:root{--bg:#070817;--text:#fff;--muted:#cbd5e1;--card:rgba(255,255,255,.12);--border:rgba(255,255,255,.18);--accent:#7c3aed;--accent2:#06b6d4;--good:#22c55e;--warn:#f97316;--shadow:0 30px 80px rgba(0,0,0,.35)}
[data-theme="light"]{--bg:#f8fafc;--text:#0f172a;--muted:#475569;--card:rgba(255,255,255,.78);--border:rgba(15,23,42,.12);--shadow:0 20px 60px rgba(15,23,42,.15)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,Arial,sans-serif;background:var(--bg);color:var(--text);overflow-x:hidden}a{color:inherit;text-decoration:none}.bg{position:fixed;inset:0;z-index:-2;background:radial-gradient(circle at 15% 10%,rgba(124,58,237,.6),transparent 28%),radial-gradient(circle at 85% 15%,rgba(6,182,212,.5),transparent 30%),radial-gradient(circle at 50% 90%,rgba(249,115,22,.35),transparent 35%),var(--bg);animation:hue 14s infinite alternate}.orb{position:fixed;border-radius:999px;filter:blur(10px);opacity:.55;z-index:-1;animation:float 7s ease-in-out infinite}.orb.one{width:210px;height:210px;background:#7c3aed;left:5%;top:35%}.orb.two{width:150px;height:150px;background:#06b6d4;right:8%;top:50%;animation-delay:1.3s}.orb.three{width:110px;height:110px;background:#f97316;left:55%;top:12%;animation-delay:2.1s}.nav{max-width:1180px;margin:auto;padding:22px 20px;display:flex;align-items:center;justify-content:space-between;gap:20px}.logo{font-weight:900;font-size:28px;letter-spacing:-.04em}.logo span{background:linear-gradient(90deg,#fff,#67e8f9,#fbbf24);-webkit-background-clip:text;color:transparent}.links{display:flex;gap:18px;align-items:center;flex-wrap:wrap}.links a,.theme-toggle{padding:10px 14px;border:1px solid var(--border);border-radius:999px;background:rgba(255,255,255,.08);backdrop-filter:blur(14px);font-weight:700;color:var(--text);cursor:pointer}.links a:hover,.theme-toggle:hover{transform:translateY(-2px);background:rgba(255,255,255,.18)}.container{max-width:1180px;margin:auto;padding:50px 20px}.hero{min-height:76vh;display:grid;grid-template-columns:1.1fr .9fr;align-items:center;gap:40px}.eyebrow{display:inline-flex;gap:8px;align-items:center;padding:9px 14px;border:1px solid var(--border);border-radius:999px;background:var(--card);backdrop-filter:blur(16px);color:var(--muted);font-weight:800}.h1{font-size:clamp(44px,7vw,88px);line-height:.95;letter-spacing:-.07em;margin:22px 0}.grad{background:linear-gradient(90deg,#67e8f9,#a78bfa,#fbbf24);-webkit-background-clip:text;color:transparent}.lead{font-size:clamp(18px,2vw,23px);line-height:1.7;color:var(--muted);max-width:760px}.cta{display:flex;gap:14px;flex-wrap:wrap;margin-top:30px}.btn{display:inline-flex;align-items:center;gap:8px;padding:15px 22px;border-radius:999px;background:#fff;color:#312e81;font-weight:900;box-shadow:var(--shadow)}.btn.secondary{background:var(--card);color:var(--text);border:1px solid var(--border);backdrop-filter:blur(15px)}.visual{position:relative;min-height:430px;border:1px solid var(--border);border-radius:34px;background:linear-gradient(135deg,rgba(255,255,255,.18),rgba(255,255,255,.06));box-shadow:var(--shadow);backdrop-filter:blur(18px);overflow:hidden}.formula{position:absolute;font-weight:900;color:rgba(255,255,255,.72);animation:drift 8s ease-in-out infinite}.f1{font-size:62px;left:12%;top:12%}.f2{font-size:40px;right:13%;top:25%;animation-delay:1s}.f3{font-size:52px;left:20%;bottom:18%;animation-delay:2s}.f4{font-size:30px;right:18%;bottom:15%;animation-delay:3s}.glass{position:absolute;inset:auto 28px 28px 28px;padding:24px;border-radius:26px;background:rgba(15,23,42,.55);border:1px solid rgba(255,255,255,.18);backdrop-filter:blur(16px)}.section-title{font-size:clamp(34px,4vw,58px);letter-spacing:-.05em;margin:0 0 14px}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:22px}.card{padding:26px;border-radius:26px;background:var(--card);border:1px solid var(--border);backdrop-filter:blur(16px);box-shadow:0 16px 40px rgba(0,0,0,.16);transition:.3s;position:relative;overflow:hidden}.card:before{content:"";position:absolute;inset:-80px auto auto -80px;width:160px;height:160px;background:rgba(103,232,249,.18);border-radius:50%;transition:.3s}.card:hover{transform:translateY(-10px) scale(1.015);background:rgba(255,255,255,.16)}.card h3{font-size:24px;margin:0 0 10px}.card p,.card li{color:var(--muted);line-height:1.65}.pill{display:inline-block;padding:6px 10px;border:1px solid var(--border);border-radius:999px;color:var(--muted);font-size:13px;margin:4px}.progress{height:10px;border-radius:999px;background:rgba(255,255,255,.16);overflow:hidden;margin:18px 0}.progress span{display:block;height:100%;background:linear-gradient(90deg,#06b6d4,#a78bfa,#22c55e);border-radius:inherit}.topic-list{display:grid;gap:14px}.lesson-row{display:flex;align-items:center;justify-content:space-between;gap:14px;padding:18px;border-radius:18px;background:rgba(255,255,255,.08);border:1px solid var(--border)}.lesson-row:hover{background:rgba(255,255,255,.16);transform:translateX(6px)}.code{font-weight:900;color:#67e8f9}.footer{text-align:center;color:var(--muted);padding:50px 20px}.reveal{opacity:0;transform:translateY(26px);transition:1s}.reveal.show{opacity:1;transform:none}.search{width:100%;padding:17px 20px;border-radius:999px;border:1px solid var(--border);background:var(--card);color:var(--text);font-size:17px;outline:none}.breadcrumb{color:var(--muted);font-weight:700;margin-bottom:20px}.breadcrumb a{text-decoration:underline;text-underline-offset:4px}@keyframes float{0%,100%{transform:translateY(0)}50%{transform:translateY(-28px)}}@keyframes drift{0%,100%{transform:translate(0,0) rotate(0)}50%{transform:translate(18px,-22px) rotate(4deg)}}@keyframes hue{0%{filter:hue-rotate(0)}100%{filter:hue-rotate(25deg)}}@media(max-width:850px){.hero{grid-template-columns:1fr;min-height:auto}.visual{min-height:320px}.nav{align-items:flex-start;flex-direction:column}.links{gap:8px}.links a{font-size:14px;padding:8px 10px}.lesson-row{align-items:flex-start;flex-direction:column}}

/* Mathiation interactive lesson additions */
.lesson-hero{padding-top:28px}.lesson-meta{display:flex;gap:10px;flex-wrap:wrap;margin:20px 0}.lesson-shell{display:grid;grid-template-columns:1.1fr .9fr;gap:22px;align-items:start}.video-stage{min-height:420px;border-radius:30px;border:1px solid var(--border);background:linear-gradient(135deg,rgba(2,6,23,.72),rgba(124,58,237,.22));box-shadow:var(--shadow);position:relative;overflow:hidden;padding:26px}.stage-title{position:absolute;top:22px;left:24px;font-weight:900;color:#67e8f9;z-index:3}.math-board{position:absolute;inset:76px 24px 96px 24px;border-radius:24px;background:rgba(255,255,255,.08);border:1px solid var(--border);display:flex;align-items:center;justify-content:center;flex-direction:column;text-align:center;padding:20px}.proof-line{opacity:0;transform:translateY(18px) scale(.98);transition:.55s ease;font-size:clamp(22px,3vw,38px);font-weight:900;margin:8px 0}.proof-line.active{opacity:1;transform:none}.highlight-blue{color:#67e8f9}.highlight-green{color:#86efac}.highlight-orange{color:#fdba74}.highlight-purple{color:#c4b5fd}.video-controls{position:absolute;bottom:22px;left:24px;right:24px;display:flex;gap:12px;flex-wrap:wrap;align-items:center}.mini-progress{height:10px;flex:1;min-width:160px;border-radius:999px;background:rgba(255,255,255,.16);overflow:hidden}.mini-progress span{display:block;height:100%;width:0;background:linear-gradient(90deg,#06b6d4,#a78bfa,#22c55e);transition:.4s}.lesson-panel{display:grid;gap:16px}.step-card{padding:20px;border-radius:22px;border:1px solid var(--border);background:var(--card);backdrop-filter:blur(16px)}.step-card h3{margin:0 0 8px}.example-question{font-size:22px;line-height:1.6}.quiz-option{display:block;width:100%;text-align:left;margin:10px 0;padding:14px 16px;border-radius:16px;border:1px solid var(--border);background:rgba(255,255,255,.08);color:var(--text);cursor:pointer;font-weight:800}.quiz-option:hover{background:rgba(255,255,255,.18);transform:translateX(4px)}.quiz-feedback{margin-top:10px;font-weight:900;min-height:24px}.timeline{display:grid;gap:12px;margin-top:18px}.timeline-step{display:flex;gap:12px;align-items:flex-start}.timeline-dot{width:28px;height:28px;border-radius:50%;background:linear-gradient(135deg,#06b6d4,#7c3aed);display:grid;place-items:center;font-weight:900;flex:0 0 auto}.formula-rain{position:absolute;inset:0;pointer-events:none;opacity:.25}.formula-rain span{position:absolute;font-weight:900;animation:drift 7s ease-in-out infinite}.script-box{white-space:pre-wrap;line-height:1.7;color:var(--muted)}
@media(max-width:900px){.lesson-shell{grid-template-columns:1fr}.video-stage{min-height:380px}}

.lesson-video video {
  width: 100%;
  border-radius: 24px;
  box-shadow: 0 30px 80px rgba(0,0,0,.45);
  border: 2px solid rgba(255,255,255,.12);
}