:root{--primary:#1677ff;--primary-light:#e6f4ff;--bg:#f5f7fa;--card:#fff;--text:#1f1f1f;--text-secondary:#8c8c8c;--border:#f0f0f0;--success:#52c41a;--warning:#faad14;--radius:12px;--shadow:0 2px 8px #0000000f;--nav-height:64px;--safe-bottom:env(safe-area-inset-bottom,0px)}*{box-sizing:border-box;margin:0;padding:0}html,body,#root{background:var(--bg);height:100%;color:var(--text);-webkit-font-smoothing:antialiased;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif}.app-shell{min-height:100%;padding-bottom:calc(var(--nav-height) + var(--safe-bottom) + 16px)}.page{max-width:480px;margin:0 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#69b1ff);border-radius:3px;height:100%;transition:width .3s}.task-item{border-bottom:1px solid var(--border);align-items:flex-start;gap:12px;padding:12px 0;display:flex}.task-item:last-child{border-bottom:none}.task-check{cursor:pointer;border:2px solid #d9d9d9;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:22px;height:22px;margin-top:2px;transition:all .2s;display:flex}.task-check.checked{background:var(--success);border-color:var(--success);color:#fff;font-size:12px}.task-content{flex:1;min-width:0}.task-title{font-size:14px;font-weight:500;line-height:1.4}.task-title.done{color:var(--text-secondary);text-decoration:line-through}.task-detail{color:var(--text-secondary);margin-top:4px;font-size:12px;line-height:1.5}.task-meta{flex-wrap:wrap;gap:8px;margin-top:6px;display:flex}.task-tag{background:var(--bg);color:var(--text-secondary);border-radius:4px;padding:1px 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var(--border);align-items:baseline;gap:8px;padding:8px 0;font-size:13px;display:flex}.word-list-item:last-child{border-bottom:none}.word-list-item strong{min-width:100px}.material-link,.material-card{color:inherit;justify-content:space-between;align-items:center;text-decoration:none;display:flex}.material-link{border-bottom:1px solid var(--border);padding:10px 0;font-size:14px}.material-link:last-child{border-bottom:none}.material-card{display:block}.speak-btn{cursor:pointer;background:#fff3;border:none;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;transition:transform .15s,background .15s;display:inline-flex}.speak-btn:active{transform:scale(.92)}.speak-btn-sm{background:var(--bg);width:28px;height:28px;font-size:14px}.speak-btn-md{width:36px;height:36px;font-size:16px}.speak-btn-lg{background:#ffffff40;width:44px;height:44px;font-size:20px}.speak-btn.speaking{background:#fff6;animation:1s infinite 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14px;font-size:15px}.listen-input.correct{background:#52c41a14;border-color:#52c41a}.listen-input.wrong{background:#f5222d0f;border-color:#f5222d}.listen-feedback{border-radius:8px;margin-top:12px;padding:10px 12px;font-size:13px}.listen-feedback.ok{color:#389e0d;background:#52c41a1a}.listen-feedback.err{color:#cf1322;background:#f5222d14}.listen-feedback.hint{color:var(--primary);background:#1677ff14}.listen-question{border-bottom:1px solid var(--border);gap:10px;padding:12px 0;display:flex}.listen-question:last-of-type{border-bottom:none}.listen-q-num{background:var(--primary);color:#fff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:28px;height:28px;font-size:12px;font-weight:600;display:flex}.dialogue-list{margin-top:10px}.dialogue-line{border-bottom:1px solid var(--border);flex-wrap:wrap;align-items:flex-start;gap:6px;padding:8px 0;font-size:13px;display:flex}.dialogue-speaker{color:var(--primary);white-space:nowrap;font-weight:600}.listen-options{grid-template-columns:1fr 1fr;gap:8px;margin-top:12px;display:grid}.listen-option{border:1px solid var(--border);background:var(--card);cursor:pointer;text-align:center;border-radius:8px;padding:12px;font-size:13px}.listen-option.correct{background:#52c41a1f;border-color:#52c41a}.listen-option.wrong{background:#f5222d14;border-color:#f5222d}.intensive-steps{margin:12px 0}.intensive-step{border-bottom:1px solid var(--border);gap:12px;padding:10px 0;display:flex}.intensive-num{color:#fff;background:#1677ff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:28px;height:28px;font-weight:700;display:flex}.cambridge-badge{color:var(--primary);background:#1677ff1a;border-radius:20px;margin:8px 0;padding:6px 12px;font-size:13px;font-weight:600;display:inline-block}.listen-local-path{background:var(--bg);border-radius:8px;margin-top:14px;padding:12px;font-size:13px}.listen-local-path code{word-break:break-all;color:var(--text-secondary);margin-top:6px;font-size:11px;display:block}.voice-selector{background:var(--card);border:1px solid var(--border);border-radius:12px;margin-bottom:12px;padding:14px 16px}.voice-selector-title{margin-bottom:6px;font-size:14px;font-weight:600}.voice-selector-tip{color:var(--text-secondary);margin:0 0 10px;font-size:12px;line-height:1.6}.voice-ref-box{background:var(--bg);border-radius:8px;margin-bottom:12px;padding:10px 12px}.voice-row{margin-bottom:10px}.voice-row label{color:var(--text-secondary);margin-bottom:4px;font-size:12px;display:block}.voice-controls{align-items:center;gap:8px;display:flex}.voice-controls select{border:1px solid var(--border);background:var(--bg);color:var(--text);border-radius:8px;flex:1;padding:8px 10px;font-size:12px}.material-banner{background:var(--card);border:1px solid var(--border);border-left:4px solid var(--primary);border-radius:10px;margin-bottom:14px;padding:12px 14px}.material-banner-title{margin-bottom:10px;font-size:13px;font-weight:600}.material-banner-item{border-bottom:1px solid var(--border);gap:10px;padding:8px 0;display:flex}.material-banner-item:last-child{border-bottom:none}.material-banner-icon{flex-shrink:0;font-size:18px}.material-banner-label{font-size:13px;font-weight:500}.material-banner-detail{color:var(--primary);font-size:12px;font-weight:400}.material-banner-path{color:var(--text-secondary);word-break:break-all;margin-top:2px;font-size:11px;display:block}.material-banner-foot{color:var(--text-secondary);border-top:1px dashed var(--border);margin-top:8px;padding-top:8px;font-size:11px}.highlighted-text,.highlight-box{background:var(--bg);border-radius:8px;margin-top:8px;padding:12px;font-size:14px;line-height:1.8}.hl-error,mark.hl-error{color:#cf1322;background:#f5222d33;border-radius:3px;padding:1px 3px;-webkit-text-decoration:underline wavy #f5222d;text-decoration:underline wavy #f5222d}.hl-fixed,mark.hl-fixed{color:#389e0d;background:#52c41a33;border-radius:3px;padding:1px 3px}.inline-demo{padding:0 4px;font-size:11px}.grammar-list{margin-top:10px}.grammar-item{border-bottom:1px solid var(--border);flex-wrap:wrap;align-items:center;gap:8px;padding:8px 0;font-size:13px;display:flex}.grammar-err-word{color:var(--primary);font-weight:600}.grammar-msg{color:var(--text-secondary);flex:1}.grammar-ok{color:#389e0d;background:#52c41a1a;border-radius:8px;margin-top:8px;padding:10px 12px;font-size:13px}.speaking-recorder{margin-top:4px}.recorder-controls{flex-wrap:wrap;align-items:center;gap:10px;margin-bottom:12px;display:flex}.recorder-audio{max-width:100%;height:36px}.live-transcript{color:var(--primary);background:#1677ff0f;border-radius:6px;margin-bottom:8px;padding:8px;font-size:13px}.rec-dot{background:#f5222d;border-radius:50%;width:8px;height:8px;margin-right:6px;animation:1s infinite pulse;display:inline-block}@keyframes pulse{0%,to{opacity:1}50%{opacity:.3}}.translation-box{background:#1677ff0f;border-radius:8px;margin:12px 0;padding:10px 12px;font-size:14px}.corrected-box{border-top:1px dashed var(--border);margin-top:12px;padding-top:12px}.writing-textarea{border:1px solid var(--border);resize:vertical;background:var(--bg);width:100%;min-height:100px;color:var(--text);border-radius:8px;padding:12px;font-family:inherit;font-size:14px;line-height:1.7}.writing-editor{margin-bottom:14px}@media (width>=481px){.bottom-nav{border-radius:16px 16px 0 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var(--border);background:var(--bg);cursor:pointer;width:100%;color:inherit;font:inherit;border-radius:10px;align-items:center;gap:10px;padding:10px 12px;display:flex}.study-video-item.active{border-color:var(--primary);background:#1677ff0f}.study-video-play{background:var(--primary);color:#fff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:28px;height:28px;font-size:11px;display:inline-flex}.study-video-meta{flex-direction:column;gap:2px;min-width:0;display:flex}.study-video-title{font-size:14px;font-weight:600}.study-video-series{color:var(--text-secondary);white-space:nowrap;text-overflow:ellipsis;font-size:11px;overflow:hidden}.study-video-player-wrap{margin-top:12px}.study-video-player{background:#000;border-radius:10px;width:100%;max-height:240px}.study-video-caption{color:var(--text-secondary);margin-top:6px;font-size:12px}