:root,[data-theme="bear"]{--bg:#fff7ec;--primary:#e9b98f;--secondary:#f7dcc0;--accent:#f59e8b;--ink:#6b4e3d;--muted:#81624f;--paper:#fffdf8;--line:#e4d2bf;--danger:#9b3934;--success:#396340}
[data-theme="dino"]{--bg:#eef9f3;--primary:#8fd3b6;--secondary:#cdefe0;--accent:#ffcf70;--ink:#3f5d52;--muted:#526b61;--paper:#fbfefa;--line:#c7dfd2;--danger:#963b36;--success:#315d41}
*{box-sizing:border-box}html,body{height:100%;margin:0}html{touch-action:manipulation}body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;color:var(--ink);background:var(--bg);-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent;-webkit-touch-callout:none}button{font:inherit;color:inherit;cursor:pointer;touch-action:manipulation;-webkit-user-select:none;user-select:none;border:1px solid var(--line);background:var(--paper);border-radius:15px;min-height:44px;min-width:44px;padding:10px 14px;line-height:1.4}button:active{transform:scale(.98)}button:focus{outline:2px solid var(--ink);outline-offset:2px}button:disabled{opacity:.45;cursor:default}button[aria-pressed="true"]{background:var(--secondary);border-color:var(--ink)}[hidden]{display:none!important}h1,h2,h3,p{margin:0}h1{font-size:29px;line-height:1.3;letter-spacing:-.7px}h2{font-size:21px;line-height:1.4}h3{font-size:17px}p{line-height:1.7}small,.muted{font-size:13px;color:var(--muted)}svg{display:block}img{max-width:100%;height:auto}#shell{max-width:540px;height:100%;margin:auto;display:flex;flex-direction:column;padding-top:0;padding-top:var(--safe-area-inset-top, env(safe-area-inset-top, 0px));padding-left:0;padding-left:var(--safe-area-inset-left, env(safe-area-inset-left, 0px));padding-right:0;padding-right:var(--safe-area-inset-right, env(safe-area-inset-right, 0px));background:var(--bg)}#header{display:flex;align-items:center;justify-content:space-between;min-height:60px;padding:8px 18px;flex-shrink:0}#header b{font-size:17px}#header .back{padding:8px 12px;background:transparent;border:0}#header .label{font-size:12px;letter-spacing:2px}#scroll{flex:1;min-height:0;overflow-y:auto;-webkit-overflow-scrolling:touch}main{padding:12px 20px 22px;min-height:100%}.row{display:flex;align-items:center;justify-content:space-between}.row>*+*{margin-left:10px}.stack>*+*{margin-top:16px}.section{margin-top:22px}.eyebrow{font-size:12px;letter-spacing:2px;margin-bottom:8px;color:var(--muted)}.hero{display:flex;align-items:center;margin:8px 0 20px}.hero .mascot{width:112px;height:108px;margin-left:6px;flex-shrink:0}.hero p{font-size:13px;margin-top:10px}.home-card{display:flex;width:100%;align-items:center;text-align:left;padding:18px;margin-top:12px;border-radius:22px;min-height:100px;background:var(--paper);box-shadow:0 4px 0 var(--line)}.home-card.featured{background:var(--secondary)}.card-icon{font-size:23px;font-weight:700;width:48px;height:48px;border-radius:16px;display:flex;align-items:center;justify-content:center;border:1px solid var(--line);background:var(--bg);margin-right:14px;flex-shrink:0}.home-card strong{display:block;font-size:19px;margin-bottom:5px}.home-card small{display:block}.home-card .arrow{margin-left:auto;font-size:25px;padding-left:8px}.example{border-top:1px dashed var(--line);padding-top:18px;margin-top:25px;display:flex;align-items:center;justify-content:space-between}.example b{font-size:23px}.pill{border-radius:99px;background:var(--secondary);padding:5px 11px;font-size:12px}.card{background:var(--paper);border:1px solid var(--line);border-radius:22px;padding:20px}.choices{display:flex;flex-wrap:wrap;margin:-4px}.choices>button{margin:4px;flex:1 0 auto;font-size:14px}.choices.grades>button{flex:1;min-width:60px}.group-title{font-size:14px;margin:20px 0 10px;font-weight:600}.type-choices>button{text-align:left;width:calc(100% - 8px)}.notice{font-size:13px;color:var(--muted);padding:12px 0}.primary{background:var(--ink);color:var(--paper);border-color:var(--ink);font-weight:600}.secondary{background:var(--paper)}#actions{padding:10px 20px;flex-shrink:0}#actions:empty{padding:0}#actions>button{width:100%;min-height:54px;border-radius:18px}#nav{display:flex;padding:8px 12px;padding-bottom:8px;padding-bottom:calc(8px + var(--safe-area-inset-bottom, env(safe-area-inset-bottom, 0px)));border-top:1px solid var(--line);flex-shrink:0}#nav>button{flex:1;background:transparent;border:0;padding:8px 3px;font-size:13px}#nav>button+button{margin-left:8px}#nav>button.active{background:var(--secondary);font-weight:600}.doing-top{margin-bottom:18px}.progress{height:6px;background:var(--line);border-radius:6px;margin-top:15px}.progress>i{display:block;height:6px;background:var(--ink);border-radius:6px}.question{font-size:40px;font-weight:700;text-align:center;line-height:1.4;padding:22px 0 16px;white-space:nowrap;letter-spacing:-1px}.answer-box{min-height:74px;background:var(--paper);border:2px solid var(--primary);border-radius:20px;font-size:36px;text-align:center;padding:9px 5px;font-variant-numeric:tabular-nums;margin-bottom:18px}.keypad{display:grid;grid-template-columns:repeat(3,1fr);grid-gap:8px}.key{height:64px;min-height:64px;font-size:26px;border-radius:18px;background:var(--paper);padding:6px}.key-ok{background:var(--secondary);font-size:19px;font-weight:600}.key[data-key="删除"]{font-size:19px}.key.remainder{grid-column:1 / 4;height:64px}.tiny-actions{margin-top:12px}.tiny-actions button{font-size:14px}.timer-ring{width:240px;height:240px;margin:20px auto;position:relative;border-radius:50%;display:flex;align-items:center;justify-content:center;flex-direction:column}.timer-ring strong{font-size:54px;font-variant-numeric:tabular-nums}.timer-ring small{margin-bottom:6px}.timer-ring svg{position:absolute;top:0;left:0;width:100%;height:100%;pointer-events:none}.timer-ring circle{fill:none;stroke-width:14}.timer-track{stroke:var(--secondary)}.timer-arc{stroke:var(--primary)}.timer-ring.urgent .timer-arc{stroke:var(--accent)}.timer-ring.overtime .timer-arc{stroke:var(--danger)}.timer-ring.overtime #timer-over{color:var(--danger)}.laps{padding:0;list-style:none}.laps li{display:flex;justify-content:space-between;border-bottom:1px dashed var(--line);padding:12px 0;font-size:14px}.counter{display:flex;align-items:center;justify-content:center;margin:26px 0}.counter strong{font-size:52px;min-width:110px;text-align:center}.counter button{min-width:64px;min-height:64px;font-size:26px}.counter>*+*{margin-left:12px}.result-hero{text-align:center;padding:20px 0}.result-hero .mascot{width:110px;height:100px;margin:0 auto}.score{font-size:60px;font-weight:700;margin:10px 0}.score small{font-size:20px}.stats{display:flex;text-align:center;justify-content:space-around;padding:18px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.stats b{font-size:21px;display:block}.wrong-row{padding:16px 0;border-bottom:1px solid var(--line)}.wrong-row .expr{font-size:20px;font-weight:600}.wrong-row p{font-size:14px;margin-top:7px}.wrong-row .row button{font-size:13px;padding:8px}.danger{color:var(--danger)}.success{color:var(--success)}.empty{text-align:center;padding:52px 0}.empty .mascot{width:120px;height:120px;margin:auto}.empty p{margin:22px 0}.sheet-preview{width:100%;box-shadow:0 3px 12px rgba(0,0,0,.08);border:1px solid var(--line);background:white}.sheet-meta{font-size:13px;line-height:1.8;margin-bottom:16px}.check-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));grid-gap:8px;margin-top:18px}.check-grid.four{grid-template-columns:repeat(4,minmax(0,1fr))}.check-cell{min-width:0;padding:6px 2px;min-height:60px;font-size:11px;border-radius:10px}.check-cell b{display:block;font-size:16px;margin-top:4px}.check-cell.marked{background:#fbe2dc;border-color:var(--danger);color:var(--danger)}.hint-only{font-size:28px;text-align:center;padding:80px 10px;line-height:1.8}.setting-row{padding:16px 0;border-bottom:1px solid var(--line)}.setting-row button{max-width:65%;font-size:14px}.theme-choice .mascot{width:70px;height:68px;margin:auto}.theme-choice{width:calc(50% - 8px)}.chart{display:flex;height:166px;margin:24px 0 12px;padding-top:24px}.chart-column{flex:1;min-width:0;display:flex;flex-direction:column;justify-content:flex-end;align-items:center;margin:0 1px}.chart-column i{display:block;width:70%;background:var(--primary);border-radius:5px 5px 0 0;min-height:4px;flex-shrink:0}.chart-column b,.chart-column small{font-size:10px;white-space:nowrap;font-weight:400}.chart-column b{margin-bottom:4px}.chart-column small{margin-top:6px}.tag{display:inline-block;font-size:12px;padding:2px 8px;border-radius:8px;background:var(--secondary);margin-top:7px}.record{padding:17px 0;border-bottom:1px solid var(--line)}.record b{font-size:16px}.record p{font-size:13px;margin-top:7px}.number-value{font-size:38px;text-align:center;margin:20px 0;min-height:55px}.modal-panel{position:absolute;bottom:0;left:0;right:0;max-height:94%;overflow-y:auto;padding:20px;border-radius:26px 26px 0 0;background:var(--bg);padding-bottom:20px;padding-bottom:calc(20px + var(--safe-area-inset-bottom, env(safe-area-inset-bottom, 0px)))}#modal{position:fixed;top:0;left:0;right:0;bottom:0;z-index:20;max-width:540px;margin:auto}.scrim{position:absolute;top:0;left:0;right:0;bottom:0;background:rgba(40,34,28,.4)}.modal-panel h2{font-size:19px}.modal-panel>p{margin-top:20px}.modal-actions{margin-top:24px}.modal-actions>button{flex:1}.modal-panel .album-image{width:100%;margin-top:18px}.modal-panel .keypad{margin-top:14px}#toast{flex-shrink:0;margin:0 20px 8px;padding:8px 14px;background:var(--ink);color:var(--paper);border-radius:12px;font-size:14px;line-height:1.5}#toast button{margin-left:12px;color:var(--ink)}#warning{padding:8px 20px;background:#fbe2dc;color:#9b3934;font-size:13px}button.wide{width:100%}.resume{margin-bottom:16px;width:100%;text-align:left;background:var(--secondary)}.blank-space{height:12px}@media(max-height:720px){main{padding-top:4px}.question{font-size:34px;padding:12px 0}.answer-box{min-height:60px;margin-bottom:12px;font-size:30px}.doing-top{margin-bottom:8px}.hero{margin-top:0;margin-bottom:12px}.hero .mascot{width:93px;height:94px}.home-card{min-height:86px;padding:13px 16px}.timer-ring{width:210px;height:210px;margin:12px auto}#nav{padding-top:4px;padding-bottom:4px}#header{min-height:52px}#actions{padding-top:6px;padding-bottom:6px}.example{margin-top:18px}}
.home-card.primary{color:var(--ink);font-weight:400}.hero{min-height:180px}.theme-choice[data-value="bear"]{--primary:#e9b98f;--secondary:#f7dcc0;--accent:#f59e8b;--ink:#6b4e3d}.theme-choice[data-value="dino"]{--primary:#8fd3b6;--secondary:#cdefe0;--accent:#ffcf70;--ink:#3f5d52}@media(max-height:720px){.hero{min-height:140px}}
#toast{pointer-events:none}#toast button{pointer-events:auto}

.timer-actions>button:first-child{flex:1}.timer-actions>button:last-child{flex-shrink:0;min-width:88px;white-space:nowrap}.formula-keypad{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));grid-gap:8px}.formula-keypad>button{min-height:64px;font-size:25px;padding:6px}.written-value{font-size:28px;min-height:48px;line-height:1.5;word-break:break-all}.written-error{font-size:13px;line-height:1.5;margin-bottom:8px}.written-error:empty{display:none}.written-actions>button{min-height:54px}.written-actions>button:last-child{flex:1}