:root{--bg:#f7fbff;--card:#fff;--ink:#0f172a;--muted:#64748b;--primary:#2563eb;--primary2:#06b6d4;--soft:#e0f2fe;--line:#dbeafe;--good:#059669;--bad:#dc2626;--shadow:0 20px 60px rgba(15,23,42,.10)}*{box-sizing:border-box}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Arial,sans-serif;background:var(--bg);color:var(--ink);line-height:1.6}.hero{background:radial-gradient(circle at 20% 20%,#38bdf8 0,#2563eb 35%,#111827 100%);color:white;padding:22px 5vw 70px}.nav{display:flex;justify-content:space-between;align-items:center;gap:20px}.brand{font-weight:900;font-size:22px}.navlinks{display:flex;gap:16px;flex-wrap:wrap}.navlinks a{color:#dbeafe;text-decoration:none;font-weight:700;font-size:14px}.hero-content{max-width:900px;padding:70px 0 30px}.badge{display:inline-block;background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.25);padding:8px 14px;border-radius:999px;font-weight:800}.hero h1{font-size:clamp(38px,6vw,76px);line-height:1;margin:18px 0}.hero p{max-width:760px;color:#e0f2fe;font-size:18px}.btn{display:inline-block;border:0;border-radius:14px;padding:13px 18px;background:linear-gradient(135deg,var(--primary),var(--primary2));color:white;text-decoration:none;font-weight:900;cursor:pointer}.btn.secondary{background:rgba(255,255,255,.13);border:1px solid rgba(255,255,255,.25)}.btn.small{padding:10px 14px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:24px}main{padding:0 5vw}.grid{display:grid;gap:18px}.stats{grid-template-columns:repeat(4,1fr);margin-top:-42px}.stats article,.card,.note,.q-card,.flashcard,.timeline article{background:var(--card);border:1px solid var(--line);border-radius:24px;box-shadow:var(--shadow)}.stats article{padding:22px}.stats strong{font-size:34px;display:block;color:var(--primary)}.stats span{color:var(--muted);font-weight:700}.section{padding:65px 0}.section.soft{background:linear-gradient(180deg,transparent,#eff6ff,transparent);margin-left:-5vw;margin-right:-5vw;padding-left:5vw;padding-right:5vw}.section-title p{text-transform:uppercase;letter-spacing:.14em;color:var(--primary);font-weight:900;margin:0}.section-title h2{font-size:clamp(28px,4vw,46px);margin:8px 0 24px}.cards{display:grid;gap:20px}.cards.two{grid-template-columns:repeat(2,1fr)}.card{padding:26px}.card h3{margin-top:0}.card li{margin-bottom:8px}.search,select{width:100%;padding:14px 16px;border:1px solid #bfdbfe;border-radius:14px;background:white;font:inherit}.accordion{display:grid;gap:14px;margin-top:18px}.note{padding:0;overflow:hidden}.note button{width:100%;text-align:left;background:white;border:0;padding:20px 24px;font-size:18px;font-weight:900;cursor:pointer;color:var(--ink)}.note .body{display:none;padding:0 24px 24px;color:#334155}.note.open .body{display:block}.note .tag{display:inline-block;margin:8px 6px 0 0;background:#eff6ff;color:#1d4ed8;border-radius:999px;padding:4px 10px;font-weight:800;font-size:12px}.table-wrap{overflow:auto;background:white;border-radius:22px;box-shadow:var(--shadow);border:1px solid var(--line)}table{width:100%;border-collapse:collapse}th,td{padding:16px;border-bottom:1px solid var(--line);vertical-align:top}th{background:#dbeafe;text-align:left}.flashcards{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.flashcard{min-height:150px;padding:20px;cursor:pointer;perspective:1000px}.flashcard h3{margin:0 0 10px}.flashcard .answer{display:none;color:#334155}.flashcard.flipped .answer{display:block}.flashcard.flipped .front{display:none}.toolbar{display:grid;grid-template-columns:1fr 260px auto;gap:12px;margin-bottom:18px}.questions{display:grid;gap:14px}.q-card{padding:22px}.q-meta{display:flex;justify-content:space-between;gap:12px;color:var(--muted);font-weight:800;font-size:13px}.options{display:grid;gap:10px;margin-top:14px}.option{border:1px solid #cbd5e1;background:white;border-radius:14px;padding:12px;cursor:pointer;text-align:left;font:inherit}.option.correct{border-color:var(--good);background:#ecfdf5}.option.wrong{border-color:var(--bad);background:#fef2f2}.explanation{display:none;margin-top:12px;padding:14px;background:#f8fafc;border-radius:14px;color:#334155}.q-card.answered .explanation{display:block}.timeline{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}.timeline article{padding:20px}.timeline strong{color:var(--primary)}footer{text-align:center;color:var(--muted);padding:35px 5vw;border-top:1px solid var(--line)}@media(max-width:900px){.stats,.cards.two,.flashcards,.timeline{grid-template-columns:1fr}.toolbar{grid-template-columns:1fr}.nav{align-items:flex-start;flex-direction:column}.hero{padding-bottom:60px}}