:root{--bg: #fff7ee;--bg2: #ffe7d2;--ink: #3a2f2a;--muted: #8c7d70;--coral: #ff7a59;--coral-d: #e95f3e;--teal: #2bb3a3;--gold: #f6b73c;--card: #ffffff;--line: #f0e2d2;font-family:-apple-system,BlinkMacSystemFont,PingFang SC,Microsoft YaHei,Segoe UI,sans-serif}*{box-sizing:border-box;margin:0;padding:0}body{min-height:100vh;background:linear-gradient(165deg,var(--bg),var(--bg2));color:var(--ink);-webkit-font-smoothing:antialiased}#app{max-width:720px;margin:0 auto;padding:24px 20px 48px}.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:22px}.brand{display:flex;align-items:center;gap:12px}.logo{display:grid;place-items:center;width:48px;height:48px;border-radius:14px;background:var(--coral);color:#fff;font-size:24px;font-weight:700;box-shadow:0 6px 16px #ff7a5959}.brand-text h1{font-size:22px;letter-spacing:.5px}.subtitle{font-size:13px;color:var(--muted);margin-top:2px}.badge{flex-shrink:0;background:#fff;border:2px solid var(--line);border-radius:999px;padding:8px 16px;font-size:14px;color:var(--muted)}.badge strong{font-size:20px;color:var(--coral-d);margin:0 2px}.card-panel{background:var(--card);border-radius:22px;padding:28px 26px;box-shadow:0 12px 36px #3a2f2a1a}.card-panel h2{font-size:19px;margin-bottom:8px}.hint{font-size:14px;line-height:1.7;color:var(--muted)}.dropzone{margin:18px 0 14px;border:2.5px dashed #e3c9a8;border-radius:18px;padding:34px 16px;text-align:center;background:#fffdf9;transition:border-color .15s,background .15s}.dropzone.hover{border-color:var(--coral);background:#fff2ec}.dz-icon{font-size:40px}.dz-main{font-size:16px;font-weight:600;margin-top:6px}.dz-sub{font-size:13px;color:var(--muted);margin-top:4px}.paste-row{display:flex;flex-direction:column;gap:10px}textarea#paste{width:100%;min-height:88px;resize:vertical;border:2px solid var(--line);border-radius:14px;padding:12px 14px;font-size:15px;font-family:inherit;color:var(--ink)}textarea#paste:focus{outline:none;border-color:var(--teal)}.btn-primary{align-self:flex-start;background:var(--coral);color:#fff;border:none;border-radius:12px;padding:11px 22px;font-size:15px;font-weight:600;cursor:pointer;box-shadow:0 6px 14px #ff7a594d}.btn-primary:hover{background:var(--coral-d)}.btn-text{margin-top:18px;background:none;border:none;color:var(--muted);font-size:13px;cursor:pointer}.btn-text:hover{color:var(--coral-d)}.error{margin-top:14px;color:var(--coral-d);font-size:14px}.review{text-align:center}.card-wrap{position:relative;perspective:1200px}.speaker{position:absolute;top:12px;right:12px;z-index:3;width:44px;height:44px;border-radius:50%;border:2px solid var(--line);background:#fff;font-size:20px;cursor:pointer;box-shadow:0 4px 10px #3a2f2a1f}.speaker:hover:not(.disabled){background:#fff2ec;border-color:var(--coral)}.speaker.disabled{opacity:.4;cursor:not-allowed}.flashcard{position:relative;width:100%;height:320px;transform-style:preserve-3d;transition:transform .45s ease;cursor:pointer}.flashcard.flipped{transform:rotateY(180deg)}.face{position:absolute;top:0;right:0;bottom:0;left:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;border-radius:20px;backface-visibility:hidden;-webkit-backface-visibility:hidden;padding:24px}.face.front{background:linear-gradient(160deg,#fff,#fff4ea);border:2px solid var(--line)}.face.back{background:linear-gradient(160deg,#effaf8,#d9f2ee);border:2px solid #bfe6df;transform:rotateY(180deg)}.char{font-size:132px;line-height:1;font-weight:600;color:var(--ink)}.face-tip{font-size:13px;color:var(--muted)}.pinyin{font-size:56px;font-weight:600;color:var(--teal)}.pinyin.missing{font-size:30px;color:var(--muted)}.words{font-size:19px;color:var(--ink)}kbd{background:#fff;border:1px solid var(--line);border-bottom-width:2px;border-radius:6px;padding:1px 7px;font-size:12px;font-family:inherit}.ai-entry{margin-top:4px;background:#fff;border:1.5px solid var(--gold);color:var(--coral-d);border-radius:999px;padding:7px 16px;font-size:13px;cursor:pointer}.ai-entry:hover{background:#fff8e8}.ai-panel{margin-top:6px;max-width:380px;background:#fffdf3;border:1px solid #f0e0b8;border-radius:12px;padding:12px 14px;font-size:14px;line-height:1.6}.ai-note{margin-top:6px;font-size:12px;color:var(--muted)}.ratings{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:20px}.rating{display:flex;flex-direction:column;align-items:center;gap:4px;padding:12px 6px;border-radius:14px;border:2px solid var(--line);background:#fff;cursor:pointer;transition:transform .1s,box-shadow .1s}.rating:hover:not(:disabled){transform:translateY(-2px);box-shadow:0 6px 14px #3a2f2a1f}.rating:disabled{opacity:.45;cursor:not-allowed}.rk{display:grid;place-items:center;width:26px;height:26px;border-radius:8px;font-size:14px;font-weight:700;color:#fff}.rl{font-size:13px;color:var(--ink)}.rating.r0 .rk{background:#e96a6a}.rating.r1 .rk{background:var(--gold)}.rating.r2 .rk{background:#6aa9e9}.rating.r3 .rk{background:var(--teal)}.kbd-hint{margin-top:14px;font-size:13px;color:var(--muted)}.done{text-align:center}.done-emoji{font-size:56px}.done h2{margin:10px 0}.done 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