:root{--primary: #4f6ef7;--primary-dark: #3b56d4;--bg: #f5f7ff;--card: #ffffff;--text: #2b2f3a;--muted: #7a8199;--border: #dfe3f3;--accent: #ff9f43}*{box-sizing:border-box}body{margin:0;font-family:PingFang SC,Microsoft YaHei,Noto Sans SC,system-ui,sans-serif;background:var(--bg);color:var(--text)}#app{max-width:720px;margin:0 auto;padding:24px 16px 64px}header{display:flex;align-items:center;justify-content:space-between;gap:12px}h1{font-size:22px;margin:0}.badge{background:var(--primary);color:#fff;border-radius:999px;padding:4px 14px;font-size:14px;white-space:nowrap}.toolbar{display:flex;gap:8px}.toolbar button{border:1px solid var(--border);background:#fff;border-radius:8px;padding:6px 10px;font-size:13px;color:var(--muted);cursor:pointer}.toolbar button:hover{border-color:var(--primary);color:var(--primary)}.import-zone{margin-top:20px;border:2px dashed var(--primary);border-radius:16px;background:#eef1ff;padding:28px 20px;text-align:center;transition:background .15s}.import-zone.dragover{background:#dde4ff}.import-zone h2{font-size:17px;margin:0 0 6px}.import-zone p{margin:4px 0;color:var(--muted);font-size:13px}.import-actions{margin-top:12px;display:flex;gap:10px;justify-content:center;flex-wrap:wrap}.btn{background:var(--primary);color:#fff;border:none;border-radius:10px;padding:10px 18px;font-size:15px;cursor:pointer}.btn:hover{background:var(--primary-dark)}.btn.ghost{background:#fff;color:var(--primary);border:1px solid var(--primary)}textarea#paste-area{width:100%;min-height:90px;margin-top:12px;border:1px solid var(--border);border-radius:10px;padding:10px;font-size:14px;font-family:inherit;resize:vertical}.progress-bar{margin-top:20px;height:8px;background:#e6e9f7;border-radius:4px;overflow:hidden}.progress-bar>div{height:100%;background:var(--accent);transition:width .2s}.flashcard{margin-top:16px;background:var(--card);border:1px solid var(--border);border-radius:20px;min-height:300px;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:32px 20px;cursor:pointer;box-shadow:0 6px 24px #4f6ef714;position:relative;-webkit-user-select:none;user-select:none}.hanzi{font-size:120px;line-height:1.2}.pinyin{font-size:40px;color:var(--primary);font-weight:600}.words{margin-top:14px;font-size:17px;color:var(--muted)}.words b{color:var(--text);font-weight:600}.flip-hint{position:absolute;bottom:12px;font-size:12px;color:var(--muted)}.speak-btn{position:absolute;top:14px;right:14px;border:none;background:#eef1ff;border-radius:50%;width:44px;height:44px;font-size:20px;cursor:pointer}.speak-btn:hover{background:#dde4ff}.rate-row{margin-top:16px;display:flex;gap:10px;justify-content:center;flex-wrap:wrap}.rate-row .btn{min-width:120px}.btn.again{background:#e25555}.btn.again:hover{background:#c94141}.btn.good{background:var(--primary)}.btn.good:hover{background:var(--primary-dark)}.btn.easy{background:#2fb469}.btn.easy:hover{background:#269157}.done-box{text-align:center;margin-top:40px}.done-box h2{font-size:20px}.done-box p{color:var(--muted)}.notice{margin-top:12px;font-size:14px;border-radius:10px;padding:10px 12px}.notice.ok{background:#e5f7ec;color:#1c7a43}.notice.warn{background:#fff3e0;color:#a06010}.stats{margin-top:8px;font-size:13px;color:var(--muted)}kbd{background:#eef1ff;border:1px solid var(--border);border-radius:4px;padding:1px 6px;font-size:12px;font-family:inherit}.help{margin-top:18px;font-size:13px;color:var(--muted);line-height:1.8}