/* 仲达数字化学习系统 · 手机优先样式 2026-09-29 */
:root{
  --ink:#0f172a; --dim:#64748b; --line:#e2e8f0; --bg:#f6f8fb; --card:#fff;
  --ok:#16a34a; --bad:#dc2626; --brand:#0b6bcb; --brand2:#0e7490; --warn:#b45309;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);
  font:16px/1.75 -apple-system,"PingFang SC","Microsoft YaHei",system-ui,sans-serif}
a{color:var(--brand);text-decoration:none}
h1{font-size:20px;margin:0 0 10px}
h2{font-size:17px;margin:22px 0 8px}
h3{font-size:16px;margin:18px 0 6px}
h4{font-size:15px;margin:14px 0 6px}
p{margin:8px 0}
hr{border:none;border-top:1px solid var(--line);margin:18px 0}
code{background:#eef2f7;padding:1px 5px;border-radius:4px;font-family:Consolas,Monaco,monospace;font-size:14px}
pre{background:#0f172a;color:#e2e8f0;padding:12px;border-radius:8px;overflow-x:auto;font-size:13px;line-height:1.6}
pre code{background:none;color:inherit;padding:0}
table{border-collapse:collapse;width:100%;margin:10px 0;font-size:14.5px;display:block;overflow-x:auto}
th,td{border:1px solid var(--line);padding:7px 9px;text-align:left;vertical-align:top}
th{background:#f1f5f9;font-weight:600;white-space:nowrap}
blockquote{margin:10px 0;padding:9px 12px;background:#f1f5f9;border-left:3px solid var(--brand);border-radius:0 6px 6px 0}
.top{position:sticky;top:0;z-index:9;display:flex;align-items:center;gap:10px;
  background:#fff;border-bottom:1px solid var(--line);padding:10px 14px;flex-wrap:wrap}
.brand{font-weight:700;color:var(--ink)}
.top nav{margin-left:auto;display:flex;gap:12px;align-items:center;flex-wrap:wrap;font-size:14.5px}
.inline{display:inline}
button.link{background:none;border:none;color:var(--brand);font-size:14.5px;padding:0;cursor:pointer}
main{max-width:760px;margin:0 auto;padding:14px}
.foot{max-width:760px;margin:26px auto 40px;padding:0 14px;color:var(--dim);font-size:12.5px;text-align:center}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:16px;margin-bottom:14px;
  box-shadow:0 1px 2px rgba(15,23,42,.04)}
.card.wide{overflow-x:auto}
.card.login{max-width:400px;margin:6vh auto}
label{display:block;margin:12px 0;font-size:14.5px;color:var(--dim)}
input,select{display:block;width:100%;margin-top:5px;padding:11px 12px;font-size:16px;
  border:1px solid var(--line);border-radius:9px;background:#fff;color:var(--ink)}
input:focus,select:focus{outline:2px solid #bfdbfe;border-color:var(--brand)}
.btn{display:block;width:100%;margin:14px 0 0;padding:13px;font-size:16px;font-weight:600;
  text-align:center;border:1px solid var(--line);border-radius:10px;background:#fff;color:var(--ink);cursor:pointer}
.btn.primary{background:var(--brand);border-color:var(--brand);color:#fff}
.btn.block{display:block}
.row{display:flex;gap:10px;flex-wrap:wrap}
.row .btn{flex:1;min-width:120px}
.grid2 label{margin:10px 0}
.alert{padding:10px 12px;border-radius:9px;margin:10px 0;font-size:14.5px}
.alert.err{background:#fef2f2;color:#991b1b;border:1px solid #fecaca}
.alert.ok{background:#f0fdf4;color:#166534;border:1px solid #bbf7d0}
.dim{color:var(--dim);font-size:14px}
.ok{color:var(--ok)} .bad{color:var(--bad)} .big{font-size:20px}
.bar{height:9px;background:#e6edf5;border-radius:99px;overflow:hidden;margin:12px 0 6px}
.bar>div{height:100%;background:linear-gradient(90deg,var(--brand),var(--brand2))}
.stages{display:block;margin-top:12px}
.stage{display:block;border:1px solid var(--line);border-radius:10px;padding:12px;margin:9px 0;background:#fff;color:var(--ink)}
.stage.done{border-color:#bbf7d0;background:#f7fef9}
.stage.lock{opacity:.55}
.sn{font-size:12.5px;color:var(--dim)}
.st{font-size:16.5px;font-weight:600;margin:3px 0}
.meta{font-size:13px;color:var(--dim)}
.kicker{font-size:12.5px;color:var(--brand);font-weight:600;letter-spacing:.3px}
.must{background:#eff6ff;border:1px solid #bfdbfe;border-radius:9px;padding:9px 11px;font-size:14.5px}
.memo{margin:14px 0;border-left:4px solid var(--warn);background:#fffbeb;border-radius:0 8px 8px 0;padding:10px 12px}
.memo p{margin:4px 0;font-weight:600}
.note{margin:12px 0;background:#f8fafc;border:1px dashed var(--line);border-radius:9px;padding:10px 12px;font-size:14.5px}
.note ol,.note ul{margin:6px 0 6px 20px;padding:0}
.body p{margin:10px 0}
.q .stem{font-weight:600;margin:8px 0 10px}
.opt{display:block;width:100%;text-align:left;margin:8px 0;padding:12px;font-size:15.5px;line-height:1.6;
  border:1px solid var(--line);border-radius:10px;background:#fff;cursor:pointer}
.opt b{display:inline-block;width:20px;color:var(--brand)}
.opt:disabled{opacity:.85}
.opt.right{border-color:#86efac;background:#f0fdf4}
.opt.wrong{border-color:#fecaca;background:#fef2f2}
.explain{margin:12px 0 0;padding:11px 12px;border-radius:9px;font-size:14.5px}
.explain.ok{background:#f0fdf4;border:1px solid #bbf7d0}
.explain.bad{background:#fef2f2;border:1px solid #fecaca}
.qbox{border-top:1px solid var(--line);padding-top:14px;margin-top:14px}
.tbl{font-size:14px}
@media (max-width:520px){
  main{padding:10px} .card{padding:13px;border-radius:10px}
  .stage{padding:11px} .st{font-size:15.5px}
}