/* Shared visual shell for the course home, lessons, and MATLAB Lite. */
:root{
  --course-accent:#0b7f8b;
  --course-accent-2:#10a0a5;
  --course-control-bg:rgba(255,255,255,.84);
  --course-control-border:#d6e2e6;
  --course-control-text:#18333a;
  --course-header-shadow:0 1px 0 rgba(18,48,57,.08);
}
:root[data-theme="dark"]{
  --course-control-bg:rgba(25,38,43,.92);
  --course-control-border:#3b5057;
  --course-control-text:#e8f3f5;
}
*{box-sizing:border-box}
html{font-size:var(--course-font-size,16px)}

/* One identical 72 px header and one fixed five-slot toolbar on every page. */
.topbar,.titlebar,.bar{
  height:72px!important;min-height:72px!important;
  padding-left:24px!important;padding-right:24px!important;
  border-bottom:1px solid var(--course-control-border)!important;
  background:var(--paper,var(--surface,#fff))!important;
  box-shadow:var(--course-header-shadow);
  backdrop-filter:none!important;-webkit-backdrop-filter:none!important;
}
.top-actions,.controls,.top-controls,.bar-actions,.shared-settings{align-items:center}
.course-toolbar-host{
  display:flex!important;align-items:center!important;justify-content:flex-end!important;
  flex:0 0 auto!important;width:auto!important;height:72px!important;
  margin-left:auto!important;align-self:center!important;overflow:visible!important;
}
.course-toolbar{
  display:flex;align-items:center;justify-content:flex-end;
  width:500px!important;max-width:500px!important;height:72px!important;
  gap:10px!important;min-width:0;overflow:visible!important;
}
.course-tool-button,.course-font-control,.course-runtime-link,.course-runtime-slot{
  position:relative;flex:none;align-self:center!important;
  height:44px!important;min-height:44px!important;
  border:1px solid var(--course-control-border)!important;border-radius:14px!important;
  color:var(--course-control-text)!important;
  background:linear-gradient(180deg,color-mix(in srgb,var(--course-control-bg) 92%,#fff 8%),color-mix(in srgb,var(--course-control-bg) 96%,#000 4%))!important;
  box-shadow:inset 0 1px 0 rgba(255,255,255,.72),inset 0 -1px 0 rgba(18,47,55,.12),0 7px 18px rgba(18,47,55,.08)!important;
}
:root[data-theme="dark"] .course-tool-button,
:root[data-theme="dark"] .course-font-control,
:root[data-theme="dark"] .course-runtime-slot{
  box-shadow:inset 0 1px 0 rgba(255,255,255,.14),inset 0 -1px 0 rgba(0,0,0,.38),0 7px 18px rgba(0,0,0,.18)!important;
}
.course-tool-button{
  width:44px!important;min-width:44px!important;padding:0!important;
  display:grid!important;place-items:center!important;
  text-decoration:none;line-height:1;cursor:pointer;transition:transform .16s ease,border-color .16s ease,background .16s ease,box-shadow .16s ease;
}
.course-tool-button svg{
  width:21px!important;height:21px!important;display:block;margin:0!important;transform:none!important;
  fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;
}
.course-tool-button:hover,.course-tool-button:focus-visible{
  background:color-mix(in srgb,var(--course-accent) 10%,var(--course-control-bg))!important;
  border-color:color-mix(in srgb,var(--course-accent) 55%,var(--course-control-border))!important;
  transform:translateY(-1px);outline:none;box-shadow:0 8px 20px rgba(17,65,72,.12)!important;
}
.course-language-button{display:grid!important;place-items:center!important;padding:0!important;font:800 17px/1 "Segoe UI","Microsoft YaHei",sans-serif!important;letter-spacing:0}

.course-font-control{
  width:128px!important;min-width:128px!important;display:grid!important;
  grid-template-columns:42px 42px 42px!important;align-items:stretch!important;
  overflow:visible!important;padding:0!important;
}
.course-font-control button,.course-font-control>span{
  width:42px!important;min-width:42px!important;height:42px!important;min-height:42px!important;
  display:grid!important;place-items:center!important;margin:0!important;padding:0!important;
  border:0!important;background:transparent!important;color:var(--course-control-text)!important;line-height:1!important;
}
.course-font-control button{position:relative;font:800 15px/1 "Segoe UI",sans-serif;cursor:pointer}
.course-font-control button:first-child{border-radius:13px 0 0 13px!important}
.course-font-control button:last-child{border-radius:0 13px 13px 0!important}
.course-font-control button:hover{background:color-mix(in srgb,var(--course-accent) 10%,transparent)!important}
.course-font-control>span{
  border-left:1px solid color-mix(in srgb,var(--course-control-border) 78%,transparent)!important;
  border-right:1px solid color-mix(in srgb,var(--course-control-border) 78%,transparent)!important;
  box-shadow:inset 0 1px 0 rgba(255,255,255,.55),inset 0 -1px 0 rgba(18,47,55,.1)!important;
  font-weight:700;font-variant-numeric:tabular-nums;
}
:root[data-theme="dark"] .course-font-control>span{box-shadow:inset 0 1px 0 rgba(255,255,255,.11),inset 0 -1px 0 rgba(0,0,0,.32)!important}

.course-runtime-link,.course-runtime-slot{
  width:178px!important;min-width:178px!important;max-width:178px!important;
  margin-left:8px!important;padding:0 17px;
  display:flex;align-items:center;justify-content:center;gap:9px;
  text-decoration:none;font-weight:800;white-space:nowrap;
}
.course-runtime-link{
  color:#fff!important;border-color:#174650!important;
  background:linear-gradient(180deg,#174650,#10353d)!important;
}
.course-runtime-link:hover{background:linear-gradient(180deg,#0d7883,#0c5962)!important;border-color:#0d6973!important;transform:translateY(-1px)}
.course-runtime-link svg{width:19px;height:19px;stroke:currentColor;fill:none}.course-runtime-link svg .fill{fill:currentColor;stroke:none}
.course-runtime-slot{justify-content:flex-start;background:transparent!important;border-color:transparent!important;box-shadow:none!important;padding-left:26px}
.course-runtime-slot .state-dot{width:9px;height:9px;border-radius:50%;background:#2fb171;box-shadow:0 0 0 4px color-mix(in srgb,#2fb171 18%,transparent)}
.course-runtime-slot b{font-size:.92rem;white-space:nowrap}

/* Hover labels for icon-only controls. */
.course-tool-button[data-course-tip]::after,.course-font-control button[data-course-tip]::after{
  content:attr(data-course-tip);position:absolute;right:0;top:calc(100% + 9px);z-index:10000;
  width:max-content;max-width:240px;padding:7px 10px;border-radius:8px;
  background:#10282d;color:#f5ffff;font:600 12px/1.35 "Segoe UI","Microsoft YaHei",sans-serif;
  opacity:0;visibility:hidden;transform:translateY(-3px);pointer-events:none;
  box-shadow:0 10px 28px rgba(0,0,0,.22);transition:.14s ease;
}
.course-tool-button:hover::after,.course-tool-button:focus-visible::after,
.course-font-control button:hover::after,.course-font-control button:focus-visible::after{opacity:1;visibility:visible;transform:translateY(0)}
.course-tool-attention{animation:courseToolPulse .85s ease}
@keyframes courseToolPulse{0%,100%{box-shadow:none}45%{box-shadow:0 0 0 6px color-mix(in srgb,var(--course-accent) 22%,transparent)}}
.course-visually-hidden{position:absolute!important;width:1px!important;height:1px!important;padding:0!important;margin:-1px!important;overflow:hidden!important;clip:rect(0,0,0,0)!important;white-space:nowrap!important;border:0!important}

/* Embedded MATLAB lab layout. */
.matlab-lab .lab-body{
  display:grid!important;grid-template-columns:minmax(0,var(--lab-left,50%)) 10px minmax(0,1fr)!important;
  align-items:stretch!important;
}
.matlab-lab .lab-pane{min-width:0!important;width:auto!important;flex:none!important}
.matlab-lab .lab-code-pane{flex-basis:auto!important}
.matlab-lab .lab-splitter{width:10px!important;height:auto!important;cursor:col-resize!important;touch-action:none}
.matlab-lab .lab-extension:not(.has-figure){display:none!important}
.matlab-lab .lab-extension.has-figure .lab-large-figures{min-height:500px;padding:15px}

/* Selectable MATLAB-style figures. */
.figure-card{transition:border-color .18s,box-shadow .18s,transform .18s}
.figure-card canvas{touch-action:none;user-select:none}
.figure-card.plot-selected{border:2px solid var(--course-accent-2)!important;box-shadow:0 0 0 4px color-mix(in srgb,var(--course-accent-2) 22%,transparent),0 18px 42px rgba(14,85,92,.18);transform:translateY(-1px)}
.figure-card.plot-selected header{background:color-mix(in srgb,var(--course-accent-2) 14%,#eef2f4)!important;font-weight:800}
.figure-card.plot-selected canvas{cursor:grab}.figure-card.plot-selected canvas.is-panning{cursor:grabbing}
:root[data-theme="dark"] .figure-card.plot-selected header{background:color-mix(in srgb,var(--course-accent-2) 18%,#24343a)!important;color:#eafafa}

/* Shared, promise-based prompt and confirmation dialog. */
.course-dialog-open{overflow:hidden}
.course-dialog-host{position:fixed;inset:0;z-index:20000;display:grid;place-items:center;padding:24px}
.course-dialog-host[hidden]{display:none!important}
.course-dialog-backdrop{position:absolute;inset:0;background:rgba(2,13,16,.72);backdrop-filter:blur(5px)}
.course-dialog{
  position:relative;width:min(460px,calc(100vw - 32px));padding:28px;
  border:1px solid color-mix(in srgb,var(--course-accent) 35%,var(--course-control-border));border-radius:22px;
  background:color-mix(in srgb,var(--course-control-bg) 96%,#fff);color:var(--course-control-text);
  box-shadow:0 28px 90px rgba(0,0,0,.34);animation:courseDialogIn .2s ease-out;
}
.course-dialog-x{position:absolute;right:13px;top:12px;width:34px;height:34px;border:0;border-radius:50%;background:transparent;color:inherit;font-size:1.45rem;cursor:pointer}
.course-dialog-x:hover{background:color-mix(in srgb,var(--course-accent) 10%,transparent)}
.course-dialog-icon{width:48px;height:48px;display:grid;place-items:center;border-radius:15px;background:linear-gradient(135deg,var(--course-accent),var(--course-accent-2));color:#fff;font:800 1rem/1 ui-monospace,Consolas,monospace;box-shadow:0 10px 25px color-mix(in srgb,var(--course-accent) 24%,transparent)}
.course-dialog h2{margin:17px 0 6px;font-size:1.35rem}.course-dialog p{margin:0 0 18px;color:color-mix(in srgb,var(--course-control-text) 68%,transparent);white-space:pre-wrap}
.course-dialog-field{display:grid;gap:8px;margin:14px 0 22px}.course-dialog-field span{font-size:.82rem;font-weight:750}
.course-dialog-field input{width:100%;height:44px;border:1px solid var(--course-control-border);border-radius:11px;background:color-mix(in srgb,var(--course-control-bg) 92%,#fff);color:var(--course-control-text);padding:0 13px;font:650 1rem/1.2 ui-monospace,Consolas,"Microsoft YaHei",monospace;outline:none}
.course-dialog-field input:focus{border-color:var(--course-accent);box-shadow:0 0 0 4px color-mix(in srgb,var(--course-accent) 16%,transparent)}
.course-dialog-actions{display:flex;justify-content:flex-end;gap:10px}.course-dialog-actions button{min-width:88px;height:40px;border-radius:11px;border:1px solid var(--course-control-border);background:transparent;color:inherit;font-weight:750;cursor:pointer}
.course-dialog-confirm{background:var(--course-accent)!important;border-color:var(--course-accent)!important;color:#fff!important}.course-dialog-confirm.danger{background:#c84438!important;border-color:#c84438!important}
@keyframes courseDialogIn{from{opacity:0;transform:translateY(10px) scale(.98)}to{opacity:1;transform:none}}

@media(max-width:860px){
  .course-toolbar{width:auto!important;max-width:none!important;gap:6px!important}
  .course-tool-button{width:40px!important;min-width:40px!important;height:40px!important;min-height:40px!important}
  .course-runtime-link,.course-runtime-slot{width:45px!important;min-width:45px!important;max-width:45px!important;height:40px!important;margin-left:0!important;padding:0}
  .course-runtime-link span,.course-runtime-slot b{display:none}.course-runtime-slot{justify-content:center}.course-font-control{display:none!important}
}
@media(max-width:760px){
  .matlab-lab .lab-body{grid-template-columns:1fr!important;grid-template-rows:minmax(0,var(--lab-top,50%)) 10px minmax(0,1fr)!important}
  .matlab-lab .lab-splitter{width:auto!important;height:10px!important;cursor:row-resize!important}
}

/* v1.3.0: Chinese display headings need a little more breathing room. */
html[lang="zh-CN"] .hero h1,html[lang="zh-CN"] .hero-copy h1{line-height:1.08!important}
html[lang="zh-CN"] .section-head h2,html[lang="zh-CN"] .lesson-title,html[lang="zh-CN"] .hero-title{line-height:1.16!important}


/* v1.3.1: compact-layout polish, calm typography, and minimal scroll affordances. */
html[lang="zh-CN"] .hero h1,
html[lang="zh-CN"] .hero-copy h1{
  font-size:clamp(3rem,5.2vw,5.65rem)!important;
  line-height:1.14!important;
  letter-spacing:-.042em!important;
}
html[lang="zh-CN"] .section-head h2,
html[lang="zh-CN"] .lesson-title,
html[lang="zh-CN"] .hero-title{
  font-size:clamp(2rem,3.55vw,3.6rem)!important;
  line-height:1.23!important;
  letter-spacing:-.032em!important;
}
html[lang="zh-CN"] .lead,
html[lang="zh-CN"] .section-head p{line-height:1.76!important}
html[lang="zh-CN"] h3{line-height:1.36}

/* The lab divider is a resize handle, not a heavy grey scrollbar. */
.matlab-lab .lab-splitter{
  position:relative!important;
  background:transparent!important;
  border:0!important;
}
.matlab-lab .lab-splitter::after{
  content:"";
  position:absolute;
  left:50%;top:50%;
  width:3px;height:42px;
  transform:translate(-50%,-50%);
  border-radius:999px;
  background:color-mix(in srgb,var(--course-accent) 46%,var(--course-control-border));
  opacity:.55;
  transition:opacity .16s,background .16s,box-shadow .16s;
}
.matlab-lab .lab-splitter:hover::after,
body.resizing .matlab-lab .lab-splitter::after{
  opacity:1;
  background:var(--course-accent-2);
  box-shadow:0 0 0 4px color-mix(in srgb,var(--course-accent-2) 13%,transparent);
}

/* Native scrollbars stay unobtrusive and become visible only when useful. */
:where(.side-nav,.source-slide-thumbs,.source-slide-frame,.course-dialog,.figure-gallery,.file-list,.workspace-list,.command-log,.script-output,.bottom-panel){
  scrollbar-width:thin;
  scrollbar-color:color-mix(in srgb,var(--course-accent) 42%,transparent) transparent;
}
:where(.side-nav,.source-slide-thumbs,.source-slide-frame,.course-dialog,.figure-gallery,.file-list,.workspace-list,.command-log,.script-output,.bottom-panel)::-webkit-scrollbar{width:6px;height:6px}
:where(.side-nav,.source-slide-thumbs,.source-slide-frame,.course-dialog,.figure-gallery,.file-list,.workspace-list,.command-log,.script-output,.bottom-panel)::-webkit-scrollbar-track{background:transparent}
:where(.side-nav,.source-slide-thumbs,.source-slide-frame,.course-dialog,.figure-gallery,.file-list,.workspace-list,.command-log,.script-output,.bottom-panel)::-webkit-scrollbar-thumb{
  border-radius:999px;
  background:color-mix(in srgb,var(--course-accent) 38%,transparent);
}
:where(.side-nav,.source-slide-thumbs,.source-slide-frame,.course-dialog,.figure-gallery,.file-list,.workspace-list,.command-log,.script-output,.bottom-panel)::-webkit-scrollbar-thumb:hover{background:color-mix(in srgb,var(--course-accent-2) 70%,transparent)}
.side-nav{scrollbar-gutter:stable}

@media(max-width:1450px) and (min-width:1101px){
  .page-shell{grid-template-columns:270px minmax(0,1fr)!important}
  .side-nav{padding-left:18px!important;padding-right:14px!important}
  .lesson-section{padding-top:72px!important;padding-bottom:72px!important}
  .hero{gap:44px!important}
}
@media(max-width:1100px){
  html[lang="zh-CN"] .hero h1,
  html[lang="zh-CN"] .hero-copy h1{font-size:clamp(3rem,7.2vw,5rem)!important}
}
@media(max-width:760px){
  .matlab-lab .lab-body{grid-template-rows:minmax(0,var(--lab-top,50%)) 8px minmax(0,1fr)!important}
  .matlab-lab .lab-splitter{height:8px!important}
  .matlab-lab .lab-splitter::after{width:48px;height:3px}
  html[lang="zh-CN"] .hero h1,
  html[lang="zh-CN"] .hero-copy h1{font-size:clamp(2.7rem,12vw,3.65rem)!important;line-height:1.16!important}
  html[lang="zh-CN"] .section-head h2{font-size:clamp(1.9rem,9vw,2.65rem)!important;line-height:1.26!important}
}

/* Keep MathJax assistive MathML available to screen readers without duplicating the visible formula. */
mjx-assistive-mml {
  position: absolute !important;
  top: 0;
  left: 0;
  width: 1px !important;
  height: 1px !important;
  padding: 1px 0 0 !important;
  border: 0 !important;
  clip: rect(1px, 1px, 1px, 1px);
  overflow: hidden !important;
  user-select: none;
  white-space: nowrap;
}


/* Compositor-only same-page navigation. Fixed course chrome receives its own
   snapshot so only the lesson body moves during the transition. */
@supports (view-transition-name:none){
  .topbar{view-transition-name:course-anchor-topbar}
  .side-nav{view-transition-name:course-anchor-sidebar}
  ::view-transition-group(course-anchor-topbar),
  ::view-transition-group(course-anchor-sidebar){animation:none}
  ::view-transition-old(course-anchor-topbar),
  ::view-transition-new(course-anchor-topbar),
  ::view-transition-old(course-anchor-sidebar),
  ::view-transition-new(course-anchor-sidebar){animation:none;mix-blend-mode:normal}
  ::view-transition-old(root),::view-transition-new(root){animation-duration:var(--course-anchor-duration,.92s);animation-timing-function:cubic-bezier(.22,.8,.24,1);animation-fill-mode:both;mix-blend-mode:normal}
  html[data-course-anchor-direction="down"]::view-transition-old(root){animation-name:course-anchor-old-down}
  html[data-course-anchor-direction="down"]::view-transition-new(root){animation-name:course-anchor-new-down}
  html[data-course-anchor-direction="up"]::view-transition-old(root){animation-name:course-anchor-old-up}
  html[data-course-anchor-direction="up"]::view-transition-new(root){animation-name:course-anchor-new-up}
}
@keyframes course-anchor-old-down{to{transform:translateY(-22vh)}}
@keyframes course-anchor-new-down{from{transform:translateY(22vh)}}
@keyframes course-anchor-old-up{to{transform:translateY(22vh)}}
@keyframes course-anchor-new-up{from{transform:translateY(-22vh)}}

/* v1.8.12 mobile shell, keyboard-safe practice mode, and first-use guidance. */
.course-menu-button{display:none!important}
.course-nav-scrim{display:none;position:fixed;inset:0;border:0;padding:0;background:rgba(2,14,17,.58);z-index:840;cursor:pointer}
.course-nav-open .course-nav-scrim{display:block}
.course-nav-open{overflow:hidden}

.course-first-use[hidden]{display:none!important}
.course-first-use{position:fixed;inset:0;z-index:30000;pointer-events:none}
.course-first-use-shade{position:fixed;background:rgba(2,13,16,.66);pointer-events:auto;transition:all .22s ease}
.course-first-use-card{
  position:fixed;z-index:30003;width:min(390px,calc(100vw - 24px));max-height:min(380px,calc(var(--course-visual-height,100vh) - 24px));
  overflow:auto;padding:20px;border:1px solid color-mix(in srgb,var(--course-accent) 38%,var(--course-control-border));border-radius:20px;
  background:var(--paper,var(--surface,#fff));color:var(--course-control-text);box-shadow:0 24px 80px rgba(0,0,0,.38);pointer-events:auto
}
.course-first-use-kicker{font-size:.72rem;font-weight:900;letter-spacing:.18em;color:var(--course-accent);margin-bottom:7px}
.course-first-use-card h2{font-size:1.28rem;line-height:1.25;margin:0 0 8px}
.course-first-use-card p{margin:0;color:color-mix(in srgb,var(--course-control-text) 72%,transparent);line-height:1.65}
.course-first-use-footer{display:flex;align-items:center;gap:8px;margin-top:18px}
.course-first-use-footer button{min-height:40px;border:1px solid var(--course-control-border);border-radius:11px;padding:0 13px;background:transparent;color:inherit;font-weight:750;cursor:pointer}
.course-first-use-footer .course-first-use-next{background:var(--course-accent);border-color:var(--course-accent);color:#fff}
.course-first-use-later{margin-right:auto}
.course-first-use-count{font-size:.78rem;color:color-mix(in srgb,var(--course-control-text) 58%,transparent);white-space:nowrap}
.course-first-use-target{position:relative!important;z-index:30002!important;outline:4px solid color-mix(in srgb,var(--course-accent-2) 82%,#fff)!important;outline-offset:4px!important;border-radius:12px}
.course-first-use-open{overflow:hidden}

.course-mobile-input-done{display:none}

@media(max-width:760px){
  :root{--course-mobile-header-h:116px}
  .topbar,.titlebar,.bar{
    height:var(--course-mobile-header-h)!important;min-height:var(--course-mobile-header-h)!important;
    display:grid!important;grid-template-columns:minmax(0,1fr)!important;grid-template-rows:52px 64px!important;
    align-items:center!important;padding:0 12px!important;padding-top:env(safe-area-inset-top,0)!important
  }
  .topbar>.brand,.titlebar>.brand,.bar>.brand{
    width:100%;min-width:0;height:52px;display:flex!important;align-items:center!important;overflow:hidden
  }
  .topbar>.brand span:last-child,.titlebar>.brand span:last-child,.bar>.brand span:last-child{min-width:0}
  .topbar>.brand b,.titlebar>.brand b,.bar>.brand b{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .topbar>.brand small,.titlebar>.brand em,.bar>.brand small{display:none!important}
  .course-toolbar-host{
    width:100%!important;max-width:none!important;height:64px!important;margin:0!important;justify-content:stretch!important;align-self:stretch!important
  }
  .course-toolbar{
    width:100%!important;max-width:none!important;height:64px!important;gap:8px!important;justify-content:space-between!important;overflow:visible!important
  }
  .course-tool-button,.course-runtime-link,.course-runtime-slot{
    width:44px!important;min-width:44px!important;max-width:44px!important;height:44px!important;min-height:44px!important;border-radius:13px!important;margin:0!important;padding:0!important
  }
  .course-menu-button{display:grid!important}
  .course-runtime-link span,.course-runtime-slot b{display:none!important}
  .course-runtime-link{display:grid!important;place-items:center!important}
  .course-runtime-slot{justify-content:center!important}
  .course-font-control{display:none!important}
  .course-tool-button[data-course-tip]::after,.course-font-control button[data-course-tip]::after{display:none!important}
  .side-nav{
    top:var(--course-mobile-header-h)!important;height:calc(100dvh - var(--course-mobile-header-h))!important;
    max-height:calc(var(--course-visual-height,100dvh) - var(--course-mobile-header-h))!important;padding-bottom:calc(24px + env(safe-area-inset-bottom,0px))!important;
    z-index:850!important
  }
  .lesson-section{scroll-margin-top:calc(var(--course-mobile-header-h) + 14px)!important}
  .hero{min-height:calc(100dvh - var(--course-mobile-header-h))!important}

  .matlab-lab .lab-editor,.matlab-lab textarea,.matlab-lab input{font-size:max(16px,var(--course-font-size,16px))!important}
  body.course-mobile-input-mode{overflow:hidden!important}
  .lesson-section.course-mobile-active-section{contain:none!important;content-visibility:visible!important}
  .matlab-lab.mobile-focus-lab{
    position:fixed!important;z-index:26000!important;left:0!important;right:0!important;
    top:var(--course-visual-offset,0px)!important;height:var(--course-visual-height,100dvh)!important;
    width:100vw!important;max-width:none!important;margin:0!important;border-radius:0!important;background:var(--paper,var(--surface,#fff))!important;
    overflow:auto!important;padding-bottom:calc(58px + env(safe-area-inset-bottom,0px))!important;box-shadow:none!important
  }
  .matlab-lab.mobile-focus-lab .lab-head,.matlab-lab.mobile-focus-lab .lab-toolbar,.matlab-lab.mobile-focus-lab>header{
    position:sticky!important;top:0!important;z-index:4!important;background:inherit!important
  }
  .matlab-lab.mobile-focus-lab .lab-header{
    position:sticky!important;top:0!important;z-index:5!important;background:linear-gradient(90deg,#0a6f88,#0e8795)!important;color:#fff!important
  }
  .matlab-lab.mobile-focus-lab .lab-body{
    display:grid!important;height:calc(var(--course-visual-height,100dvh) - 58px)!important;min-height:360px!important;
    grid-template-columns:1fr!important;grid-template-rows:minmax(220px,1.15fr) 7px minmax(150px,.85fr)!important
  }
  .matlab-lab.mobile-focus-lab .lab-code-pane,.matlab-lab.mobile-focus-lab .lab-result-pane{min-width:0!important;width:100%!important;flex:none!important}
  .matlab-lab.mobile-focus-lab .lab-splitter{cursor:row-resize!important}
  .matlab-lab.mobile-focus-lab .lab-splitter:after{width:45px!important;height:2px!important;left:calc(50% - 22px)!important;top:2px!important}
  .matlab-lab.mobile-focus-lab .lab-extension{display:none!important}
  .matlab-lab.mobile-focus-lab .course-mobile-input-done{display:block}
  .course-mobile-input-done{
    position:fixed;z-index:26005;right:12px;bottom:calc(10px + env(safe-area-inset-bottom,0px));height:42px;padding:0 18px;
    border:0;border-radius:999px;background:var(--course-accent);color:#fff;font-weight:800;box-shadow:0 10px 26px rgba(0,0,0,.28)
  }
  .course-first-use-card{width:calc(100vw - 24px);padding:17px}
  .course-first-use-footer{flex-wrap:wrap}
  .course-first-use-later{order:4;width:100%;margin:2px 0 0}
}

@media(max-width:420px){
  .topbar,.titlebar,.bar{padding-left:9px!important;padding-right:9px!important}
  .course-toolbar{gap:5px!important}
  .course-tool-button,.course-runtime-link,.course-runtime-slot{width:42px!important;min-width:42px!important;max-width:42px!important;height:42px!important;min-height:42px!important}
  .brand-wave,.brand-mark{width:38px!important;height:38px!important;min-width:38px!important}
}

@media(prefers-reduced-motion:reduce){
  .course-first-use-shade,.course-first-use-card{transition:none!important;animation:none!important}
}

/* v1.8.18 Help glass fix: portal the shell to <body> so the browser samples
   the real lesson/page behind it instead of the opaque sticky-header backdrop root. */
.course-toolbar{
  width:auto!important;max-width:none!important;height:72px!important;gap:8px!important;
  overflow:visible!important;justify-content:flex-end!important
}
.course-tool-button{width:42px!important;min-width:42px!important;height:42px!important;min-height:42px!important}
.course-font-control{width:116px!important;min-width:116px!important;grid-template-columns:38px 38px 38px!important}
.course-font-control button,.course-font-control>span{width:38px!important;min-width:38px!important;height:40px!important;min-height:40px!important}
.course-runtime-link,.course-runtime-slot{
  width:154px!important;min-width:154px!important;max-width:154px!important;height:42px!important;min-height:42px!important;
  margin-left:2px!important;padding-left:12px!important;padding-right:12px!important
}
.course-help-shell{
  --course-help-height:560px;
  position:fixed!important;left:50%;top:14px;z-index:31000;transform:translateX(-50%) translateZ(0);
  width:clamp(350px,calc(100vw - 970px),520px);height:44px;min-width:0;
  color:var(--course-control-text);overflow:hidden;container-type:inline-size;
  border:1px solid rgba(42,43,48,.18);border-radius:22px;
  background:rgba(248,249,251,.56);
  -webkit-backdrop-filter:blur(16px) saturate(1.10) brightness(1.02) contrast(.98);
  backdrop-filter:blur(16px) saturate(1.10) brightness(1.02) contrast(.98);
  box-shadow:inset 0 1px 0 rgba(255,255,255,.72),0 10px 32px rgba(0,0,0,.14);
  transition:height .48s cubic-bezier(.22,.88,.24,1),border-color .22s ease,box-shadow .28s ease,background-color .24s ease
}
.course-help-shell::before{
  content:"";position:absolute;inset:0;z-index:0;pointer-events:none;
  background:linear-gradient(145deg,rgba(255,255,255,.34),rgba(255,255,255,.045) 43%,rgba(255,255,255,.13));
  opacity:.62
}
:root[data-theme="dark"] .course-help-shell{
  border-color:rgba(255,255,255,.15);background:rgba(11,14,17,.42);
  -webkit-backdrop-filter:blur(16px) saturate(.94) brightness(.74) contrast(.94);
  backdrop-filter:blur(16px) saturate(.94) brightness(.74) contrast(.94);
  box-shadow:inset 0 1px 0 rgba(255,255,255,.11),0 18px 46px rgba(0,0,0,.42)
}
:root[data-theme="dark"] .course-help-shell::before{
  background:linear-gradient(145deg,rgba(255,255,255,.095),rgba(255,255,255,.012) 46%,rgba(255,255,255,.035));opacity:.52
}
.course-help-shell.course-help-expanded{
  height:var(--course-help-height);max-height:calc(100vh - 24px);
  border-color:rgba(42,43,48,.21);background:rgba(248,249,251,.48);
  -webkit-backdrop-filter:blur(24px) saturate(1.06) brightness(1.01) contrast(.97);
  backdrop-filter:blur(24px) saturate(1.06) brightness(1.01) contrast(.97);
  box-shadow:0 30px 88px rgba(0,0,0,.24),inset 0 1px 0 rgba(255,255,255,.76)
}
:root[data-theme="dark"] .course-help-shell.course-help-expanded{
  border-color:rgba(255,255,255,.17);background:rgba(10,12,15,.36);
  -webkit-backdrop-filter:blur(24px) saturate(.92) brightness(.76) contrast(.94);
  backdrop-filter:blur(24px) saturate(.92) brightness(.76) contrast(.94);
  box-shadow:0 34px 96px rgba(0,0,0,.58),inset 0 1px 0 rgba(255,255,255,.12)
}
/* Retire the v1.8.17 auxiliary glass rectangle. It lived in a different
   stacking context and could cover the Help content instead of blurring it. */
.course-help-glass-layer{display:none!important}
@supports not ((-webkit-backdrop-filter:blur(1px)) or (backdrop-filter:blur(1px))){
  .course-help-shell{background:rgba(244,244,246,.96)}
  :root[data-theme="dark"] .course-help-shell{background:rgba(20,20,23,.96)}
}

.course-help-shell.course-help-resizing-shell{transition:none!important}
.course-help-capsule{
  position:relative;z-index:2;width:100%;height:43px;display:flex;align-items:center;gap:9px;padding:0 12px;
  border:0;background:transparent;box-shadow:none;overflow:hidden
}
.course-help-shell.course-help-expanded .course-help-capsule{box-shadow:inset 0 -1px 0 rgba(127,127,132,.22)}
.course-help-capsule svg{width:21px;height:21px;flex:none;fill:none;stroke:var(--course-accent);stroke-width:1.9;stroke-linecap:round;stroke-linejoin:round}
.course-help-capsule input{
  min-width:0;flex:1;height:40px;border:0!important;outline:0!important;background:transparent!important;color:inherit!important;
  font:700 14px/1.2 "Segoe UI","Microsoft YaHei",sans-serif;padding:0!important;box-shadow:none!important
}
.course-help-capsule input::-webkit-search-cancel-button{display:none}
.course-help-capsule input::placeholder{color:color-mix(in srgb,var(--course-control-text) 53%,transparent);font-weight:650}
.course-help-hint{flex:none;padding:3px 7px;border-radius:999px;background:color-mix(in srgb,var(--course-accent) 11%,transparent);color:var(--course-accent);font:900 10px/1 ui-monospace,Consolas,monospace;letter-spacing:.08em}
.course-help-panel{
  position:absolute;z-index:2;inset:44px 0 0;width:100%;min-height:0;display:grid;grid-template-rows:auto minmax(0,1fr);
  overflow:hidden;border:0;background:transparent;color:var(--course-control-text);
  opacity:0;visibility:hidden;pointer-events:none;clip-path:inset(0 0 100% 0 round 0 0 22px 22px);
  transition:clip-path .44s cubic-bezier(.22,.88,.24,1),opacity .16s ease,visibility 0s linear .46s
}
.course-help-shell.course-help-expanded .course-help-panel{opacity:1;visibility:visible;pointer-events:auto;clip-path:inset(0 0 0 0 round 0 0 22px 22px);transition-delay:0s,.06s,0s}
.course-help-results[hidden]{display:none!important}
.course-help-results{
  padding:12px 16px 13px;border-bottom:1px solid rgba(127,127,132,.18);overflow:hidden;background:rgba(127,127,132,.035)
}
.course-help-result-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:9px;color:color-mix(in srgb,var(--course-control-text) 64%,transparent);font-size:12px}
.course-help-result-head span{font-weight:800;letter-spacing:.025em}.course-help-result-head small{font-size:11px;white-space:nowrap}
.course-help-result-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}
.course-help-result{
  min-width:0;min-height:48px;display:flex;flex-direction:column;justify-content:center;align-items:flex-start;gap:3px;
  border:1px solid rgba(127,127,132,.22);border-radius:12px;padding:7px 10px;background:rgba(127,127,132,.055);color:inherit;cursor:pointer;text-align:left;transition:border-color .16s,background .16s,transform .16s
}
.course-help-result span{display:block;width:100%;white-space:normal;overflow-wrap:anywhere;font-weight:800;font-size:12px;line-height:1.3}
.course-help-result small{display:block;width:100%;color:color-mix(in srgb,var(--course-control-text) 56%,transparent);font-size:10px;line-height:1.2;white-space:normal;overflow-wrap:anywhere}
.course-help-result:hover,.course-help-result:focus-visible{border-color:color-mix(in srgb,var(--course-accent) 52%,rgba(127,127,132,.3));background:rgba(127,127,132,.105);outline:none;transform:translateY(-1px)}
.course-help-detail{
  min-height:0;overflow:auto;padding:19px 18px 34px;overscroll-behavior:contain;
  scrollbar-width:thin;scrollbar-color:transparent transparent
}
.course-help-detail:hover,.course-help-detail:focus-within{scrollbar-color:color-mix(in srgb,var(--course-control-text) 30%,transparent) transparent}
.course-help-detail::-webkit-scrollbar{width:5px;height:5px}.course-help-detail::-webkit-scrollbar-track{background:transparent}.course-help-detail::-webkit-scrollbar-thumb{border-radius:999px;background:transparent}.course-help-detail:hover::-webkit-scrollbar-thumb,.course-help-detail:focus-within::-webkit-scrollbar-thumb{background:color-mix(in srgb,var(--course-control-text) 28%,transparent)}
.course-help-detail>*{animation:courseHelpContentIn .28s cubic-bezier(.2,.8,.2,1) both}
.course-help-entry-head{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;padding-right:2px}
.course-help-entry-head h2,.course-help-welcome h2{margin:5px 0 0;font-size:1.38rem;line-height:1.2;letter-spacing:-.02em;overflow-wrap:anywhere}
.course-help-entry-head>code{flex:none;max-width:38%;margin-top:5px;padding:6px 9px;border-radius:9px;background:color-mix(in srgb,var(--course-accent) 10%,transparent);color:var(--course-accent);font-weight:850;white-space:normal;overflow-wrap:anywhere;text-align:right}
.course-help-category{display:inline-flex;max-width:100%;padding:4px 8px;border-radius:999px;background:color-mix(in srgb,var(--course-accent) 10%,transparent);color:var(--course-accent);font-size:11px;font-weight:900;letter-spacing:.07em;white-space:normal}
.course-help-summary{margin:11px 0 16px;color:color-mix(in srgb,var(--course-control-text) 80%,transparent);font-size:13.5px;line-height:1.7}
.course-help-section{margin-top:17px}.course-help-section h3{margin:0 0 9px;color:var(--course-accent);font-size:11.5px;letter-spacing:.075em;text-transform:uppercase}.course-help-section p{margin:0;font-size:13px;line-height:1.7;color:color-mix(in srgb,var(--course-control-text) 80%,transparent);overflow-wrap:anywhere}
.course-help-syntax-list{display:grid;gap:10px}
.course-help-syntax-item{padding:12px;border:1px solid rgba(127,127,132,.20);border-radius:14px;background:rgba(127,127,132,.045)}
.course-help-syntax-item>code{display:block;padding:8px 10px;border-radius:10px;background:rgba(8,18,22,.84);color:#def7f5;font:700 12.5px/1.5 ui-monospace,SFMono-Regular,Consolas,monospace;white-space:pre-wrap;overflow-wrap:anywhere}
.course-help-syntax-item>p{margin-top:9px}
.course-help-parameter-box{margin-top:10px;padding-top:10px;border-top:1px solid rgba(127,127,132,.16)}
.course-help-parameter-box h4,.course-help-options h4{margin:0 0 7px;font-size:11.5px;color:color-mix(in srgb,var(--course-control-text) 68%,transparent)}
.course-help-parameter-box dl{display:grid;gap:6px;margin:0}
.course-help-parameter-box dl>div{display:grid;grid-template-columns:minmax(64px,max-content) 1fr;gap:9px;align-items:start}
.course-help-parameter-box dt{padding:3px 7px;border-radius:7px;background:color-mix(in srgb,var(--course-accent) 9%,transparent);color:var(--course-accent);font:750 11.5px/1.35 ui-monospace,Consolas,monospace;overflow-wrap:anywhere}
.course-help-parameter-box dd{margin:0;color:color-mix(in srgb,var(--course-control-text) 76%,transparent);font-size:12.5px;line-height:1.55}
.course-help-options{display:grid;gap:10px}.course-help-options>h3{margin-bottom:0}.course-help-options article{padding:11px 12px;border:1px solid rgba(127,127,132,.20);border-radius:13px;background:rgba(127,127,132,.04)}
.course-help-option-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px}
.course-help-option-grid>div{display:grid;grid-template-columns:minmax(42px,max-content) 1fr;gap:7px;align-items:center;padding:6px 7px;border-radius:9px;background:rgba(127,127,132,.055)}
.course-help-option-grid code{color:var(--course-accent);font:800 11.5px/1.35 ui-monospace,Consolas,monospace;overflow-wrap:anywhere}
.course-help-option-grid span{font-size:11.8px;line-height:1.45;color:color-mix(in srgb,var(--course-control-text) 75%,transparent)}
.course-help-example pre{margin:0 0 10px;padding:13px 14px;border:1px solid color-mix(in srgb,var(--course-accent) 20%,var(--course-control-border));border-radius:13px;background:rgba(5,18,22,.88);color:#dff8f6;overflow:auto;white-space:pre-wrap;overflow-wrap:anywhere;tab-size:4}
.course-help-example pre code{font:650 12.5px/1.62 ui-monospace,SFMono-Regular,Consolas,monospace}.course-help-example p b{color:var(--course-control-text)}
.course-help-two-column{display:grid;grid-template-columns:1fr;gap:10px}.course-help-two-column .course-help-section{padding:12px;border:1px solid rgba(127,127,132,.20);border-radius:13px;background:rgba(127,127,132,.04)}
.course-help-section ul{margin:0;padding-left:18px;color:color-mix(in srgb,var(--course-control-text) 80%,transparent);font-size:12.5px;line-height:1.62}.course-help-section li{overflow-wrap:anywhere}.course-help-section li+li{margin-top:5px}
.course-help-lessons>div{display:grid;gap:7px}.course-help-lessons a{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 11px;border:1px solid color-mix(in srgb,var(--course-accent) 25%,rgba(127,127,132,.2));border-radius:12px;background:color-mix(in srgb,var(--course-accent) 7%,transparent);color:inherit;text-decoration:none;transition:border-color .16s,background .16s,transform .16s}.course-help-lessons a:hover,.course-help-lessons a:focus-visible{border-color:var(--course-accent);background:color-mix(in srgb,var(--course-accent) 12%,transparent);transform:translateY(-1px);outline:none}.course-help-lessons a span{font-size:12.5px;font-weight:800}.course-help-lessons a small{flex:none;color:var(--course-accent);font-size:10.5px;font-weight:800}
.course-help-related>div,.course-help-quick{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:7px}
.course-help-related button,.course-help-quick button{min-width:0;border:1px solid rgba(127,127,132,.22);border-radius:11px;background:rgba(127,127,132,.045);color:inherit;padding:8px 9px;cursor:pointer;text-align:left;transition:border-color .16s,background .16s,transform .16s}.course-help-related button:hover,.course-help-related button:focus-visible,.course-help-quick button:hover,.course-help-quick button:focus-visible{border-color:var(--course-accent);background:color-mix(in srgb,var(--course-accent) 8%,transparent);transform:translateY(-1px);outline:none}.course-help-related button span{display:block;font-size:12px;font-weight:800;line-height:1.3;overflow-wrap:anywhere}.course-help-related button small{display:block;margin-top:3px;color:color-mix(in srgb,var(--course-control-text) 55%,transparent);font-size:10px}.course-help-quick button{font:750 12px/1.3 ui-monospace,Consolas,monospace}
.course-help-welcome p{color:color-mix(in srgb,var(--course-control-text) 72%,transparent);line-height:1.68}.course-help-quick{margin-top:16px}
.course-help-no-match{padding-top:4px}.course-help-no-match h2{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:1.05rem;overflow-wrap:anywhere}
.course-help-resizer{
  position:absolute;z-index:8;left:0;right:0;bottom:0;width:100%;height:18px;display:grid;place-items:center;cursor:ns-resize;touch-action:none;outline:none;border:0;padding:0;
  background:linear-gradient(to bottom,transparent,rgba(127,127,132,.045));color:inherit
}
.course-help-resizer span{width:48px;height:4px;border-radius:999px;background:color-mix(in srgb,var(--course-control-text) 27%,transparent);transition:width .18s,background .18s,transform .18s}
.course-help-resizer:hover span,.course-help-resizer:focus-visible span,.course-help-shell.course-help-resizing-shell .course-help-resizer span{width:68px;background:color-mix(in srgb,var(--course-accent) 72%,transparent)}
.course-help-shell.course-help-near-close .course-help-resizer span{width:76px;transform:translateY(-2px);background:var(--course-accent)}
.course-help-resizing{cursor:ns-resize!important;user-select:none!important}
@keyframes courseHelpContentIn{from{opacity:0;transform:translateY(5px)}to{opacity:1;transform:none}}

@media(max-width:1320px) and (min-width:1041px){
  .course-help-shell{width:clamp(290px,calc(100vw - 970px),350px)}
  .course-runtime-link,.course-runtime-slot{width:44px!important;min-width:44px!important;max-width:44px!important;padding:0!important;margin-left:0!important}
  .course-runtime-link span,.course-runtime-slot b{display:none!important}.course-runtime-link{display:grid!important;place-items:center!important}.course-runtime-slot{justify-content:center!important}
}
@media(max-width:1040px) and (min-width:761px){
  .topbar>.brand span:last-child,.titlebar>.brand span:last-child,.bar>.brand span:last-child{display:none!important}
  .topbar>.brand,.titlebar>.brand,.bar>.brand{width:42px!important;min-width:42px!important;overflow:visible!important}
  .course-help-shell{width:270px}.course-help-hint{display:none}
  .course-font-control{display:none!important}
  .course-runtime-link,.course-runtime-slot{width:44px!important;min-width:44px!important;max-width:44px!important;padding:0!important;margin-left:0!important}
  .course-runtime-link span,.course-runtime-slot b{display:none!important}.course-runtime-link{display:grid!important;place-items:center!important}.course-runtime-slot{justify-content:center!important}
}
@media(max-width:760px){
  .course-toolbar{width:100%!important;max-width:none!important;height:64px!important;gap:8px!important;justify-content:space-between!important}
  .course-tool-button,.course-runtime-link,.course-runtime-slot{width:44px!important;min-width:44px!important;max-width:44px!important;height:44px!important;min-height:44px!important}
  .course-font-control{display:none!important}
  .course-help-shell{position:relative!important;left:auto;top:auto;transform:none;flex:1 1 112px;width:auto;min-width:92px;height:44px}
  .course-help-shell.course-help-expanded{position:fixed!important;left:8px;right:8px;top:calc(8px + env(safe-area-inset-top,0px));width:auto;max-width:none;height:min(var(--course-help-height),calc(var(--course-visual-height,100dvh) - 16px - env(safe-area-inset-top,0px)));transform:none}
  .course-help-capsule{padding:0 10px;gap:7px}.course-help-capsule input{font-size:13px}.course-help-hint{display:none}
  .course-help-results{padding:11px 12px 12px}.course-help-detail{padding:17px 15px 34px}
  .course-help-option-grid{grid-template-columns:1fr}
  body.course-help-open{overflow:hidden!important}
}
@media(max-width:420px){
  .course-help-shell{min-width:74px}.course-help-capsule svg{width:19px;height:19px}.course-help-capsule input{font-size:12px}.course-help-capsule input::placeholder{font-size:11px}
  .course-help-entry-head{display:block}.course-help-entry-head>code{display:inline-block;max-width:100%;margin-top:9px;text-align:left}
  .course-help-parameter-box dl>div{grid-template-columns:1fr;gap:4px}.course-help-parameter-box dt{width:max-content;max-width:100%}
  .course-help-result-list,.course-help-related>div,.course-help-quick{grid-template-columns:1fr 1fr}
}
@media(prefers-reduced-motion:reduce){
  .course-help-shell,.course-help-panel,.course-help-detail>*{transition:none!important;animation:none!important}
}


/* v1.8.18: the closed Help stays in the toolbar; only the expanded surface is
   portaled to <body> so backdrop-filter samples the real page. */
.course-help-slot-placeholder{display:none}
.course-help-resizer-tip[hidden]{display:none!important}
.course-help-resizer-tip{
  position:absolute;z-index:12;left:50%;bottom:23px;max-width:calc(100% - 34px);
  transform:translate(-50%,8px) scale(.985);opacity:0;pointer-events:none;
  padding:8px 12px;border:1px solid rgba(127,127,132,.22);border-radius:12px;
  background:rgba(248,249,251,.72);color:color-mix(in srgb,var(--course-control-text) 84%,transparent);
  -webkit-backdrop-filter:blur(18px) saturate(1.04);backdrop-filter:blur(18px) saturate(1.04);
  box-shadow:0 9px 28px rgba(0,0,0,.18),inset 0 1px 0 rgba(255,255,255,.62);
  font:700 11.5px/1.45 "Segoe UI","Microsoft YaHei",sans-serif;text-align:center;
  transition:opacity .22s ease,transform .28s cubic-bezier(.2,.8,.2,1)
}
.course-help-resizer-tip::after{
  content:"";position:absolute;left:50%;bottom:-5px;width:9px;height:9px;
  transform:translateX(-50%) rotate(45deg);background:inherit;border-right:1px solid rgba(127,127,132,.18);border-bottom:1px solid rgba(127,127,132,.18)
}
.course-help-resizer-tip.course-help-resizer-tip-visible{opacity:1;transform:translate(-50%,0) scale(1)}
:root[data-theme="dark"] .course-help-resizer-tip{
  background:rgba(18,20,23,.70);border-color:rgba(255,255,255,.14);
  box-shadow:0 12px 34px rgba(0,0,0,.42),inset 0 1px 0 rgba(255,255,255,.09)
}

@media(max-width:760px){
  .course-help-slot-placeholder{display:block;flex:1 1 112px;min-width:92px;height:44px}
  .course-help-shell.course-help-portaled{
    position:fixed!important;left:8px;right:8px;top:calc(8px + env(safe-area-inset-top,0px));
    width:auto;max-width:none;transform:none
  }
  .course-help-resizer-tip{max-width:calc(100% - 24px);width:max-content;font-size:11px}
}

/* v1.8.21 anchor-flight rendering: keep long directory jumps compositor-smooth.
   Intermediate sections retain their current layout size but skip paint/layout
   until the destination is visible. They are restored in idle slices after the
   landing frame, with scroll compensation handled by course-anchor-nav.js. */
html[data-course-anchor-flight] .lesson-section.course-anchor-flight-skip {
  box-sizing:border-box!important;
  content-visibility:hidden!important;
  contain:strict!important;
  height:var(--course-anchor-flight-size)!important;
  min-height:var(--course-anchor-flight-size)!important;
  max-height:var(--course-anchor-flight-size)!important;
  overflow:hidden!important;
}
html[data-course-anchor-flight] .lesson-section.course-anchor-flight-target {
  content-visibility:visible!important;
  contain:none!important;
}