*{box-sizing:border-box}html{scroll-behavior:smooth}
:root{--bg:#f6f7fb;--surface:#fff;--surface2:#f9f9fc;--text:#172033;--muted:#727b8d;--line:#e7e9ef;--primary:#6655e8;--primary2:#8a75ff;--soft:#efedff;--green:#18a873;--red:#e0525d;--shadow:0 10px 35px rgba(25,32,55,.07)}
body.dark{--bg:#0b1017;--surface:#141a23;--surface2:#10161e;--text:#eef2f8;--muted:#9ca7b8;--line:#28313e;--soft:#282440;--shadow:0 15px 35px rgba(0,0,0,.25)}
body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif}
button,input{font:inherit}.app{display:flex;min-height:100vh}.sidebar{width:270px;background:var(--surface);border-right:1px solid var(--line);padding:20px 14px;position:fixed;left:0;top:0;bottom:0;overflow:auto;z-index:50}.brand{display:flex;gap:11px;align-items:center;padding:5px 9px 21px}.brand-mark{height:42px;width:42px;border-radius:12px;background:linear-gradient(135deg,var(--primary),var(--primary2));color:#fff;display:grid;place-items:center;font-weight:900}.brand b{display:block;font-size:18px}.brand span{display:block;color:var(--muted);font-size:10px;margin-top:2px}.user-mini{display:flex;gap:10px;align-items:center;padding:11px;border:1px solid var(--line);border-radius:13px;background:var(--surface2);margin-bottom:18px}.avatar,.top-avatar{background:linear-gradient(135deg,var(--primary),var(--primary2));color:#fff;display:grid;place-items:center;font-weight:800}.avatar{height:35px;width:35px;border-radius:10px}.user-mini b,.top-user b{display:block;font-size:12px}.user-mini small,.top-user small{display:block;color:var(--muted);font-size:10px;margin-top:2px}.side-label{font-size:9px;color:var(--muted);font-weight:800;letter-spacing:1.4px;padding:10px 12px 7px}.nav{width:100%;text-align:left;border:0;background:transparent;color:var(--text);padding:10px 12px;border-radius:9px;margin:2px 0;cursor:pointer;font-size:12.5px}.nav:hover,.nav.active{background:var(--soft);color:var(--primary);font-weight:750}.nav span{margin-left:4px}.page{width:calc(100% - 270px);margin-left:270px}.topbar{height:70px;background:var(--surface);border-bottom:1px solid var(--line);display:flex;align-items:center;padding:0 30px;gap:18px;position:sticky;top:0;z-index:30}.search{position:relative;max-width:620px;flex:1}.search span{position:absolute;left:14px;top:8px;color:var(--muted);font-size:22px}.search input{width:100%;border:1px solid var(--line);background:var(--bg);color:var(--text);outline:0;border-radius:11px;padding:11px 14px 11px 40px}.icon-btn,.mobile-menu{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:10px;padding:9px 12px;cursor:pointer}.top-user{display:flex;gap:9px;align-items:center}.top-avatar{height:34px;width:34px;border-radius:10px}.mobile-menu{display:none}
main{max-width:1150px;margin:auto;padding:34px 30px 80px}.hero{border-radius:24px;background:linear-gradient(135deg,#5d48df,#8a70ff);color:#fff;padding:42px;position:relative;overflow:hidden;box-shadow:var(--shadow)}.hero:after{content:"C";position:absolute;right:30px;bottom:-100px;font-size:300px;font-weight:900;color:#fff1}.eyebrow{font-size:11px;letter-spacing:1.3px;font-weight:800;color:#dcd7ff}.hero h1{font-size:43px;line-height:1.08;margin:10px 0}.hero p{max-width:670px;color:#eeeaff;line-height:1.65}.btn{border:0;border-radius:10px;padding:12px 18px;cursor:pointer;font-weight:800}.btn-primary{background:#fff;color:#5c46d6}.btn-purple{background:var(--primary);color:#fff}.btn-outline{background:var(--surface);border:1px solid var(--line);color:var(--text)}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:20px 0}.stat,.card,.note,.quiz-card,.rank{background:var(--surface);border:1px solid var(--line);border-radius:15px;box-shadow:var(--shadow)}.stat{padding:17px}.stat b{font-size:25px}.stat small{display:block;color:var(--muted);margin-top:3px}.section-title{font-size:23px;margin:32px 0 14px}.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px}.card{padding:19px;cursor:pointer;transition:.18s}.card:hover{transform:translateY(-3px);border-color:var(--primary)}.card .ico{font-size:27px}.card h3{margin:9px 0 6px;font-size:16px}.card p{margin:0;color:var(--muted);font-size:12.5px;line-height:1.55}.progress{height:8px;background:var(--line);border-radius:30px;overflow:hidden;margin-top:12px}.progress i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--primary),var(--primary2))}
.topic-head{display:flex;justify-content:space-between;gap:15px;margin-bottom:22px}.topic-head h1{font-size:34px;margin:0 0 6px}.muted{color:var(--muted)}.back{background:var(--surface);color:var(--text);border:1px solid var(--line);border-radius:9px;padding:9px 12px;height:max-content;cursor:pointer}.note{padding:23px;margin:14px 0}.note h2{margin:0 0 9px}.note h3{margin-top:20px}.note p,.note li{color:var(--muted);line-height:1.75}.note ul{padding-left:22px}.tag{display:inline-block;color:var(--primary);background:var(--soft);padding:4px 8px;border-radius:6px;font-size:10px;font-weight:800}.table{width:100%;border-collapse:collapse}.table th,.table td{padding:11px;border-bottom:1px solid var(--line);text-align:left}.table th{color:var(--primary);font-size:12px}.table td{color:var(--muted);font-size:12.5px}pre{background:#0f141c;color:#e7edf7;border-radius:12px;padding:18px;overflow:auto;line-height:1.6;margin:13px 0}code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace}.copy{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:8px;padding:7px 11px;cursor:pointer}.output{margin-top:11px;padding:11px;border-left:4px solid var(--green);background:#eafaf2;color:#155e42;border-radius:7px}.dark .output{background:#10271e;color:#a8e5c6}.two{display:grid;grid-template-columns:1fr 1fr;gap:14px}.roadmap-step{display:flex;gap:15px;align-items:flex-start;padding:17px;border-bottom:1px solid var(--line)}.roadmap-step:last-child{border-bottom:0}.step-num{height:35px;width:35px;border-radius:50%;background:var(--soft);color:var(--primary);display:grid;place-items:center;font-weight:800;flex:none}.quiz-card{padding:22px;margin:13px 0}.option{display:block;width:100%;text-align:left;padding:12px;margin:8px 0;border-radius:9px;border:1px solid var(--line);background:var(--surface);color:var(--text);cursor:pointer}.option:hover{border-color:var(--primary)}.option.correct{border-color:var(--green);background:#eafaf2}.option.wrong{border-color:var(--red);background:#fff0f1}.dark .option.correct{background:#10271e}.dark .option.wrong{background:#32171a}.result{font-weight:750;margin-top:9px}.rank{display:flex;align-items:center;gap:14px;padding:14px;margin:8px 0}.rankno{font-size:18px;font-weight:900;width:24px}.medal{font-size:23px}.rank small{display:block;color:var(--muted);font-size:10px}.xp{margin-left:auto;color:var(--primary);font-weight:800}.search-results{margin-top:20px}.empty{text-align:center;padding:70px;color:var(--muted)}.toast{position:fixed;right:20px;bottom:20px;background:#171c25;color:#fff;padding:11px 15px;border-radius:9px;display:none;z-index:100}
@media(max-width:900px){.stats{grid-template-columns:1fr 1fr}.hero h1{font-size:36px}}
@media(max-width:700px){.sidebar{left:-280px;transition:.2s}.sidebar.open{left:0}.page{width:100%;margin-left:0}.topbar{height:62px;padding:0 12px}.mobile-menu{display:block}.top-user{display:none}main{padding:23px 14px 60px}.hero{padding:30px 24px}.hero h1{font-size:31px}.two{grid-template-columns:1fr}.topic-head h1{font-size:27px}}