overflow: hidden;
  background:
    radial-gradient(circle at 67% 10%, rgba(112,37,255,.1), transparent 27%),
    #020307;
}

.exercise-page .topbar {
  position: fixed;
  height: 64px;
}

.exercise-page .brand-mark { width: 46px; height: 34px; font-size: 18px; }
.exercise-app {
  position: fixed;
  inset: 64px 0 42px;
  display: grid;
  grid-template-columns: minmax(390px, 36vw) minmax(520px, 1fr);
  overflow: hidden;
}

.exercise-index {
  min-width: 0;
  overflow: hidden;
  border-right: 1px solid rgba(145,71,255,.18);
  background: rgba(2,3,8,.38);
}

.exercise-index > header {
  height: 74px;
  padding: 16px 18px;
  display: flex;
  align-items: end;
  justify-content: space-between;
  border-bottom: 1px solid rgba(145,71,255,.13);
}

.exercise-index header small { color: var(--acid); font-size: 8px; letter-spacing: .17em; }
.exercise-index header strong { color: #9d9bab; font: 500 12px/1 ui-monospace, monospace; }
.exercise-index nav {
  height: calc(100% - 74px);
  padding: 10px 0 40px;
  overflow: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(145,71,255,.3) transparent;
}

.exercise-index nav a {
  min-height: 43px;
  padding: 8px 15px;
  display: grid;
  grid-template-columns: 31px minmax(0, 1fr) auto;
  align-items: center;
  gap: 6px;
  color: #6f7081;
  font-size: 12px;
  transition: color .2s ease, padding .3s cubic-bezier(.16,1,.3,1), background .2s ease;
}

.exercise-index nav a b { color: #4f5061; font: 500 10px/1 ui-monospace, monospace; }
.exercise-index nav a span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.exercise-index nav a i { opacity: 0; color: var(--acid); font-style: normal; }
.exercise-index nav a:hover { padding-left: 20px; color: #d2d0da; }
.exercise-index nav a.active {
  color: #fff;
  background: linear-gradient(90deg, rgba(145,71,255,.13), transparent);
  box-shadow: inset 2px 0 var(--acid);
}
.exercise-index nav a.active b { color: var(--acid); }
.exercise-index nav a.active i { opacity: 1; }

.problem-pane {
  min-width: 0;
  padding: 46px clamp(26px, 3vw, 50px) 70px;
  overflow: auto;
  border-right: 1px solid rgba(145,71,255,.17);
  background: rgba(3,4,10,.42);
  scrollbar-width: thin;
  scrollbar-color: rgba(145,71,255,.3) transparent;
}

.problem-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--acid);
  font: 600 9px/1 ui-monospace, monospace;
  letter-spacing: .16em;
}
.problem-meta i { height: 1px; flex: 1; background: linear-gradient(90deg, rgba(223,255,36,.4), transparent); }
.problem-pane h1 {
  margin: 20px 0 16px;
  font-size: clamp(34px, 3.2vw, 54px);
  line-height: 1.04;
  letter-spacing: -.045em;
}
.difficulty-tag {
  width: fit-content;
  margin: 0 0 32px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: #b8b7c3;
  font: 700 13px/1 ui-monospace, monospace;
  letter-spacing: .14em;
}
.difficulty-tag i {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--acid);
  box-shadow: 0 0 9px rgba(223,255,36,.6);
}
.difficulty-easy i { background: #58e7bf; }
.difficulty-middle i { background: #ffcb6b; }
.difficulty-hard i { background: #ff6a8a; }

.problem-section {
  margin: 0;
  padding: 24px 0;
  border-top: 1px solid rgba(151,142,194,.13);
}
.problem-section h2,
.problem-sample h2 {
  margin: 0 0 12px;
  color: #d9d7e1;
  font-size: 14px;
  letter-spacing: .06em;
}
.problem-section p {
  margin: 0;
  color: #b7b5c1;
  font-size: 16px;
  line-height: 1.85;
}

.problem-sample {
  margin-top: 10px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-top: 1px solid rgba(151,142,194,.13);
  border-bottom: 1px solid rgba(151,142,194,.13);
}
.problem-sample > div { min-width: 0; padding: 24px 0; }
.problem-sample > div + div { padding-left: 22px; border-left: 1px solid rgba(151,142,194,.13); }
.problem-sample pre {
  min-height: 64px;
  margin: 0;
  padding: 13px 14px;
  overflow: auto;
  background: rgba(10,12,20,.62);
  color: #d7f5e8;
  font: 14px/1.6 Consolas, "Cascadia Mono", monospace;
}
.problem-note { color: #6f7080; font-size: 11px; line-height: 1.6; }

.rich-text { display: inline; }
.math-inline,
.math-block {
  color: #eef4ff;
  font-family: "Cambria Math", "STIX Two Math", "Times New Roman", serif;
  letter-spacing: .02em;
}
.math-inline {
  margin-inline: .18em;
  padding: .06em .28em;
  border-bottom: 1px solid rgba(145,71,255,.45);
  background: rgba(145,71,255,.07);
  white-space: nowrap;
}
.math-block {
  width: fit-content;
  margin: 18px auto;
  padding: 14px 24px;
  display: block;
  border: solid rgba(145,71,255,.28);
  border-width: 1px 0;
  font-size: 1.18em;
}
.math-frac { display: inline-grid; grid-template-rows: auto auto; vertical-align: middle; text-align: center; line-height: 1.05; }
.math-frac > span:first-child { padding: 0 .25em .08em; border-bottom: 1px solid currentColor; }
.math-frac > span:last-child { padding-top: .08em; }
.math-root { display: inline-flex; align-items: stretch; }
.math-root i { font-size: 1.25em; font-style: normal; }
.math-root > span { padding: .02em .2em 0; border-top: 1px solid currentColor; }

.problem-solution-link {
  margin-top: 28px;
  padding: 22px 4px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border: solid rgba(223,255,36,.24);
  border-width: 1px 0;
  background: linear-gradient(90deg, rgba(223,255,36,.05), transparent);
  transition: padding .3s cubic-bezier(.16,1,.3,1), background .3s;
}
.problem-solution-link:hover { padding-inline: 15px; background: linear-gradient(90deg, rgba(223,255,36,.11), transparent 78%); }
.problem-solution-link > span { display: grid; gap: 7px; }
.problem-solution-link small { color: var(--acid); font: 700 9px/1 ui-monospace,monospace; letter-spacing: .16em; }
.problem-solution-link strong { color: #e7e5ed; font-size: 15px; }
.problem-solution-link i { color: var(--acid); font-size: 24px; font-style: normal; }

body.editorial-open { overflow: hidden; }
.editorial-modal-shell {
  position: fixed;
  z-index: 120;
  inset: 0;
  padding: 4vh 3vw;
  display: grid;
  place-items: center;
  background: rgba(0,1,5,.82);
  backdrop-filter: blur(16px);
}
.editorial-modal-shell[hidden] { display: none; }
.editorial-modal {
  position: relative;
  width: min(1180px, 96vw);
  height: min(92vh, 980px);
  overflow: hidden;
  border: 1px solid rgba(145,71,255,.42);
  border-radius: 4px;
  background: radial-gradient(circle at 86% 8%, rgba(115,42,255,.2), transparent 23%), #050711;
  box-shadow: 0 45px 160px rgba(0,0,0,.82), 0 0 80px rgba(101,36,255,.12);
}
.editorial-modal-close {
  position: absolute;
  z-index: 4;
  right: 18px;
  top: 18px;
  width: 42px;
  height: 42px;
  border: 0;
  background: rgba(3,4,10,.7);
  color: #b9b7c5;
  cursor: pointer;
  font-size: 27px;
}
.editorial-modal-close:hover { color: var(--acid); }
.editorial-modal-scroll { height: 100%; overflow: auto; }
.editorial-article {
  width: min(1040px, calc(100% - 64px));
  margin: 0 auto;
  padding: 90px 0 120px;
}
.editorial-hero {
  position: relative;
  min-height: 360px;
  padding: 48px 0 70px;
  border-bottom: 1px solid rgba(145,71,255,.24);
}
.editorial-hero::after {
  content: "∵";
  position: absolute;
  right: 0;
  top: -10px;
  color: transparent;
  -webkit-text-stroke: 1px rgba(145,71,255,.3);
  font: 700 250px/.8 serif;
  text-shadow: 0 0 45px rgba(145,71,255,.15);
}
.editorial-hero small { color: var(--acid); font: 700 9px/1 ui-monospace,monospace; letter-spacing: .18em; }
.editorial-hero h1 {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 24px 0 30px;
  font-size: clamp(48px,6.5vw,88px);
  line-height: .94;
  letter-spacing: -.055em;
}
.editorial-hero p {
  position: relative;
  z-index: 1;
  max-width: 780px;
  margin: 0;
  color: #c1bfca;
  font-size: 18px;
  line-height: 1.9;
}
.editorial-section {
  padding: 64px 0;
  display: grid;
  grid-template-columns: 62px minmax(0,1fr);
  gap: 28px;
  border-bottom: 1px solid rgba(145,71,255,.16);
}
.editorial-section > span {
  color: transparent;
  -webkit-text-stroke: 1px rgba(223,255,36,.42);
  font: 700 36px/1 "Arial Narrow",sans-serif;
}
.editorial-section > div { min-width: 0; }
.editorial-section h2 { margin: 0 0 22px; font-size: clamp(28px,3vw,42px); letter-spacing: -.04em; }
.editorial-section p,
.editorial-steps li,
.editorial-pitfalls li { color: #c0bec9; font-size: 17px; line-height: 1.85; }
.editorial-insight > div {
  padding: 28px;
  border-left: 2px solid var(--acid);
  background: linear-gradient(90deg, rgba(223,255,36,.065), transparent);
}
.editorial-steps { margin: 0; padding: 0; list-style: none; counter-reset: editorial-step; }
.editorial-steps li {
  position: relative;
  padding: 17px 0 17px 48px;
  border-bottom: 1px solid rgba(145,71,255,.12);
  counter-increment: editorial-step;
}
.editorial-steps li::before {
  content: counter(editorial-step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 21px;
  color: var(--acid);
  font: 700 10px/1 ui-monospace,monospace;
}
.editorial-pitfalls { margin: 0; padding: 0; display: grid; gap: 12px; list-style: none; }
.editorial-pitfalls li { padding: 18px 20px; border-left: 1px solid #ff6a8a; background: rgba(255,73,111,.045); }
.editorial-diagram {
  margin: 34px 0 0;
  padding: 0;
  display: flex;
  align-items: stretch;
  gap: 8px;
  list-style: none;
  overflow-x: auto;
}
.editorial-diagram li {
  position: relative;
  min-width: 150px;
  min-height: 116px;
  padding: 18px;
  display: grid;
  align-content: space-between;
  border: 1px solid rgba(145,71,255,.24);
  background: rgba(8,10,19,.72);
}
.editorial-diagram li > span { color: var(--acid); font: 700 9px/1 ui-monospace,monospace; }
.editorial-diagram li > strong { font-size: 14px; line-height: 1.5; }
.editorial-diagram li > i { position: absolute; right: -13px; top: 47%; z-index: 2; color: var(--acid); font-style: normal; }
.editorial-code {
  margin-top: 28px;
  overflow: hidden;
  border: 1px solid #27313e;
  background: #080c14;
  font-family: Consolas, "Cascadia Mono", "Cascadia Code", monospace;
}
.editorial-code-head {
  height: 42px;
  padding: 0 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid #202834;
  color: #6f8599;
  font: 700 9px/1 ui-monospace,monospace;
  letter-spacing: .13em;
}
.editorial-code-body {
  display: grid;
  grid-template-columns: 58px minmax(0,1fr);
  overflow: auto;
  font: 15px/1.7 Consolas, "Cascadia Mono", "Cascadia Code", monospace;
}
.editorial-code-gutter { padding: 22px 12px 22px 0; border-right: 1px solid #202834; color: #526679; text-align: right; user-select: none; }
.editorial-code-gutter span { display: block; height: 1.7em; }
.editorial-code pre { margin: 0; padding: 22px 25px; overflow: visible; white-space: pre; font: inherit; }

.solution-page {
  min-height: 100vh;
  background: radial-gradient(circle at 84% 8%, rgba(119,43,255,.15), transparent 24%), repeating-linear-gradient(0deg, rgba(145,71,255,.018) 0 1px, transparent 1px 6px), #04050b;
}
.solution-page .topbar { position: fixed; }
.solution-main { position: relative; z-index: 2; }
.solution-main .editorial-article { padding-top: 150px; }
.solution-footer {
  min-height: 72px;
  padding: 0 4vw;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid rgba(145,71,255,.2);
  background: #05060c;
}
.solution-footer button { border: 0; background: transparent; color: #aaa8b5; cursor: pointer; }
.solution-footer button:hover { color: var(--acid); }
.solution-footer button:disabled { opacity: .25; cursor: default; }
.solution-footer span { color: #656675; font: 9px/1 ui-monospace,monospace; letter-spacing: .14em; }

.coding-pane {
  min-width: 0;
  min-height: 0;
  display: grid;
  grid-template-rows: 58px minmax(0, 1fr) auto;
  overflow: hidden;
  background: #090b10;
}

.coding-heading {
  padding: 0 13px 0 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border-bottom: 1px solid #2b2b2b;
  background: #181818;
}
.coding-heading > div:first-child { display: grid; gap: 4px; }
.coding-heading small { color: #d4d4d4; font-size: 10px; letter-spacing: .08em; }
.coding-heading [data-draft-state] { color: #747474; font-size: 9px; }
.coding-heading .exercise-actions { margin: 0; }
.exercise-actions button {
  min-height: 32px;
  padding: 0 12px;
  border: 0;
  border-radius: 2px;
  background: transparent;
  color: #bcbcbc;
  font-size: 11px;
}
.exercise-actions button:hover { background: #2b2b2b; color: #fff; }
.exercise-actions .submit-button {
  margin-left: 0;
  border: 1px solid rgba(223,255,36,.5);
  background: rgba(223,255,36,.08);
  color: #edff82;
}
.coding-pane .exercise-editor {
  min-height: 0;
  height: 100%;
}
.coding-pane .code-editor-shell {
  height: 100%;
  grid-template-rows: minmax(0, 1fr) auto;
  border: 0;
}
.coding-pane .embed-editor-toolbar { display: none; }
.coding-pane .judge-results {
  max-height: 190px;
  margin: 0;
  overflow: auto;
  border-top: 1px solid #303030;
  background: #181818;
}
.coding-pane .submission-banner,
.coding-pane .judge-case {
  margin: 0;
  border: 0;
  border-bottom: 1px solid #2b2b2b;
  border-radius: 0;
  background: transparent;
  font-size: 12px;
}

.exercise-footer {
  position: fixed;
  inset: auto 0 0;
  height: 42px;
  padding: 0 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid rgba(145,71,255,.18);
  background: rgba(3,4,9,.92);
  color: #6f7080;
}
.exercise-footer button {
  border: 0;
  background: transparent;
  color: #b9b7c1;
  cursor: pointer;
  font-size: 12px;
}
.exercise-footer button:hover { color: var(--acid); }
.exercise-footer button:disabled { color: #41424e; cursor: default; }
.exercise-footer span { font: 9px/1 ui-monospace, monospace; letter-spacing: .13em; }
.exercise-footer i {
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-right: 8px;
  border-radius: 50%;
  background: var(--acid);
  box-shadow: 0 0 10px var(--acid);
}

.help-panel,
.slide-viewer,
.terminal-window,
.translation-bubble {
  border-radius: 4px;
  background: rgba(5, 6, 12, .8);
  backdrop-filter: blur(20px);
}

.terminal-window { border-color: rgba(145,71,255,.42); }
.terminal-titlebar { background: rgba(14,12,24,.88); }
.terminal-titlebar i { background: var(--acid); box-shadow: 0 0 10px var(--acid); }

@media (max-width: 1100px) {
  .exercise-app { grid-template-columns: minmax(350px, 42vw) minmax(460px, 1fr); }
  .course-deck { min-width: 1050px; }
  .inline-checkpoint-body { grid-template-columns: 1fr; }
  .inline-problem { padding-right: 0; border-right: 0; }
  .review-lesson-grid { grid-template-columns: repeat(2,1fr); }
}

@media (max-width: 860px) {
  .exercise-page { height: auto; overflow: auto; }
  .exercise-app {
    position: relative;
    inset: auto;
    padding-top: 64px;
    display: grid;
    grid-template-columns: 1fr;
    overflow: visible;
  }
  .exercise-index {
    position: sticky;
    z-index: 4;
    top: 64px;
    height: 64px;
    border: 0;
    border-bottom: 1px solid rgba(145,71,255,.2);
    background: rgba(3,4,9,.94);
  }
  .exercise-index > header { display: none; }
  .exercise-index nav {
    height: 64px;
    padding: 0 10px;
    display: flex;
    overflow-x: auto;
  }
  .exercise-index nav a {
    min-width: 72px;
    grid-template-columns: 1fr;
    place-items: center;
  }
  .exercise-index nav a span,
  .exercise-index nav a i { display: none; }
  .problem-pane {
    padding: 44px max(22px, 6vw);
    border: 0;
    overflow: visible;
  }
  .coding-pane { height: 720px; margin-bottom: 42px; }
  .exercise-footer { z-index: 8; }
}

@media (max-width: 720px) {
  .home-page .hero { min-height: 770px; }
  .hero-copy { width: auto; margin: 80px 23px 0; }
  .hero h1 { font-size: clamp(62px, 20vw, 96px); }
  .hero::before { inset-inline: 16px; }
  .eyebrow::before,
  .section-kicker::before { width: 25px; margin-right: 9px; }
  .course-deck { min-width: 880px; }
  .course-deck .course-card { height: 345px; }
  .course-deck-viewport { padding-top: 80px; }
  .lesson-hero { padding-top: 120px; }
  .lesson-preview { margin: 0; transform: none; }
  .lesson-layout { width: min(100% - 34px, 1080px); margin-inline: auto; }
  .lesson-module { margin-bottom: 130px; }
  .lesson-module::before { right: 0; left: 0; }
  .content-grid { grid-template-columns: 1fr; }
  .lesson-code { grid-template-columns: 47px minmax(0, 1fr); font-size: 14px; }
  .lesson-code-gutter { padding-right: 8px; }
  .lesson-code pre { padding-inline: 17px; }
  .module-practice-link { grid-template-columns: 1fr auto; }
  .module-practice-link > span:nth-child(2) { grid-column: 1 / -1; font-size: 14px; }
  .mobile-toc-open .lesson-toc-zone {
    background: rgba(1,2,7,.82);
    backdrop-filter: blur(12px);
  }
  .mobile-toc-open .lesson-toc {
    width: 100%;
    max-height: 75vh;
    padding: 24px;
    border-radius: 0;
    background: #04050b;
  }
  .problem-sample { grid-template-columns: 1fr; }
  .problem-sample > div + div { padding-left: 0; border: 0; border-top: 1px solid rgba(151,142,194,.13); }
  .coding-heading { height: auto; min-height: 92px; align-items: flex-start; flex-direction: column; padding: 13px; }
  .coding-heading .exercise-actions { width: 100%; display: grid; grid-template-columns: repeat(3, 1fr); }
  .inline-actions { flex-wrap: wrap; }
  .quick-check-section > header { align-items: flex-start; flex-direction: column; }
  .quick-check-grid { grid-template-columns: 1fr; }
  .quick-check-card { padding: 20px 17px; }
  .quick-check-card h3 { min-height: 0; font-size: 17px; }
  .editorial-modal-shell { padding: 0; }
  .editorial-modal { width: 100vw; height: 100dvh; border: 0; }
  .editorial-article { width: calc(100% - 34px); padding: 72px 0 90px; }
  .editorial-hero { min-height: 0; padding: 45px 0 60px; }
  .editorial-hero::after { right: -12px; top: 10px; font-size: 150px; opacity: .5; }
  .editorial-hero h1 { font-size: 45px; }
  .editorial-hero p { font-size: 16px; }
  .editorial-section { padding: 46px 0; grid-template-columns: 1fr; gap: 18px; }
  .editorial-section > span { font-size: 25px; }
  .editorial-section p,
  .editorial-steps li,
  .editorial-pitfalls li { font-size: 15px; }
  .editorial-diagram { padding-bottom: 10px; }
  .editorial-code-body { grid-template-columns: 44px minmax(0,1fr); font-size: 12px; }
  .editorial-code pre { padding-inline: 15px; }
  .solution-main .editorial-article { padding-top: 110px; }
  .solution-footer { padding: 12px 16px; gap: 10px; }
  .solution-footer span { display: none; }
  .exercise-footer span { display: none; }
  .review-section {
    width: calc(100% - 30px);
    min-height: 0;
    padding: 55px 22px;
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .review-copy h2 { font-size: 48px; }
  .review-copy > p:not(.section-kicker) { font-size: 16px; }
  .review-main { width: calc(100% - 24px); padding-top: 110px; }
  .review-hero { min-height: 640px; }
  .review-hero h1 { font-size: 65px; line-height: .86; }
  .review-live-signal { right: 0; top: 26px; }
  .review-total { right: 0; bottom: 60px; }
  .review-list-track { margin-top: 72px; }
  .review-list-track > header strong { font-size: 45px; }
  .review-lesson-summary {
    min-height: 110px;
    padding-inline: 10px;
    grid-template-columns: 48px minmax(0,1fr) auto;
    gap: 10px;
  }
  .review-lesson-summary > b { font-size: 42px; }
  .review-summary-title strong { font-size: 19px; }
  .review-summary-progress { font-size: 17px; }
  .review-lesson-summary > em {
    grid-column: 2 / -1;
    min-width: 0;
    justify-self: end;
  }
  .review-lesson-accordion.is-open .review-lesson-summary { min-height: 130px; }
  .review-lesson-accordion.planned .review-lesson-summary { grid-template-columns: 38px minmax(0,1fr); }
  .review-lesson-accordion.planned .review-summary-title { display: grid; gap: 5px; }
  .review-summary-planned { display: none; }
  .review-lesson-list > header {
    min-height: 145px;
    grid-template-columns: 68px 1fr auto;
    gap: 12px;
    padding-inline: 10px;
  }
  .review-lesson-list > header > b { font-size: 55px; }
  .review-lesson-list > header h2 { font-size: 25px; }
  .review-lesson-list > header > span { padding-right: 6px; font-size: 20px; }
  .review-task-head { display: none; }
  .review-task-row {
    min-height: 128px;
    padding: 17px 10px;
    grid-template-columns: 38px minmax(0,1fr) auto;
    grid-template-rows: auto auto;
    gap: 12px 10px;
  }
  .review-task-title strong { font-size: 15px; }
  .review-task-tags { grid-column: 2; }
  .review-task-difficulty { grid-column: 3; grid-row: 1; }
  .review-task-state { grid-column: 3; grid-row: 2; justify-self: end; font-size: 8px; }
  .review-task-state i { width: 9px; height: 9px; }
  .review-planned-lesson { padding-inline: 10px; grid-template-columns: 38px 1fr; }
  .review-planned-lesson > span { display: grid; gap: 5px; }
  .review-planned-lesson > i { display: none; }
  .final-review-row { padding: 40px 18px; grid-template-columns: 1fr; }
  .final-review-glyph { position: absolute; right: 15px; top: 20px; opacity: .2; }
  .final-review-row > span { justify-self: start; }
  .final-challenge-lanes { grid-template-columns: 1fr; }
  .final-challenge-card { padding: 18px; }
  .final-challenge-card li {
    grid-template-columns: 1fr auto;
    gap: 8px 10px;
  }
  .final-challenge-card li > b { grid-column: 1 / -1; }
  .final-challenge-card li mark { justify-self: end; }
}

.tour-shell {
  position: fixed;
  z-index: 32000;
  inset: 0;
  pointer-events: none;
}

.tour-ring {
  position: fixed;
  left: var(--tour-x);
  top: var(--tour-y);
  width: var(--tour-w);
  height: var(--tour-h);
  border: 2px solid #8edcff;
  border-radius: 14px;
  box-shadow:
    0 0 0 4px rgba(116,210,255,.13),
    0 0 34px rgba(76,195,255,.42),
    inset 0 0 24px rgba(103,211,255,.08);
  pointer-events: none;
  transition: left .2s cubic-bezier(.2,.8,.2,1), top .2s cubic-bezier(.2,.8,.2,1), width .2s cubic-bezier(.2,.8,.2,1), height .2s cubic-bezier(.2,.8,.2,1);
}

.tour-ring::after {
  content: "";
  position: absolute;
  inset: -8px;
  border-radius: inherit;
  border: 1px solid rgba(137,222,255,.32);
  animation: tourPulse 1.9s ease-out infinite;
}

@keyframes tourPulse {
  from { opacity: .9; scale: 1; }
  to { opacity: 0; scale: 1.07; }
}

.tour-popover {
  position: fixed;
  max-width: calc(100vw - 28px);
  padding: 21px 22px 17px;
  border: 1px solid rgba(126,215,255,.44);
  border-radius: 16px;
  background:
    linear-gradient(135deg, rgba(12,23,34,.97), rgba(5,10,18,.97)),
    repeating-linear-gradient(0deg, rgba(255,255,255,.04) 0 1px, transparent 1px 7px);
  box-shadow: 0 26px 75px rgba(0,0,0,.62), 0 0 34px rgba(85,199,255,.16);
  color: #f4f5ff;
  pointer-events: auto;
  transition: left .2s cubic-bezier(.2,.8,.2,1), top .2s cubic-bezier(.2,.8,.2,1);
}

.tour-popover small {
  color: #87d9ff;
  font: 700 10px/1 ui-monospace, monospace;
  letter-spacing: .2em;
}

.tour-popover h2 {
  margin: 12px 0 10px;
  font-size: 25px;
  line-height: 1.08;
}

.tour-popover p {
  margin: 0;
  color: #bfc0ce;
  font-size: 15px;
  line-height: 1.75;
}

.tour-actions {
  margin-top: 19px;
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

.tour-actions button {
  min-height: 34px;
  padding: 0 13px;
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 10px 2px 10px 2px;
  background: rgba(255,255,255,.04);
  color: #e8e8f2;
  cursor: pointer;
  font: 700 12px/1 "Segoe UI", sans-serif;
}

.tour-actions button:last-child {
  border-color: rgba(126,215,255,.72);
  background: rgba(76,190,255,.12);
  color: #dff7ff;
  box-shadow: 0 0 18px rgba(83,197,255,.12);
}

.tour-actions button:disabled {
  opacity: .36;
  cursor: not-allowed;
}

.tour-target-active {
  filter: drop-shadow(0 0 13px rgba(101,208,255,.24));
}

.tour-close {
  position: fixed;
  z-index: 2;
  top: max(12px, env(safe-area-inset-top));
  right: 14px;
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(142,222,255,.52);
  border-radius: 50%;
  background: rgba(6,13,22,.94);
  color: #dff7ff;
  box-shadow: 0 10px 34px rgba(0,0,0,.45), 0 0 24px rgba(76,195,255,.18);
  cursor: pointer;
  pointer-events: auto;
  font: 300 27px/1 "Segoe UI", sans-serif;
}

.tour-close:hover,
.tour-close:focus-visible {
  border-color: #a6e6ff;
  background: rgba(17,42,58,.98);
  outline: 2px solid rgba(113,214,255,.25);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  .hero h1,
  .depth-field i,
  .lesson-module { animation: none !important; }
  #fluid-canvas,
  #home-space-canvas,
  #lesson-space-canvas { display: none; }
}

html[data-eco="on"] #fluid-canvas,
html[data-eco="on"] #home-space-canvas,
html[data-eco="on"] #lesson-space-canvas,
html[data-eco="on"] .fluid-fallback { display: none !important; }
html[data-eco="on"] .home-page {
  background:
    radial-gradient(circle at 72% 18%, rgba(74,44,130,.08), transparent 28%),
    #020307 !important;
}
html[data-eco="on"] .home-page .hero {
  background:
    linear-gradient(180deg, rgba(2,3,7,.18), rgba(2,3,7,.72)),
    radial-gradient(circle at 64% 44%, rgba(72,47,118,.12), transparent 28%) !important;
}
html[data-eco="on"] .hero h1::after,
html[data-eco="on"] .hero h1 em,
html[data-eco="on"] .track-ghost,
html[data-eco="on"] .review-orbit span,
html[data-eco="on"] .review-progress-preview span:last-child b,
html[data-eco="on"] .final-review-glyph,
html[data-eco="on"] .tour-ring::before,
html[data-eco="on"] .tour-ring::after {
  animation: none !important;
}
html[data-eco="on"] .depth-field i,
html[data-eco="on"] .lesson-hero-motion i,
html[data-eco="on"] .home-scan-beams,
html[data-eco="on"] .lesson-data-scan,
html[data-eco="on"] .track-ghost,
html[data-eco="on"] .review-space::before,
html[data-eco="on"] .review-space::after,
html[data-eco="on"] .review-space > i,
html[data-eco="on"] .review-horizon,
html[data-eco="on"] .review-scan,
html[data-eco="on"] .review-live-signal i {
  animation: none !important;
}
html[data-eco="on"] .review-fx-canvas,
html[data-eco="on"] .review-cursor-field,
html[data-eco="on"] .home-scan-beams,
html[data-eco="on"] .lesson-data-scan { display: none !important; }
html[data-eco="on"] .course-card,
html[data-eco="on"] .course-card::before,
html[data-eco="on"] .lesson-toc,
html[data-eco="on"] .lesson-layout {
  transition-duration: .12s !important;
}
html[data-eco="on"] .topbar,
html[data-eco="on"] .help-panel,
html[data-eco="on"] .terminal-window {
  backdrop-filter: none !important;
  -webkit-backdrop-filter: none !important;
}