:root{--primary: #6c63ff;--primary-light: #a29bfe;--success: #00b894;--danger: #d63031;--warning: #fdcb6e;--bg: #f8f9fa;--surface: #ffffff;--text: #2d3436;--text-muted: #636e72;--border: #dfe6e9;--radius: 12px;--shadow: 0 2px 12px rgba(0,0,0,.08);--nav-h: 64px}*{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:var(--bg);color:var(--text);min-height:100vh}#root{max-width:480px;margin:0 auto;min-height:100vh;display:flex;flex-direction:column;position:relative}.page{flex:1;padding:20px 16px calc(var(--nav-h) + 20px);overflow-y:auto}h2{font-size:1.4rem;font-weight:700;margin-bottom:16px}h3{font-size:1rem;font-weight:600}button{cursor:pointer;border:none;border-radius:var(--radius);font-size:.95rem;font-family:inherit;transition:opacity .15s,transform .1s}button:active{transform:scale(.97)}.btn-primary{background:var(--primary);color:#fff;padding:10px 20px}.btn-primary:hover{opacity:.9}.btn-ghost{background:transparent;color:var(--primary);padding:8px 16px;border:1.5px solid var(--primary)}.btn-danger{background:var(--danger);color:#fff;padding:6px 12px;font-size:.85rem}.card{background:var(--surface);border-radius:var(--radius);box-shadow:var(--shadow);padding:16px}.flip-scene{width:100%;height:220px;perspective:800px;cursor:pointer;margin:0 auto 20px}.flip-card{width:100%;height:100%;position:relative;transform-style:preserve-3d;transition:transform .5s ease}.flip-card.flipped{transform:rotateY(180deg)}.flip-face{position:absolute;top:0;right:0;bottom:0;left:0;backface-visibility:hidden;border-radius:var(--radius);display:flex;flex-direction:column;align-items:center;justify-content:center;padding:24px;text-align:center}.flip-front{background:linear-gradient(135deg,var(--primary),var(--primary-light));color:#fff}.flip-front .word{font-size:2rem;font-weight:700}.flip-front .hint{font-size:.85rem;opacity:.8;margin-top:8px}.flip-back{background:var(--surface);border:2px solid var(--primary-light);transform:rotateY(180deg)}.flip-back .definition{font-size:1.1rem;line-height:1.6}.flip-back .example{font-size:.85rem;color:var(--text-muted);margin-top:10px;font-style:italic}.navbar{position:fixed;bottom:0;left:50%;transform:translate(-50%);width:100%;max-width:480px;height:var(--nav-h);background:var(--surface);border-top:1px solid var(--border);display:flex;align-items:stretch;box-shadow:0 -2px 12px #0000000f}.nav-item{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px;background:none;border-radius:0;color:var(--text-muted);font-size:.72rem;padding:0}.nav-item.active{color:var(--primary)}.nav-item svg{width:22px;height:22px}.calendar{margin-top:12px}.cal-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px}.cal-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:4px}.cal-day-label{text-align:center;font-size:.72rem;color:var(--text-muted);padding:4px 0}.cal-day{aspect-ratio:1;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:.78rem;color:var(--text-muted)}.cal-day.checked{background:var(--primary);color:#fff;font-weight:600}.cal-day.today{border:2px solid var(--primary);color:var(--primary);font-weight:600}.cal-day.today.checked{border-color:transparent}.cal-day.empty{visibility:hidden}.quiz-option{width:100%;text-align:left;padding:12px 16px;margin-bottom:10px;background:var(--surface);border:2px solid var(--border);border-radius:var(--radius);font-size:.95rem;transition:border-color .2s,background .2s}.quiz-option:hover:not(:disabled){border-color:var(--primary-light)}.quiz-option.correct{border-color:var(--success);background:#e8f8f5}.quiz-option.wrong{border-color:var(--danger);background:#ffeaea}.word-form{display:flex;flex-direction:column;gap:10px}.word-form input,.word-form textarea,.word-form select{padding:10px 12px;border:1.5px solid var(--border);border-radius:8px;font-size:.95rem;font-family:inherit;background:var(--surface);color:var(--text);outline:none;transition:border-color .2s}.word-form input:focus,.word-form textarea:focus,.word-form select:focus{border-color:var(--primary)}.word-form textarea{resize:vertical;min-height:72px}.word-item{display:flex;align-items:center;justify-content:space-between;padding:12px 16px;background:var(--surface);border-radius:var(--radius);margin-bottom:8px;box-shadow:var(--shadow)}.word-item .word-text{font-weight:600}.word-item .word-def{font-size:.85rem;color:var(--text-muted);margin-top:2px}.streak-badge{display:inline-flex;align-items:center;gap:6px;background:linear-gradient(135deg,#fd7272,#ff9f43);color:#fff;padding:6px 14px;border-radius:20px;font-weight:700;font-size:1rem}.empty-state{text-align:center;color:var(--text-muted);padding:40px 0;font-size:.95rem}.row{display:flex;gap:8px;align-items:center}.mt-12{margin-top:12px}.mt-16{margin-top:16px}.tag{display:inline-block;background:var(--primary-light);color:#fff;font-size:.72rem;padding:2px 8px;border-radius:10px;margin-left:6px}.grade-bar{display:flex;gap:6px;padding:12px 16px 8px;overflow-x:auto;white-space:nowrap;-ms-overflow-style:none;scrollbar-width:none}.grade-bar::-webkit-scrollbar{display:none}.grade-pill{flex-shrink:0;padding:5px 14px;border-radius:20px;font-size:.82rem;background:var(--border);color:var(--text);border:none;cursor:pointer;transition:background .2s,color .2s}.grade-pill.active{background:var(--primary);color:#fff;font-weight:600}.speak-btn{display:inline-flex;align-items:center;justify-content:center;width:28px;height:28px;padding:4px;background:#ffffff40;border:none;border-radius:50%;cursor:pointer;color:inherit;vertical-align:middle;margin-left:4px;transition:background .2s}.speak-btn:hover{background:#fff6}.speak-btn svg{width:16px;height:16px}.speak-btn.speaking{animation:pulse-speak .8s ease-in-out infinite}@keyframes pulse-speak{0%,to{opacity:1;transform:scale(1)}50%{opacity:.6;transform:scale(1.15)}}.flip-front .speak-btn{color:#fff}.word-item .speak-btn{color:var(--primary);background:transparent}.word-item .speak-btn:hover{background:var(--border)}.card .speak-btn{color:var(--primary);background:transparent}.card .speak-btn:hover{background:var(--border)}.speak-sentence-btn{display:inline-flex;align-items:center;gap:3px;padding:2px 8px;background:transparent;border:1px solid var(--primary-light);border-radius:12px;cursor:pointer;color:var(--primary);font-size:.72rem;margin-left:6px;vertical-align:middle;transition:background .2s}.speak-sentence-btn:hover{background:#6c63ff14}.speak-sentence-btn svg{width:12px;height:12px}.speak-sentence-btn.speaking{animation:pulse-speak .8s ease-in-out infinite}.progress-bar{height:6px;background:var(--border);border-radius:3px;margin:8px 0;overflow:hidden}.progress-fill{height:100%;background:var(--success);border-radius:3px;transition:width .3s ease}.btn-ghost.mastered{border-color:var(--success);color:var(--success)}.word-example{font-size:.8rem;color:var(--text-muted);font-style:italic;margin-top:4px}.quiz-hint{font-size:.9rem;padding:12px;background:#fff5f5;border-radius:var(--radius);margin-top:12px}.speak-top-right{position:absolute;top:12px;right:12px}