*{box-sizing:border-box}
:root{
 --bg:#0b0f14;--panel:#111720;--panel2:#161e29;--line:#253142;
 --text:#edf3f8;--muted:#94a3b8;--green:#35d07f;--green2:#1e9e5d;
 --blue:#6aa9ff;--red:#ff6f7d;--amber:#f5c26b
}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,sans-serif}
button,select{font:inherit}
.topbar{
 position:sticky;top:0;z-index:20;height:68px;display:flex;align-items:center;justify-content:space-between;
 padding:0 28px;border-bottom:1px solid var(--line);background:rgba(11,15,20,.94);backdrop-filter:blur(14px)
}
.brand{display:flex;align-items:center;gap:12px;color:var(--text);text-decoration:none;font-weight:650}
.terminal-mark{
 display:inline-grid;place-items:center;width:34px;height:34px;border-radius:9px;background:#12251b;
 color:var(--green);font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-weight:800
}
nav{display:flex;gap:5px}.nav-link{background:none;border:0;color:var(--muted);padding:9px 11px;border-radius:8px;cursor:pointer}
.nav-link:hover{color:var(--text);background:#131a23}
.shell{max-width:1120px;margin:0 auto;padding:46px 22px 84px}
.hero{display:grid;grid-template-columns:1.4fr .6fr;gap:24px;align-items:stretch;margin-bottom:38px}
.kicker{color:var(--green);font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.82rem;letter-spacing:.05em}
h1{font-size:clamp(2.7rem,6vw,5rem);line-height:.98;margin:.18em 0 .28em;letter-spacing:-.045em}
h2{letter-spacing:-.02em}
.lead{color:var(--muted);font-size:1.08rem;line-height:1.7;max-width:720px}
.panel{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:22px}
.metric-box{display:flex;flex-direction:column;justify-content:space-between;min-height:220px}
.metric{font-size:3.1rem;font-weight:800;letter-spacing:-.04em}
.muted{color:var(--muted)}
.action-row{display:flex;gap:10px;flex-wrap:wrap;margin-top:24px}
.btn{border:1px solid var(--line);background:var(--panel2);color:var(--text);padding:11px 15px;border-radius:10px;cursor:pointer}
.btn:hover{border-color:#3d516d;background:#1b2532}
.btn.primary{background:var(--green2);border-color:var(--green2);color:#fff}
.btn.ghost{background:transparent}
.section-head{display:flex;justify-content:space-between;align-items:flex-end;gap:15px;margin:34px 0 14px}
.section-head h2{margin:0}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:13px}
.topic{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:18px;text-align:left;cursor:pointer;color:var(--text)}
.topic:hover{border-color:#3a4e6a;transform:translateY(-1px)}
.topic strong{display:block;margin-bottom:8px}.topic span{color:var(--muted);font-size:.92rem}
.form-row{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:22px 0}
label{display:block;color:var(--muted);font-size:.9rem}
select{margin-top:7px;width:100%;background:#0d131b;color:var(--text);border:1px solid var(--line);padding:12px;border-radius:10px}
.quiz-wrap{max-width:820px;margin:0 auto}
.quiz-meta{display:flex;justify-content:space-between;gap:16px;color:var(--muted);font-size:.9rem}
.progress{height:7px;background:#0a0e14;border-radius:999px;overflow:hidden;margin:14px 0 26px}
.progress div{height:100%;background:var(--green)}
.question{font-size:1.65rem;line-height:1.3;margin:8px 0 8px}
.options{display:grid;gap:11px;margin-top:20px}
.option{
 text-align:left;background:#0e141d;border:1px solid var(--line);color:var(--text);
 padding:15px 16px;border-radius:11px;cursor:pointer;display:flex;gap:12px;align-items:flex-start
}
.option:hover{border-color:#415672;background:#121a24}
.option .letter{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--muted);min-width:20px}
.option.correct{border-color:var(--green);background:#10261b}
.option.wrong{border-color:var(--red);background:#2a161b}
.feedback{margin-top:18px;border-left:3px solid var(--line);padding:12px 14px;background:#0d131b;border-radius:8px;color:#dce5ef}
.feedback.good{border-color:var(--green)}.feedback.bad{border-color:var(--red)}
.stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:12px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:18px}
.stat .n{font-size:2rem;font-weight:800;margin-top:5px}
.badge{display:inline-block;padding:5px 8px;border:1px solid var(--line);border-radius:999px;color:var(--muted);font-size:.78rem}
.score{font-size:4rem;font-weight:850;letter-spacing:-.05em}
footer{text-align:center;color:var(--muted);padding:28px;border-top:1px solid var(--line)}
@media(max-width:760px){
 .topbar{padding:0 14px}.brand span:last-child{display:none}
 .hero{grid-template-columns:1fr}.form-row{grid-template-columns:1fr}
 .shell{padding:30px 14px 68px}
}