:root{
  --bg:#f4f6fa; --card:#fff; --line:#e3e8f0; --txt:#1f2733; --sub:#66707f;
  --main:#2563eb; --main-d:#1d4ed8; --ok:#16a34a; --bad:#dc2626; --warn:#d97706;
  --rad:12px; --shadow:0 1px 3px rgba(20,30,50,.08),0 4px 14px rgba(20,30,50,.05);
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:"Microsoft YaHei",system-ui,sans-serif;background:var(--bg);color:var(--txt);font-size:14px}
button{font-family:inherit}

/* ===== 顶栏 ===== */
.topbar{position:sticky;top:0;z-index:50;display:flex;align-items:center;gap:18px;background:#fff;border-bottom:1px solid var(--line);padding:0 20px;height:52px}
.brand{font-weight:700;font-size:16px}
.brand .sub{font-size:11px;color:var(--sub);font-weight:400;margin-left:8px}
.topnav{display:flex;gap:6px;margin-left:auto}
.topnav button{border:none;background:transparent;padding:7px 16px;border-radius:8px;cursor:pointer;color:var(--sub);font-size:14px;font-weight:600}
.topnav button:hover{background:#eef2f8}
.topnav button.on{background:var(--main);color:#fff}
#userChip{font-size:12px;color:var(--sub);white-space:nowrap}

/* ===== 布局 ===== */
#view{max-width:1080px;margin:0 auto;padding:22px 18px 60px}
.loading{padding:60px;text-align:center;color:var(--sub)}
.page-t{font-size:19px;font-weight:700;margin-bottom:4px}
.page-sub{color:var(--sub);font-size:12.5px;margin-bottom:18px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--rad);box-shadow:var(--shadow);padding:18px;margin-bottom:16px}
.card-t{font-weight:700;font-size:15px;margin-bottom:12px;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.grid3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:12px}
@media(max-width:760px){.grid2,.grid3{grid-template-columns:1fr}}

/* ===== 表单 ===== */
label.f{display:flex;flex-direction:column;gap:5px;font-size:12.5px;color:var(--sub)}
input[type=text],input[type=number],input[type=password],input[type=datetime-local],select,textarea{
  border:1px solid var(--line);border-radius:8px;padding:8px 10px;font-size:14px;font-family:inherit;background:#fff;color:var(--txt);width:100%}
input:focus,select:focus,textarea:focus{outline:2px solid #bfdbfe;border-color:var(--main)}
textarea{resize:vertical}
.btn{display:inline-flex;align-items:center;gap:6px;border:1px solid var(--line);background:#fff;color:var(--txt);
  padding:8px 16px;border-radius:8px;cursor:pointer;font-size:14px;font-weight:600}
.btn:hover{background:#f3f6fb}
.btn:disabled{opacity:.45;cursor:not-allowed}
.btn-main{background:var(--main);border-color:var(--main);color:#fff}
.btn-main:hover{background:var(--main-d)}
.btn-ok{background:var(--ok);border-color:var(--ok);color:#fff}
.btn-danger{background:#fff;border-color:#fecaca;color:var(--bad)}
.btn-danger:hover{background:#fef2f2}
.btn-sm{padding:4px 10px;font-size:12.5px;border-radius:7px}

/* ===== 提示 / 徽标 ===== */
.msg{min-height:20px;font-size:12.5px;color:var(--ok);margin:8px 0}
.msg.err{color:var(--bad)}
.pill{display:inline-block;font-size:11.5px;padding:2px 9px;border-radius:99px;background:#eef2f8;color:var(--sub);font-weight:600}
.pill.blue{background:#dbeafe;color:var(--main-d)}
.pill.green{background:#dcfce7;color:#15803d}
.pill.red{background:#fee2e2;color:#b91c1c}
.pill.orange{background:#fef3c7;color:#b45309}
#toast{position:fixed;left:50%;bottom:36px;transform:translateX(-50%) translateY(20px);background:#1f2733;color:#fff;
  padding:10px 22px;border-radius:10px;font-size:13.5px;opacity:0;pointer-events:none;transition:.25s;z-index:999;max-width:80vw}
#toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
#toast.err{background:var(--bad)}
.hint{font-size:12px;color:var(--sub)}

/* ===== 表格 ===== */
table{width:100%;border-collapse:collapse;font-size:13px}
th,td{padding:8px 10px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
th{color:var(--sub);font-weight:600;background:#f8fafc;white-space:nowrap}
tr:hover td{background:#fafbfd}

/* ===== 考试列表卡片 ===== */
.exam-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:14px}
.exam-card{background:#fff;border:1px solid var(--line);border-radius:var(--rad);padding:18px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:8px}
.exam-card h3{font-size:15.5px}
.exam-card .meta{font-size:12.5px;color:var(--sub);display:flex;flex-direction:column;gap:4px}

/* ===== 答题页 ===== */
.q-card{background:#fff;border:1px solid var(--line);border-radius:var(--rad);padding:16px 18px;margin-bottom:12px}
.q-head{display:flex;gap:8px;align-items:center;margin-bottom:8px}
.q-no{width:26px;height:26px;border-radius:50%;background:var(--main);color:#fff;display:inline-flex;align-items:center;justify-content:center;font-size:13px;font-weight:700;flex:none}
.q-stem{font-size:14.5px;font-weight:600;white-space:pre-wrap}
.opt{display:flex;gap:8px;align-items:flex-start;padding:8px 10px;border:1px solid var(--line);border-radius:8px;margin:6px 0;cursor:pointer}
.opt:hover{background:#f5f8ff}
.opt.sel{border-color:var(--main);background:#eff6ff}
.opt .abc{font-weight:700;color:var(--main);flex:none;width:20px}
textarea.essay{min-height:110px}
.timer-bar{position:sticky;top:52px;z-index:40;background:#111827;color:#fff;border-radius:10px;padding:9px 16px;
  display:flex;gap:14px;align-items:center;margin-bottom:14px;box-shadow:var(--shadow)}
.timer-bar .t{font-size:19px;font-weight:700;font-variant-numeric:tabular-nums}
.timer-bar .t.low{color:#fca5a5}
.progress{flex:1;height:6px;background:#374151;border-radius:99px;overflow:hidden}
.progress i{display:block;height:100%;background:#60a5fa;transition:.3s}

/* ===== 结果 ===== */
.score-hero{text-align:center;padding:28px}
.score-hero .big{font-size:46px;font-weight:800;color:var(--main)}
.score-hero .big small{font-size:16px;color:var(--sub);font-weight:400}

/* ===== 管理端 ===== */
.tabs{display:flex;gap:6px;margin-bottom:16px;flex-wrap:wrap}
.tabs button{border:1px solid var(--line);background:#fff;padding:7px 18px;border-radius:99px;cursor:pointer;font-size:13.5px;font-weight:600;color:var(--sub)}
.tabs button.on{background:var(--main);border-color:var(--main);color:#fff}
.grp-list{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:10px}
.grp-tag{display:inline-flex;align-items:center;gap:6px;padding:4px 12px;border-radius:99px;border:1px solid var(--line);background:#fff;cursor:pointer;font-size:13px}
.grp-tag.on{background:var(--main);border-color:var(--main);color:#fff}
.grp-tag .x{opacity:.55;font-weight:700}
.q-item{border:1px solid var(--line);border-radius:10px;padding:10px 12px;margin-bottom:8px;background:#fff}
.q-item .stem{font-weight:600;font-size:13.5px}
.q-item .row-r{display:flex;gap:6px;margin-top:6px;flex-wrap:wrap}
.check-line{display:flex;gap:8px;align-items:flex-start;padding:6px 8px;border-radius:8px}
.check-line:hover{background:#f5f8ff}
.dlg-mask{position:fixed;inset:0;background:rgba(15,23,42,.45);display:flex;align-items:center;justify-content:center;z-index:200;opacity:0;transition:.2s}
.dlg-mask.show{opacity:1}
.dlg{background:#fff;border-radius:14px;padding:22px;width:min(460px,92vw);box-shadow:0 20px 50px rgba(0,0,0,.25)}
.dlg-t{font-weight:700;font-size:15.5px;margin-bottom:10px}
.dlg-m{font-size:13.5px;color:var(--sub);white-space:pre-wrap;margin-bottom:18px}
.dlg-btns{display:flex;gap:10px;justify-content:flex-end}
.login-box{max-width:380px;margin:60px auto}
.ans-letter{font-weight:700;color:var(--ok)}
.mono{font-family:Consolas,monospace;font-size:12px}