:root{--bg: #f5f8f7;--surface: #ffffff;--ink: #17211f;--muted: #5f6f6a;--line: #dfe8e4;--brand: #0b6b5e;--brand-deep: #084f46;--brand-soft: #e6f3ef;--warn-soft: #fff4e5;--warn-ink: #8a4b00;--danger-soft: #fff1f0;--danger-ink: #a61b1b;--radius: 18px;--shadow: 0 10px 30px rgba(18, 51, 43, .08)}*{box-sizing:border-box}html,body,#root{min-height:100%;margin:0}body{background:radial-gradient(1200px 500px at 50% -180px,#d9eee8,#d9eee800 62%),var(--bg);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif;font-size:18px;line-height:1.65;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}a{color:inherit;text-decoration:none}button,input{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.55}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.page{width:100%;max-width:760px;min-height:100vh;margin:0 auto;padding:max(24px,env(safe-area-inset-top)) 20px max(28px,env(safe-area-inset-bottom))}.center-page{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:12px;text-align:center}.eyebrow{margin:0 0 2px;color:var(--brand);font-size:14px;font-weight:700;letter-spacing:1.5px;text-transform:uppercase}h1,h2,p{margin-top:0}h1{font-size:clamp(28px,7vw,36px);line-height:1.25;letter-spacing:-.5px}h2{font-size:22px;line-height:1.35}.muted{color:var(--muted)}.tiny{font-size:14px;line-height:1.6}.brand-block{padding:44px 6px 26px;text-align:center}.brand-block h1{margin-bottom:6px}.brand-subtitle{color:var(--muted);font-size:17px;margin-bottom:0}.brand-mark{display:flex;width:72px;height:72px;margin:0 auto 18px;align-items:center;justify-content:center;border-radius:22px;background:var(--brand);box-shadow:0 12px 24px #0b6b5e38;color:#fff;font-size:28px;padding-left:5px}.activate-card{padding:26px 22px 24px;border:1px solid var(--line);border-radius:24px;background:var(--surface);box-shadow:var(--shadow)}.activate-card h2{margin-bottom:8px}.activate-card form{margin-top:22px}.code-input{width:100%;min-height:76px;padding:8px 10px;border:2px solid #c9d8d3;border-radius:16px;background:#fbfdfc;color:var(--ink);font-size:clamp(34px,12vw,46px);font-variant-numeric:tabular-nums;font-weight:700;letter-spacing:10px;text-align:center;outline:none;transition:border-color .15s ease,box-shadow .15s ease}.code-input::placeholder{color:#9aa8a3;font-size:20px;font-weight:500;letter-spacing:1px}.code-input:focus{border-color:var(--brand);box-shadow:0 0 0 4px #0b6b5e1f}.code-input[aria-invalid=true]{border-color:#d64545}.primary-button,.secondary-button{display:inline-flex;min-height:54px;align-items:center;justify-content:center;padding:12px 22px;border-radius:14px;font-size:18px;font-weight:700;text-align:center;transition:transform .1s ease,background .15s ease}.primary-button{width:100%;margin-top:18px;border:0;background:var(--brand);color:#fff;box-shadow:0 8px 18px #0b6b5e33}.primary-button:not(:disabled):active,.secondary-button:not(:disabled):active{transform:translateY(1px)}.primary-button:hover:not(:disabled){background:var(--brand-deep)}.secondary-button{border:1px solid var(--line);background:var(--surface);color:var(--brand)}.as-button{text-decoration:none}.alert{padding:12px 14px;border-radius:12px;margin-top:12px;font-size:16px;line-height:1.55}.alert-error{border:1px solid #f3c5c5;background:var(--danger-soft);color:var(--danger-ink)}.legal-note{margin-top:28px;color:var(--muted);font-size:13px;line-height:1.65;text-align:center}.legal-note p{margin-bottom:4px}.app-header{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;padding:12px 2px 20px}.app-header h1{margin-bottom:0;font-size:clamp(26px,6vw,32px)}.text-button{min-height:44px;padding:8px 10px;border:0;background:transparent;color:var(--muted);font-size:15px;white-space:nowrap}.column-description{margin:0 2px 20px;color:var(--muted);font-size:16px}.lesson-list{display:flex;flex-direction:column;gap:14px;margin:0;padding:0;list-style:none}.lesson-card{display:flex;align-items:center;gap:16px;min-height:112px;padding:18px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);box-shadow:0 4px 18px #12332b0a}.lesson-card:active{background:#fbfdfc}.lesson-number{display:flex;width:52px;height:52px;flex:0 0 52px;align-items:center;justify-content:center;border-radius:15px;background:var(--brand-soft);color:var(--brand);font-size:18px;font-weight:800;font-variant-numeric:tabular-nums}.lesson-body{min-width:0;flex:1}.lesson-topline{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:4px}.state-chip{display:inline-flex;padding:2px 9px;border-radius:999px;font-size:13px;font-weight:700}.state-not_started{background:#eef1f0;color:#5c6b66}.state-in_progress{background:#e8f2ff;color:#1f5fa8}.state-completed{background:#e7f6ea;color:#24722e}.duration{color:var(--muted);font-size:14px;font-variant-numeric:tabular-nums}.lesson-card h2{margin:0 0 3px;font-size:20px;line-height:1.4}.lesson-meta{margin:0;color:var(--muted);font-size:15px}.lesson-arrow{color:#9fb0aa;font-size:34px;line-height:1}.bottom-note{margin-top:22px;text-align:center}.empty-card{padding:30px 22px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);text-align:center}.empty-card h1,.empty-card h2{margin-bottom:8px}.empty-card p{color:var(--muted)}.loading-dot{width:34px;height:34px;border:3px solid #cfe1dc;border-top-color:var(--brand);border-radius:50%;animation:spin .9s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.detail-nav{padding:8px 2px 20px}.back-link{display:inline-flex;min-height:44px;align-items:center;color:var(--brand);font-size:17px;font-weight:700}.detail-hero{display:flex;flex-direction:column;gap:18px;margin-bottom:18px}.detail-poster{display:flex;aspect-ratio:16 / 9;align-items:center;justify-content:center;border-radius:22px;background:linear-gradient(135deg,#0b6b5eeb,#084f46fa),var(--brand);box-shadow:var(--shadow);color:#fff;font-size:52px;padding-left:8px}.detail-heading h1{margin:10px 0 6px}.detail-heading-compact h1{font-size:clamp(24px,6vw,31px)}.player-shell{overflow:hidden;margin-bottom:16px;border:1px solid #1d2b27;border-radius:22px;background:#111816;box-shadow:0 18px 40px #0f26202e;color:#fff}.video-frame{position:relative;aspect-ratio:16 / 9;background:#0b100f}.video-element{display:block;width:100%;height:100%;object-fit:contain;background:#0b100f}.player-overlay{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px;border:0;background:linear-gradient(180deg,#06141114,#06141159);color:#fff}.player-overlay span{display:flex;width:68px;height:68px;align-items:center;justify-content:center;border-radius:50%;background:#fffffff0;color:var(--brand-deep);font-size:28px;padding-left:4px;box-shadow:0 8px 22px #00000047}.player-overlay small{font-size:15px;font-weight:700;text-shadow:0 1px 4px rgba(0,0,0,.4)}.player-error{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:12px;padding:24px;background:#0e1714f0;text-align:center}.player-error p{margin:0;color:#ffd9d9}.player-error .secondary-button{min-height:44px;background:#fff}.player-controls{padding:14px 16px 16px}.player-row{display:flex;align-items:center;gap:12px}.round-button{display:flex;width:48px;height:48px;flex:0 0 48px;align-items:center;justify-content:center;border:0;border-radius:50%;background:#fff;color:var(--brand-deep);font-size:15px;font-weight:800}.time-readout{flex:1;font-size:14px;font-variant-numeric:tabular-nums}.time-readout .muted{color:#9bb1aa}.sync-pill{display:inline-flex;padding:3px 8px;border-radius:999px;font-size:12px;white-space:nowrap}.sync-synced{background:#47a47033;color:#9be1b7}.sync-syncing{background:#4a90e233;color:#a9d0ff}.sync-offline{background:#e59a4733;color:#ffd19c}.progress-track{position:relative;height:10px;overflow:hidden;margin:14px 0 10px;border-radius:999px;background:#33413d}.progress-track span,.progress-track i{position:absolute;top:0;bottom:0;left:0;display:block;height:100%;width:0;border-radius:inherit}.progress-track span{background:#d9e6e1;opacity:.72}.progress-track i{background:#42b883;opacity:.55;height:4px;top:3px}.seek-range{width:100%;height:30px;margin:8px 0 2px;accent-color:#42b883}.player-meta{display:flex;align-items:center;justify-content:space-between;gap:10px;color:#a7bcb5;font-size:13px;line-height:1.5}.completed-label{color:#9be1b7;white-space:nowrap}.player-hint{margin:10px 0 0;padding:8px 10px;border-radius:10px;background:#e59a4729;color:#ffd19c;font-size:13px;line-height:1.5}.info-card{padding:20px;margin-bottom:14px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface)}.info-card h2{margin-bottom:8px;font-size:20px}.info-card p:last-child{margin-bottom:0}.notice-card{border-color:#f1dfc2;background:var(--warn-soft);color:#4a3217}.notice-card .muted,.notice-card p{color:#6b4b23}@media(max-width:380px){.page{padding-left:16px;padding-right:16px}.lesson-card{gap:12px;padding:15px}.lesson-number{width:46px;height:46px;flex-basis:46px}.lesson-card h2{font-size:18px}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;animation-duration:.01ms!important;transition-duration:.01ms!important}}