:root{--ko-color: #1a73e8;--en-color: #e8711a;--neutral: #333;--bg: #f5f5f5;--card: #ffffff;--radius: 8px;--shadow: 0 1px 3px rgba(0,0,0,.08);--safe-bottom: env(safe-area-inset-bottom, 0px)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:var(--bg);color:#333;-webkit-font-smoothing:antialiased;overflow-x:hidden}#root{max-width:480px;margin:0 auto;min-height:100vh;padding-top:60px;position:relative}.tab-bar{position:fixed;top:0;left:0;right:0;max-width:480px;width:100%;display:flex;background:#fff;border-bottom:1px solid #eee;z-index:100;margin:0 auto}.tab-bar a{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:8px 0;text-decoration:none;color:#999;font-size:11px;font-weight:600;transition:color .2s}.tab-bar a.active{color:var(--ko-color)}.tab-bar a .tab-icon{font-size:22px;margin-bottom:2px}.card{background:var(--card);border-radius:var(--radius);padding:16px;margin:8px 16px;box-shadow:var(--shadow)}.page-header{padding:16px;font-size:24px;font-weight:800}.unit-header{display:flex;align-items:center;justify-content:space-between;padding:12px 16px 4px;cursor:pointer;font-size:16px;font-weight:700}.unit-header .arrow{transition:transform .2s}.unit-header .arrow.open{transform:rotate(90deg)}.lesson-card{background:var(--card);border-radius:var(--radius);padding:14px 16px;margin:6px 16px;box-shadow:var(--shadow);display:flex;align-items:center;cursor:pointer;border-left:4px solid #e0e0e0;transition:opacity .2s,border-color .2s}.lesson-card.locked{opacity:.5;cursor:default}.lesson-card.has-overdue{border:2px dashed #ff3b30;border-left:4px solid #ff3b30}.lesson-card .lesson-info{flex:1}.lesson-card .lesson-title{font-size:15px;font-weight:600;margin-bottom:4px}.lesson-card .lesson-stars{color:#f5a623;font-size:13px;letter-spacing:2px}.lesson-card .status-icon{font-size:20px;margin-left:12px}.review-banner{margin:12px 16px 4px;padding:12px 16px;border-radius:var(--radius);color:#fff;display:flex;justify-content:space-between;align-items:center;cursor:pointer;font-weight:700;font-size:14px}.guide-banner{margin:12px 16px 4px;padding:12px 16px;border-radius:var(--radius);background:#fff3e0;border:1px solid #ffcc02;cursor:pointer;font-size:13px;color:#666}.progress-bar{height:6px;background:#e8e8e8;margin:12px 16px;border-radius:3px;overflow:hidden}.progress-bar .fill{height:100%;border-radius:3px;transition:width .3s}.question-card{background:var(--card);border-radius:16px;padding:24px;margin:16px;box-shadow:0 2px 8px #00000014}.question-card .prompt-label{font-size:13px;color:#888;margin-bottom:8px;text-align:center}.question-card .prompt-text{font-size:22px;font-weight:700;text-align:center;line-height:1.4;margin-bottom:16px}.question-card .hint{font-size:13px;color:#aaa;font-style:italic;text-align:center;margin-bottom:12px}.answer-input{width:100%;padding:14px 16px;font-size:18px;border:2px solid transparent;border-radius:12px;background:#f5f5f5;outline:none;transition:border-color .2s}.answer-input:focus{border-color:var(--ko-color)}.answer-input.correct{border-color:#34c759;background:#e8f8ed}.answer-input.wrong{border-color:#ff3b30;background:#ffeceb}.btn{display:block;width:100%;padding:14px;border:none;border-radius:12px;font-size:16px;font-weight:700;cursor:pointer;text-align:center;transition:opacity .2s}.btn:disabled{opacity:.5;cursor:default}.btn-primary{background:var(--ko-color);color:#fff}.btn-orange{background:var(--en-color);color:#fff}.btn-speak{background:#ff6b35;color:#fff}.options{display:flex;flex-direction:column;gap:10px}.option-btn{background:#f5f5f5;padding:14px 20px;border-radius:12px;border:2px solid transparent;font-size:16px;font-weight:500;cursor:pointer;text-align:center;transition:all .2s}.option-btn:hover{background:#eee}.option-btn.selected{border-color:var(--ko-color);background:#e8f0fe}.option-btn.correct{border-color:#34c759;background:#e8f8ed}.option-btn.wrong{border-color:#ff3b30;background:#ffeceb}.feedback{margin-top:16px;padding:12px;border-radius:10px;text-align:center;font-weight:600}.feedback.correct{background:#e8f8ed;color:#2d8f4e}.feedback.wrong{background:#ffeceb;color:#cc2b22}.listen-btn{display:inline-block;padding:10px 24px;border-radius:24px;background:#f0f4ff;border:none;color:var(--ko-color);font-size:15px;font-weight:600;cursor:pointer;margin:8px auto}.stats-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;padding:0 16px}.stat-card{background:var(--card);border-radius:var(--radius);padding:16px;text-align:center;box-shadow:var(--shadow)}.stat-card .stat-value{font-size:28px;font-weight:800}.stat-card .stat-label{font-size:13px;color:#888;margin-top:4px}.heatmap{display:flex;flex-direction:column;gap:12px;padding:16px}.heatmap-row{display:flex;align-items:center;gap:8px}.heatmap-label{width:36px;font-size:13px;font-weight:600;color:#555}.heatmap-cells{display:flex;gap:6px}.heatmap-cell{width:28px;height:28px;border-radius:6px;background:#e8e8e8}.heatmap-day{font-size:10px;color:#999;text-align:center}.vocab-list{padding:0 16px}.vocab-item{background:var(--card);border-radius:var(--radius);padding:12px 16px;margin-bottom:8px;box-shadow:var(--shadow);display:flex;align-items:center;cursor:pointer}.vocab-item .vocab-word{flex:1;font-weight:600;font-size:15px}.vocab-item .vocab-trans{color:#888;font-size:13px}.search-bar{margin:8px 16px;padding:10px 16px;border-radius:24px;border:1px solid #ddd;background:#fff;font-size:15px;width:calc(100% - 32px);outline:none}.search-bar:focus{border-color:var(--ko-color)}.settings-section{padding:16px}.settings-section h3{font-size:15px;font-weight:700;margin-bottom:12px}.settings-input{width:100%;padding:12px;border:1px solid #ddd;border-radius:var(--radius);font-size:14px;margin-bottom:8px;outline:none}.settings-input:focus{border-color:var(--ko-color)}.settings-btn{padding:10px 24px;border-radius:var(--radius);border:none;font-weight:600;cursor:pointer;margin-right:8px;margin-top:8px}.generate-form{padding:16px}.generate-form label{display:block;font-size:14px;font-weight:600;margin-bottom:6px;margin-top:16px}.generate-form input,.generate-form select{width:100%;padding:12px;border:1px solid #ddd;border-radius:var(--radius);font-size:15px;outline:none}.lesson-header{display:flex;justify-content:space-between;align-items:center;padding:8px 16px}.lesson-header .title{font-size:17px;font-weight:700}.lesson-header .counter{font-size:14px;color:#888}.result-card{background:var(--card);border-radius:20px;padding:40px;margin:40px 20px;text-align:center;box-shadow:0 4px 12px #0000001a}.result-card .emoji{font-size:48px;margin-bottom:16px}.result-card h2{font-size:24px;margin-bottom:12px}.result-card p{color:#666;margin-bottom:28px}.section{margin-bottom:24px}.section-header{display:flex;align-items:center;gap:8px;padding:0 16px;margin-bottom:8px}.section-dot{width:10px;height:10px;border-radius:50%}.section-title{font-size:17px;font-weight:700;flex:1}.overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#00000080;display:flex;align-items:center;justify-content:center;z-index:200}.modal{background:#fff;border-radius:16px;padding:24px;width:90%;max-width:400px}.modal h3{margin-bottom:12px}.modal p{font-size:14px;color:#666;margin-bottom:16px;line-height:1.6}.dict-result{background:var(--card);border-radius:var(--radius);padding:16px;margin:8px 16px;box-shadow:var(--shadow)}.dict-result .word{font-size:20px;font-weight:700}.dict-result .phonetic{color:#888;font-size:14px;margin-left:8px}.dict-result .explain{padding:4px 0;font-size:14px}.dict-result .web-item{font-size:13px;color:#666;padding:2px 0}.review-empty{text-align:center;padding:60px 20px;color:#888}.review-empty .emoji{font-size:48px;margin-bottom:12px}