:root{--bg:#f7f8fb;--card:#fff;--text:#182033;--muted:#667085;--line:#e6e8ef;--brand:#2563eb;--brand2:#7c3aed;--ok:#16a34a;--bad:#dc2626;--shadow:0 18px 50px rgba(15,23,42,.10)}
.dark{--bg:#090d18;--card:#111827;--text:#f8fafc;--muted:#a7b0c0;--line:#263043;--brand:#60a5fa;--brand2:#a78bfa;--shadow:0 18px 50px rgba(0,0,0,.35)}
*{box-sizing:border-box}body{margin:0;font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;background:var(--bg);color:var(--text)}a{color:inherit;text-decoration:none}.hero{min-height:760px;position:relative;overflow:hidden;padding:22px 22px 120px}.hero-bg{position:absolute;inset:0;background:radial-gradient(circle at 20% 20%,rgba(124,58,237,.32),transparent 35%),radial-gradient(circle at 80% 10%,rgba(37,99,235,.35),transparent 35%),linear-gradient(135deg,#0f172a,#1e293b 55%,#111827);z-index:-2}.hero:after{content:"";position:absolute;inset:auto -20% -42% -20%;height:300px;background:var(--bg);transform:rotate(-4deg);z-index:-1}nav{max-width:1160px;margin:auto;display:flex;align-items:center;justify-content:space-between;color:#fff}.brand{font-weight:900;font-size:22px;letter-spacing:-.03em}.brand span{display:block;font-size:12px;font-weight:600;opacity:.75;letter-spacing:.06em;text-transform:uppercase}.ghost{border:1px solid rgba(255,255,255,.25);background:rgba(255,255,255,.08);color:#fff;border-radius:999px;padding:10px 16px;cursor:pointer}.hero-content{max-width:980px;margin:92px auto 0;color:#fff;position:relative;z-index:1}.eyebrow{text-transform:uppercase;letter-spacing:.14em;font-weight:800;font-size:12px;color:var(--brand)}.hero .eyebrow{color:#bfdbfe}.hero h1{font-size:clamp(42px,8vw,84px);line-height:.95;margin:10px 0;letter-spacing:-.07em}.sub{max-width:680px;font-size:20px;line-height:1.55;color:#dbeafe}.btn{border:0;border-radius:16px;padding:14px 20px;font-weight:900;cursor:pointer;transition:.2s transform,.2s opacity;display:inline-flex;align-items:center;justify-content:center}.btn:hover{transform:translateY(-2px)}.primary{background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff}.secondary{background:var(--card);color:var(--text);border:1px solid var(--line)}.hero-actions{display:flex;gap:12px;margin:28px 0;flex-wrap:wrap}.stats-row{display:grid;grid-template-columns:repeat(3,minmax(140px,1fr));gap:16px;max-width:620px;position:relative;z-index:2;margin-top:16px}.stats-row div{background:rgba(15,23,42,.26);border:1px solid rgba(255,255,255,.18);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border-radius:24px;padding:20px 18px;box-shadow:0 14px 34px rgba(0,0,0,.18)}.stats-row strong{display:block;font-size:34px;line-height:1}.stats-row span{display:block;color:#dbeafe;margin-top:8px;line-height:1.35;font-weight:600}.panel,.section{max-width:1160px;margin:36px auto;padding:0 22px}.progress-panel{display:flex;gap:28px;align-items:center;justify-content:space-between;background:var(--card);border:1px solid var(--line);border-radius:30px;padding:28px;box-shadow:var(--shadow)}.progress-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;min-width:min(520px,100%)}.progress-item{border:1px solid var(--line);border-radius:18px;padding:14px;background:linear-gradient(180deg,rgba(37,99,235,.08),transparent)}.progress-item strong{display:block;font-size:22px}.section-title{margin:66px 0 22px}.section-title h2{font-size:clamp(30px,4vw,48px);letter-spacing:-.04em;margin:5px 0}.section-title p{color:var(--muted);max-width:760px}.tabs{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:20px}.tab{border:1px solid var(--line);background:var(--card);color:var(--text);padding:12px 16px;border-radius:999px;font-weight:800;cursor:pointer}.tab.active{background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff}.cards-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px}.concept-card{background:var(--card);border:1px solid var(--line);border-radius:24px;padding:20px;box-shadow:0 10px 24px rgba(15,23,42,.05)}.concept-card h3{margin:0 0 10px}.concept-card p{color:var(--muted);line-height:1.55}.concept-card button{margin-top:12px;border:1px solid var(--line);background:transparent;color:var(--text);border-radius:12px;padding:9px 12px;cursor:pointer}.concept-card.learned{outline:2px solid rgba(22,163,74,.35)}.flash-wrap{background:var(--card);border:1px solid var(--line);border-radius:28px;padding:22px;box-shadow:var(--shadow)}.flashcard{height:260px;perspective:1000px;cursor:pointer}.flash-inner{height:100%;transition:transform .55s;transform-style:preserve-3d}.flashcard.flipped .flash-inner{transform:rotateY(180deg)}.flash-front,.flash-back{position:absolute;inset:0;backface-visibility:hidden;border-radius:24px;padding:28px;display:flex;align-items:center;justify-content:center;text-align:center;font-size:26px;font-weight:900;background:linear-gradient(135deg,rgba(37,99,235,.16),rgba(124,58,237,.13));border:1px solid var(--line)}.flash-back{transform:rotateY(180deg);font-size:20px;font-weight:700;line-height:1.5;color:var(--text)}.flash-actions{display:flex;gap:10px;justify-content:center;margin-top:16px}.exam-setup{display:flex;gap:14px;align-items:end;flex-wrap:wrap;background:var(--card);border:1px solid var(--line);border-radius:24px;padding:20px}.exam-setup label{font-weight:800;display:grid;gap:8px;color:var(--muted)}select{padding:13px 14px;border-radius:14px;border:1px solid var(--line);background:var(--bg);color:var(--text);font-weight:800;min-width:190px}.exam-box,.results{background:var(--card);border:1px solid var(--line);border-radius:28px;padding:24px;box-shadow:var(--shadow)}.hidden{display:none}.exam-top{display:grid;gap:12px}.exam-top span{display:block;color:var(--muted);margin-top:4px}.bar{height:12px;background:var(--bg);border-radius:999px;overflow:hidden}.bar span{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--brand),var(--brand2));transition:.25s}.options{display:grid;gap:12px;margin:20px 0}.option{border:1px solid var(--line);background:var(--bg);color:var(--text);padding:15px;border-radius:16px;text-align:left;font-weight:800;cursor:pointer}.option.correct{border-color:var(--ok);background:rgba(22,163,74,.12)}.option.wrong{border-color:var(--bad);background:rgba(220,38,38,.12)}.explain{border-left:5px solid var(--brand);background:var(--bg);padding:14px;border-radius:14px;color:var(--muted);line-height:1.5}.exam-actions{display:flex;justify-content:space-between;gap:10px}.tips-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:14px}.tips-grid article{background:var(--card);border:1px solid var(--line);border-radius:24px;padding:20px}.tips-grid p{color:var(--muted);line-height:1.5}.result-score{font-size:56px;font-weight:950;letter-spacing:-.06em;margin:0}.review-list{display:grid;gap:10px;margin-top:18px}.review-item{border:1px solid var(--line);border-radius:16px;padding:14px;background:var(--bg)}footer{text-align:center;color:var(--muted);padding:36px 20px}@media(max-width:760px){.progress-panel{display:block}.progress-grid{grid-template-columns:repeat(2,1fr);margin-top:18px}.hero{min-height:820px;padding-bottom:90px}.stats-row{grid-template-columns:1fr;max-width:100%}.exam-actions{display:grid}.btn{width:100%}}



.site-footer{max-width:1160px;margin:34px auto 0;padding:0 22px 38px;text-align:left;color:var(--text)}
.footer-card{position:relative;overflow:hidden;border:1px solid var(--line);background:linear-gradient(135deg,rgba(37,99,235,.10),rgba(124,58,237,.08)),var(--card);border-radius:28px;padding:24px 26px;display:flex;align-items:center;justify-content:space-between;gap:22px;box-shadow:0 16px 38px rgba(15,23,42,.08)}
.footer-card:before{content:"";position:absolute;inset:0 auto 0 0;width:6px;background:linear-gradient(180deg,var(--brand),var(--brand2))}
.footer-card strong{display:block;font-size:19px;font-weight:950;letter-spacing:-.025em;margin-bottom:6px}
.footer-card span{display:inline-flex;align-items:center;justify-content:center;border:1px solid var(--line);background:var(--card);border-radius:999px;padding:10px 14px;font-weight:950;color:var(--brand);white-space:nowrap}
.footer-card p{margin:0;color:var(--muted);max-width:620px;line-height:1.5}
@media(max-width:760px){.footer-card{display:grid;text-align:left}.footer-card span{width:100%;white-space:normal;text-align:center}.site-footer{padding-bottom:28px}}