:root{
  --ink:#172026;
  --muted:#64717d;
  --paper:#fbfaf6;
  --panel:#ffffff;
  --line:#d9e0df;
  --teal:#087f8c;
  --teal-dark:#075d68;
  --coral:#ef6f5e;
  --sun:#f5b84b;
  --mint:#dff3ea;
  --blue:#2364aa;
  --red:#c94f4f;
  --green:#16845b;
  --shadow:0 18px 45px rgba(23,32,38,.09);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:Georgia,"Times New Roman",serif;
  color:var(--ink);
  background:
    radial-gradient(circle at 12% 0%, rgba(239,111,94,.16), transparent 28rem),
    radial-gradient(circle at 88% 6%, rgba(8,127,140,.14), transparent 24rem),
    linear-gradient(180deg,#fcfbf5 0%,#eef6f1 100%);
  min-height:100vh;
}
body::before{
  content:"";
  position:fixed;
  inset:0;
  pointer-events:none;
  opacity:.32;
  background-image:linear-gradient(rgba(23,32,38,.045) 1px,transparent 1px),linear-gradient(90deg,rgba(23,32,38,.045) 1px,transparent 1px);
  background-size:28px 28px;
  mask-image:linear-gradient(180deg,#000,transparent 75%);
}
a{color:inherit}
header,.site-hero{
  position:relative;
  overflow:hidden;
  color:#fff;
  background:#17313a;
  border-bottom:5px solid var(--sun);
}
header::after,.site-hero::after{
  content:"";
  position:absolute;
  inset:auto -8% -22% 42%;
  height:220px;
  background:repeating-linear-gradient(135deg,rgba(245,184,75,.75) 0 12px,rgba(239,111,94,.76) 12px 24px,rgba(8,127,140,.68) 24px 36px);
  transform:rotate(-5deg);
  opacity:.82;
}
header .hero-inner,.site-hero .hero-inner{position:relative;z-index:1;max-width:1180px;margin:0 auto;padding:34px 24px}
h1,h2,h3,p{margin-top:0}
h1{font-size:clamp(2.2rem,5vw,5.4rem);line-height:.95;margin-bottom:16px;letter-spacing:0}
h2{font-size:clamp(1.55rem,2.8vw,2.55rem);line-height:1.05;margin-bottom:10px}
h3{font-size:1.18rem;margin-bottom:10px}
p,li{line-height:1.55}
.kicker{font-family:Verdana,Geneva,sans-serif;text-transform:uppercase;letter-spacing:.08em;font-size:.78rem;font-weight:800;color:var(--sun);margin-bottom:12px}
.container{position:relative;max-width:1180px;margin:0 auto;padding:24px}
.narrow{max-width:760px}
.card,.panel,.chapter-card,.stat-card{
  background:rgba(255,255,255,.88);
  border:1px solid var(--line);
  border-radius:8px;
  box-shadow:var(--shadow);
}
.card,.panel{padding:24px;margin-bottom:20px}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:18px}
.dashboard-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px}
.chapter-card{
  display:flex;
  flex-direction:column;
  min-height:260px;
  padding:18px;
  overflow:hidden;
  position:relative;
}
.chapter-card::before{
  content:"";
  height:6px;
  width:72px;
  background:var(--accent,var(--teal));
  border-radius:999px;
  margin-bottom:14px;
}
.chapter-card p{color:var(--muted)}
.chapter-card .btn{margin-top:auto;align-self:flex-start}
.tag,.chip{
  display:inline-flex;
  align-items:center;
  width:max-content;
  max-width:100%;
  gap:6px;
  background:var(--mint);
  color:var(--teal-dark);
  padding:5px 9px;
  border-radius:999px;
  font-family:Verdana,Geneva,sans-serif;
  font-size:12px;
  font-weight:800;
  margin-bottom:10px;
}
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  min-height:42px;
  border:1px solid transparent;
  background:var(--teal);
  color:#fff;
  padding:10px 15px;
  border-radius:8px;
  cursor:pointer;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:800;
  text-decoration:none;
  transition:transform .16s ease,background .16s ease,box-shadow .16s ease;
}
.btn:hover{background:var(--teal-dark);transform:translateY(-1px);box-shadow:0 8px 18px rgba(8,127,140,.18)}
.btn.secondary{background:#fff;color:var(--ink);border-color:var(--line)}
.btn.secondary:hover{background:#f2f7f3}
.btn.coral{background:var(--coral)}
.topbar{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:20px}
.toolbar{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.hidden{display:none!important}
.feedback{margin-top:12px;font-weight:800}
.correct{color:var(--green)}
.wrong{color:var(--red)}
.progress-wrap{background:#dbe5e3;height:12px;border-radius:999px;overflow:hidden;margin-top:8px}
.progress-bar{height:100%;background:linear-gradient(90deg,var(--teal),var(--sun));width:0;transition:width .3s}
input,select{width:100%;padding:12px;border:1px solid var(--line);border-radius:8px;background:#fff;font:inherit}
label{display:block;font-family:Verdana,Geneva,sans-serif;font-weight:800;margin:14px 0 6px}
.home-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:22px}
.hero-copy{max-width:760px}
.hero-copy p{font-size:1.1rem;color:#dfeeed}
.stat-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:12px;margin:18px 0}
.stat-card{padding:16px}
.stat-card strong{display:block;font-size:1.75rem;color:var(--teal)}
.stat-card span{font-family:Verdana,Geneva,sans-serif;font-size:.78rem;font-weight:800;color:var(--muted);text-transform:uppercase}
.chapter-hero{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:20px;align-items:stretch}
.chapter-summary{font-size:1.08rem;color:#33424a}
.cockpit-hero{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:20px;
  align-items:start;
  padding:22px 0 10px;
}
.cockpit-hero h1{
  max-width:850px;
  font-size:clamp(2.35rem,4.4vw,4.8rem);
  color:var(--teal-dark);
}
.cockpit-hero p:not(.kicker){
  max-width:760px;
  color:#33424a;
  font-size:1.08rem;
}
.cockpit-actions,.teacher-actions{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  justify-content:flex-end;
}
.icon-btn{
  width:44px;
  min-width:44px;
  height:44px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  color:var(--ink);
  text-decoration:none;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:900;
  box-shadow:0 8px 18px rgba(23,32,38,.06);
}
.lesson-control{
  position:sticky;
  top:0;
  z-index:20;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  padding:12px;
  background:rgba(255,255,255,.92);
  backdrop-filter:blur(18px);
}
.mode-tabs{
  display:inline-grid;
  grid-template-columns:repeat(3,1fr);
  gap:4px;
  padding:4px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#f3f7f4;
}
.mode-tab{
  min-width:104px;
  min-height:38px;
  border:0;
  border-radius:6px;
  background:transparent;
  color:var(--muted);
  cursor:pointer;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.82rem;
  font-weight:900;
}
.mode-tab.active{
  background:#17313a;
  color:#fff;
  box-shadow:0 8px 18px rgba(23,32,38,.12);
}
.chapter-cockpit[data-mode="teach"] [data-mode-section]:not([data-modes~="teach"]),
.chapter-cockpit[data-mode="revise"] [data-mode-section]:not([data-modes~="revise"]),
.chapter-cockpit[data-mode="practise"] [data-mode-section]:not([data-modes~="practise"]){
  display:none!important;
}
.chapter-cockpit .lesson-layout{
  grid-template-columns:1fr;
}
.chapter-cockpit .side-menu{
  display:none;
}
.lesson-route{
  display:grid;
  grid-template-columns:minmax(0,280px) 1fr;
  gap:18px;
  align-items:center;
  border-top:5px solid var(--accent,var(--teal));
}
.lesson-route h2{margin-bottom:0}
.route-steps{
  display:grid;
  grid-template-columns:repeat(4,1fr);
  gap:10px;
}
.route-steps a{
  display:grid;
  grid-template-columns:auto 1fr;
  gap:4px 10px;
  align-items:center;
  min-height:86px;
  padding:12px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  color:var(--ink);
  text-decoration:none;
}
.route-steps b{
  grid-row:span 2;
  width:32px;
  height:32px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  background:var(--accent,var(--teal));
  color:#fff;
  font-family:Verdana,Geneva,sans-serif;
}
.route-steps span{
  font-family:Verdana,Geneva,sans-serif;
  font-weight:900;
}
.route-steps small{color:var(--muted);line-height:1.3}
.compact-hero .panel{margin-bottom:0}
.section-browser{
  border-top:5px solid var(--accent,var(--teal));
  background:
    linear-gradient(135deg,rgba(255,255,255,.98),rgba(246,249,248,.96)),
    radial-gradient(circle at 100% 0%,rgba(8,127,140,.1),transparent 24rem);
}
.section-browser-head{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:18px;
  align-items:end;
  margin-bottom:18px;
}
.section-browser-head p:not(.kicker){
  max-width:820px;
  color:#3d4a50;
}
.section-stats{
  min-width:176px;
  display:grid;
  grid-template-columns:auto 1fr;
  gap:4px 10px;
  padding:14px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
}
.section-stats strong{
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:1.45rem;
  line-height:1;
}
.section-stats span{
  align-self:center;
  color:var(--muted);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.72rem;
  font-weight:900;
  text-transform:uppercase;
}
.section-layout{
  display:grid;
  grid-template-columns:minmax(240px,.34fr) minmax(0,1fr);
  gap:16px;
  align-items:start;
}
.section-list{
  display:grid;
  gap:10px;
  position:sticky;
  top:104px;
}
.section-card{
  width:100%;
  min-height:116px;
  display:grid;
  grid-template-columns:auto 1fr;
  gap:4px 12px;
  align-items:start;
  padding:14px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  color:var(--ink);
  text-align:left;
  cursor:pointer;
  box-shadow:0 8px 20px rgba(23,32,38,.05);
}
.section-card:hover,.section-card:focus-visible,.section-card.active{
  border-color:var(--accent,var(--teal));
  box-shadow:0 14px 32px rgba(23,32,38,.1);
  transform:translateY(-1px);
}
.section-card span{
  grid-row:span 3;
  width:34px;
  height:34px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  background:#eff5f2;
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.74rem;
  font-weight:900;
}
.section-card.active span{
  background:var(--accent,var(--teal));
  color:#fff;
}
.section-card b{
  font-family:Verdana,Geneva,sans-serif;
  font-size:.95rem;
  line-height:1.2;
}
.section-card small,.section-card em{
  color:var(--muted);
  font-style:normal;
  line-height:1.35;
}
.section-card em{
  font-size:.76rem;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:900;
}
.section-detail-panel{
  min-height:620px;
  padding:0;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  box-shadow:0 18px 44px rgba(23,32,38,.08);
  overflow:hidden;
}
.section-detail-head{
  display:flex;
  justify-content:space-between;
  gap:16px;
  padding:20px 20px 16px;
  border-bottom:1px solid var(--line);
  background:#fbfcfc;
}
.section-detail-head h3{
  margin:0 0 6px;
  font-size:1.65rem;
}
.section-detail-head p{margin:0;color:var(--muted)}
.section-tabs{
  display:flex;
  gap:6px;
  padding:10px 20px;
  border-bottom:1px solid var(--line);
  background:#f5f7f7;
}
.section-tab{
  min-height:34px;
  padding:0 12px;
  border:1px solid transparent;
  border-radius:6px;
  background:transparent;
  color:var(--muted);
  cursor:pointer;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.74rem;
  font-weight:900;
}
.section-tab.active{
  border-color:var(--line);
  background:#fff;
  color:var(--teal-dark);
}
.section-tab-panel{padding:20px}
.teaching-focus{
  display:grid;
  gap:14px;
}
.teaching-card{
  padding:16px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
}
.teaching-card.objective{
  background:#17313a;
  color:#fff;
}
.teaching-card.objective p{color:#edf6f1}
.teaching-card b,.teaching-mini-grid b{
  display:block;
  margin-bottom:8px;
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  font-weight:900;
  text-transform:uppercase;
}
.teaching-card.objective b{color:#f5c86a}
.teaching-card ol,.teaching-card ul{margin:8px 0 0;padding-left:20px}
.teaching-card li{margin-bottom:8px;color:#33424a}
.teaching-mini-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:10px;
}
.teaching-mini-grid article{
  min-height:124px;
  padding:14px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#f8faf9;
}
.teaching-mini-grid span{color:#33424a;line-height:1.5}
.resource-stage{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(250px,.38fr);
  gap:14px;
}
.resource-stage-main{
  min-height:480px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#f5f7f7;
  overflow:hidden;
}
.resource-stage-main iframe{
  width:100%;
  height:100%;
  min-height:480px;
  border:0;
  background:#fff;
}
.slide-empty{
  min-height:480px;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:28px;
  color:var(--muted);
  text-align:center;
}
.slide-empty b{
  color:var(--ink);
  font-size:1.5rem;
}
.resource-list{
  display:grid;
  gap:8px;
  align-content:start;
}
.resource-list.compact{
  max-height:430px;
  overflow:auto;
  padding-right:4px;
}
.resource-card,.video-link-card{
  display:grid;
  gap:4px;
  padding:12px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  color:var(--ink);
  text-decoration:none;
}
.resource-card:hover,.video-link-card:hover{
  border-color:var(--accent,var(--teal));
  box-shadow:0 10px 22px rgba(23,32,38,.08);
}
.resource-card span{
  color:var(--coral);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.68rem;
  font-weight:900;
  text-transform:uppercase;
}
.resource-card b,.video-link-card b{
  font-size:.9rem;
  line-height:1.3;
}
.resource-card small,.video-link-card span{
  color:var(--muted);
  line-height:1.35;
  word-break:break-word;
}
.practice-section-grid{
  display:grid;
  grid-template-columns:minmax(0,.9fr) minmax(0,1.1fr);
  gap:12px;
}
.practice-section-grid .teaching-card:last-child{
  grid-column:1 / -1;
}
.video-workspace{
  display:grid;
  gap:14px;
}
.video-link-form{
  display:grid;
  grid-template-columns:minmax(160px,.28fr) minmax(220px,1fr) auto;
  gap:8px;
}
.video-link-form input{
  min-height:42px;
  padding:0 12px;
  border:1px solid var(--line);
  border-radius:6px;
  font:inherit;
}
.video-link-list{
  display:grid;
  gap:8px;
}
.textbook-lesson{
  border-top:5px solid var(--sun);
  background:
    linear-gradient(135deg,rgba(255,255,255,.96),rgba(255,250,236,.9)),
    radial-gradient(circle at 100% 0%,rgba(245,184,75,.2),transparent 18rem);
}
.textbook-lesson-head{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(230px,.42fr);
  gap:18px;
  align-items:start;
  margin-bottom:16px;
}
.textbook-lesson-head p:not(.kicker){
  max-width:820px;
  color:#33424a;
}
.textbook-sections{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  justify-content:flex-end;
}
.textbook-sections span{
  display:inline-flex;
  align-items:center;
  min-height:32px;
  padding:6px 9px;
  border:1px solid var(--line);
  border-radius:999px;
  background:#fff;
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.72rem;
  font-weight:900;
}
.teacher-flow{
  display:grid;
  grid-template-columns:repeat(5,minmax(0,1fr));
  gap:10px;
}
.teacher-flow article{
  padding:13px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
}
.teacher-flow b{
  display:block;
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  margin-bottom:7px;
}
.teacher-flow p{margin:0;color:#33424a}
.board-plan{
  display:grid;
  grid-template-columns:1.4fr .8fr;
  gap:10px;
  margin-top:10px;
}
.board-plan article{
  padding:14px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
}
.board-plan h3{color:var(--teal-dark)}
.board-plan p{margin-bottom:0}
.subtopic-workbench{
  border-top:5px solid var(--accent,var(--teal));
  background:
    linear-gradient(135deg,rgba(255,255,255,.94),rgba(247,251,249,.96)),
    radial-gradient(circle at 88% 0%,rgba(8,127,140,.11),transparent 22rem);
}
.subtopic-header{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:18px;
  align-items:start;
  margin-bottom:18px;
}
.subtopic-header p:not(.kicker){
  max-width:760px;
  color:var(--muted);
}
.subtopic-meter{
  min-width:118px;
  padding:14px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  text-align:center;
}
.subtopic-meter strong{
  display:block;
  color:var(--teal-dark);
  font-size:1.65rem;
  line-height:1;
}
.subtopic-meter span{
  font-family:Verdana,Geneva,sans-serif;
  font-size:.72rem;
  font-weight:900;
  color:var(--muted);
  text-transform:uppercase;
}
.subtopic-shell{
  display:grid;
  grid-template-columns:minmax(260px,.9fr) minmax(0,1.35fr);
  gap:18px;
  align-items:start;
}
.subtopic-grid{
  display:grid;
  gap:10px;
}
.subtopic-tile{
  width:100%;
  display:grid;
  grid-template-columns:auto minmax(0,1fr) auto;
  gap:4px 10px;
  align-items:center;
  min-height:94px;
  padding:13px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  color:var(--ink);
  text-align:left;
  cursor:pointer;
  box-shadow:0 8px 20px rgba(23,32,38,.045);
}
.subtopic-tile span{
  grid-row:span 2;
  width:34px;
  height:34px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  background:#eef6f3;
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  font-weight:900;
}
.subtopic-tile b{
  overflow-wrap:anywhere;
  color:var(--teal-dark);
  font-size:1rem;
}
.subtopic-tile small{
  justify-self:end;
  padding:4px 7px;
  border-radius:999px;
  background:#f3f7f4;
  color:var(--muted);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.68rem;
  font-weight:900;
  text-transform:uppercase;
}
.subtopic-tile em{
  grid-column:2 / 4;
  color:var(--muted);
  font-style:normal;
  line-height:1.35;
}
.subtopic-tile:hover,.subtopic-tile:focus-visible,.subtopic-tile.active{
  border-color:var(--accent,var(--teal));
  outline:none;
  box-shadow:0 14px 30px rgba(8,127,140,.13);
}
.subtopic-tile.ready small{
  background:#eaf8f1;
  color:var(--green);
}
.subtopic-tile.ready span{
  background:var(--green);
  color:#fff;
}
.subtopic-detail{
  position:sticky;
  top:84px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:18px;
  box-shadow:0 18px 38px rgba(23,32,38,.08);
}
.detail-top{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:12px;
}
.detail-top h3{
  margin-bottom:0;
  color:var(--teal-dark);
  font-size:1.85rem;
}
.ready-toggle{
  min-height:38px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#f7faf8;
  color:var(--ink);
  padding:8px 12px;
  cursor:pointer;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  font-weight:900;
}
.ready-toggle.active{
  border-color:var(--green);
  background:#eaf8f1;
  color:var(--green);
}
.detail-definition{
  margin:12px 0 16px;
  color:#33424a;
  font-size:1.04rem;
}
.learning-lane{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:10px;
}
.lane-card{
  display:grid;
  gap:7px;
  padding:12px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#f8fbf8;
}
.lane-card.warning{
  background:#fff8e6;
  border-color:#f0d28b;
}
.lane-card b,.subtopic-actions summary{
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  font-weight:900;
  text-transform:uppercase;
  letter-spacing:.06em;
}
.lane-card span{line-height:1.45}
.lane-card .mini-flow{gap:5px}
.lane-card .mini-flow strong,.lane-card .mini-flow span{
  min-height:28px;
  padding:5px 7px;
  font-size:.68rem;
}
.subtopic-actions{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:10px;
  margin-top:12px;
}
.subtopic-actions details{
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:12px;
}
.subtopic-actions p{margin:8px 0 0}
.resource-strip{
  display:flex;
  align-items:center;
  flex-wrap:wrap;
  gap:10px;
  margin-top:14px;
  padding-top:14px;
  border-top:1px solid var(--line);
}
.resource-strip span{
  color:var(--muted);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  font-weight:800;
}
.exam-strip{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px}
.exam-tile{background:#fff;border:1px solid var(--line);border-radius:8px;padding:14px}
.exam-tile b{display:block;color:var(--teal-dark);font-family:Verdana,Geneva,sans-serif;font-size:.84rem;margin-bottom:6px}
.lesson-layout{display:grid;grid-template-columns:280px 1fr;gap:20px;align-items:start}
.side-menu{position:sticky;top:16px;background:#fff;border:1px solid var(--line);border-radius:8px;padding:12px;box-shadow:var(--shadow)}
.side-menu a,.side-menu button{
  width:100%;
  display:block;
  text-align:left;
  margin-bottom:8px;
  background:#f3f7f4;
  color:var(--ink);
  border:1px solid transparent;
  padding:10px;
  border-radius:7px;
  cursor:pointer;
  text-decoration:none;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.86rem;
  font-weight:800;
}
.side-menu a.active,.side-menu button.active{background:var(--teal);color:#fff}
.note,.exam-note{
  background:#fff8e6;
  border-left:5px solid var(--sun);
  padding:12px 14px;
  border-radius:7px;
  color:#674400;
}
.concept-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px}
.concept{border:1px solid var(--line);border-radius:8px;background:#fff;padding:14px}
.concept b{color:var(--teal-dark)}
.mindmap{
  min-height:310px;
  display:grid;
  place-items:center;
  padding:18px;
  overflow:auto;
}
.mindmap-workspace{
  display:grid;
  grid-template-columns:minmax(0,1.25fr) minmax(280px,.75fr);
  gap:18px;
  align-items:stretch;
}
.cockpit-map-panel .mindmap{padding:0}
.map-hint{
  margin:0;
  color:var(--muted);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.82rem;
  font-weight:800;
}
.map-canvas{
  position:relative;
  width:min(760px,100%);
  aspect-ratio:16/9;
  min-height:330px;
}
.map-center,.map-node{
  position:absolute;
  display:flex;
  align-items:center;
  justify-content:center;
  text-align:center;
  border:2px solid var(--line);
  background:#fff;
  border-radius:8px;
  padding:10px;
  box-shadow:0 9px 18px rgba(23,32,38,.08);
}
.map-center{
  left:50%;
  top:50%;
  transform:translate(-50%,-50%);
  width:190px;
  min-height:78px;
  background:#17313a;
  color:#fff;
  border-color:#17313a;
  font-weight:800;
}
.map-node{
  width:155px;
  min-height:64px;
  flex-direction:column;
  gap:4px;
  color:var(--ink);
  text-decoration:none;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.8rem;
  font-weight:800;
  transition:transform .16s ease,border-color .16s ease,box-shadow .16s ease;
}
.map-node small{
  color:var(--teal-dark);
  font-size:.68rem;
  text-transform:uppercase;
  letter-spacing:.06em;
}
.map-node:hover,.map-node:focus-visible{
  border-color:var(--accent,var(--teal));
  box-shadow:0 14px 28px rgba(8,127,140,.16);
  outline:none;
}
.map-node.active{
  border-color:var(--accent,var(--teal));
  background:#f2fbf8;
  box-shadow:0 16px 34px rgba(8,127,140,.18);
}
.map-node::before{
  content:"";
  position:absolute;
  width:70px;
  height:2px;
  background:var(--accent,var(--teal));
  top:50%;
  z-index:-1;
}
.map-node.n1{left:2%;top:7%}.map-node.n1::before{right:-70px;transform:rotate(24deg)}
.map-node.n2{right:2%;top:7%}.map-node.n2::before{left:-70px;transform:rotate(-24deg)}
.map-node.n3{left:0;bottom:12%}.map-node.n3::before{right:-70px;transform:rotate(-22deg)}
.map-node.n4{right:0;bottom:12%}.map-node.n4::before{left:-70px;transform:rotate(22deg)}
.map-node.n5{left:50%;top:0;transform:translateX(-50%)}.map-node.n5::before{left:50%;top:100%;width:2px;height:66px}
.map-focus{
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:18px;
  box-shadow:0 14px 30px rgba(23,32,38,.08);
}
.map-focus h3{
  color:var(--teal-dark);
  font-size:1.45rem;
}
.focus-stack{
  display:grid;
  gap:10px;
  margin-top:16px;
}
.focus-stack article{
  display:grid;
  gap:5px;
  padding:12px;
  border:1px solid var(--line);
  border-radius:8px;
  background:#f8fbf8;
}
.focus-stack b{
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  text-transform:uppercase;
  letter-spacing:.06em;
}
.focus-stack span{line-height:1.45}
.diagram{
  display:grid;
  gap:10px;
  padding:16px;
  background:#f6faf7;
  border:1px solid var(--line);
  border-radius:8px;
}
.flow{display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.flow span,.mini-box{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  min-height:42px;
  padding:10px 12px;
  border-radius:7px;
  border:1px solid var(--line);
  background:#fff;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:800;
  font-size:.82rem;
}
.arrow{color:var(--coral);font-weight:900}
.qa-list{display:grid;gap:12px}
.qa-item{border:1px solid var(--line);border-radius:8px;background:#fff;padding:14px}
.qa-item summary{cursor:pointer;font-family:Verdana,Geneva,sans-serif;font-weight:800}
.quiz-option{
  display:block;
  width:100%;
  text-align:left;
  margin:8px 0;
  padding:10px;
  border:1px solid var(--line);
  background:#fff;
  border-radius:7px;
  cursor:pointer;
  font:inherit;
}
.quiz-option.correct-choice{border-color:var(--green);background:#eefaf4}
.quiz-option.wrong-choice{border-color:var(--red);background:#fff0f0}
.answer-shape-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(190px,1fr));
  gap:12px;
}
.answer-shape{
  border:1px solid var(--line);
  background:#fff;
  border-radius:8px;
  padding:14px;
}
.answer-shape b{
  display:block;
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  margin-bottom:8px;
}
.answer-shape p{margin:0;color:#33424a}
.worked-example{
  background:linear-gradient(180deg,#fff,#f4faf7);
}
.worked-layout{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:14px;
}
.worked-layout article{
  border:1px solid var(--line);
  background:#fff;
  border-radius:8px;
  padding:16px;
}
.worked-layout h3{color:var(--teal-dark)}
.lesson-open{overflow:hidden}
.lesson-mode{
  position:fixed;
  inset:0;
  z-index:100;
  box-sizing:border-box;
  height:100dvh;
  background:#edf8f7;
  color:#142529;
  padding:clamp(12px,2.4vh,24px);
  overflow:hidden;
}
.lesson-mode::before{
  content:"";
  position:absolute;
  inset:0;
  background-image:linear-gradient(90deg,rgba(247,253,251,.96),rgba(247,253,251,.82) 48%,rgba(247,253,251,.6)),var(--lesson-bg);
  background-size:cover;
  background-position:center;
  opacity:.94;
}
.lesson-mode::after{
  content:"";
  position:absolute;
  inset:0;
  background:
    radial-gradient(circle at 78% 26%,rgba(43,162,176,.18),transparent 24rem),
    radial-gradient(circle at 12% 78%,rgba(247,173,80,.16),transparent 18rem),
    linear-gradient(180deg,rgba(255,255,255,.2),rgba(237,248,247,.72));
}
.lesson-stage{
  position:relative;
  z-index:1;
  height:100%;
  min-height:0;
  display:grid;
  grid-template-rows:auto auto minmax(0,1fr) auto;
  max-width:1280px;
  margin:0 auto;
}
.lesson-top,.lesson-controls{
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:12px;
}
.lesson-top span{
  display:block;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:800;
  color:#087f8c;
}
.lesson-top strong{
  display:block;
  max-width:860px;
  margin-top:4px;
  color:#253238;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.85rem;
  line-height:1.35;
}
.lesson-close{
  border:1px solid rgba(8,127,140,.24);
  background:rgba(255,255,255,.72);
  color:#17313a;
  border-radius:8px;
  padding:10px 14px;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:800;
  cursor:pointer;
}
.lesson-deck-rail{
  display:flex;
  gap:10px;
  padding:clamp(8px,1.5vh,14px) 0;
  overflow:auto;
  scrollbar-width:thin;
}
.lesson-deck-rail button{
  min-width:168px;
  max-width:210px;
  min-height:72px;
  display:grid;
  grid-template-columns:auto 1fr;
  gap:3px 10px;
  align-items:start;
  padding:12px;
  border:1px solid rgba(8,127,140,.18);
  border-radius:8px;
  background:
    linear-gradient(90deg,rgba(255,255,255,.88),rgba(255,255,255,.58)),
    var(--deck-thumb);
  background-size:cover;
  background-position:center;
  color:#142529;
  text-align:left;
  cursor:pointer;
  box-shadow:0 10px 24px rgba(23,49,58,.08);
}
.lesson-deck-rail button.active{
  border-color:#087f8c;
  background:
    linear-gradient(90deg,rgba(230,250,247,.94),rgba(255,255,255,.54)),
    var(--deck-thumb);
  background-size:cover;
  background-position:center;
}
.lesson-deck-rail span{
  grid-row:span 2;
  width:32px;
  height:32px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  background:#087f8c;
  color:#fff;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.72rem;
  font-weight:900;
}
.lesson-deck-rail b{
  overflow-wrap:anywhere;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.82rem;
  line-height:1.2;
}
.lesson-deck-rail small{
  color:#3d5860;
  font-weight:800;
}
.lesson-slide-stack{
  min-height:0;
  display:grid;
}
.lesson-slide{
  display:none;
  min-height:0;
  padding:clamp(12px,2vh,30px) 0;
  overflow:auto;
}
.lesson-slide.active{display:grid}
.lesson-slide-inner{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(280px,380px);
  gap:clamp(20px,4vh,44px);
  align-items:center;
  align-self:center;
  min-height:100%;
}
.lesson-copy{
  min-width:0;
}
.lesson-meta-row{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  margin-bottom:14px;
}
.lesson-meta-row span{
  display:inline-flex;
  align-items:center;
  min-height:30px;
  padding:4px 10px;
  border:1px solid rgba(8,127,140,.2);
  border-radius:999px;
  background:rgba(255,255,255,.72);
  color:#087f8c;
  font-family:"Avenir Next","Gill Sans",Verdana,sans-serif;
  font-size:.78rem;
  font-weight:900;
  text-transform:uppercase;
}
.lesson-slide h2{
  margin:0;
  font-family:"Avenir Next","Trebuchet MS",Verdana,sans-serif;
  font-size:4.4rem;
  font-weight:900;
  line-height:.98;
  max-width:980px;
  color:#132126;
}
.lesson-slide h2 span{
  color:#087f8c;
}
.lesson-slide h2.compact-title{
  font-size:3.35rem;
  line-height:1.04;
}
.lesson-slide p,.lesson-slide li{
  max-width:920px;
  font-size:1.45rem;
  line-height:1.38;
  color:#263a42;
}
.lesson-lead{
  margin:22px 0 0;
  padding:18px 20px;
  border-left:5px solid #087f8c;
  border-radius:0 14px 14px 0;
  background:rgba(255,255,255,.74);
  font-family:"Iowan Old Style",Georgia,serif;
  font-size:1.58rem!important;
}
.lesson-point-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:12px;
  max-width:960px;
  margin-top:22px;
}
.lesson-point-card{
  display:grid;
  grid-template-columns:auto 1fr;
  gap:12px;
  align-items:start;
  min-height:82px;
  padding:14px;
  border:1px solid rgba(8,127,140,.16);
  border-radius:14px;
  background:rgba(255,255,255,.78);
  box-shadow:0 12px 30px rgba(23,49,58,.08);
}
.lesson-point-card span{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  width:34px;
  height:34px;
  border-radius:50%;
  background:#087f8c;
  color:#fff;
  font-family:"Avenir Next",Verdana,sans-serif;
  font-size:.74rem;
  font-weight:900;
}
.lesson-point-card p{
  margin:0;
  font-family:"Iowan Old Style",Georgia,serif;
  font-size:1.14rem;
  line-height:1.34;
}
.lesson-point-card strong{
  display:inline-block;
  padding:0 5px;
  border-radius:6px;
  background:#fff2cd;
  color:#17313a;
  font-family:"Avenir Next",Verdana,sans-serif;
  font-size:.92em;
}
.lesson-source{
  margin-top:24px;
  color:#5a7379!important;
  font-family:Verdana,Geneva,sans-serif;
  font-size:15px!important;
  font-weight:800;
}
.lesson-visual{
  margin:0;
  min-height:360px;
  display:grid;
  grid-template-rows:1fr auto;
  position:relative;
  border:1px solid rgba(8,127,140,.18);
  border-radius:18px;
  background:
    linear-gradient(145deg,rgba(255,255,255,.95),rgba(236,249,247,.82)),
    radial-gradient(circle at 80% 8%,rgba(247,173,80,.22),transparent 11rem);
  box-shadow:0 30px 80px rgba(23,49,58,.14);
  overflow:hidden;
}
.visual-orbit{
  position:absolute;
  inset:18px;
  pointer-events:none;
}
.visual-orbit span{
  position:absolute;
  width:10px;
  height:10px;
  border-radius:50%;
  background:#087f8c;
  box-shadow:0 0 0 8px rgba(8,127,140,.08);
}
.visual-orbit span:nth-child(1){left:8%;top:16%}
.visual-orbit span:nth-child(2){right:12%;top:28%;background:#f26d5b}
.visual-orbit span:nth-child(3){left:22%;bottom:14%;background:#f5b84b}
.visual-scene{
  min-height:280px;
  display:grid;
  place-items:center;
  padding:28px;
}
.lesson-visual figcaption{
  display:grid;
  gap:4px;
  padding:16px 18px;
  border-top:1px solid rgba(8,127,140,.14);
  background:rgba(255,255,255,.7);
}
.lesson-visual figcaption b{
  color:#17313a;
  font-family:Verdana,Geneva,sans-serif;
  font-size:1rem;
}
.lesson-visual figcaption span{
  color:#536970;
  line-height:1.35;
}
.visual-keywords{
  display:flex;
  flex-wrap:wrap;
  gap:6px;
  margin-top:8px;
}
.visual-keywords em{
  display:inline-flex;
  align-items:center;
  min-height:24px;
  padding:3px 8px;
  border-radius:999px;
  background:#e7fbf7;
  color:#087f8c;
  font-family:"Avenir Next",Verdana,sans-serif;
  font-size:.68rem;
  font-style:normal;
  font-weight:900;
}
.chip-core{
  width:220px;
  min-height:150px;
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:10px;
  padding:18px;
  border:3px solid #087f8c;
  border-radius:22px;
  background:#e7fbf7;
}
.chip-core span,.device-row b,.packet-train span,.translator-flow i,.control-loop span,.flowchart-visual span,.array-blocks i,.table-grid i,.logic-gates span{
  display:flex;
  align-items:center;
  justify-content:center;
  min-height:46px;
  border-radius:10px;
  background:#fff;
  color:#17313a;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.8rem;
  font-weight:900;
  box-shadow:0 8px 18px rgba(23,49,58,.08);
}
.bus-lines{display:grid;gap:9px;width:250px;margin-top:-18px}
.bus-lines i{height:6px;border-radius:99px;background:linear-gradient(90deg,#087f8c,#f5b84b)}
.device-row,.packet-train,.translator-flow,.control-loop,.flowchart-visual,.array-blocks,.logic-gates{
  display:flex;
  gap:10px;
  flex-wrap:wrap;
  justify-content:center;
  margin-top:16px;
}
.binary-rain,.network-map,.secure-dots,.trace-grid,.table-grid,.truth-mini{
  display:grid;
  gap:8px;
}
.binary-rain{grid-template-columns:repeat(2,110px)}
.binary-rain span{
  padding:18px 12px;
  border-radius:14px;
  background:#17313a;
  color:#e7fbf7;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:900;
  text-align:center;
}
.data-cubes{display:flex;gap:12px;margin-top:18px}
.data-cubes b{
  width:54px;height:54px;border-radius:12px;background:linear-gradient(135deg,#087f8c,#7bd7ca);
  box-shadow:0 14px 24px rgba(8,127,140,.18);
}
.network-map{
  width:260px;height:170px;position:relative;
}
.network-map b{
  position:absolute;width:50px;height:50px;border-radius:50%;background:#fff;border:3px solid #087f8c;
}
.network-map b:nth-child(1){left:8px;top:54px}.network-map b:nth-child(2){left:105px;top:8px}.network-map b:nth-child(3){right:8px;top:58px}.network-map b:nth-child(4){left:112px;bottom:8px}
.network-map i{
  position:absolute;height:4px;border-radius:99px;background:#f5b84b;transform-origin:left center;
}
.network-map i:nth-of-type(1){left:52px;top:74px;width:94px;transform:rotate(-28deg)}
.network-map i:nth-of-type(2){left:148px;top:76px;width:78px;transform:rotate(28deg)}
.network-map i:nth-of-type(3){left:130px;top:56px;width:88px;transform:rotate(92deg)}
.shield-lock{
  width:180px;height:210px;position:relative;border-radius:90px 90px 26px 26px;background:linear-gradient(160deg,#087f8c,#7bd7ca);
  clip-path:polygon(50% 0,100% 18%,88% 78%,50% 100%,12% 78%,0 18%);
}
.shield-lock b{position:absolute;left:62px;top:72px;width:56px;height:46px;border:10px solid #fff;border-bottom:0;border-radius:22px 22px 0 0}
.shield-lock span{position:absolute;left:53px;top:112px;width:74px;height:58px;border-radius:12px;background:#fff}
.code-window{
  width:260px;padding:16px;border-radius:18px;background:#17313a;box-shadow:0 18px 34px rgba(23,49,58,.18);
}
.code-window b{display:block;width:90px;height:10px;border-radius:99px;background:#f5b84b;margin-bottom:14px}
.code-window span{display:block;margin:8px 0;padding:10px;border-radius:8px;background:rgba(255,255,255,.12);color:#fff;font-family:Verdana,Geneva,sans-serif;font-weight:900}
.robot-arm{position:relative;width:230px;height:170px;margin-top:20px}
.robot-arm b{position:absolute;border-radius:18px;background:#087f8c}
.robot-arm b:nth-child(1){width:92px;height:26px;left:38px;top:84px;transform:rotate(-24deg)}
.robot-arm b:nth-child(2){width:92px;height:26px;left:112px;top:58px;transform:rotate(28deg);background:#f5b84b}
.robot-arm b:nth-child(3){width:54px;height:54px;left:92px;top:70px;border-radius:50%;background:#fff;border:8px solid #087f8c}
.flowchart-visual{flex-direction:column}
.flowchart-visual span:nth-child(2){border-radius:50%;min-width:106px}
.trace-grid,.table-grid,.truth-mini{grid-template-columns:repeat(3,64px)}
.trace-grid i{height:34px;border-radius:8px;background:#dff3ef}
.database-cylinder{width:160px;height:190px;position:relative;border-radius:80px / 32px;background:linear-gradient(180deg,#fff,#dff3ef);border:3px solid #087f8c}
.database-cylinder b,.database-cylinder span{position:absolute;left:-3px;right:-3px;height:48px;border:3px solid #087f8c;border-radius:80px / 24px;background:rgba(255,255,255,.45)}
.database-cylinder b{top:-3px}.database-cylinder span:nth-child(2){top:58px}.database-cylinder span:nth-child(3){top:116px}
.logic-gates span{min-width:84px;border-radius:999px;background:#17313a;color:#fff}
.truth-mini{grid-template-columns:repeat(2,58px);margin-top:18px}
.truth-mini i{display:flex;align-items:center;justify-content:center;height:44px;border-radius:10px;background:#fff;color:#087f8c;font-weight:900}
}
.lesson-slide .note{
  color:#4a3100;
  font-size:22px;
}
.lesson-chip-row{
  display:flex;
  flex-wrap:wrap;
  gap:14px;
  max-width:900px;
}
.lesson-chip-row span{
  border:1px solid rgba(255,255,255,.24);
  background:rgba(255,255,255,.1);
  border-radius:999px;
  padding:14px 18px;
  font-size:24px;
  font-weight:800;
}
.classroom-planner{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(240px,1fr));
  gap:14px;
  margin-bottom:20px;
}
.teacher-card{
  background:#fff;
  border:1px solid var(--line);
  border-radius:8px;
  padding:18px;
  box-shadow:var(--shadow);
}
.paper-policy{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:12px;
}
.policy-card{
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:14px;
}
.policy-card strong{
  display:block;
  font-size:1.8rem;
  color:var(--teal-dark);
  margin-bottom:8px;
}
.policy-card a{
  display:inline-block;
  margin-top:10px;
  color:var(--blue);
  font-family:Verdana,Geneva,sans-serif;
  font-weight:800;
  font-size:.82rem;
}
.resource-controls{
  display:grid;
  grid-template-columns:1fr 220px 1.2fr;
  gap:14px;
  align-items:end;
  margin-bottom:18px;
}
.resource-list{display:grid;gap:12px}
.resource-row{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:16px;
  align-items:center;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:14px;
}
.resource-row h3{margin:8px 0 6px}
.resource-row p{
  margin:0;
  color:var(--muted);
  font-family:"SFMono-Regular",Consolas,monospace;
  font-size:.82rem;
  overflow-wrap:anywhere;
}
.resource-actions{
  display:flex;
  gap:8px;
  align-items:center;
  flex-wrap:wrap;
  justify-content:flex-end;
}
.classified-list{display:grid;gap:12px}
.classified-row{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:16px;
  align-items:center;
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:14px;
}
.classified-row h3{margin:8px 0 6px}
.classified-row p{
  margin:0;
  color:var(--muted);
  font-family:"SFMono-Regular",Consolas,monospace;
  font-size:.82rem;
}
.classified-year-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(230px,1fr));
  gap:12px;
}
.classified-year{
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:14px;
}
.classified-mini-row{
  display:grid;
  grid-template-columns:auto minmax(0,1fr) auto;
  gap:8px;
  align-items:center;
  padding:8px 0;
  border-top:1px solid var(--line);
}
.classified-mini-row:first-of-type{border-top:none}
.classified-mini-row a{
  overflow-wrap:anywhere;
  color:var(--blue);
  font-weight:800;
}
.copy-classified{
  border:1px solid var(--line);
  border-radius:7px;
  background:#f7faf8;
  color:var(--ink);
  padding:7px 9px;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.76rem;
  font-weight:800;
  cursor:pointer;
}
.chapter-summary-box{
  background:
    linear-gradient(135deg,rgba(255,255,255,.96),rgba(248,251,248,.92)),
    radial-gradient(circle at 8% 10%,rgba(245,184,75,.22),transparent 18rem);
  border-top:5px solid var(--accent,var(--teal));
}
.summary-columns{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:14px;
  margin-top:18px;
}
.summary-columns article,.one-page-grid article{
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:16px;
}
.summary-columns h3,.one-page-grid h3{
  color:var(--teal-dark);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.95rem;
}
.summary-columns ul,.one-page-grid ul{padding-left:20px;margin-bottom:0}
.one-page-summary{
  break-inside:avoid;
  border-top:5px solid var(--sun);
}
.one-page-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:14px;
}
.term-cloud{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
}
.term-cloud span{
  display:inline-flex;
  align-items:center;
  min-height:32px;
  padding:6px 9px;
  border:1px solid var(--line);
  border-radius:999px;
  background:#f7faf8;
  font-family:Verdana,Geneva,sans-serif;
  font-size:.78rem;
  font-weight:800;
}
.mini-flow{
  display:flex;
  align-items:center;
  flex-wrap:wrap;
  gap:8px;
}
.mini-flow b,.mini-flow strong,.mini-flow span{
  display:inline-flex;
  align-items:center;
  min-height:34px;
  padding:7px 9px;
  border-radius:7px;
  background:#f6faf7;
  border:1px solid var(--line);
  font-family:Verdana,Geneva,sans-serif;
  font-size:.76rem;
}
.mini-flow span{
  color:var(--coral);
  background:transparent;
  border:none;
  padding:0;
}
.practice-pack,.teacher-pack{break-inside:avoid}
.teacher-pack{
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:18px;
  margin-bottom:18px;
  box-shadow:var(--shadow);
}
.pack-focus{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(240px,1fr));
  gap:14px;
  margin:16px 0;
}
.pack-focus article,.pack-focus section{
  border:1px solid var(--line);
  background:#f8fbf8;
  border-radius:8px;
  padding:14px;
}
.pack-columns{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(280px,1fr));
  gap:14px;
  margin-top:16px;
}
.pack-card{
  border:1px solid var(--line);
  border-radius:8px;
  background:#fff;
  padding:14px;
}
.pack-question{
  border-top:1px solid var(--line);
  padding:12px 0;
}
.pack-question:first-of-type{border-top:none}
.pack-question summary{
  cursor:pointer;
  font-family:Verdana,Geneva,sans-serif;
  font-weight:800;
  line-height:1.45;
}
.pack-question p{margin:10px 0 0;color:#33424a}
pre,code{font-family:"SFMono-Regular",Consolas,monospace}
pre{overflow:auto;white-space:pre-wrap}
table{width:100%;border-collapse:collapse;background:#fff;border-radius:8px;overflow:hidden}
th,td{border:1px solid var(--line);padding:10px;text-align:left;vertical-align:top}
th{background:#edf5f1;font-family:Verdana,Geneva,sans-serif;font-size:.82rem}
footer{padding:28px 24px;color:var(--muted);text-align:center}

.apple-home{
  font-family:-apple-system,BlinkMacSystemFont,"SF Pro Display","SF Pro Text","Helvetica Neue",Arial,sans-serif;
  background:#f5f5f7;
  color:#1d1d1f;
}
.apple-home::before{display:none}
.apple-nav{
  position:sticky;
  top:0;
  z-index:10;
  height:44px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:0 clamp(18px,4vw,64px);
  background:rgba(245,245,247,.78);
  border-bottom:1px solid rgba(0,0,0,.08);
  backdrop-filter:saturate(180%) blur(20px);
  -webkit-backdrop-filter:saturate(180%) blur(20px);
}
.apple-nav a{
  color:#1d1d1f;
  text-decoration:none;
  font-size:12px;
  line-height:1;
}
.apple-nav div{display:flex;gap:24px;align-items:center}
.brand-mark{font-weight:700;letter-spacing:0}
.apple-hero{
  min-height:calc(100vh - 44px);
  padding:56px clamp(18px,4vw,64px) 34px;
  display:flex;
  flex-direction:column;
  align-items:center;
  text-align:center;
  overflow:hidden;
  background:
    linear-gradient(180deg,#fff 0%,#f5f5f7 54%,#e8edf3 100%);
}
.apple-eyebrow{
  margin:0 0 12px;
  color:#6e6e73;
  font-size:17px;
  font-weight:600;
  letter-spacing:0;
}
.apple-hero h1{
  max-width:980px;
  margin:0;
  color:#1d1d1f;
  font-size:88px;
  line-height:.95;
  font-weight:700;
  letter-spacing:0;
}
.apple-subtitle{
  max-width:720px;
  margin:20px auto 0;
  color:#424245;
  font-size:28px;
  line-height:1.18;
  font-weight:500;
}
.apple-actions{
  display:flex;
  align-items:center;
  justify-content:center;
  flex-wrap:wrap;
  gap:22px;
  margin:28px 0 30px;
}
.apple-primary{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:11px 22px;
  border-radius:999px;
  background:#0071e3;
  color:#fff;
  text-decoration:none;
  font-size:17px;
  font-weight:500;
}
.apple-primary:hover{background:#0077ed}
.apple-link{
  color:#0066cc;
  font-size:17px;
  text-decoration:none;
  font-weight:500;
}
.apple-link::after{content:" >";font-size:16px}
.product-stage{
  width:min(1100px,100%);
  margin-top:auto;
  perspective:1400px;
}
.device-shell{
  width:min(980px,96%);
  margin:0 auto;
  border-radius:30px;
  padding:10px;
  background:linear-gradient(145deg,#fbfbfd,#b9c1ca 48%,#fefefe);
  box-shadow:0 34px 90px rgba(0,0,0,.25), inset 0 1px 0 rgba(255,255,255,.9);
  transform:rotateX(3deg);
}
.device-toolbar{
  height:42px;
  display:flex;
  align-items:center;
  gap:8px;
  padding:0 16px;
  border-radius:22px 22px 0 0;
  background:#111;
  color:#a1a1a6;
}
.device-toolbar span{
  width:10px;
  height:10px;
  border-radius:50%;
  background:#ff5f57;
}
.device-toolbar span:nth-child(2){background:#ffbd2e}
.device-toolbar span:nth-child(3){background:#28c840}
.device-toolbar b{
  margin-left:auto;
  margin-right:auto;
  font-size:12px;
  font-weight:600;
  color:#d2d2d7;
}
.device-screen{
  min-height:420px;
  display:grid;
  grid-template-columns:150px 1fr;
  gap:0;
  overflow:hidden;
  border-radius:0 0 22px 22px;
  background:#fff;
  text-align:left;
}
.screen-sidebar{
  padding:28px 18px;
  background:#f5f5f7;
  border-right:1px solid #e5e5ea;
}
.screen-sidebar span{
  display:block;
  height:14px;
  margin-bottom:18px;
  border-radius:999px;
  background:#d2d2d7;
}
.screen-sidebar .active{width:92%;background:#0071e3}
.screen-sidebar span:nth-child(2){width:70%}
.screen-sidebar span:nth-child(3){width:82%}
.screen-sidebar span:nth-child(4){width:58%}
.screen-main{padding:30px}
.screen-header{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:20px;
  margin-bottom:28px;
}
.screen-header p{
  margin:0;
  color:#86868b;
  font-size:17px;
  font-weight:600;
}
.screen-header strong{
  font-size:38px;
  letter-spacing:0;
}
.screen-map{
  position:relative;
  height:220px;
  border-radius:24px;
  background:
    radial-gradient(circle at 50% 50%,rgba(0,113,227,.16),transparent 31%),
    linear-gradient(135deg,#f5f5f7,#edf6ff);
  border:1px solid #e5e5ea;
}
.screen-map::before,.screen-map::after{
  content:"";
  position:absolute;
  left:18%;
  right:18%;
  top:50%;
  height:2px;
  background:#c7d9ee;
}
.screen-map::after{transform:rotate(90deg)}
.map-dot{
  position:absolute;
  display:flex;
  align-items:center;
  justify-content:center;
  min-width:74px;
  min-height:38px;
  padding:8px 10px;
  border-radius:999px;
  background:#fff;
  color:#1d1d1f;
  box-shadow:0 12px 28px rgba(0,0,0,.12);
  font-size:13px;
  font-weight:700;
}
.map-dot.center{
  left:50%;
  top:50%;
  transform:translate(-50%,-50%);
  min-width:70px;
  min-height:70px;
  color:#fff;
  background:#1d1d1f;
}
.d1{left:12%;top:18%}.d2{right:12%;top:18%}.d3{left:12%;bottom:18%}.d4{right:12%;bottom:18%}
.screen-cards{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:14px;
  margin-top:18px;
}
.screen-cards span{
  min-height:74px;
  padding:18px;
  border-radius:18px;
  background:#f5f5f7;
  font-weight:700;
  color:#1d1d1f;
}
.apple-overview{
  display:grid;
  grid-template-columns:minmax(0,420px) 1fr;
  gap:32px;
  align-items:start;
  padding:56px clamp(18px,4vw,64px) 72px;
  background:#fff;
}
.apple-overview h2{
  max-width:620px;
  font-size:56px;
  line-height:1;
  font-weight:700;
  letter-spacing:0;
  color:#1d1d1f;
}
.apple-feature-grid{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:14px;
}
.apple-feature-grid article{
  min-height:170px;
  padding:24px;
  border-radius:24px;
  background:#f5f5f7;
}
.apple-feature-grid strong{
  display:block;
  margin-bottom:14px;
  font-size:56px;
  line-height:1;
  letter-spacing:0;
}
.apple-feature-grid span{
  color:#424245;
  font-size:18px;
  line-height:1.25;
  font-weight:600;
}

/* Apple-style system pass for every teaching page */
:root{
  --ink:#1d1d1f;
  --muted:#6e6e73;
  --paper:#f5f5f7;
  --panel:#ffffff;
  --line:#d2d2d7;
  --teal:#0071e3;
  --teal-dark:#005bb8;
  --coral:#ff6b2b;
  --sun:#ffd60a;
  --mint:#eaf4ff;
  --blue:#0066cc;
  --red:#d70015;
  --green:#248a3d;
  --shadow:0 18px 45px rgba(0,0,0,.08);
}
body{
  font-family:-apple-system,BlinkMacSystemFont,"SF Pro Display","SF Pro Text","Helvetica Neue",Arial,sans-serif;
  color:#1d1d1f;
  background:
    linear-gradient(180deg,#ffffff 0,#f5f5f7 330px,#f5f5f7 100%);
}
body::before{
  display:none;
}
body:not(.apple-home) header,
body:not(.apple-home) .site-hero{
  color:#1d1d1f;
  background:
    linear-gradient(180deg,rgba(255,255,255,.92),rgba(245,245,247,.92)),
    url("../assets/lesson-backgrounds/cs-light-classroom.png") center 38%/cover no-repeat;
  border-bottom:1px solid rgba(0,0,0,.08);
}
body:not(.apple-home) header::after,
body:not(.apple-home) .site-hero::after{
  display:none;
}
body:not(.apple-home) header .hero-inner,
body:not(.apple-home) .site-hero .hero-inner{
  max-width:1180px;
  min-height:310px;
  display:flex;
  flex-direction:column;
  justify-content:center;
  padding:52px 24px 58px;
}
body:not(.apple-home) header h1,
body:not(.apple-home) .site-hero h1{
  max-width:820px;
  margin:0 0 18px;
  color:#1d1d1f;
  font-size:4.8rem;
  line-height:.96;
  font-weight:700;
  letter-spacing:0;
}
body:not(.apple-home) header p:not(.kicker),
body:not(.apple-home) .site-hero p:not(.kicker){
  max-width:640px;
  color:#424245;
  font-size:1.32rem;
  line-height:1.28;
  font-weight:500;
}
h1,h2,h3{
  font-family:inherit;
  letter-spacing:0;
}
h2{
  color:#1d1d1f;
  font-weight:700;
}
h3{
  color:#1d1d1f;
  font-weight:700;
}
p,li{
  color:inherit;
}
.container{
  max-width:1180px;
  padding:34px 24px;
}
.kicker{
  font-family:inherit;
  color:#86868b;
  text-transform:none;
  letter-spacing:0;
  font-size:.82rem;
  font-weight:700;
}
.card,
.panel,
.chapter-card,
.stat-card,
.teacher-card,
.teacher-pack,
.pack-card,
.summary-columns article,
.one-page-grid article,
.teaching-card,
.policy-card,
.resource-row,
.classified-row,
.classified-year{
  background:rgba(255,255,255,.88);
  border:1px solid rgba(0,0,0,.08);
  border-radius:8px;
  box-shadow:0 10px 30px rgba(0,0,0,.06);
}
.card,
.panel{
  padding:26px;
  margin-bottom:22px;
}
.topbar{
  align-items:flex-end;
  margin-bottom:24px;
}
.topbar h2{
  margin-bottom:6px;
  font-size:2.05rem;
}
.topbar p{
  color:#6e6e73;
  font-size:1.02rem;
}
.toolbar{
  gap:9px;
}
.btn,
.apple-primary{
  min-height:42px;
  border:1px solid transparent;
  border-radius:999px;
  background:#0071e3;
  color:#fff;
  padding:10px 19px;
  font-family:inherit;
  font-size:.95rem;
  font-weight:600;
  box-shadow:none;
}
.btn:hover,
.apple-primary:hover{
  background:#0077ed;
  transform:none;
  box-shadow:none;
}
.btn.secondary{
  background:rgba(255,255,255,.72);
  color:#0066cc;
  border-color:rgba(0,0,0,.12);
}
.btn.secondary:hover{
  background:#fff;
}
.btn.coral{
  background:#1d1d1f;
}
.btn.coral:hover{
  background:#333336;
}
.icon-btn{
  width:42px;
  min-width:42px;
  height:42px;
  border-color:rgba(0,0,0,.12);
  border-radius:50%;
  background:rgba(255,255,255,.78);
  color:#1d1d1f;
  font-family:inherit;
  box-shadow:none;
}
.tag,
.chip{
  background:#e8f2ff;
  color:#0066cc;
  border-radius:999px;
  font-family:inherit;
  text-transform:none;
  letter-spacing:0;
}
input,
select{
  border-color:rgba(0,0,0,.12);
  border-radius:8px;
  background:#fff;
  color:#1d1d1f;
  font-family:inherit;
}
label{
  color:#424245;
  font-family:inherit;
  font-size:.86rem;
  letter-spacing:0;
}
.progress-wrap{
  height:9px;
  background:#e5e5ea;
}
.progress-bar{
  background:#0071e3;
}
.dashboard-grid{
  grid-template-columns:repeat(auto-fit,minmax(280px,1fr));
  gap:18px;
}
.chapter-card{
  min-height:285px;
  padding:24px;
  background:#fff;
  transition:transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.chapter-card::before{
  width:46px;
  height:4px;
  background:#0071e3;
  margin-bottom:18px;
}
.chapter-card:hover{
  transform:translateY(-3px);
  border-color:rgba(0,113,227,.28);
  box-shadow:0 18px 44px rgba(0,0,0,.1);
}
.chapter-card h3{
  font-size:1.34rem;
  line-height:1.12;
}
.chapter-card p{
  color:#6e6e73;
}
.cockpit-hero{
  position:relative;
  grid-template-columns:minmax(0,1fr) auto;
  align-items:center;
  min-height:350px;
  margin:0 -24px 20px;
  padding:54px 24px 64px;
  overflow:hidden;
  border-bottom:1px solid rgba(0,0,0,.08);
}
.cockpit-hero::before{
  content:"";
  position:absolute;
  inset:0;
  z-index:-2;
  background:
    linear-gradient(90deg,rgba(255,255,255,.98) 0%,rgba(255,255,255,.82) 52%,rgba(245,245,247,.42) 100%),
    url("../assets/lesson-backgrounds/cs-light-classroom.png") right center/cover no-repeat;
}
.cockpit-hero::after{
  content:"";
  position:absolute;
  right:6%;
  bottom:24px;
  z-index:-1;
  width:280px;
  height:170px;
  border-radius:8px;
  background:
    radial-gradient(circle at 28px 24px,#ff5f57 0 5px,transparent 6px),
    radial-gradient(circle at 48px 24px,#ffbd2e 0 5px,transparent 6px),
    radial-gradient(circle at 68px 24px,#28c840 0 5px,transparent 6px),
    linear-gradient(90deg,transparent 28px,rgba(0,113,227,.14) 28px 30px,transparent 30px 100%),
    linear-gradient(180deg,transparent 58px,rgba(0,113,227,.16) 58px 62px,transparent 62px 78px,rgba(29,29,31,.1) 78px 82px,transparent 82px 106px,rgba(0,113,227,.16) 106px 110px,transparent 110px),
    radial-gradient(circle at 78% 70%,rgba(0,113,227,.16),transparent 36%),
    linear-gradient(180deg,#fff,#f5f5f7);
  box-shadow:0 22px 60px rgba(0,0,0,.14);
  opacity:.72;
}
.cockpit-hero h1{
  max-width:840px;
  margin:0 0 16px;
  color:#1d1d1f;
  font-size:4.7rem;
  line-height:.96;
  font-weight:700;
}
.cockpit-hero p:not(.kicker){
  max-width:700px;
  color:#424245;
  font-size:1.24rem;
  line-height:1.35;
  font-weight:500;
}
.cockpit-actions,
.teacher-actions{
  align-items:center;
}
.lesson-control{
  top:12px;
  border-radius:999px;
  padding:8px;
  background:rgba(255,255,255,.78);
  border-color:rgba(0,0,0,.08);
  box-shadow:0 12px 30px rgba(0,0,0,.08);
}
.mode-tabs{
  border:0;
  border-radius:999px;
  background:#e8e8ed;
}
.mode-tab{
  min-height:36px;
  border-radius:999px;
  color:#424245;
  font-family:inherit;
  font-size:.88rem;
  font-weight:700;
}
.mode-tab.active{
  background:#1d1d1f;
  color:#fff;
  box-shadow:none;
}
.section-browser{
  border-top:0;
  background:
    linear-gradient(180deg,#ffffff,#f9f9fb);
}
.section-browser-head{
  align-items:center;
}
.section-browser-head h2{
  font-size:2.55rem;
}
.section-browser-head p:not(.kicker){
  color:#6e6e73;
}
.section-stats{
  border-color:rgba(0,0,0,.08);
  background:#f5f5f7;
}
.section-stats strong{
  color:#1d1d1f;
  font-family:inherit;
}
.section-stats span{
  color:#86868b;
  font-family:inherit;
  text-transform:none;
}
.section-card{
  min-height:118px;
  border-color:rgba(0,0,0,.08);
  background:#fff;
  box-shadow:none;
  transition:transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.section-card:hover,
.section-card:focus-visible,
.section-card.active{
  border-color:rgba(0,113,227,.32);
  box-shadow:0 14px 32px rgba(0,0,0,.08);
}
.section-card span,
.section-card.active span{
  background:#1d1d1f;
  color:#fff;
  font-family:inherit;
}
.section-card b{
  font-family:inherit;
  font-size:1rem;
}
.section-card small,
.section-card em{
  color:#6e6e73;
  font-family:inherit;
}
.section-detail-panel{
  border-color:rgba(0,0,0,.08);
  box-shadow:0 16px 46px rgba(0,0,0,.08);
}
.section-detail-head{
  background:#fff;
  border-bottom-color:rgba(0,0,0,.08);
}
.section-detail-head h3{
  font-size:1.9rem;
}
.section-tabs{
  background:#f5f5f7;
  border-bottom-color:rgba(0,0,0,.08);
}
.section-tab{
  border-radius:999px;
  color:#6e6e73;
  font-family:inherit;
  font-size:.84rem;
  font-weight:700;
}
.section-tab.active{
  border-color:transparent;
  background:#fff;
  color:#1d1d1f;
}
.teaching-card.objective{
  background:#1d1d1f;
  color:#fff;
}
.teaching-card.objective p{
  color:#f5f5f7;
}
.teaching-card b,
.teaching-mini-grid b,
.pack-question summary,
.summary-columns h3,
.one-page-grid h3{
  font-family:inherit;
  color:#1d1d1f;
  text-transform:none;
  letter-spacing:0;
}
.teaching-card.objective b{
  color:#a7d7ff;
}
.teaching-card li,
.teaching-mini-grid span{
  color:#424245;
}
.teaching-mini-grid article,
.pack-focus article,
.pack-focus section{
  background:#f5f5f7;
  border-color:rgba(0,0,0,.08);
}
.resource-card,
.video-link-card{
  border-color:rgba(0,0,0,.08);
  background:#fff;
  border-radius:8px;
}
.resource-stage-main,
.slide-empty{
  background:#f5f5f7;
  border-color:rgba(0,0,0,.08);
}
.chapter-summary-box,
.one-page-summary{
  border-top:0;
  background:#fff;
}
.summary-columns,
.one-page-grid,
.pack-columns,
.pack-focus,
.classroom-planner{
  gap:16px;
}
.term-cloud span,
.mini-flow b,
.mini-flow strong,
.mini-flow span{
  border-color:rgba(0,0,0,.08);
  background:#f5f5f7;
  font-family:inherit;
}
.exam-tile,
.concept,
.qa-item,
.quiz-card,
.lane-card,
.subtopic-tile,
.detail-top,
.resource-card,
.copy-classified{
  border-color:rgba(0,0,0,.08);
}
.mindmap,
.map-canvas{
  background:#f5f5f7;
}
.map-center{
  background:#1d1d1f;
  color:#fff;
  box-shadow:0 16px 38px rgba(0,0,0,.16);
}
.map-node{
  background:#fff;
  border-color:rgba(0,0,0,.08);
  color:#1d1d1f;
}
.map-node.active,
.map-node:hover{
  border-color:#0071e3;
  box-shadow:0 14px 34px rgba(0,113,227,.14);
}
.resource-controls{
  padding:18px;
  border-radius:8px;
  background:#f5f5f7;
}
.teacher-card{
  min-height:180px;
  padding:22px;
}
.teacher-card h3,
.teacher-pack h2,
.pack-card h3{
  font-size:1.28rem;
}
.teacher-card p,
.teacher-pack p,
.pack-card p,
.classified-row p,
.resource-row p{
  color:#6e6e73;
}
table,
th,
td{
  border-color:rgba(0,0,0,.12);
}
th{
  background:#f5f5f7;
  font-family:inherit;
}
footer{
  color:#86868b;
  background:#f5f5f7;
}
@media(max-width:860px){
  body:not(.apple-home) header .hero-inner,body:not(.apple-home) .site-hero .hero-inner{min-height:0;padding:38px 24px 42px}
  body:not(.apple-home) header h1,body:not(.apple-home) .site-hero h1{font-size:3.2rem;line-height:1}
  body:not(.apple-home) header p:not(.kicker),body:not(.apple-home) .site-hero p:not(.kicker){font-size:1.08rem}
  .container{padding:24px}
  .cockpit-hero{min-height:0;margin:0 -24px 20px;padding:44px 24px 40px}
  .cockpit-hero::after{display:none}
  .cockpit-hero h1{font-size:3.55rem;line-height:.96}
  .cockpit-hero p:not(.kicker){font-size:1.08rem}
  .lesson-control{border-radius:8px}
  .cockpit-hero,.lesson-route,.mindmap-workspace,.textbook-lesson-head,.teacher-flow,.board-plan,.subtopic-header,.subtopic-shell,.learning-lane,.subtopic-actions,.section-browser-head,.section-layout,.resource-stage,.practice-section-grid,.video-link-form,.teaching-mini-grid{grid-template-columns:1fr}
  .cockpit-actions,.teacher-actions{justify-content:flex-start}
  .textbook-sections{justify-content:flex-start}
  .lesson-control{position:static;align-items:flex-start;flex-direction:column}
  .mode-tabs{width:100%}
  .mode-tab{min-width:0}
  .route-steps{grid-template-columns:1fr}
  .section-list{position:static}
  .section-detail-head{align-items:flex-start;flex-direction:column}
  .section-tabs{overflow:auto}
  .section-stats{width:100%}
  .resource-stage-main,.resource-stage-main iframe,.slide-empty{min-height:320px}
  .subtopic-detail{position:static}
  .subtopic-meter{text-align:left}
  .chapter-hero,.lesson-layout{grid-template-columns:1fr}
  .side-menu{position:static}
  .exam-strip{grid-template-columns:1fr}
  .topbar{align-items:flex-start;flex-direction:column}
  .map-canvas{aspect-ratio:auto;min-height:0;display:grid;gap:10px}
  .map-center,.map-node{position:static;transform:none!important;width:auto;min-height:auto}
  .map-node::before{display:none}
  .worked-layout{grid-template-columns:1fr}
  .lesson-mode{padding:18px}
  .lesson-deck-rail button{min-width:150px}
  .lesson-slide-inner{grid-template-columns:1fr;gap:18px}
  .lesson-visual{max-width:360px;min-height:280px}
  .visual-scene{min-height:200px}
  .lesson-slide h2{font-size:42px}
  .lesson-slide h2.compact-title{font-size:34px}
  .lesson-slide p,.lesson-slide li{font-size:20px}
  .lesson-point-grid{grid-template-columns:1fr}
  .lesson-point-card{min-height:0}
  .apple-nav div{gap:14px}
  .apple-nav a{font-size:11px}
  .apple-hero{padding-top:38px;min-height:auto}
  .apple-hero h1{font-size:48px}
  .apple-subtitle{font-size:21px}
  .device-shell{width:100%;border-radius:22px;padding:7px}
  .device-screen{grid-template-columns:1fr;min-height:360px}
  .screen-sidebar{display:none}
  .screen-main{padding:18px}
  .screen-header strong{font-size:28px}
  .screen-map{height:190px}
  .screen-cards{grid-template-columns:1fr}
  .apple-overview{grid-template-columns:1fr}
  .apple-overview h2{font-size:34px}
  .apple-feature-grid{grid-template-columns:1fr}
  .resource-controls,.resource-row{grid-template-columns:1fr}
  .classified-row,.classified-mini-row{grid-template-columns:1fr}
  .resource-actions{justify-content:flex-start}
  .summary-columns,.one-page-grid{grid-template-columns:1fr}
}
@media(max-height:760px){
  .lesson-mode{padding:10px 16px}
  .lesson-top strong{font-size:.74rem}
  .lesson-deck-rail{padding:8px 0}
  .lesson-deck-rail button{min-height:58px;min-width:148px;padding:8px}
  .lesson-deck-rail span{width:28px;height:28px}
  .lesson-deck-rail small{display:none}
  .lesson-slide{padding:8px 0}
  .lesson-slide-inner{grid-template-columns:minmax(0,1fr) minmax(220px,300px);gap:22px}
  .lesson-slide h2{font-size:3rem}
  .lesson-slide h2.compact-title{font-size:2.45rem}
  .lesson-slide p,.lesson-slide li{font-size:1.08rem}
  .lesson-meta-row{margin-bottom:8px}
  .lesson-meta-row span{min-height:24px;font-size:.66rem}
  .lesson-point-grid{gap:8px;margin-top:12px}
  .lesson-point-card{min-height:0;padding:10px}
  .lesson-point-card p{font-size:.95rem}
  .lesson-lead{margin-top:12px;padding:12px 14px;font-size:1.05rem!important}
  .lesson-source{margin-top:12px;font-size:12px!important}
  .lesson-visual{min-height:260px}
  .visual-scene{min-height:190px;padding:18px}
  .lesson-controls .btn{min-height:40px;padding:9px 14px}
}
@media(max-height:620px){
  .lesson-slide-inner{grid-template-columns:1fr}
  .lesson-visual{display:none}
}
@media(min-width:1200px){
  .apple-hero h1{font-size:104px}
  .apple-overview h2{font-size:64px}
}
@media print{
  body{background:#fff;color:#000}
  body::before,header,.side-menu,.toolbar,.btn,.print-btn,footer,.apple-nav{display:none!important}
  .container{max-width:none;padding:0}
  .panel,.teacher-pack,.card{box-shadow:none;border-color:#999}
  details{break-inside:avoid}
  details:not([open]) > *:not(summary){display:block}
  a{text-decoration:none;color:#000}
}