:root{--bg: #0f172a;--surface: #1e293b;--surface-hi: #334155;--text: #f1f5f9;--text-dim: #94a3b8;--accent: #60a5fa;--accent-hi: #93c5fd;--good: #34d399;--bad: #f87171;--warn: #fbbf24;--radius: 14px;--tap: 56px;--safe-top: env(safe-area-inset-top, 0);--safe-bottom: env(safe-area-inset-bottom, 0);--safe-left: env(safe-area-inset-left, 0);--safe-right: env(safe-area-inset-right, 0)}*{box-sizing:border-box}#root{display:contents}html,body{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,SF Pro Text,system-ui,sans-serif;font-size:16px;line-height:1.4;min-height:100vh;min-height:100dvh;overscroll-behavior-y:contain;-webkit-tap-highlight-color:transparent}button,input,select{font:inherit;color:inherit}button{background:var(--surface);border:1px solid var(--surface-hi);border-radius:var(--radius);padding:14px 18px;min-height:var(--tap);cursor:pointer;touch-action:manipulation}button:active{background:var(--surface-hi)}button.primary{background:var(--accent);color:#0b1220;border-color:var(--accent);font-weight:600}button.primary:active{background:var(--accent-hi)}.hidden{display:none!important}body.auth-page{display:flex;align-items:center;justify-content:center;padding:calc(24px + var(--safe-top)) 20px calc(24px + var(--safe-bottom))}.auth-card{width:100%;max-width:420px;background:var(--surface);border-radius:var(--radius);padding:24px 20px 28px}.brand{font-size:36px;margin:0 0 4px;text-align:center;font-weight:700;letter-spacing:-.5px}.brand-sub{color:var(--accent);font-size:20px;vertical-align:middle;margin-left:6px}.tabs{display:flex;gap:8px;margin:18px 0}.tab{flex:1;background:transparent;border:1px solid var(--surface-hi);color:var(--text-dim)}.tab.active{background:var(--surface-hi);color:var(--text)}.auth-form{display:flex;flex-direction:column;gap:14px}.auth-form label{display:flex;flex-direction:column;gap:6px;font-size:14px;color:var(--text-dim)}.auth-form input{background:#0b1220;border:1px solid var(--surface-hi);border-radius:10px;padding:14px;font-size:16px}.auth-form input:focus{outline:2px solid var(--accent);outline-offset:0;border-color:var(--accent)}.hint{font-size:12px;color:var(--text-dim)}.msg{min-height:1.2em;margin:4px 0 0;font-size:14px}.msg.error{color:var(--bad)}.msg.ok{color:var(--good)}body.app-page,body.stats-page{display:flex;flex-direction:column;min-height:100vh;min-height:100dvh;padding-top:var(--safe-top);padding-left:var(--safe-left);padding-right:var(--safe-right)}body.drawing-active{-webkit-user-select:none;user-select:none;-webkit-touch-callout:none}.topbar{display:flex;align-items:center;justify-content:space-between;padding:10px 14px;border-bottom:1px solid var(--surface);gap:10px}.topbar-left,.topbar-right{display:flex;align-items:center;gap:8px}.topbar .title{font-weight:600}.iconbtn{min-width:44px;min-height:44px;display:inline-flex;align-items:center;justify-content:center;text-decoration:none;color:var(--text);background:transparent;border:none;font-size:22px;padding:0;border-radius:10px}.iconbtn:active{background:var(--surface)}.iconbtn.on{background:var(--warn);color:#1a1408}.iconbtn.on:active{background:#fcd34d}.pill{background:var(--surface);border-radius:999px;padding:6px 12px;font-size:14px;color:var(--text-dim)}.card-stage{flex:1;display:flex;align-items:center;justify-content:center;padding:20px;min-height:0;position:relative}.card{width:100%;max-width:480px;background:var(--surface);border-radius:20px;padding:28px 20px 32px;display:flex;flex-direction:column;align-items:center;gap:18px;text-align:center}.card-level{color:var(--text-dim);font-size:13px;letter-spacing:1px;text-transform:uppercase}.card-front{display:flex;flex-direction:column;align-items:center;gap:10px;padding:12px 0}.card-english{font-size:28px;font-weight:500;line-height:1.2;color:var(--text);text-align:center}.card-pinyin{font-size:22px;color:var(--accent-hi);text-align:center}.card-back{display:flex;flex-direction:column;align-items:center}.card-hanzi{font-size:120px;line-height:1;font-weight:500;font-family:PingFang SC,Hiragino Sans GB,Microsoft YaHei,Heiti SC,system-ui,sans-serif;user-select:none}.empty{text-align:center;padding:40px 20px}.loading{color:var(--text-dim);padding:40px}.offline-banner{background:#7f1d1d;color:#fee2e2;text-align:center;font-size:13px;padding:8px 12px;padding-top:calc(8px + var(--safe-top));border-bottom:1px solid #991b1b;position:relative;z-index:10}.offline-banner+.topbar{padding-top:10px}.hist-banner{display:flex;align-items:center;gap:10px;background:#422006;color:#fde68a;padding:10px 14px calc(10px + var(--safe-left));font-size:13px;border-bottom:1px solid #78350f}.hist-banner.hidden{display:none}.hist-banner-text{flex:1;min-width:0}.hist-rating-chip{display:inline-block;background:#78350f;color:#fef3c7;border-radius:999px;padding:2px 8px;font-weight:600;margin-left:2px}.hist-delete{flex-shrink:0;background:transparent;border:1px solid #78350f;color:#fde68a;font-size:12px;padding:6px 10px;min-height:36px;border-radius:8px}.hist-delete:active{background:#78350f}.iconbtn:disabled{opacity:.35;cursor:not-allowed}.rate.recorded{background:#78350f;border-color:#fbbf24}.draw-canvas{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;touch-action:none}.draw-canvas.active{pointer-events:auto}.draw-hint{position:absolute;left:50%;bottom:12px;transform:translate(-50%);background:#0f172ad9;color:var(--text-dim);font-size:12px;padding:6px 10px;border-radius:999px;pointer-events:none;opacity:0;transition:opacity .2s ease}.draw-hint.visible{opacity:1}.actions{padding:12px 14px calc(14px + var(--safe-bottom));background:linear-gradient(180deg,transparent,var(--bg) 30%)}.reveal-btn{width:100%;background:var(--accent);color:#0b1220;border:none;font-weight:600;font-size:18px;min-height:64px;border-radius:16px}.reveal-btn:active{background:var(--accent-hi)}.rate-row{display:grid;grid-template-columns:repeat(5,1fr);gap:6px}.rate{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;padding:10px 4px;min-height:76px;border-radius:14px;font-size:13px}.rate .r-num{font-size:20px;font-weight:600}.rate .r-label{font-size:11px;color:var(--text-dim)}.rate .r-int{font-size:10px;color:var(--text-dim);min-height:12px}.rate[data-rating="1"]{border-color:#7f1d1d}.rate[data-rating="2"]{border-color:#92400e}.rate[data-rating="3"]{border-color:#3f6212}.rate[data-rating="4"]{border-color:#14532d}.rate[data-rating="5"]{border-color:#1e3a8a}.stats-main{padding:16px 16px calc(24px + var(--safe-bottom))}.stats-main h2{font-size:17px;margin:24px 0 10px;color:var(--text-dim);font-weight:600}.stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.stat{background:var(--surface);border-radius:var(--radius);padding:14px 8px;display:flex;flex-direction:column;align-items:center;gap:2px}.stat-num{font-size:24px;font-weight:700}.stat-lbl{font-size:12px;color:var(--text-dim)}.levels{display:flex;flex-direction:column;gap:8px}.level-row{background:var(--surface);border-radius:var(--radius);padding:12px 14px;display:flex;flex-direction:column;gap:6px}.level-row-top{display:flex;justify-content:space-between;font-size:14px}.bar{height:8px;background:#0b1220;border-radius:999px;overflow:hidden}.bar-fill{height:100%;background:var(--good)}.char-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(36px,1fr));gap:4px;margin-top:8px}.char-cell{aspect-ratio:1;display:flex;align-items:center;justify-content:center;font-size:18px;font-family:PingFang SC,Hiragino Sans GB,Microsoft YaHei,Heiti SC,system-ui,sans-serif;border-radius:6px;background:#1e293b;color:var(--text-dim)}.char-cell.known{background:#14532d;color:#d1fae5}.char-cell.learning{background:#78350f;color:#fef3c7}