:root{--bg: #f8fafc;--ink: #1e2937;--accent: #2563eb;--accent2: #7c3aed;--ok: #16a34a;--warn: #f59e0b;--bad: #dc2626;--card: #fff;--line: #e2e8f0;--radius: 14px}*,*:before,*:after{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--ink)}html{overflow-x:hidden}img,video{max-width:100%}a{color:var(--accent);text-decoration:none}h1,h2,h3{margin:0 0 .5em}button{font:inherit;cursor:pointer}input{font:inherit}.container{max-width:1100px;margin:0 auto;padding:0 14px}.main{padding-top:16px;padding-bottom:90px;min-height:60vh}@media (min-width:768px){.main{padding-bottom:24px}}.site-header{position:sticky;top:0;z-index:20;background:#ffffffeb;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}.header-inner{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 0}.brand{font-weight:700;font-size:1.15rem;color:var(--ink)}.nav-desktop{display:none;gap:16px;align-items:center}.navlink{color:var(--ink);font-size:.95rem}.navlink:hover{color:var(--accent)}@media (min-width:768px){.nav-desktop{display:flex}}.tabbar{position:fixed;left:0;right:0;bottom:0;display:flex;background:#fff;border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom);z-index:30}.tab{flex:1;display:flex;flex-direction:column;align-items:center;gap:2px;padding:8px 4px;font-size:.72rem;color:#64748b}.tab.active,.tab:hover{color:var(--accent)}@media (min-width:768px){.tabbar{display:none}}.site-footer{text-align:center;font-size:.75rem;color:#94a3b8;padding:24px 8px;border-top:1px solid var(--line);margin-top:32px}.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:0 1px 2px #0f172a0d}.grid{display:grid;gap:14px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}.course-card{display:flex;flex-direction:column;gap:8px}.empty{text-align:center;padding:44px 16px;display:flex;flex-direction:column;align-items:center;gap:10px}.hero-emoji{font-size:3rem}.error{background:#fef2f2;color:#b91c1c;border:1px solid #fecaca;border-radius:10px;padding:10px 14px;margin:10px 0}.badge{display:inline-block;background:#eef2ff;color:#4338ca;border-radius:999px;padding:3px 10px;font-size:.75rem}.chip{display:inline-block;background:#fef3c7;color:#92400e;border-radius:999px;padding:3px 10px;font-size:.75rem}.muted{color:#64748b}.section{margin:18px 0}.row{display:flex;gap:10px;align-items:center}.between{justify-content:space-between}.center{justify-content:center}.col{display:flex;flex-direction:column;gap:4px}.page-title{font-size:1.6rem;margin:6px 0 16px}.back{margin-bottom:14px;display:inline-block}.page{padding:14px 0}.auth-wrap{max-width:520px;margin:24px auto}.form{display:flex;flex-direction:column;gap:14px;max-width:440px}.label{font-size:.85rem;font-weight:600}.input{width:100%;padding:11px 12px;border:1px solid #cbd5e1;border-radius:10px;background:#fff}.input:focus{outline:2px solid var(--accent);outline-offset:1px;border-color:var(--accent)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:10px 16px;border-radius:10px;border:1px solid #cbd5e1;background:#fff;color:var(--ink);transition:transform .05s}.btn:active{transform:scale(.98)}.btn-primary{background:var(--accent);border-color:var(--accent);color:#fff}.btn-ghost{background:transparent;border-color:transparent}.btn:disabled{opacity:.5;cursor:not-allowed}.alt-link{margin-top:14px;text-align:center;font-size:.9rem}.fine{font-size:.8rem;color:#64748b;text-align:center}.sections{display:flex;flex-direction:column;gap:18px}.section-title{font-size:1.1rem;border-bottom:1px solid var(--line);padding-bottom:8px}.lesson-row{display:flex;align-items:center;gap:12px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:13px 16px}.status-dot{width:20px;height:20px;border-radius:50%;border:2px solid #cbd5e1;display:inline-flex;align-items:center;justify-content:center;font-size:.7rem;flex:none}.status-dot.done{border-color:var(--ok);background:#dcfce7;color:var(--ok)}.lesson-title{flex:1}.enroll-card{background:#eff6ff;border:1px solid #bfdbfe;margin:16px 0}.progress-track{height:8px;background:#e2e8f0;border-radius:99px;overflow:hidden;margin:10px 0}.progress-fill{height:100%;background:var(--accent);border-radius:99px;transition:width .3s}.meta{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:10px;font-size:.85rem;margin:8px 0}.details-raw{margin-top:10px;font-size:.8rem;color:#64748b}.tutor{display:flex;flex-direction:column;gap:10px;height:calc(100dvh - 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