/* ===== Python 题库 · 浅色简洁风（主色 Python 蓝 #3776ab + 黄 #ffd43b 点缀） ===== */
:root{
  --primary:#3776ab; --primary-dark:#2b5d8a; --primary-light:#e8f1f9;
  --accent:#d9a400; --accent-light:#fff3cd;
  --ink:#1f2937; --ink-2:#4b5563; --ink-3:#6b7280;
  --line:#e5e7eb; --bg:#f5f7fa; --card:#ffffff;
  --ok:#15803d; --ok-bg:#e9f7ee; --err:#b91c1c; --err-bg:#fdecec; --warn:#a16207;
  --code-bg:#282c34;
  --radius:12px; --shadow:0 1px 3px rgba(16,24,40,.08), 0 1px 2px rgba(16,24,40,.04);
  --shadow-lg:0 8px 24px rgba(16,24,40,.10);
  --mono:Consolas,"Cascadia Code","Cascadia Mono",Menlo,"Courier New",monospace;
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0;padding:0;max-width:100%;overflow-x:hidden}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg); color:var(--ink); font-size:15px; line-height:1.65; overflow-x:hidden}
pre,code,table,img{max-width:100%}
#app{min-height:100vh; display:flex; flex-direction:column; max-width:100%}

/* 顶栏 */
.topbar{background:var(--card); border-bottom:1px solid var(--line); position:sticky; top:0; z-index:50; box-shadow:var(--shadow)}
.topbar-inner{max-width:1080px; margin:0 auto; padding:0 16px; height:60px; display:flex; align-items:center; gap:18px}
.brand{display:flex; align-items:center; gap:10px; cursor:pointer; user-select:none}
.brand-logo{width:38px;height:38px;border-radius:10px;background:var(--primary);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:15px;font-family:var(--mono);border-bottom:3px solid #ffd43b}
.brand-text{display:flex;flex-direction:column;line-height:1.2}
.brand-text strong{font-size:16px;color:var(--ink)}
.brand-text small{font-size:11px;color:var(--ink-3)}
.mainnav{margin-left:auto; display:flex; gap:2px; flex-wrap:wrap}
.nav-item{padding:7px 12px; border-radius:8px; color:var(--ink-2); cursor:pointer; font-size:14px; text-decoration:none; white-space:nowrap; position:relative}
.nav-item:hover{background:var(--primary-light); color:var(--primary-dark)}
.nav-item.active{background:var(--primary); color:#fff}
.badge{display:inline-block;min-width:18px;height:18px;padding:0 5px;margin-left:3px;border-radius:9px;background:var(--err);color:#fff;font-size:11px;line-height:18px;text-align:center;vertical-align:middle}
.badge:empty{display:none}
.menu-btn{display:none; margin-left:auto; background:none; border:none; font-size:24px; color:var(--ink); cursor:pointer}

.container{max-width:1080px; width:100%; margin:0 auto; padding:20px 16px 40px; flex:1}
.footer{border-top:1px solid var(--line); padding:14px 16px; text-align:center; color:var(--ink-3); font-size:12px; background:var(--card)}
.footer div{max-width:1080px;margin:0 auto}

/* 通用组件 */
.card{background:var(--card); border:1px solid var(--line); border-radius:var(--radius); padding:18px; box-shadow:var(--shadow); margin-bottom:16px}
.card h2{margin:0 0 12px; font-size:17px}
.card h3{margin:16px 0 8px; font-size:15px}
.muted{color:var(--ink-3)}
.row{display:flex; gap:12px; flex-wrap:wrap}
.grid{display:grid; gap:14px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:10px 18px;border-radius:9px;border:1px solid var(--primary);background:var(--primary);color:#fff;font-size:15px;cursor:pointer;transition:.15s;font-family:inherit}
.btn:hover{background:var(--primary-dark);border-color:var(--primary-dark)}
.btn.ghost{background:#fff;color:var(--primary)}
.btn.ghost:hover{background:var(--primary-light)}
.btn.gray{background:#fff;color:var(--ink-2);border-color:var(--line)}
.btn.gray:hover{background:#f3f4f6}
.btn.sm{padding:6px 12px;font-size:13px}
.btn.block{width:100%}
.btn:disabled{opacity:.5;cursor:not-allowed}
.tag{display:inline-block;padding:1px 8px;border-radius:6px;font-size:12px;line-height:1.7;background:var(--primary-light);color:var(--primary-dark);margin-right:6px}
.tag.cert{background:#fff7e0;color:#8a6d00;border:1px solid #ffe08a}
.tag.code{background:#eef2f5;color:#33475b;border:1px solid #d3dce4}
.tag.diff1{background:#e9f7ee;color:var(--ok)}
.tag.diff2{background:#fef6e7;color:var(--warn)}
.tag.diff3{background:#fdecec;color:var(--err)}
.tag.type{background:#f1f3f5;color:var(--ink-2)}

/* 首页统计卡 */
.stat{display:flex;flex-direction:column;gap:4px;padding:16px}
.stat .num{font-size:28px;font-weight:800;color:var(--primary-dark)}
.stat .lbl{font-size:13px;color:var(--ink-3)}
.entry{display:flex;align-items:center;gap:12px;min-width:0;padding:16px;border-radius:var(--radius);background:var(--card);border:1px solid var(--line);cursor:pointer;box-shadow:var(--shadow);transition:.15s}
.entry:hover{border-color:var(--primary);transform:translateY(-1px);box-shadow:var(--shadow-lg)}
.entry .ico{width:42px;height:42px;border-radius:10px;background:var(--primary-light);color:var(--primary-dark);display:flex;align-items:center;justify-content:center;font-size:20px;flex:none}
.entry .t{font-weight:600;min-width:0}
.entry .s{font-size:12.5px;color:var(--ink-3);word-break:break-word}
.entry .arrow{margin-left:auto;color:var(--ink-3);flex:none}

/* 筛选面板 */
.filter-group{margin-bottom:14px}
.filter-group > .fg-label{font-size:13px;color:var(--ink-3);margin-bottom:6px;font-weight:600}
.chip{display:inline-block;max-width:100%;padding:5px 13px;border-radius:18px;border:1px solid var(--line);background:#fff;font-size:13px;color:var(--ink-2);cursor:pointer;margin:0 6px 6px 0;user-select:none;white-space:normal;word-break:break-word}
.chip.on{background:var(--primary);border-color:var(--primary);color:#fff}
.chip .cnt{font-size:11px;opacity:.8;margin-left:2px}
select,input[type=text],input[type=number],textarea{font-family:inherit;font-size:14px;padding:8px 10px;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--ink)}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--primary)}
.inline-num{width:80px}
.mod-group{border:1px solid var(--line);border-radius:10px;margin-bottom:8px;overflow:hidden}
.mod-group > summary{padding:9px 12px;cursor:pointer;background:#f8fafc;font-size:13.5px;font-weight:600;color:var(--ink-2);list-style:none}
.mod-group > summary::-webkit-details-marker{display:none}
.mod-group > summary::before{content:"▸ ";color:var(--primary)}
.mod-group[open] > summary::before{content:"▾ "}
.mod-chips{padding:10px 12px;word-break:break-word}

/* 进度条 */
.progress{height:8px;background:#e9edf0;border-radius:5px;overflow:hidden}
.progress > i{display:block;height:100%;background:var(--primary);border-radius:5px;transition:width .3s}

/* 题目卡 */
.q-head{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:10px}
.q-meta{font-size:12.5px;color:var(--ink-3);margin-left:auto}
.q-stem{font-size:16px;font-weight:600;line-height:1.7;margin:6px 0 16px;white-space:pre-wrap;word-break:break-word}
.q-stem .blank{display:inline-block;min-width:64px;border-bottom:1px solid var(--ink-3);text-align:center;color:var(--ink-3)}
.opts{display:flex;flex-direction:column;gap:10px}
.opt{display:flex;gap:10px;align-items:flex-start;min-width:0;padding:11px 14px;border:1.5px solid var(--line);border-radius:10px;cursor:pointer;background:#fff;transition:.12s}
.opt:hover{border-color:var(--primary)}
.opt .k{width:24px;height:24px;border-radius:50%;border:1.5px solid var(--ink-3);color:var(--ink-2);display:flex;align-items:center;justify-content:center;font-size:13px;flex:none;margin-top:1px}
.opt.sel{border-color:var(--primary);background:var(--primary-light)}
.opt.sel .k{background:var(--primary);border-color:var(--primary);color:#fff}
.opt.correct{border-color:var(--ok);background:var(--ok-bg)}
.opt.correct .k{background:var(--ok);border-color:var(--ok);color:#fff}
.opt.wrong{border-color:var(--err);background:var(--err-bg)}
.opt.wrong .k{background:var(--err);border-color:var(--err);color:#fff}
.opt.disabled{cursor:default;pointer-events:none}
.judge-opts{display:flex;gap:12px}
.judge-opts .opt{flex:1;justify-content:center;font-weight:600}
.blank-inputs{display:flex;flex-direction:column;gap:10px}
.blank-inputs .bi-row{display:flex;align-items:center;gap:8px}
.blank-inputs .bi-row label{min-width:72px;color:var(--ink-3);font-size:13px;flex:none}
.blank-inputs input{flex:1;min-width:0}

.q-actions{display:flex;gap:10px;align-items:center;margin-top:16px;flex-wrap:wrap}
.explain{margin-top:16px;border-radius:10px;padding:14px;border:1px solid var(--line);background:#f8fafb;font-size:14px;display:none}
.explain.show{display:block}
.explain .res{font-weight:700;margin-bottom:6px}
.explain .res.ok{color:var(--ok)} .explain .res.err{color:var(--err)}
.explain .ans{color:var(--primary-dark);font-weight:600}
.explain .src{margin-top:8px;font-size:12.5px;color:var(--ink-3)}
.explain .src b{color:var(--accent)}
.icon-btn{background:none;border:1px solid var(--line);border-radius:8px;padding:7px 12px;font-size:13px;color:var(--ink-2);cursor:pointer;background:#fff}
.icon-btn.on{color:var(--accent);border-color:var(--accent);background:var(--accent-light)}

/* ===== 代码块 ===== */
.codeblock{position:relative;max-width:100%;margin:8px 0 14px;border-radius:10px;overflow:hidden;background:var(--code-bg);cursor:zoom-in;box-shadow:var(--shadow)}
.codeblock > .cb-bar{display:flex;justify-content:space-between;align-items:center;padding:4px 12px;font-size:11.5px;color:#9aa3b2;background:#21252b}
.codeblock > .cb-bar .cb-zoom{color:#c9d1d9}
.codeblock pre{margin:0;padding:12px 14px;overflow-x:auto;background:transparent}
.codeblock code{font-family:var(--mono);font-size:13.5px;line-height:1.6;display:block;white-space:pre}
.cb-output{margin:8px 0 14px;border-radius:10px;border:1px solid #cfe3cf;background:#f0f7f0;padding:10px 14px}
.cb-output .cb-label{font-size:12px;color:var(--ok);font-weight:700;margin-bottom:6px}
.cb-output pre{margin:0;white-space:pre-wrap;word-break:break-all;font-family:var(--mono);font-size:13px;color:#1f3d1f}
.cb-error{margin:8px 0 14px;border-radius:10px;border:1px solid #f3c1c1;background:#fdf1f1;padding:10px 14px}
.cb-error .cb-label{font-size:12px;color:var(--err);font-weight:700;margin-bottom:4px}
.cb-error .cb-etext{font-family:var(--mono);font-size:13px;color:#7a1a1a}
.cb-stdin{margin:8px 0 14px;border-radius:10px;border:1px solid #c9d8e6;background:#f1f6fa;padding:10px 14px}
.cb-stdin .cb-label{font-size:12px;color:var(--primary-dark);font-weight:700;margin-bottom:6px}
.cb-stdin pre{margin:0;white-space:pre-wrap;word-break:break-all;font-family:var(--mono);font-size:13px;color:#1f3d55}
.opt .codeblock{margin:6px 0 0;cursor:zoom-in}
.opt .opt-text{flex:1;min-width:0}
.opt .opt-text .inline-code{font-family:var(--mono);font-size:13.5px}
code.inline-code{font-family:var(--mono);font-size:13px;background:#f1f5f9;border-radius:4px;padding:1px 5px;color:var(--primary-dark);word-break:break-word}

/* 代码全屏浮层 */
.codelightbox{position:fixed;inset:0;background:rgba(15,23,42,.92);z-index:300;display:none;align-items:center;justify-content:center;padding:20px;cursor:zoom-out;overflow:auto}
.codelightbox.show{display:flex}
.codelightbox .cb-inner{max-width:960px;width:100%;max-height:92vh;overflow:auto;border-radius:12px;box-shadow:0 12px 40px rgba(0,0,0,.4)}
.codelightbox .cb-inner pre{margin:0;padding:18px;font-size:14.5px}

/* 答题卡导航 */
.qnav{display:flex;flex-wrap:wrap;gap:7px;margin-top:10px}
.qnav a{width:34px;height:34px;display:flex;align-items:center;justify-content:center;border-radius:8px;border:1px solid var(--line);font-size:13px;cursor:pointer;background:#fff;color:var(--ink-2)}
.qnav a.done{background:var(--primary-light);border-color:var(--primary);color:var(--primary-dark)}
.qnav a.wrong{background:var(--err-bg);border-color:var(--err);color:var(--err)}
.qnav a.cur{outline:2px solid var(--primary);outline-offset:1px}
.session-top{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin-bottom:14px}
.session-top .pos{font-weight:700}
.timer{margin-left:auto;font-variant-numeric:tabular-nums;font-weight:700;color:var(--primary-dark)}

/* 列表 */
.qlist-item{padding:14px 16px;border-bottom:1px solid var(--line);cursor:pointer}
.qlist-item:hover{background:#f8fafb}
.qlist-item .ql-title{font-weight:600;margin-bottom:4px}
.qlist-item .ql-meta{font-size:12.5px;color:var(--ink-3)}
.empty{text-align:center;padding:50px 20px;color:var(--ink-3)}
.empty .big{font-size:42px;margin-bottom:8px}

/* 问答 */
.qa-wrap{display:flex;flex-direction:column;gap:14px;max-width:100%}
.qa-chat{display:flex;flex-direction:column;gap:14px;min-width:0}
.bubble{max-width:92%;min-width:0;padding:12px 15px;border-radius:12px;line-height:1.7;white-space:pre-wrap;word-break:break-word}
.bubble.user{align-self:flex-end;background:var(--primary);color:#fff;border-bottom-right-radius:4px}
.bubble.bot{align-self:flex-start;background:#fff;border:1px solid var(--line);border-bottom-left-radius:4px;width:100%;min-width:0}
.bubble.bot h4{margin:8px 0 4px;font-size:14.5px;color:var(--primary-dark)}
.bubble.bot .ref{display:inline-block;margin-top:6px;font-size:12.5px;color:var(--accent);background:var(--accent-light);padding:2px 9px;border-radius:6px;margin-right:6px}
.bubble.bot .qa-qrel{margin-top:8px;border-top:1px dashed var(--line);padding-top:8px;font-size:13.5px;display:flex;flex-wrap:wrap;gap:6px 10px}
.bubble.bot .qa-qrel a{color:var(--primary);cursor:pointer;white-space:normal;word-break:break-word}
.qa-input-bar{display:flex;gap:10px;position:sticky;bottom:10px}
.qa-input-bar input{flex:1;min-width:0;padding:12px 14px;box-shadow:var(--shadow)}
.qa-suggestions{display:flex;gap:8px;flex-wrap:wrap}
.qa-suggestions .chip{font-size:12.5px}
.bot-warn{color:var(--warn);font-size:13px;margin-top:6px}

/* 考试结果 */
.score-ring{width:150px;height:150px;border-radius:50%;display:flex;flex-direction:column;align-items:center;justify-content:center;margin:0 auto;color:#fff}
.score-ring .s-num{font-size:38px;font-weight:800;line-height:1}
.score-ring .s-lbl{font-size:13px;opacity:.9}
.dl-table{width:100%;border-collapse:collapse;font-size:13.5px}
.dl-table td{padding:7px 6px;border-bottom:1px solid var(--line);word-break:break-word}
.dl-table td:first-child{color:var(--ink-3);width:42%}
.list-filter-bar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-bottom:12px}
.list-filter-bar input[type=text]{flex:1;min-width:140px}
.list-filter-bar select{flex:none}

/* 统计 */
.accbar{display:flex;align-items:center;gap:10px;margin-bottom:8px;font-size:13.5px}
.accbar .al{width:170px;flex:none;color:var(--ink-2);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.accbar .at{flex:1}
.accbar .av{width:110px;flex:none;text-align:right;color:var(--ink-3);font-size:12.5px}

.toast{position:fixed;left:50%;bottom:30px;transform:translateX(-50%);background:#111827;color:#fff;padding:10px 18px;border-radius:10px;font-size:14px;z-index:200;opacity:0;transition:.25s;pointer-events:none;max-width:90%}
.toast.show{opacity:.95}

/* 排行榜 */
.lb-submit{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:14px 0}
.lb-submit input{flex:1;min-width:180px;padding:10px 12px;border:1px solid var(--line);border-radius:9px;font-family:inherit;font-size:14px;color:var(--ink)}
.lb-submit input:focus{outline:none;border-color:var(--primary)}
.lb-table{width:100%;border-collapse:collapse;font-size:14px}
.lb-table th{font-size:12.5px;color:var(--ink-3);text-align:left;padding:8px 6px;border-bottom:2px solid var(--line);white-space:nowrap}
.lb-table td{padding:9px 6px;border-bottom:1px solid var(--line);vertical-align:middle}
.lb-table tr.me{background:var(--primary-light)}
.lb-rank{display:inline-flex;min-width:30px;height:30px;padding:0 8px;border-radius:50%;background:#eef0f2;color:var(--ink-2);align-items:center;justify-content:center;font-weight:700;font-size:13px}
.lb-rank.r1{background:#f59e0b;color:#fff}
.lb-rank.r2{background:#94a3b8;color:#fff}
.lb-rank.r3{background:#b45309;color:#fff}
.lb-wrap{overflow-x:auto;-webkit-overflow-scrolling:touch}
.lb-tip{font-size:13px;color:var(--ink-3);margin-top:10px}
.lb-loading{text-align:center;padding:40px 0;color:var(--ink-3)}
.lk{text-decoration:none}

@media(max-width:860px){
  .grid-3,.grid-4{grid-template-columns:repeat(2,1fr)}
  .mainnav{position:fixed;top:60px;left:0;right:0;background:#fff;border-bottom:1px solid var(--line);flex-direction:column;padding:8px 14px;gap:2px;display:none;box-shadow:var(--shadow-lg);z-index:49}
  .mainnav.open{display:flex}
  .nav-item{padding:11px 12px}
  .menu-btn{display:block}
  .brand-text small{display:none}
}
@media(max-width:560px){
  .grid-2,.grid-3,.grid-4{grid-template-columns:1fr}
  .container{padding:14px 12px 30px}
  .q-stem{font-size:15px}
  .accbar .al{width:120px}
  .codeblock code{font-size:12.5px}
  .lb-table{font-size:13px}
  .lb-table th,.lb-table td{padding:8px 4px}
  .lb-submit{gap:8px}
  .lb-submit input{min-width:0;flex:1 1 100%}
}

/* ---- 图片题支持（NEUP 开源真题） ---- */
.fig{margin:10px 0;text-align:center}
.fig .q-img{display:block;max-width:100%;width:auto;margin:0 auto;border-radius:8px;cursor:zoom-in;box-shadow:0 1px 4px rgba(16,24,40,.10);transition:transform .15s}
.fig .q-img:active{transform:scale(.985)}
.fig-cap{font-size:12.5px;color:var(--ink-2);margin-top:6px}
.opt-img{max-width:100%;width:auto;max-height:200px;border-radius:6px;vertical-align:middle;background:#fff}
.exp-img{max-width:100%;width:auto;border-radius:8px;margin-top:8px;background:#fff}