/* IB Chemistry DP · Modern Teaching Resource · Shared Design System */
:root{
  --bg:#0a0e1a; --bg-2:#111729;
  --ink:#f3f6ff; --ink-2:#a9b3cf; --ink-3:#6e789b;
  --card:rgba(255,255,255,.04); --card-line:rgba(255,255,255,.08); --card-hover:rgba(255,255,255,.06);

  /* Chemistry default brand = warm amber/orange */
  --accent:#f59e0b;
  --accent-2:#ef4444;
  --accent-3:#fb923c;
  --accent-soft:rgba(245,158,11,.14);
  --accent-glow:rgba(245,158,11,.4);
  --accent-text:#fcd34d;
  --bg-tint-1:rgba(245,158,11,.18);
  --bg-tint-2:rgba(239,68,68,.22);
}

/* Theme F (Foundations: Units 1-3) = electric blue */
body[data-theme="f"]{
  --accent:#3b82f6; --accent-2:#06b6d4; --accent-3:#22d3ee;
  --accent-soft:rgba(59,130,246,.14); --accent-glow:rgba(59,130,246,.4); --accent-text:#93c5fd;
  --bg-tint-1:rgba(59,130,246,.18); --bg-tint-2:rgba(6,182,212,.22);
}
/* Theme R (Reactivity: Units 4, 5, 9, 10) = warm flame */
body[data-theme="r"]{
  --accent:#f97316; --accent-2:#ef4444; --accent-3:#facc15;
  --accent-soft:rgba(249,115,22,.14); --accent-glow:rgba(249,115,22,.4); --accent-text:#fdba74;
  --bg-tint-1:rgba(249,115,22,.18); --bg-tint-2:rgba(239,68,68,.22);
}
/* Theme S (Structure: Units 6, 7) = electric violet */
body[data-theme="s"]{
  --accent:#a78bfa; --accent-2:#d946ef; --accent-3:#f472b6;
  --accent-soft:rgba(167,139,250,.14); --accent-glow:rgba(167,139,250,.4); --accent-text:#c4b5fd;
  --bg-tint-1:rgba(167,139,250,.18); --bg-tint-2:rgba(217,70,239,.22);
}
/* Theme O (Organic: Units 8, 11) = emerald */
body[data-theme="o"]{
  --accent:#10b981; --accent-2:#34d399; --accent-3:#84cc16;
  --accent-soft:rgba(16,185,129,.14); --accent-glow:rgba(16,185,129,.4); --accent-text:#6ee7b7;
  --bg-tint-1:rgba(16,185,129,.18); --bg-tint-2:rgba(132,204,22,.22);
}

*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--bg);color:var(--ink);font-family:"Inter",-apple-system,system-ui,"Segoe UI",sans-serif;font-size:17px;line-height:1.6;-webkit-font-smoothing:antialiased}
body{background:
  radial-gradient(900px 600px at 80% -10%, var(--bg-tint-1), transparent 60%),
  radial-gradient(900px 600px at -10% 30%, var(--bg-tint-2), transparent 60%),
  var(--bg); min-height:100vh}
a{color:var(--accent);text-decoration:none}
img,svg{max-width:100%;display:block}
::selection{background:var(--accent);color:#001}

.topnav{position:sticky;top:0;z-index:50;background:rgba(10,14,26,.7);backdrop-filter:saturate(180%) blur(14px);border-bottom:1px solid var(--card-line)}
.topnav-inner{max-width:1320px;margin:0 auto;padding:14px 28px;display:flex;align-items:center;gap:24px;flex-wrap:wrap}
.brand{font-weight:800;font-size:15px;letter-spacing:-.01em;display:flex;align-items:center;gap:10px;color:var(--ink)}
.brand .logo{width:30px;height:30px;border-radius:9px;background:linear-gradient(135deg,var(--accent),var(--accent-2));display:grid;place-items:center;color:#001;font-weight:900;font-size:14px}
.brand .label{display:flex;flex-direction:column;line-height:1.1}
.brand .label small{font-size:10px;color:var(--ink-3);font-weight:600;letter-spacing:.14em;text-transform:uppercase;margin-top:1px}
.crumbs{font-size:13px;color:var(--ink-2);font-weight:500;flex:1}
.crumbs a{color:var(--ink-2);border-bottom:1px solid transparent;padding-bottom:2px}
.crumbs a:hover{color:var(--ink);border-bottom-color:var(--accent)}
.crumbs .sep{margin:0 8px;color:var(--ink-3)}
.crumbs b{color:var(--ink);font-weight:600}
.btn{display:inline-flex;align-items:center;gap:8px;padding:9px 16px;border-radius:10px;font-weight:600;font-size:13px;border:1px solid var(--card-line);background:var(--card);color:var(--ink);transition:transform .2s,background .2s,border-color .2s;cursor:pointer;font-family:inherit;text-decoration:none}
.btn:hover{transform:translateY(-1px);background:var(--card-hover);border-color:var(--accent)}
.btn.primary{background:linear-gradient(120deg,var(--accent),var(--accent-2));border:none;color:#fff;box-shadow:0 12px 30px -10px var(--accent-glow)}
.btn.primary:hover{filter:brightness(1.1)}

section{padding:120px 6vw;max-width:1280px;margin:0 auto;position:relative}
section.tight{padding:60px 6vw}
.section-head{margin-bottom:48px;max-width:780px}
.section-head .num{font-size:13px;font-weight:700;letter-spacing:.2em;color:var(--accent-text);text-transform:uppercase}
.section-head h2{font-size:clamp(36px,5vw,68px);font-weight:800;letter-spacing:-.02em;line-height:1.05;margin:14px 0 14px}
.section-head p.lede{font-size:20px;color:var(--ink-2);margin:0;line-height:1.5}
.grad-text{background:linear-gradient(120deg,var(--accent),var(--accent-2));-webkit-background-clip:text;background-clip:text;color:transparent}
.grad-text-3{background:linear-gradient(120deg,var(--accent),var(--accent-2),var(--accent-3));-webkit-background-clip:text;background-clip:text;color:transparent}

.hero{min-height:96vh;display:flex;align-items:center;padding:60px 6vw;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;inset:0;background:radial-gradient(circle at 70% 50%,var(--accent-soft),transparent 50%);filter:blur(20px);z-index:0}
.hero-inner{position:relative;z-index:1;max-width:1280px;margin:0 auto;width:100%;display:grid;grid-template-columns:1.2fr 1fr;gap:48px;align-items:center}
.eyebrow{display:inline-flex;align-items:center;gap:10px;padding:8px 16px;border:1px solid var(--card-line);border-radius:999px;font-size:12px;letter-spacing:.18em;text-transform:uppercase;color:var(--accent-text);font-weight:600;backdrop-filter:blur(8px);background:rgba(10,14,26,.4)}
.eyebrow .dot{width:8px;height:8px;border-radius:50%;background:var(--accent);box-shadow:0 0 18px var(--accent-glow);animation:pulse 2s ease-in-out infinite}
@keyframes pulse{50%{opacity:.4;transform:scale(.8)}}
h1.mega{font-size:clamp(56px,9vw,144px);font-weight:800;line-height:.95;letter-spacing:-.04em;margin:24px 0 28px}
.hero p.tag{font-size:22px;color:var(--ink-2);max-width:560px;margin:0 0 32px;line-height:1.4}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap}
.stats{display:flex;gap:30px;margin-top:38px;flex-wrap:wrap}
.stats div b{display:block;font-size:32px;font-weight:800;background:linear-gradient(120deg,var(--accent),var(--accent-2));-webkit-background-clip:text;color:transparent;letter-spacing:-.03em;line-height:1.1}
.stats div span{color:var(--ink-2);font-size:12px;text-transform:uppercase;letter-spacing:.1em;font-weight:600}
.hero-visual{position:relative;width:100%;aspect-ratio:1;max-width:520px;margin:0 auto}
.hero-visual svg{width:100%;height:100%;filter:drop-shadow(0 30px 60px var(--accent-glow))}
.hero-visual .ring{position:absolute;inset:0;border-radius:50%;border:1px dashed rgba(255,255,255,.12);animation:spin 60s linear infinite;pointer-events:none}
.hero-visual .ring.r2{inset:-30px;border-color:rgba(255,255,255,.06);animation-duration:90s;animation-direction:reverse}
@keyframes spin{to{transform:rotate(360deg)}}

.guiding{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:18px;margin-top:36px}
.gq{background:linear-gradient(140deg,var(--accent-soft),rgba(99,102,241,.04));border:1px solid var(--card-line);border-radius:22px;padding:30px 32px;position:relative;overflow:hidden}
.gq::before{content:attr(data-n);position:absolute;top:-14px;right:18px;font-size:160px;font-weight:900;color:rgba(255,255,255,.04);line-height:1}
.gq h3{margin:0 0 8px;font-size:11px;letter-spacing:.16em;color:var(--accent-text);text-transform:uppercase;font-weight:700}
.gq p{margin:0;font-size:21px;line-height:1.35;font-weight:500}

.grid{display:grid;gap:16px}
.grid.c2{grid-template-columns:repeat(2,1fr)}
.grid.c3{grid-template-columns:repeat(3,1fr)}
.grid.c4{grid-template-columns:repeat(4,1fr)}
.card{background:var(--card);border:1px solid var(--card-line);border-radius:22px;padding:26px 28px;transition:transform .25s,border-color .25s,background .25s;position:relative;overflow:hidden;display:flex;flex-direction:column;text-decoration:none;color:inherit}
.card:hover{transform:translateY(-3px);border-color:var(--accent);background:var(--card-hover)}
.card.linked::after{content:"→";position:absolute;top:22px;right:22px;font-size:18px;color:var(--ink-3);transition:transform .2s,color .2s}
.card.linked:hover::after{color:var(--accent);transform:translateX(2px)}
.card .pill{display:inline-block;padding:4px 10px;background:var(--accent-soft);color:var(--accent-text);border-radius:8px;font-size:10px;letter-spacing:.12em;text-transform:uppercase;font-weight:700;margin-bottom:14px;align-self:flex-start}
.card .pill.hl{background:rgba(167,139,250,.16);color:#c4b5fd}
.card h3{margin:0 0 10px;font-size:20px;font-weight:700;letter-spacing:-.01em;line-height:1.2}
.card p{margin:0;color:var(--ink-2);font-size:14px;line-height:1.55;flex:1}
.card .meta{margin-top:14px;font-size:12px;color:var(--ink-3);letter-spacing:.04em;display:flex;gap:14px}
.card .meta b{color:var(--accent-text);font-weight:600}

.deep{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:center;margin-top:50px}
.deep .frame{background:linear-gradient(140deg,var(--accent-soft),rgba(99,102,241,.04));border:1px solid var(--card-line);border-radius:28px;padding:32px}
.deep .frame svg{width:100%;height:auto;display:block}
.deep .legend{display:flex;flex-direction:column;gap:14px}
.deep .legend .row{display:flex;gap:14px;align-items:flex-start;padding:18px;border-left:3px solid var(--accent);background:rgba(255,255,255,.02);border-radius:0 12px 12px 0}
.deep .legend .row b{display:block;font-size:13px;color:var(--accent-text);text-transform:uppercase;letter-spacing:.08em;margin-bottom:4px;font-weight:700}
.deep .legend .row span{color:var(--ink-2);font-size:15px;line-height:1.5}

.props{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-top:36px}
.prop{padding:28px 22px;border-radius:20px;background:var(--card);border:1px solid var(--card-line);position:relative;overflow:hidden;transition:transform .25s,border-color .25s}
.prop:hover{transform:translateY(-3px);border-color:var(--accent)}
.prop .icon{font-size:34px;margin-bottom:14px;display:block;line-height:1}
.prop h4{margin:0 0 6px;font-size:17px;font-weight:700;letter-spacing:-.01em}
.prop p{margin:0;color:var(--ink-2);font-size:13px;line-height:1.5}
.prop:nth-child(4n+1){background:linear-gradient(140deg,var(--accent-soft),transparent)}
.prop:nth-child(4n+2){background:linear-gradient(140deg,rgba(99,102,241,.14),transparent)}
.prop:nth-child(4n+3){background:linear-gradient(140deg,rgba(236,72,153,.14),transparent)}
.prop:nth-child(4n+4){background:linear-gradient(140deg,rgba(251,191,36,.14),transparent)}

.vocab{display:flex;flex-wrap:wrap;gap:8px;margin-top:24px}
.vocab span{padding:9px 15px;border-radius:999px;background:var(--card);border:1px solid var(--card-line);font-size:13px;color:var(--ink-2);transition:all .2s;cursor:pointer;font-weight:500;user-select:none;font-family:inherit}
.vocab span:hover{background:var(--accent-soft);color:var(--accent-text);border-color:var(--accent);transform:translateY(-2px)}
.vocab span.active{background:linear-gradient(120deg,var(--accent),var(--accent-2));color:#001;border-color:transparent;font-weight:700}
.vocab span[data-no-def]{cursor:default}
.vocab span[data-no-def]:hover{background:var(--card);color:var(--ink-2);border-color:var(--card-line);transform:none}

.def-panel{margin-top:22px;background:linear-gradient(140deg,var(--accent-soft),rgba(99,102,241,.05));border:1px solid var(--card-line);border-radius:18px;padding:24px 28px;display:none;animation:defin .25s ease}
.def-panel.shown{display:block}
.def-panel .def-head{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-bottom:8px}
.def-panel h4{margin:0;font-size:22px;font-weight:800;letter-spacing:-.01em;color:var(--ink);text-transform:lowercase}
.def-panel h4::first-letter{text-transform:uppercase}
.def-panel .def-close{background:transparent;border:1px solid var(--card-line);color:var(--ink-2);width:28px;height:28px;border-radius:8px;cursor:pointer;font-family:inherit;font-size:14px;display:grid;place-items:center;transition:all .15s}
.def-panel .def-close:hover{border-color:var(--accent);color:var(--accent)}
.def-panel p{margin:0;font-size:16px;line-height:1.55;color:var(--ink)}
.def-panel .def-meta{margin-top:10px;font-size:12px;color:var(--ink-3);font-family:ui-monospace,Menlo,Consolas,monospace;letter-spacing:.04em}
@keyframes defin{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:none}}

.callout{background:linear-gradient(140deg,var(--accent-soft),rgba(99,102,241,.04));border:1px solid var(--card-line);border-left:4px solid var(--accent);border-radius:14px;padding:22px 26px;margin:28px 0;display:grid;grid-template-columns:auto 1fr;gap:16px;align-items:center}
.callout .icon{font-size:32px;line-height:1}
.callout h4{margin:0 0 4px;font-size:13px;letter-spacing:.14em;text-transform:uppercase;color:var(--accent-text);font-weight:700}
.callout p{margin:0;font-size:16px;color:var(--ink);line-height:1.5;max-width:none}
.callout.warn{border-left-color:#f59e0b}
.callout.warn h4{color:#fcd34d}

.factstrip{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:14px;margin:32px 0}
.factbox{background:var(--card);border:1px solid var(--card-line);border-radius:18px;padding:22px;position:relative;overflow:hidden}
.factbox .label{font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--ink-3);font-weight:700;margin-bottom:8px}
.factbox .value{font-size:34px;font-weight:800;background:linear-gradient(120deg,var(--accent),var(--accent-2));-webkit-background-clip:text;color:transparent;letter-spacing:-.02em;line-height:1;margin-bottom:6px;font-variant-numeric:tabular-nums}
.factbox .value small{font-size:14px;color:var(--ink-2);font-weight:600;-webkit-text-fill-color:initial;background:none;margin-left:4px}
.factbox p{margin:0;font-size:13px;color:var(--ink-2);line-height:1.5}

.hl-zone{padding:80px 6vw;background:
  radial-gradient(800px 500px at 50% 0%, rgba(167,139,250,.16), transparent 60%),
  linear-gradient(180deg,rgba(99,102,241,.06),transparent);
  border-top:1px solid var(--card-line);border-bottom:1px solid var(--card-line);margin-top:60px}
.hl-zone .inner{max-width:1280px;margin:0 auto}
.hl-tag{display:inline-block;padding:6px 14px;border-radius:999px;background:linear-gradient(120deg,#a78bfa,#ec4899);color:#fff;font-size:11px;font-weight:800;letter-spacing:.16em;text-transform:uppercase}

.linking-cta{margin:80px auto 0;padding:46px 48px;text-align:center;border:1px solid var(--card-line);border-radius:28px;background:linear-gradient(140deg,var(--accent-soft),rgba(236,72,153,.06));max-width:1100px}
.linking-cta h3{margin:0 0 14px;font-size:13px;letter-spacing:.18em;text-transform:uppercase;color:var(--accent-text);font-weight:700}
.linking-cta p{margin:8px 0;font-size:21px;font-weight:500;color:var(--ink);line-height:1.45}

.pager{display:grid;grid-template-columns:1fr 1fr;gap:16px;max-width:1280px;margin:60px auto 80px;padding:0 6vw}
.pager a{display:block;padding:22px 26px;background:var(--card);border:1px solid var(--card-line);border-radius:18px;color:var(--ink);transition:all .2s;text-decoration:none}
.pager a:hover{border-color:var(--accent);transform:translateY(-2px)}
.pager small{font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-3);font-weight:700;display:block;margin-bottom:6px}
.pager b{font-size:17px;font-weight:700;letter-spacing:-.01em;display:block}
.pager span{font-size:13px;color:var(--ink-2);display:block;margin-top:3px}
.pager .next{text-align:right}
.pager .prev::before{content:"← ";color:var(--accent-text)}
.pager .next::after{content:" →";color:var(--accent-text)}
.pager .blank{visibility:hidden}

footer.site-footer{padding:60px 6vw 80px;text-align:center;color:var(--ink-3);font-size:13px;border-top:1px solid var(--card-line);margin-top:40px}

/* Lesson-by-lesson cards */
.lesson-card{background:linear-gradient(160deg,var(--accent-soft),rgba(99,102,241,.03));border:1px solid var(--card-line);border-radius:24px;padding:36px 36px 30px;margin:30px 0;scroll-margin-top:80px}
.lesson-head{margin-bottom:24px;border-bottom:1px solid var(--card-line);padding-bottom:18px}
.lesson-num{font-size:11px;letter-spacing:.18em;text-transform:uppercase;color:var(--accent-text);font-weight:800;margin-bottom:6px;display:flex;align-items:center;gap:10px}
.lesson-hl-pill{display:inline-block;padding:2px 9px;border-radius:999px;background:linear-gradient(120deg,#a78bfa,#ec4899);color:#fff;font-size:9px;font-weight:800;letter-spacing:.16em;text-transform:uppercase}
.lesson-title{font-size:clamp(26px,3.5vw,40px);font-weight:800;letter-spacing:-.02em;line-height:1.1;margin:6px 0 14px}
.syllabus-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px}
.syllabus-chip{display:inline-block;padding:4px 11px;border-radius:8px;background:rgba(255,255,255,.06);border:1px solid var(--card-line);font-size:11px;color:var(--ink-2);font-weight:600;font-family:ui-monospace,Menlo,Consolas,monospace}
.outcomes{margin:18px 0 22px;padding:18px 22px;background:rgba(255,255,255,.03);border-left:3px solid var(--accent);border-radius:0 14px 14px 0}
.outcomes h4{margin:0 0 8px;font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--accent-text);font-weight:800}
.outcomes ul{margin:0;padding-left:20px;color:var(--ink);font-size:14px;line-height:1.6}
.lesson-content{font-size:16px;line-height:1.6;color:var(--ink)}
.lesson-content p{margin:0 0 14px}
.lesson-content h3{font-size:18px;margin:28px 0 12px;font-weight:700;letter-spacing:-.01em}
.lesson-content h4{font-size:15px;margin:20px 0 8px;font-weight:700;color:var(--accent-text);letter-spacing:.04em}
.lesson-content code{font-family:ui-monospace,Menlo,Consolas,monospace;font-size:14px;padding:2px 6px;background:rgba(255,255,255,.06);border-radius:4px;color:#fcd34d}
.worked-ex{background:linear-gradient(140deg,rgba(34,211,238,.10),rgba(99,102,241,.04));border:1px solid var(--card-line);border-radius:16px;padding:22px 26px;margin:24px 0}
.worked-head{display:flex;align-items:center;gap:12px;margin-bottom:12px}
.worked-label{display:inline-block;padding:4px 10px;border-radius:6px;background:rgba(34,211,238,.20);color:#67e8f9;font-size:10px;font-weight:800;letter-spacing:.14em;text-transform:uppercase}
.worked-head h4{margin:0;font-size:17px;font-weight:700;color:var(--ink)}
.worked-problem{font-size:15px;line-height:1.55;color:var(--ink);margin-bottom:10px}
.worked-solution{font-size:15px;line-height:1.55;color:var(--ink);padding:12px 16px;background:rgba(0,0,0,.25);border-radius:10px;font-family:ui-monospace,Menlo,Consolas,monospace}
.worked-solution b{font-family:"Inter",sans-serif;color:var(--accent-text)}
.practice{margin-top:24px;padding:22px 26px;background:rgba(255,255,255,.025);border:1px solid var(--card-line);border-radius:16px}
.practice h4{margin:0 0 12px;font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--accent-text);font-weight:800}
.questions{margin:0;padding-left:24px;color:var(--ink)}
.questions li{margin:0 0 14px;font-size:15px;line-height:1.6}
.qa-q{display:inline-block}
.qa-answer{margin-top:8px;font-size:14px}
.qa-answer summary{cursor:pointer;color:var(--accent-text);font-weight:600;font-size:12px;letter-spacing:.08em;text-transform:uppercase;outline:none;list-style:none;padding:6px 12px;background:rgba(255,255,255,.04);border-radius:6px;display:inline-block;border:1px solid var(--card-line);user-select:none}
.qa-answer summary::-webkit-details-marker{display:none}
.qa-answer summary:hover{background:var(--accent-soft);color:var(--accent)}
.qa-answer[open] summary{margin-bottom:10px}
.qa-answer > div{padding:12px 16px;background:rgba(0,0,0,.25);border-radius:8px;font-size:14px;line-height:1.55;color:var(--ink)}

/* 3D molecule viewer (3Dmol.js) */
.mol3d{position:relative;width:100%;height:260px;margin:0 auto 8px;cursor:grab;border-radius:14px;overflow:hidden;background:radial-gradient(circle at 50% 50%,rgba(255,255,255,.06),transparent 75%)}
.mol3d:active{cursor:grabbing}
.mol3d canvas{background:transparent !important;outline:none}
.mol3d-hint{font-size:10px;letter-spacing:.14em;text-transform:uppercase;color:var(--ink-3);font-weight:700;text-align:center;margin:0 0 8px}

/* Unit grid on hub */
.unit-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:18px;margin-top:32px}
.unit-card{position:relative;overflow:hidden;border-radius:24px;padding:34px 32px;background:var(--card);border:1px solid var(--card-line);transition:transform .25s,border-color .25s;display:flex;flex-direction:column;justify-content:space-between;text-decoration:none;color:var(--ink);min-height:260px}
.unit-card:hover{transform:translateY(-4px)}
.unit-card[data-theme="f"]{background:linear-gradient(160deg,rgba(59,130,246,.18),rgba(6,182,212,.10),var(--card))}
.unit-card[data-theme="f"]:hover{border-color:#3b82f6}
.unit-card[data-theme="r"]{background:linear-gradient(160deg,rgba(249,115,22,.18),rgba(239,68,68,.10),var(--card))}
.unit-card[data-theme="r"]:hover{border-color:#f97316}
.unit-card[data-theme="s"]{background:linear-gradient(160deg,rgba(167,139,250,.18),rgba(217,70,239,.10),var(--card))}
.unit-card[data-theme="s"]:hover{border-color:#a78bfa}
.unit-card[data-theme="o"]{background:linear-gradient(160deg,rgba(16,185,129,.18),rgba(132,204,22,.10),var(--card))}
.unit-card[data-theme="o"]:hover{border-color:#10b981}
.unit-card .number{font-size:76px;font-weight:900;line-height:.85;letter-spacing:-.05em;margin:0 0 6px;background:linear-gradient(120deg,#fff,rgba(255,255,255,.45));-webkit-background-clip:text;color:transparent}
.unit-card h3{font-size:22px;font-weight:800;margin:0 0 8px;letter-spacing:-.01em;line-height:1.15}
.unit-card p{font-size:14px;color:var(--ink-2);margin:0 0 18px;line-height:1.5}
.unit-card .lesson-count{font-size:12px;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-3);font-weight:700}
.unit-card .lesson-count b{color:#fff;font-weight:800;font-size:14px;margin-right:4px}

@media (max-width:960px){
  section{padding:80px 5vw}
  .hero{padding:36px 5vw 50px;min-height:auto}
  .hero-inner{grid-template-columns:1fr;gap:30px}
  .hero-visual{max-width:340px}
  .deep{grid-template-columns:1fr}
  .grid.c2,.grid.c3,.grid.c4,.props{grid-template-columns:repeat(2,1fr)}
  .topnav-inner{padding:12px 18px;gap:14px}
  .crumbs{font-size:12px;width:100%;order:3}
}
@media (max-width:560px){
  .grid.c2,.grid.c3,.grid.c4,.props{grid-template-columns:1fr}
  h1.mega{font-size:44px}
  .pager{grid-template-columns:1fr}
}