:root {
  --bg: #f4f6fa;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-soft: #eff4ff;
  --success: #16a34a;
  --success-soft: #ecfdf3;
  --danger: #dc2626;
  --danger-soft: #fef2f2;
  --warn: #d97706;
  --warn-soft: #fffbeb;
  --border: #e4e7ec;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(16, 24, 40, .06), 0 1px 2px rgba(16, 24, 40, .04);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
  font-size: 15px;
  line-height: 1.6;
}

a { color: var(--primary); text-decoration: none; }

/* ---------- 通用元素 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 8px 16px; border-radius: 8px; border: 1px solid var(--border);
  background: #fff; color: var(--text); font-size: 14px; cursor: pointer;
  transition: all .15s ease; white-space: nowrap;
}
.btn:hover { border-color: #c8cdd6; background: #fafbfc; }
.btn-primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); color: #fff; }
.btn-success { background: var(--success); border-color: var(--success); color: #fff; }
.btn-success:hover { filter: brightness(.94); color: #fff; }
.btn-danger { background: #fff; border-color: #f3c2c2; color: var(--danger); }
.btn-danger:hover { background: var(--danger-soft); }
.btn-sm { padding: 5px 10px; font-size: 13px; border-radius: 6px; }
.btn-lg { padding: 12px 28px; font-size: 16px; border-radius: 10px; }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-block { width: 100%; }

.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow);
}
.card-body { padding: 20px; }
.card-head {
  padding: 14px 20px; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  font-weight: 600;
}

input[type=text], input[type=password], input[type=number], select, textarea {
  width: 100%; padding: 8px 12px; border: 1px solid var(--border);
  border-radius: 8px; font-size: 14px; font-family: inherit; background: #fff; color: var(--text);
}
input:focus, select:focus, textarea:focus {
  outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37, 99, 235, .1);
}
label.field { display: block; margin-bottom: 14px; }
label.field > span { display: block; margin-bottom: 6px; font-size: 13px; color: var(--muted); }

.tag {
  display: inline-block; padding: 2px 9px; border-radius: 999px;
  font-size: 12px; background: #f1f3f7; color: var(--muted); border: 1px solid var(--border);
}
.tag-blue { background: var(--primary-soft); color: var(--primary); border-color: #d8e4ff; }
.tag-green { background: var(--success-soft); color: var(--success); border-color: #cdeed8; }
.tag-red { background: var(--danger-soft); color: var(--danger); border-color: #f6d4d4; }
.tag-orange { background: var(--warn-soft); color: var(--warn); border-color: #f5e2b8; }

.muted { color: var(--muted); }
.small { font-size: 13px; }
.row { display: flex; gap: 12px; align-items: center; }
.row-wrap { flex-wrap: wrap; }
.spacer { flex: 1; }
.mt8 { margin-top: 8px; } .mt16 { margin-top: 16px; } .mt24 { margin-top: 24px; }
.mb8 { margin-bottom: 8px; } .mb16 { margin-bottom: 16px; }
.text-right { text-align: right; }
.text-center { text-align: center; }

table.grid { width: 100%; border-collapse: collapse; font-size: 14px; }
table.grid th, table.grid td {
  padding: 10px 12px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top;
}
table.grid th { background: #fafbfc; font-weight: 600; color: var(--muted); font-size: 13px; }
table.grid tr:last-child td { border-bottom: none; }
table.grid tbody tr:hover { background: #fcfcfd; }

.empty { padding: 48px 20px; text-align: center; color: var(--muted); }

/* ---------- 布局 ---------- */
.topbar {
  background: #fff; border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50;
}
.topbar-inner {
  max-width: 1120px; margin: 0 auto; padding: 0 20px;
  display: flex; align-items: center; gap: 20px; height: 58px;
}
.brand { font-size: 17px; font-weight: 700; letter-spacing: .3px; white-space: nowrap; }
.brand i { font-style: normal; color: var(--primary); }
.nav { display: flex; gap: 4px; flex: 1; }
.nav a {
  padding: 6px 12px; border-radius: 8px; color: var(--muted);
  font-size: 14px; font-weight: 500;
}
.nav a:hover { background: #f4f6fa; color: var(--text); }
.nav a.active { background: var(--primary-soft); color: var(--primary); }
.userbox { display: flex; align-items: center; gap: 10px; font-size: 14px; }
.avatar {
  width: 30px; height: 30px; border-radius: 50%; background: var(--primary);
  color: #fff; display: flex; align-items: center; justify-content: center;
  font-size: 13px; font-weight: 600;
}
.page { max-width: 1120px; margin: 0 auto; padding: 24px 20px 60px; }
.page-narrow { max-width: 760px; }
.grid2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.grid4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
@media (max-width: 1024px) {
  .grid3, .grid4 { grid-template-columns: repeat(2, 1fr); }
  .grid2 { grid-template-columns: 1fr; }
  .nav { overflow-x: auto; }
  .topbar-inner { gap: 10px; }
  /* 平板/大屏手机：顶栏明确分两行（品牌+用户操作 / 导航横滑），避免所有按钮挤在一行 */
  .topbar-inner { height: auto; flex-wrap: wrap; padding: 8px 14px; gap: 8px; align-items: center; }
  .brand { flex: 1 1 auto; min-width: 0; }
  .userbox { flex: 0 0 auto; align-items: center; justify-content: flex-end; order: 2; gap: 8px; }
  .userbox > span:not(.avatar) { display: none; }
  /* 关键：覆盖基础样式的 flex:1，让导航占满整行并强制换到第二行 */
  .nav { order: 3; flex: 0 0 100%; width: 100%; border-top: 1px solid var(--border); padding-top: 8px; }
}

.stat {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px; box-shadow: var(--shadow);
}
.stat .num { font-size: 26px; font-weight: 700; line-height: 1.2; }
.stat .label { font-size: 13px; color: var(--muted); margin-top: 2px; }

/* ---------- 登录 ---------- */
.login-wrap { min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 20px; }
.login-box { width: 100%; max-width: 380px; }
.login-box .card-body { padding: 28px; }
.login-title { text-align: center; margin-bottom: 4px; font-size: 22px; font-weight: 700; }
.login-sub { text-align: center; color: var(--muted); font-size: 13px; margin-bottom: 22px; }
.tabs { display: flex; gap: 4px; background: #f1f3f7; padding: 4px; border-radius: 10px; margin-bottom: 20px; }
.tabs button {
  flex: 1; padding: 7px; border: none; background: transparent; border-radius: 7px;
  cursor: pointer; font-size: 14px; font-family: inherit; color: var(--muted);
}
.tabs button.active { background: #fff; color: var(--text); font-weight: 600; box-shadow: var(--shadow); }

/* ---------- 考试卡片 ---------- */
.exam-card { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.exam-card h3 { margin: 0 0 6px; font-size: 16px; }
.exam-meta { display: flex; flex-wrap: wrap; gap: 6px; margin: 10px 0 14px; }

/* ---------- 答题 ---------- */
.exam-bar {
  position: sticky; top: 58px; z-index: 40; background: #fff;
  border-bottom: 1px solid var(--border); padding: 10px 0;
}
.exam-bar-inner { max-width: 1120px; margin: 0 auto; padding: 0 20px; display: flex; align-items: center; gap: 16px; }
.timer { font-size: 17px; font-weight: 700; font-variant-numeric: tabular-nums; }
.timer.warn { color: var(--danger); }
.progress-wrap { flex: 1; height: 6px; background: #eceff4; border-radius: 999px; overflow: hidden; }
.progress-bar { height: 100%; background: var(--primary); transition: width .25s ease; }

.qcard { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); }
.qhead { padding: 16px 20px; border-bottom: 1px solid var(--border); display: flex; gap: 10px; align-items: center; }
.qstem { font-size: 16px; font-weight: 600; line-height: 1.7; padding: 18px 20px 4px; }
.qbody { padding: 12px 20px 20px; }

.opt {
  display: flex; gap: 10px; padding: 11px 14px; border: 1px solid var(--border);
  border-radius: 10px; margin-bottom: 10px; cursor: pointer; transition: all .12s ease; background: #fff;
}
.opt:hover { border-color: #b9cbef; background: #fafbff; }
.opt.selected { border-color: var(--primary); background: var(--primary-soft); }
.opt .letter {
  width: 24px; height: 24px; flex: none; border-radius: 50%; border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center; font-size: 13px; font-weight: 600; background: #fff;
}
.opt.selected .letter { background: var(--primary); border-color: var(--primary); color: #fff; }
.opt.correct { border-color: var(--success); background: var(--success-soft); }
.opt.correct .letter { background: var(--success); border-color: var(--success); color: #fff; }
.opt.wrong { border-color: var(--danger); background: var(--danger-soft); }
.opt.wrong .letter { background: var(--danger); border-color: var(--danger); color: #fff; }
.opt.disabled { cursor: default; }

/* 考试配置：题库多选标签 */
.bank-pick {
  display: inline-flex; align-items: center; gap: 6px; padding: 7px 12px;
  border: 1px solid var(--border); border-radius: 10px; background: #fff;
  cursor: pointer; font-size: 14px; user-select: none;
}
.bank-pick:hover { border-color: #b9cbef; background: #fafbff; }
.bank-pick input { margin: 0; }

.blank-input { margin-bottom: 10px; }
.blank-row { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.blank-row .no { width: 62px; flex: none; color: var(--muted); font-size: 14px; }
.blank-row input.correct { border-color: var(--success); background: var(--success-soft); }
.blank-row input.wrong { border-color: var(--danger); background: var(--danger-soft); }

.navgrid { display: flex; flex-wrap: wrap; gap: 8px; }
.navgrid button {
  width: 38px; height: 38px; border-radius: 8px; border: 1px solid var(--border);
  background: #fff; cursor: pointer; font-size: 14px; font-family: inherit; color: var(--text);
}
.navgrid button.answered { background: var(--primary-soft); border-color: #c9daff; color: var(--primary); }
.navgrid button.current { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(37, 99, 235, .18); font-weight: 700; }
.navgrid button.ok { background: var(--success-soft); border-color: #cdeed8; color: var(--success); }
.navgrid button.bad { background: var(--danger-soft); border-color: #f6d4d4; color: var(--danger); }

.answer-tip { padding: 12px 14px; border-radius: 10px; background: #f8fafc; border: 1px dashed var(--border); font-size: 14px; }
.answer-tip .ok { color: var(--success); font-weight: 600; }
.answer-tip .bad { color: var(--danger); font-weight: 600; }

/* ---------- 结果页 ---------- */
.score-box { text-align: center; padding: 28px 20px; }
.score-num { font-size: 46px; font-weight: 800; line-height: 1.1; }
.score-num.pass { color: var(--success); }
.score-num.fail { color: var(--danger); }

/* ---------- 提示 / 弹窗 ---------- */
#toast { position: fixed; top: 20px; left: 50%; transform: translateX(-50%); z-index: 9999; }
.toast-item {
  background: #1f2937; color: #fff; padding: 9px 18px; border-radius: 8px;
  margin-bottom: 8px; font-size: 14px; box-shadow: 0 4px 12px rgba(0, 0, 0, .15);
  animation: slideDown .2s ease;
}
.toast-item.error { background: var(--danger); }
.toast-item.success { background: var(--success); }
@keyframes slideDown { from { opacity: 0; transform: translateY(-8px); } to { opacity: 1; transform: none; } }

.mask {
  position: fixed; inset: 0; background: rgba(15, 23, 42, .45); z-index: 900;
  display: flex; align-items: center; justify-content: center; padding: 20px;
}
.modal {
  background: #fff; border-radius: 14px; width: 100%; max-width: 520px;
  max-height: 86vh; overflow: auto; box-shadow: 0 20px 50px rgba(0, 0, 0, .2);
}
.modal-head { padding: 16px 20px; border-bottom: 1px solid var(--border); font-weight: 600; display: flex; justify-content: space-between; align-items: center; }
.modal-body { padding: 20px; }
.modal-foot { padding: 14px 20px; border-top: 1px solid var(--border); display: flex; justify-content: flex-end; gap: 10px; }
.close-x { cursor: pointer; color: var(--muted); font-size: 20px; line-height: 1; border: none; background: none; }

.pager { display: flex; gap: 8px; justify-content: center; align-items: center; margin-top: 18px; }

.chart-bar { display: flex; align-items: flex-end; gap: 6px; height: 90px; padding: 8px 0; }
.chart-bar .col { flex: 1; background: var(--primary-soft); border-radius: 4px 4px 0 0; position: relative; min-height: 3px; }
.chart-bar .col span { position: absolute; top: -18px; left: 0; right: 0; text-align: center; font-size: 11px; color: var(--muted); }

.rule-row { display: grid; grid-template-columns: 100px 1fr 1fr auto; gap: 10px; align-items: center; margin-bottom: 10px; }
@media (max-width: 640px) { .rule-row { grid-template-columns: 1fr 1fr; } }

/* ---------- 移动端适配（手机答题） ---------- */
@media (max-width: 640px) {
  html, body { font-size: 16px; }
  /* 顶栏：第一行=品牌+用户操作（头像/改密码/退出）右对齐；第二行=导航横滑，导航本身不动 */
  .topbar-inner { height: auto; flex-wrap: wrap; padding: 7px 12px; gap: 6px; align-items: center; }
  .brand { font-size: 16px; flex: 1 1 auto; min-width: 0; }
  .userbox { gap: 6px; flex: 0 0 auto; align-items: center; justify-content: flex-end; }
  .userbox > span:not(.avatar) { display: none; }
  .userbox .btn { padding: 7px 11px; min-height: 34px; font-size: 13px; }
  .nav { order: 3; width: 100%; overflow-x: auto; margin-top: 4px; border-top: 1px solid var(--border); padding-top: 7px; }
  .nav a { padding: 6px 9px; font-size: 13px; white-space: nowrap; }
  .page { padding: 14px 12px 90px; }
  /* 更大的触控目标，手指更好点 */
  .btn { padding: 11px 16px; font-size: 15px; min-height: 42px; }
  .btn-sm { padding: 8px 12px; min-height: 36px; }
  .btn-lg { padding: 14px 28px; font-size: 17px; }
  .opt { padding: 13px 15px; font-size: 16px; }
  .opt .letter { width: 26px; height: 26px; }
  .navgrid button { width: 42px; height: 42px; font-size: 15px; }
  /* 首页/列表：考试卡片单列铺满，避免窄屏挤压与过长 */
  /* 首页统计：手机端 2x2 紧凑布局，缩小字号与内边距，减少占据空间 */
  .grid3 { grid-template-columns: 1fr; }
  .grid4 { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .stat { padding: 12px 12px; }
  .stat .num { font-size: 22px; }
  .stat .label { font-size: 12px; margin-top: 1px; }
  .card.mt24 > .card-head { flex-wrap: wrap; gap: 6px; }
  .card.mt24 > .card-head .small.muted { width: 100%; }
  .exam-card { padding: 14px; }
  .exam-card h3 { font-size: 15px; margin: 0 0 4px; }
  .exam-card .exam-meta { gap: 4px; margin: 6px 0 10px; }
  .exam-card .exam-meta .tag { font-size: 11px; padding: 1px 6px; }
  .exam-card .small.muted { font-size: 12px; margin-bottom: 10px; display: block; }
  .exam-card .btn-block { margin-top: 2px; }
  .card-body { padding: 16px; overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .card-head { padding: 12px 16px; }
  /* 答题页：答题卡移到题目下方，整列排列，避免窄屏挤压 */
  .exam-layout { flex-direction: column; }
  .exam-side { width: 100% !important; flex: 1 1 auto !important; }
  /* 顶部进度条换行，保证计时与交卷按钮始终可见 */
  .exam-bar-inner { flex-wrap: wrap; gap: 8px; row-gap: 6px; }
  .exam-bar-inner .timer { margin-left: auto; }
  /* 历史/错题库表格横向滚动，窄屏不挤不溢出 */
  table.grid { min-width: 560px; }
  .qstem { font-size: 16px; line-height: 1.6; }
  .login-box .card-body { padding: 24px 18px; }
}
@media (max-width: 380px) {
  .exam-meta .tag { font-size: 12px; }
}

/* ---------- 答题历史：手机端表格转卡片 ---------- */
@media (max-width: 768px) {
  table.history.grid { display: block; width: 100%; min-width: 0; font-size: 14px; }
  table.history.grid thead { display: none; }
  table.history.grid tbody,
  table.history.grid tr,
  table.history.grid td { display: block; width: 100%; box-sizing: border-box; }
  table.history.grid tr {
    border: 1px solid var(--border); border-radius: 12px;
    margin-bottom: 12px; box-shadow: var(--shadow); overflow: hidden;
  }
  table.history.grid td {
    border: none; border-bottom: 1px solid #f1f3f7;
    padding: 10px 14px; display: flex; align-items: center;
    justify-content: space-between; gap: 12px; text-align: right;
  }
  table.history.grid tr td:last-child { border-bottom: none; }
  table.history.grid td::before {
    content: attr(data-label); color: var(--muted);
    font-size: 13px; font-weight: 500; flex: none; text-align: left;
  }
  /* 最后一列（查看详情）不要字段名，按钮占满整行 */
  table.history.grid td:last-child { justify-content: stretch; }
  table.history.grid td:last-child::before { display: none; }
  table.history.grid td:last-child .btn { width: 100%; }
}