/* ===== 共用骨架（JEV 架構：A 頂部列／B 泡泡列／D 題幹＋圖／E 選項／F 回饋＋詳解／G 操作列） ===== */
:root{--r-xs:6px;--r-sm:8px;--r:12px;--r-lg:20px;
 --ease:cubic-bezier(.22,1,.36,1);--ease-out:cubic-bezier(.22,1,.36,1);--ease-in:cubic-bezier(.4,0,1,1);--ease-move:cubic-bezier(.65,0,.35,1);
 --spring:cubic-bezier(.34,1.3,.64,1);--spring-soft:cubic-bezier(.3,1.15,.6,1)}
@supports (transition-timing-function:linear(0,1)){:root{
 --spring:linear(0,.006,.025 2.8%,.101 6.1%,.539 18.9%,.721 25.3%,.849 31.5%,.937 38.1%,.968 41.8%,.991 45.7%,1.006 50.1%,1.015 55%,1.017 63.9%,1.001 85.9%,1);
 --spring-soft:linear(0,.009,.037 2.7%,.142 5.8%,.564 17.6%,.751 24.2%,.876 31.2%,.954 39.1%,.991 47.7%,1.005 56.9%,1.003 76.1%,1)}}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%;overflow-x:hidden;overflow-x:clip;scrollbar-gutter:stable}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font);font-size:16px;line-height:1.8;letter-spacing:.02em;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;overflow-x:hidden;overflow-x:clip;min-height:100dvh}
::selection{background:var(--sel);color:var(--ink)}
button{font:inherit;letter-spacing:inherit;color:inherit}
p{margin:0}
.katex{font-size:1.06em;letter-spacing:0}
.katex-display{margin:.6em 0;overflow-x:auto;overflow-y:hidden;padding:2px 0}
/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:48px;padding:0 20px;border:0;cursor:pointer;font-size:15px;font-weight:500;white-space:nowrap;text-decoration:none;touch-action:manipulation;-webkit-tap-highlight-color:transparent;position:relative;user-select:none;-webkit-user-select:none;
 transition:background-color .22s var(--ease),color .22s var(--ease),border-color .22s var(--ease),box-shadow .22s var(--ease),transform .14s var(--ease),opacity .22s var(--ease)}
.btn:focus-visible,.opt:focus-visible,.bub:focus-visible,.acc-b:focus-visible,.g1 button:focus-visible,.th-sort:focus-visible,.nav-avatar:focus-visible,.tab:focus-visible,.ctrl-select:focus-visible,.round:focus-visible,.import-row:focus-visible{outline:none;box-shadow:var(--halo)}
.btn:active:not(:disabled){transform:scale(.97)}
.btn:disabled{opacity:.45;cursor:not-allowed}
.b1{background:var(--b1-bg);color:var(--b1-fg);border-radius:999px;font-weight:600}
@media (hover:hover) and (pointer:fine){.b1:hover:not(:disabled){background:var(--b1-hover)}}
.b2{background:transparent;color:var(--ink);border:1px solid var(--line);border-radius:var(--r-sm)}
@media (hover:hover) and (pointer:fine){.b2:hover:not(:disabled){background:var(--surface);border-color:var(--line-strong)}}
.b5{background:none;color:var(--ink);padding:0 8px;border-radius:var(--r-sm);min-height:44px}
.b5::after{content:"";position:absolute;left:8px;right:8px;bottom:10px;height:1px;background:currentColor;opacity:.5;transform:scaleX(.35);transform-origin:left;transition:transform .22s var(--ease)}
@media (hover:hover) and (pointer:fine){.b5:hover::after{transform:scaleX(1)}}
.b5:disabled::after{display:none}
/* A 頂部列 */
.top{position:sticky;top:0;z-index:30;background:var(--top-bg);-webkit-backdrop-filter:saturate(1.4) blur(14px);backdrop-filter:saturate(1.4) blur(14px)}
.top-in{max-width:808px;margin:0 auto;height:56px;display:flex;align-items:center;gap:8px;padding:0 max(12px,env(safe-area-inset-right)) 0 max(8px,env(safe-area-inset-left))}
.leave{gap:2px;padding:0 10px 0 4px;font-size:15px}
.leave::after{display:none}
.title{flex:1;min-width:0;font-size:15px;font-weight:600;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;text-align:center}
.count{font-variant-numeric:tabular-nums;font-size:14px;color:var(--mute);min-width:56px;text-align:right}
.count b{color:var(--ink);font-weight:600}
.prog{height:2px;background:transparent;overflow:hidden}
.prog i{display:block;height:100%;background:var(--accent);transform-origin:left;transform:scaleX(var(--p,0));transition:transform .6s var(--ease-out)}
body[data-view=result] .count,body[data-view=result] .prog{visibility:hidden}
/* B 泡泡列 */
.wrap{max-width:808px;margin:0 auto;padding:12px max(16px,env(safe-area-inset-right)) calc(112px + env(safe-area-inset-bottom)) max(16px,env(safe-area-inset-left))}
.strip{display:flex;flex-wrap:wrap;gap:4px;margin:0 -6px 12px}
.bub{width:44px;height:44px;padding:0;border:0;background:none;cursor:pointer;display:grid;place-items:center;border-radius:50%;-webkit-tap-highlight-color:transparent;touch-action:manipulation}
.bub-d{position:relative;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;font-size:13px;font-weight:600;font-variant-numeric:tabular-nums;transition:background-color .22s var(--ease),color .22s var(--ease),box-shadow .22s var(--ease),transform .22s var(--ease)}
.bub:active .bub-d{transform:scale(.92)}
.bub-m{position:absolute;right:-5px;top:-5px;width:16px;height:16px;border-radius:50%;display:grid;place-items:center}
.bub-m svg{width:11px;height:11px}
/* D 題目卡 */
.qmeta{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:10px}
.qno{font-size:14px;color:var(--mute)} .qno b{font-variant-numeric:tabular-nums;color:var(--ink)}
.tag{font-size:12px;font-weight:600;padding:3px 8px;border-radius:var(--r-xs);letter-spacing:.03em}
.stem{font-size:18px;line-height:1.85;font-family:var(--font-stem);outline:none;text-wrap:pretty}
.stem:focus-visible{outline:none;border-radius:var(--r-xs);box-shadow:var(--halo)}
.fig{margin:16px 0 4px;display:flex;justify-content:center}
.fig svg{max-width:100%;height:auto;color:var(--ink)}
.fig .fig-hi{stroke:var(--accent)} .fig .fig-dot{fill:var(--accent)} .fig .fig-mute{fill:var(--mute)}
/* E 選項 */
.opts{display:grid;gap:10px;margin-top:20px}
.opt{position:relative;display:flex;align-items:center;gap:14px;width:100%;min-height:56px;padding:10px 16px 10px 12px;text-align:left;border:0;cursor:pointer;font-size:17px;line-height:1.6;touch-action:manipulation;-webkit-tap-highlight-color:transparent;user-select:none;-webkit-user-select:none;isolation:isolate}
.opt[aria-disabled=true]{cursor:default}
.key{flex:none;width:32px;height:32px;border-radius:50%;display:grid;place-items:center;font-size:14px;font-weight:600;font-family:var(--font-num);position:relative;z-index:1}
.txt{flex:1;min-width:0;position:relative;z-index:1;overflow-wrap:anywhere;word-break:break-word}
.tx{position:relative;z-index:1;overflow-wrap:anywhere;word-break:break-word}
.hl{position:absolute;inset:-2px -6px;z-index:0;pointer-events:none;opacity:0}
.mk{flex:none;width:24px;height:24px;display:grid;place-items:center;position:relative;z-index:1}
.mk svg{width:20px;height:20px}
/* F 回饋＋詳解（A1） */
.fb{margin-top:16px}
.verdict{display:flex;align-items:center;gap:10px;font-weight:600;font-size:16px}
.vi{flex:none;width:28px;height:28px;border-radius:50%;display:grid;place-items:center}
.vi svg{width:16px;height:16px}
.acc{margin-top:8px}
.acc-h{margin:0;font:inherit}
.acc-b{width:100%;display:flex;align-items:center;gap:12px;text-align:left;background:none;border:0;cursor:pointer;min-height:48px;padding:10px 4px;font-size:15px;font-weight:500;-webkit-tap-highlight-color:transparent;border-radius:var(--r-sm)}
.acc-b .t{flex:1}
.acc-b .chev{color:var(--mute);transition:transform .3s var(--ease-out)}
.acc-i.open .chev{transform:rotate(180deg)}
.acc-p{display:grid;grid-template-rows:0fr;transition:grid-template-rows .4s var(--ease-out)}
.acc-i.open .acc-p{grid-template-rows:1fr}
.acc-i:not(.open) .acc-p{visibility:hidden}
.acc-i.open .acc-p{visibility:visible}
.acc-p>div{overflow:hidden;min-height:0}
.acc-tx{padding:2px 4px 14px;font-size:15.5px;line-height:1.85;opacity:0;transform:translateY(-4px);transition:opacity .2s var(--ease-in),transform .25s var(--ease-in)}
.acc-i.open .acc-tx{opacity:1;transform:none;transition:opacity .35s var(--ease-out) .06s,transform .4s var(--ease-out) .06s}
.a1 .acc-i{border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.a1 .acc-b:focus-visible{box-shadow:var(--halo)}
.report{margin-top:6px;font-size:14px;color:var(--mute);padding:0 4px}
.report::after{left:4px;right:4px}
/* G 操作列 */
.bar{position:fixed;left:0;right:0;bottom:0;z-index:30;background:var(--bar-bg);padding:10px max(16px,env(safe-area-inset-right)) calc(10px + env(safe-area-inset-bottom)) max(16px,env(safe-area-inset-left));transition:transform .3s var(--ease-out),opacity .3s var(--ease-out)}
/* 上一題 | 略過 …… 下一題（1280 時交卷在略過與下一題之間，同為 B2） */
.bar-in{max-width:776px;margin:0 auto;display:flex;align-items:center;gap:8px}
.bar .prev,.bar .skip{flex:0 0 auto;min-width:5.5rem;padding:0 16px;box-sizing:border-box}
.bar .skip:disabled{cursor:default}
.bar .submit{display:none;flex:0 0 auto}
/* 下一題固定寬 9.5rem（152px）：含「確定交卷」；各題／各模式寬度不變 */
.bar .next{margin-left:auto;flex:0 0 9.5rem;width:9.5rem;min-width:9.5rem;max-width:9.5rem;padding:0 12px;justify-content:center;box-sizing:border-box}
.bar .next .nx-t{display:block;width:100%;text-align:center;white-space:nowrap}
.warn{max-width:776px;margin:0 auto;font-size:14px;color:var(--bad-ink);line-height:1.6;height:0;opacity:0;overflow:hidden;transition:opacity .22s var(--ease)}
.warn.on{height:auto;opacity:1;padding:0 2px 8px}
body[data-view=result] .bar{transform:translateY(110%);opacity:0;pointer-events:none;visibility:hidden}
@media (min-width:768px){.bar .submit{display:inline-flex}.wrap{padding-top:20px}}
/* 結算 */
.r-hero{text-align:center;padding:12px 0 4px}
.eyebrow{font-size:13px;color:var(--mute);letter-spacing:.06em;font-weight:500;margin:0}
.score{display:flex;align-items:baseline;justify-content:center;gap:6px;margin:6px 0 2px}
.score .num{font-family:var(--font-num);font-size:76px;line-height:1;font-weight:600;font-variant-numeric:tabular-nums;letter-spacing:-.02em}
.score .unit{font-size:20px;color:var(--mute);font-weight:500}
.segs{display:flex;justify-content:center;gap:6px;margin:14px 0 12px}
.segs i{width:28px;height:6px;border-radius:999px}
.msg{font-size:16px;color:var(--ink)}
.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:22px 0 18px}
.stat{padding:12px 10px;text-align:center;border-radius:var(--r)}
.stat span{display:block;font-size:12.5px;color:var(--mute)}
.stat b{display:block;font-size:16px;font-weight:600;font-variant-numeric:tabular-nums;margin-top:2px;line-height:1.5}
.r-grid{display:grid;gap:16px}
.panel{border-radius:var(--r-lg);padding:16px}
.panel h2{font-size:15px;margin:0 0 6px;font-weight:600}
.t1{width:100%;border-collapse:collapse;font-size:14.5px}
.t1 th,.t1 td{padding:11px 8px;border-bottom:1px solid var(--line);text-align:left;vertical-align:middle}
.t1 th{color:var(--mute);font-size:12.5px;font-weight:500;white-space:nowrap}
.t1 td.num{white-space:nowrap;width:1%}.t1 td:last-child{width:1%}
.t1 td:last-child{white-space:nowrap}.t1 .l3{display:block;width:max-content;margin-top:4px}
.t1 tr:last-child td{border-bottom:0}
.t1 .r{text-align:right}.t1 .num{font-variant-numeric:tabular-nums}
.ucode{display:block;font-family:var(--font-num);font-size:12px;line-height:1.4;color:var(--mute);letter-spacing:.04em}
.uname{display:block;line-height:1.5}
.l2{display:inline-flex;align-items:center;gap:6px;font-size:13px;white-space:nowrap}
.l2 i{width:7px;height:7px;border-radius:50%}
.l2.good i{background:var(--ok)}.l2.mid i{background:var(--warn)}.l2.weak i{background:var(--bad)}
.l3{display:inline-block;font-size:12px;font-weight:600;padding:1px 6px;border-radius:var(--r-xs);border:1px solid var(--line-strong);color:var(--mute);white-space:nowrap}
.rv-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:4px;flex-wrap:wrap}
.g1{position:relative;display:inline-grid;grid-template-columns:1fr 1fr;padding:3px;border-radius:999px;background:var(--g1-bg)}
.g1 button{position:relative;z-index:1;border:0;background:none;min-height:44px;min-width:44px;padding:0 14px;border-radius:999px;font-size:13.5px;cursor:pointer;color:var(--mute);transition:color .22s var(--ease);white-space:nowrap}
.g1 button[aria-selected=true]{color:var(--ink);font-weight:600}
.g1-thumb{position:absolute;top:3px;bottom:3px;left:3px;width:calc(50% - 3px);border-radius:999px;background:var(--g1-thumb);box-shadow:var(--shadow);transition:transform .2s var(--ease-out)}
.g1.two .g1-thumb{transform:translateX(100%)}
.rv-list{list-style:none;margin:0;padding:0}
.rv{padding:14px 0;border-bottom:1px solid var(--line)}
.rv:last-child{border-bottom:0}
.only-wrong .rv.ok{display:none}
.rv-q{display:flex;align-items:center;gap:8px;font-size:13.5px;color:var(--mute)}
.rv-st{display:inline-flex;align-items:center;gap:3px;font-weight:600;font-size:13px;padding:1px 8px 1px 4px;border-radius:999px}
.rv-st svg{width:14px;height:14px}
.rv.ok .rv-st{color:var(--ok-ink);background:var(--ok-soft)}.rv.bad .rv-st{color:var(--bad-ink);background:var(--bad-soft)}
.rv-stem{font-size:15px;margin-top:4px;line-height:1.75}
.rv-a{font-size:14px;color:var(--mute);margin-top:4px}
.rv-ex{font-size:14px;margin-top:6px;padding:8px 12px;border-radius:var(--r-sm);background:var(--surface-2);line-height:1.8}
.rv-ex .katex-display{margin:.3em 0}
.r-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px;align-items:center;justify-content:center;width:100%;max-width:100%;box-sizing:border-box}
.r-actions .btn{white-space:nowrap}
@media (max-width:767px){
 .r-actions{position:sticky;bottom:0;z-index:40;margin:20px 0 0;padding:10px 0 calc(10px + env(safe-area-inset-bottom));background:var(--bar-bg);-webkit-backdrop-filter:saturate(1.4) blur(14px);backdrop-filter:saturate(1.4) blur(14px);box-shadow:0 -1px 0 var(--line);display:grid;grid-template-columns:1fr 1fr;gap:8px}
 .r-actions [data-act=retry],.r-actions #retry{grid-column:1/-1}
 .r-actions .b2,.r-actions .b5{min-height:44px;width:100%}
 .r-actions .b5{justify-self:stretch;padding:0 10px;font-size:14px}
 body[data-view=result] .app-main{padding-bottom:calc(24px + env(safe-area-inset-bottom))}
 body[data-view=result] .result{padding-bottom:8px}}
@media (min-width:768px){.r-grid{grid-template-columns:minmax(0,1fr) minmax(0,1.25fr);align-items:start}.stats{grid-template-columns:repeat(3,1fr)}}
/* N1 提示 */
.toast{position:fixed;left:50%;bottom:calc(92px + env(safe-area-inset-bottom));z-index:50;transform:translate(-50%,8px);opacity:0;pointer-events:none;padding:10px 16px;border-radius:999px;background:var(--toast-bg);color:var(--toast-fg);font-size:14px;box-shadow:var(--pop-shadow);transition:opacity .2s var(--ease-in),transform .2s var(--ease-in);max-width:calc(100vw - 32px);text-align:center}
.toast.on{opacity:1;transform:translate(-50%,0);transition:opacity .3s var(--ease-out),transform .4s var(--spring)}
/* 鍵盤：提示（只在有滑鼠的裝置出現） */
.kb-hint{display:none;margin:10px 2px 0;font-size:12.5px;line-height:1.5;color:var(--mute);letter-spacing:.04em;opacity:.85}
.kb-hint kbd{font:inherit;font-size:11.5px;padding:0 5px;margin:0 1px;border-radius:4px;box-shadow:inset 0 0 0 1px var(--line-strong)}
@media (hover:hover) and (pointer:fine){.kb-hint{display:block}}
.opt:focus-visible{outline:none}
/* 換題：立刻出現，不做進／出場過渡 */
@media (prefers-reduced-motion:reduce){
 *,*::before,*::after{animation-duration:1ms!important;animation-delay:0s!important;animation-iteration-count:1!important;transition-duration:1ms!important;transition-delay:0s!important;scroll-behavior:auto!important}}