:root{--bg:#fbfaf7;--surface:#fff;--surface-2:#f3f1ec;--text:#1f1e1c;--muted:#6b6862;--border:#e6e2da;--accent:#c8643c;--accent-soft:#fbeee7;--accent-text:#fff;--success:#2f7d4f;--success-soft:#e7f4ec;--danger:#b4392f;--danger-soft:#fbeaea;--code-bg:#f3f1ec;--radius:12px;--shadow:0 1px 2px #0000000a, 0 2px 8px #0000000a;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light}@media (prefers-color-scheme:dark){:root{--bg:#1a1918;--surface:#232220;--surface-2:#2b2a27;--text:#ece9e3;--muted:#a19d95;--border:#3a3834;--accent:#e07a50;--accent-soft:#3a2a22;--accent-text:#1a1918;--success:#5dbb83;--success-soft:#1f3328;--danger:#e57369;--danger-soft:#3a2220;--code-bg:#2b2a27;--shadow:none;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}}*{box-sizing:border-box}html,body{margin:0;padding:0}body{background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;font-family:system-ui,-apple-system,Segoe UI,Roboto,Noto Sans,sans-serif;font-size:16px;line-height:1.6}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}img{max-width:100%}.container{max-width:1080px;margin:0 auto;padding:0 16px}.narrow{max-width:760px;margin:0 auto;padding:0 16px}.muted{color:var(--muted)}.small{font-size:14px}.header{border-bottom:1px solid var(--border);background:var(--surface);z-index:10;position:sticky;top:0}.header-inner{justify-content:space-between;align-items:center;gap:12px;height:60px;display:flex}.logo{color:var(--text);align-items:center;gap:8px;font-size:18px;font-weight:700;display:flex}.logo:hover{text-decoration:none}.logo-mark{background:var(--accent);width:28px;height:28px;color:var(--accent-text);border-radius:8px;place-items:center;font-size:15px;display:grid}.user{align-items:center;gap:10px;font-size:14px;display:flex}.avatar{background:var(--surface-2);object-fit:cover;border-radius:50%;width:30px;height:30px}.user-name{text-overflow:ellipsis;white-space:nowrap;max-width:160px;overflow:hidden}@media (max-width:560px){.user-name{display:none}}.btn{font:inherit;cursor:pointer;background:var(--accent);color:var(--accent-text);border:1px solid #0000;border-radius:10px;justify-content:center;align-items:center;gap:8px;padding:10px 18px;font-size:15px;font-weight:600;text-decoration:none;transition:opacity .15s;display:inline-flex}.btn:hover{opacity:.9;text-decoration:none}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-ghost{color:var(--text);border-color:var(--border);background:0 0}.btn-ghost:hover{background:var(--surface-2);opacity:1}.btn-success{background:var(--success);color:#fff}.btn-sm{padding:6px 12px;font-size:14px}.btn-block{width:100%}.hero{padding:56px 0 32px}.hero h1{margin:0 0 12px;font-size:clamp(28px,5vw,40px);line-height:1.2}.hero p{color:var(--muted);max-width:620px;margin:0;font-size:18px}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow)}.course-grid{grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px;padding-bottom:64px;display:grid}.course-card{color:var(--text);flex-direction:column;gap:12px;padding:22px;display:flex}.course-card:hover{border-color:var(--accent);text-decoration:none}.course-card h3{margin:0;font-size:20px}.course-card p{color:var(--muted);margin:0;font-size:15px}.tag{background:var(--accent-soft);color:var(--accent);border-radius:999px;padding:3px 10px;font-size:12px;font-weight:600;display:inline-block}.meta{color:var(--muted);flex-wrap:wrap;gap:12px;font-size:14px;display:flex}.progress{background:var(--surface-2);border-radius:999px;height:8px;overflow:hidden}.progress>span{background:var(--success);border-radius:999px;height:100%;transition:width .3s;display:block}.progress-label{color:var(--muted);justify-content:space-between;margin-bottom:6px;font-size:13px;display:flex}.course-head{padding:40px 0 24px}.course-head h1{margin:8px 0;font-size:clamp(26px,4vw,34px)}.course-head p{color:var(--muted);margin:0 0 20px;font-size:17px}.section-block{margin-bottom:20px;overflow:hidden}.section-title{background:var(--surface-2);border-bottom:1px solid var(--border);padding:14px 18px;font-size:15px;font-weight:700}.lesson-row{border-bottom:1px solid var(--border);color:var(--text);align-items:center;gap:12px;padding:13px 18px;display:flex}.lesson-row:last-child{border-bottom:0}.lesson-row:hover{background:var(--surface-2);text-decoration:none}.lesson-row .grow{flex:1}.check{border:2px solid var(--border);color:#0000;border-radius:50%;flex-shrink:0;place-items:center;width:22px;height:22px;font-size:12px;display:grid}.check.done{background:var(--success);border-color:var(--success);color:#fff}.lesson-layout{grid-template-columns:280px 1fr;gap:32px;max-width:1180px;margin:0 auto;padding:24px 16px 64px;display:grid}.sidebar{font-size:14px}.lesson-layout>aside>div{scrollbar-width:thin;max-height:calc(100vh - 100px);overflow-y:auto}.sidebar>a:first-child{margin-bottom:12px}.sidebar-section{margin-bottom:16px}.sidebar-section-title{text-transform:uppercase;letter-spacing:.04em;color:var(--muted);margin:0 0 6px 8px;font-size:12px;font-weight:700}.sidebar a{color:var(--text);border-radius:8px;align-items:center;gap:8px;padding:7px 8px;display:flex}.sidebar a:hover{background:var(--surface-2);text-decoration:none}.sidebar a.active{background:var(--accent-soft);color:var(--accent);font-weight:600}.sidebar .check{width:18px;height:18px;font-size:10px}.mobile-nav{display:none}@media (max-width:900px){.lesson-layout{grid-template-columns:1fr;padding-top:16px}.lesson-layout>aside{display:none}.mobile-nav{margin-bottom:16px;display:block}.mobile-nav summary{cursor:pointer;padding:10px 14px;font-size:14px;font-weight:600}.mobile-nav .sidebar{padding:0 8px 8px}}.lesson-main{min-width:0;max-width:760px}.crumbs{color:var(--muted);margin-bottom:8px;font-size:14px}.lesson-footer{border-top:1px solid var(--border);flex-direction:column;gap:20px;margin-top:48px;padding-top:24px;display:flex}.pager{flex-wrap:wrap;justify-content:space-between;gap:12px;display:flex}.pager a{min-width:200px;color:var(--text);flex:1;padding:14px 16px}.pager a:hover{border-color:var(--accent);text-decoration:none}.pager .label{color:var(--muted);font-size:13px;display:block}.pager .next{text-align:right}.prose{font-size:17px;line-height:1.75}.prose h1{margin:0 0 20px;font-size:clamp(28px,4vw,34px);line-height:1.25}.prose h2{margin:40px 0 12px;font-size:23px;line-height:1.3}.prose h3{margin:28px 0 8px;font-size:19px}.prose p,.prose ul,.prose ol{margin:0 0 16px}.prose li{margin-bottom:6px}.prose li>p{margin:0}.prose strong{font-weight:650}.prose code{background:var(--code-bg);border-radius:6px;padding:2px 6px;font-family:ui-monospace,SF Mono,Menlo,Consolas,monospace;font-size:.88em}.prose pre{color:#ece9e3;background:#1f1e1c;border-radius:10px;margin:0 0 20px;padding:16px 18px;font-size:14.5px;line-height:1.6;overflow-x:auto}.prose pre code{font-size:inherit;color:inherit;background:0 0;padding:0}.prose blockquote{background:var(--accent-soft);border-left:4px solid var(--accent);border-radius:0 10px 10px 0;margin:0 0 20px;padding:14px 18px}.prose blockquote p:last-child{margin-bottom:0}.prose table{border-collapse:collapse;width:100%;margin:0 0 20px;font-size:15px;display:block;overflow-x:auto}.prose th,.prose td{border:1px solid var(--border);text-align:left;vertical-align:top;padding:9px 12px}.prose th{background:var(--surface-2)}.prose figure{margin:24px 0}.prose figure img{border:1px solid var(--border);border-radius:12px;width:100%;height:auto;display:block}.prose figcaption{color:var(--muted);text-align:center;margin-top:8px;font-size:14px}.prose hr{border:0;border-top:1px solid var(--border);margin:32px 0}.login-box{text-align:center;max-width:400px;margin:72px auto;padding:32px}.login-box h1{margin:0 0 8px;font-size:26px}.login-box p{color:var(--muted);margin:0 0 24px}.login-box form{margin-bottom:10px}.provider-btn{background:var(--surface);width:100%;color:var(--text);border:1px solid var(--border)}.provider-btn:hover{background:var(--surface-2);opacity:1}.notice{background:var(--danger-soft);color:var(--danger);text-align:left;border-radius:10px;padding:12px 14px;font-size:14px}.quiz-q{margin-bottom:16px;padding:20px}.quiz-q h3{margin:0 0 14px;font-size:17px;line-height:1.5}.quiz-q .num{color:var(--muted);margin-right:6px;font-weight:600}.option{border:1px solid var(--border);cursor:pointer;border-radius:10px;align-items:flex-start;gap:10px;margin-bottom:8px;padding:10px 12px;font-size:15px;display:flex}.option:hover{background:var(--surface-2)}.option input{accent-color:var(--accent);margin-top:5px}.option.correct{border-color:var(--success);background:var(--success-soft)}.option.wrong{border-color:var(--danger);background:var(--danger-soft)}.explain{color:var(--muted);background:var(--surface-2);border-radius:8px;margin:8px 0 0;padding:10px 12px;font-size:14px}.result-box{text-align:center;margin-bottom:24px;padding:24px}.result-box .score{margin:4px 0;font-size:40px;font-weight:700}.pass{color:var(--success)}.fail{color:var(--danger)}.footer{border-top:1px solid var(--border);color:var(--muted);text-align:center;padding:24px 0;font-size:14px}.quiz-q code,.explain code{background:var(--code-bg);border-radius:5px;padding:1px 5px;font-family:ui-monospace,SF Mono,Menlo,Consolas,monospace;font-size:.9em}