:root{--bg:#fdfaf5;--text:#2b2630;--muted:#6b6375;--accent:#2e7d32;--accent-dark:#1b5e20;--danger:#c62828;--border:#e5e0d8;--card-bg:#fff;color:var(--text);background:var(--bg);-webkit-font-smoothing:antialiased;font:17px/1.45 system-ui,-apple-system,Segoe UI,Roboto,sans-serif}@media (prefers-color-scheme:dark){:root{--bg:#15171a;--text:#f0ede6;--muted:#a8a29a;--accent:#66bb6a;--accent-dark:#4caf50;--border:#2d2f33;--card-bg:#1f2226}}*{box-sizing:border-box}body{margin:0}#root{max-width:480px;min-height:100svh;margin:0 auto;padding:16px}button{font:inherit;cursor:pointer}.deck-list{flex-direction:column;gap:10px;display:flex}.deck-list h1{margin:8px 0 0;font-size:28px}.subtitle{color:var(--muted);margin-bottom:12px}.deck-row{border:1px solid var(--border);background:var(--card-bg);width:100%;color:var(--text);text-align:left;border-radius:12px;align-items:center;gap:12px;padding:16px;font-size:17px;display:flex}.deck-row-all{border-color:var(--accent);font-weight:600}.deck-emoji{font-size:24px}.deck-title{flex:1}.deck-count{text-align:center;background:var(--accent);color:#fff;border-radius:999px;min-width:28px;padding:2px 8px;font-size:14px;font-weight:600}.session-header{align-items:center;gap:10px;margin-bottom:20px;display:flex}.exit-btn{color:var(--muted);background:0 0;border:none;padding:4px 8px;font-size:20px}.progress-bar{background:var(--border);border-radius:999px;flex:1;height:8px;overflow:hidden}.progress-fill{background:var(--accent);height:100%;transition:width .2s}.progress-count{color:var(--muted);text-align:right;min-width:40px;font-size:14px}.exercise-card{flex-direction:column;gap:16px;display:flex}.exercise-label{text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin:0;font-size:12px}.flashcard{border:1px solid var(--border);background:var(--card-bg);text-align:center;border-radius:16px;justify-content:center;align-items:center;min-height:220px;padding:40px 20px;display:flex}.flashcard-front h2,.flashcard-back h2{margin:0 0 8px;font-size:28px}.tap-hint{color:var(--muted);margin-top:12px;font-size:14px}.example{margin-top:12px;font-style:italic}.example-en{color:var(--muted);margin-top:4px;font-size:15px}.grade-prompt{color:var(--muted);margin:0;font-size:14px}.grade-row{gap:8px;display:flex}.grade-row button{color:#fff;border:none;border-radius:10px;flex:1;padding:14px;font-weight:600}.grade-again{background:var(--danger)}.grade-good{background:#f9a825}.grade-easy{background:var(--accent)}.prompt-en{margin:0;font-size:20px;font-weight:600}.answer-row,.bank-row{flex-wrap:wrap;gap:8px;min-height:44px;display:flex}.answer-row{border-bottom:2px dashed var(--border);padding-bottom:12px}.placeholder{color:var(--muted);font-size:14px}.word-chip{border:1px solid var(--border);background:var(--card-bg);color:var(--text);border-radius:10px;padding:10px 14px;font-size:16px}.word-chip.picked{background:var(--accent);color:#fff;border-color:var(--accent)}.primary-btn{background:var(--accent);color:#fff;border:none;border-radius:10px;padding:14px;font-size:16px;font-weight:600}.primary-btn:disabled{opacity:.5}.result-block{flex-direction:column;gap:10px;display:flex}.result-correct{color:var(--accent-dark);font-weight:600}.result-wrong{color:var(--danger);font-weight:600}.self-grade-prompt{color:var(--muted);margin:0}.text-input{border:1px solid var(--border);background:var(--card-bg);color:var(--text);border-radius:10px;padding:14px;font-size:18px}.hint-btn{border:1px solid var(--border);color:var(--muted);background:0 0;border-radius:8px;align-self:flex-start;padding:8px 14px;font-size:14px}.hint-box{flex-direction:column;gap:4px;display:flex}.hint-text{color:var(--muted);margin:0;font-size:14px}.explain-btn{border:1px solid var(--accent);color:var(--accent-dark);background:0 0;border-radius:8px;align-self:flex-start;padding:8px 14px;font-size:14px;font-weight:600}.explain-panel{border:1px solid var(--border);background:var(--card-bg);border-radius:10px;padding:12px 14px}.explain-loading{color:var(--muted);margin:0;font-size:14px}.explain-error{color:var(--danger);margin:0 0 8px;font-size:14px}.explain-text{white-space:pre-wrap;margin:0;font-size:15px;line-height:1.5}.session-empty,.session-summary{text-align:center;flex-direction:column;align-items:center;gap:16px;padding-top:80px;display:flex}