:root{--ink:#102a43;--muted:#627d98;--line:#d9e2ec;--paper:#f7fafc;--blue:#0b7285;--navy:#06283d;--gold:#f4b942}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 Inter,"Microsoft YaHei",system-ui,sans-serif}header{height:64px;background:var(--navy);color:#fff;display:flex;align-items:center;justify-content:space-between;padding:0 5.5vw}.brand{font-weight:800;font-size:22px;letter-spacing:-.7px;color:#fff;text-decoration:none}.brand span{color:var(--gold)}.status{font-size:14px;color:#cfe3ef}.status i{display:inline-block;width:8px;height:8px;border-radius:50%;background:#57d69a;margin-right:8px}main{max-width:1440px;margin:auto;display:grid;grid-template-columns:350px 1fr;min-height:calc(100vh - 64px)}aside{padding:48px 36px;background:#fff;border-right:1px solid var(--line)}.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-size:12px;font-weight:800;color:var(--blue);margin:0 0 9px}h1{font-size:31px;line-height:1.18;letter-spacing:-1px;margin:0 0 18px}h2{font-size:28px;line-height:1.25;margin:0 0 6px}.intro,#lesson-description{color:var(--muted);margin:0}.tutorial{display:block;margin-top:24px;color:var(--blue);font-weight:700;text-decoration:none}.tutorial:hover{text-decoration:underline}nav{margin-top:30px;display:grid;gap:6px}.lesson{width:100%;border:0;background:transparent;text-align:left;padding:11px 13px;border-radius:8px;color:var(--muted);cursor:pointer;font:inherit}.lesson:hover{background:#edf6f7}.lesson.active{color:var(--navy);background:#dff3f1;font-weight:750}.lesson small{display:block;font-size:12px;color:#829ab1}.workspace{padding:48px clamp(24px,5vw,80px);max-width:1050px}.lesson-head{display:flex;align-items:start;justify-content:space-between;gap:20px}.reset,.solution{background:#fff;border:1px solid var(--line);border-radius:7px;padding:9px 13px;color:var(--ink);font:600 14px inherit;cursor:pointer}.reset:hover,.solution:hover{border-color:var(--blue);color:var(--blue)}.schema{border:1px solid var(--line);background:#fff;border-radius:9px;margin:27px 0 22px;padding:13px 16px;display:flex;gap:18px;flex-wrap:wrap;font-size:14px;color:var(--muted)}.schema strong{color:var(--ink)}.editor-label,.result-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px;font-size:14px;font-weight:700}.dialect,#result-meta{font-weight:500;color:var(--muted);font-size:13px}textarea{width:100%;height:225px;resize:vertical;border:1px solid #9fb3c8;border-radius:9px;background:#081c28;color:#e8f1f5;padding:20px;font:15px/1.65 "Cascadia Code",Consolas,monospace;outline:none}textarea:focus{border-color:#1c9aaa;box-shadow:0 0 0 3px #d6f4f2}.actions{margin:14px 0 28px;display:flex;gap:10px}.run{border:0;background:var(--blue);color:white;border-radius:7px;padding:10px 15px;font:700 14px inherit;cursor:pointer}.run:hover{background:#075c6c}kbd{font:12px monospace;background:#ffffff2c;border-radius:3px;padding:2px 4px;margin-left:7px}.result{background:#fff;border:1px solid var(--line);border-radius:9px;padding:17px}.output{overflow:auto;min-height:100px}.empty{color:var(--muted);padding:18px 0}table{border-collapse:collapse;width:100%;font-size:14px}th,td{padding:9px 11px;border-bottom:1px solid var(--line);white-space:nowrap;text-align:left}th{background:#f0f4f8;font-weight:750}.success{color:#178052;font-weight:700}.error{color:#b42318;white-space:pre-wrap}.note{font-size:13px;color:var(--muted);margin-top:16px}@media(max-width:820px){header{padding:0 20px}main{display:block}aside{padding:30px 24px;border-right:0;border-bottom:1px solid var(--line)}h1{font-size:26px}nav{grid-template-columns:repeat(2,minmax(0,1fr));margin-top:20px}.lesson{padding:9px}.workspace{padding:30px 20px}.lesson-head{display:block}.reset{margin-top:15px}.schema{gap:6px;display:block}.schema span{display:block;margin-top:4px}}