/* ========== 在线答题系统 全局样式 ========== */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #eff6ff;
  --success: #16a34a;
  --danger: #dc2626;
  --warn: #d97706;
  --bg: #f1f5f9;
  --card: #ffffff;
  --text: #1e293b;
  --muted: #64748b;
  --border: #e2e8f0;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.08), 0 1px 2px rgba(15, 23, 42, 0.05);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ---------- 顶部栏 ---------- */
.topbar {
  background: var(--primary);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.15);
}
.topbar-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 12px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}
.brand {
  color: #fff;
  font-size: 18px;
  font-weight: 700;
  text-decoration: none;
  letter-spacing: 0.5px;
}
.nav { display: flex; gap: 4px; flex-wrap: wrap; align-items: center; }
.nav a, .nav-link {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  padding: 6px 10px;
  border-radius: 8px;
  font-size: 14px;
  transition: background 0.15s;
}
.nav a:hover, .nav-link:hover { background: rgba(255, 255, 255, 0.15); color: #fff; }
.nav a.active { background: rgba(255, 255, 255, 0.22); color: #fff; font-weight: 600; }
.nav-link { border: 1px solid rgba(255, 255, 255, 0.4); }

/* ---------- 布局 ---------- */
.container {
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 16px 48px;
  flex: 1;
}
.footer {
  text-align: center;
  color: var(--muted);
  font-size: 13px;
  padding: 16px;
}

/* ---------- 卡片 ---------- */
.card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
  margin-bottom: 16px;
  border: 1px solid rgba(226, 232, 240, 0.6);
}
.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
  gap: 8px;
  flex-wrap: wrap;
}
.card h2 { font-size: 20px; margin-bottom: 6px; }
.card h3 { font-size: 16px; margin-bottom: 12px; }

/* ---------- Flash 消息 ---------- */
.flash {
  padding: 12px 16px;
  border-radius: 10px;
  margin-bottom: 16px;
  font-size: 14px;
}
.flash-success { background: #f0fdf4; color: #166534; border: 1px solid #bbf7d0; }
.flash-error { background: #fef2f2; color: #991b1b; border: 1px solid #fecaca; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block;
  border: none;
  border-radius: 10px;
  padding: 10px 20px;
  font-size: 15px;
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: filter 0.15s, background 0.15s;
  font-family: inherit;
}
.btn:hover { filter: brightness(0.94); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-outline {
  background: #fff;
  color: var(--primary);
  border: 1px solid var(--primary);
}
.btn-danger { background: var(--danger); color: #fff; }
.btn-lg { padding: 13px 26px; font-size: 16px; border-radius: 12px; }
.btn-sm { padding: 6px 12px; font-size: 13px; border-radius: 8px; }
.btn-block { display: block; width: 100%; }

/* 小按钮（上移/下移/删除选项/批改） */
.btn-mini {
  border: 1px solid var(--border);
  background: #f8fafc;
  color: var(--muted);
  border-radius: 6px;
  padding: 2px 8px;
  cursor: pointer;
  font-size: 13px;
  line-height: 1.6;
}
.btn-mini:hover:not(:disabled) { background: var(--primary-light); color: var(--primary); }
.btn-mini:disabled { opacity: 0.35; cursor: not-allowed; }

.inline-form { display: inline; }
.link { color: var(--primary); text-decoration: none; }
.link:hover { text-decoration: underline; }

/* ---------- 表单 ---------- */
.label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin: 0 0 6px;
  color: #334155;
}
.input {
  width: 100%;
  padding: 11px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 15px;
  background: #fff;
  color: var(--text);
  font-family: inherit;
}
.input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}
.input-lg { padding: 13px 16px; font-size: 16px; }
.textarea { resize: vertical; min-height: 70px; }
.form-row { margin-bottom: 18px; }
.form-row-2col { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.form-actions { display: flex; gap: 10px; align-items: center; margin-top: 8px; }
.hint { font-size: 13px; color: var(--muted); margin-top: 8px; }
.muted { color: var(--muted); font-size: 13px; }
.label-row { display: flex; align-items: center; justify-content: space-between; margin-bottom: 8px; }
code { background: #f1f5f9; padding: 2px 6px; border-radius: 6px; font-size: 13px; }

/* 开关行 */
.switch-row {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 0;
  font-size: 14px;
  cursor: pointer;
}
.switch-row input { width: 18px; height: 18px; margin-top: 3px; }

/* ---------- 首页 ---------- */
.hero { text-align: center; padding: 24px 0 8px; }
.hero h1 { font-size: 28px; margin-bottom: 6px; }
.hero-sub { color: var(--muted); margin-bottom: 20px; }
.start-form { text-align: left; max-width: 420px; margin: 0 auto; }

/* ---------- 答题页 ---------- */
.quiz-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 12px;
  gap: 10px;
  flex-wrap: wrap;
}
.quiz-head h2 { font-size: 20px; }
.quiz-info { color: var(--muted); font-size: 14px; }

.question-card { padding-bottom: 16px; }
.question-head {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}
.qnum {
  background: var(--primary);
  color: #fff;
  min-width: 26px;
  height: 26px;
  padding: 0 5px;
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
}
.question-content {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 12px;
  white-space: pre-wrap;
  word-break: break-word;
}
.qscore { margin-left: auto; }

/* 题型标签 */
.tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}
.tag-single, .tag-multi, .tag-judge, .tag-fill, .tag-short { background: var(--primary-light); color: var(--primary); }
.tag-good { background: #f0fdf4; color: var(--success); }
.tag-bad { background: #fef2f2; color: var(--danger); }
.tag-warn { background: #fffbeb; color: var(--warn); }

/* 选项 */
.options { display: flex; flex-direction: column; gap: 8px; }
.option-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.12s, border-color 0.12s;
  font-size: 15px;
  user-select: none;
}
.option-row:hover { background: #f8fafc; border-color: #cbd5e1; }
.option-row input[type="radio"], .option-row input[type="checkbox"] {
  width: 18px; height: 18px; flex-shrink: 0; accent-color: var(--primary);
}
.opt-letter { font-weight: 700; color: var(--primary); }
.opt-text { word-break: break-word; }
.options-static .option-row { cursor: default; }

/* 提交按钮区 */
.submit-bar { margin-top: 8px; }
.actions {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-top: 20px;
  flex-wrap: wrap;
}

/* ---------- 成绩页 ---------- */
.result-card { text-align: center; }
.result-card h2 { margin-bottom: 16px; }
.result-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 12px;
}
.result-item { padding: 10px; }
.result-num { font-size: 30px; font-weight: 800; color: var(--primary); }
.result-num small { font-size: 15px; font-weight: 500; color: var(--muted); }
.result-num.score-good { color: var(--success); }
.result-num.score-bad { color: var(--danger); }
.result-label { font-size: 13px; color: var(--muted); margin-top: 2px; }
.warn-text { color: var(--warn); }
.center { text-align: center; }

/* 答题明细 */
.detail-row { padding: 14px 0; border-bottom: 1px dashed var(--border); }
.detail-row:last-child { border-bottom: none; }
.detail-answers { margin-top: 8px; display: grid; gap: 4px; }
.answer-line { font-size: 14px; word-break: break-word; }
.answer-label { color: var(--muted); }
.detail-card { margin-bottom: 12px; }
.q-score { margin-left: auto; }

/* ---------- 管理端 ---------- */
.page-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  gap: 10px;
  flex-wrap: wrap;
}
.page-head h2 { font-size: 20px; }
.page-actions { display: flex; gap: 8px; flex-wrap: wrap; }

.stat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-bottom: 20px;
}
.stat-card { text-align: center; padding: 18px 12px; margin-bottom: 0; }
.stat-num { font-size: 30px; font-weight: 800; color: var(--primary); }
.stat-label { font-size: 13px; color: var(--muted); margin-top: 2px; }

/* 表格 */
.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.table { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 560px; }
.table th, .table td { padding: 10px 12px; text-align: left; border-bottom: 1px solid var(--border); }
.table th { background: #f8fafc; color: var(--muted); font-weight: 600; white-space: nowrap; }
.table tr:last-child td { border-bottom: none; }
.nowrap { white-space: nowrap; }

.badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  margin-left: 4px;
}
.badge-ok { background: #f0fdf4; color: var(--success); }
.badge-warn { background: #fffbeb; color: var(--warn); }

.filter-bar {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
  flex-wrap: wrap;
}
.filter-link {
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 14px;
  text-decoration: none;
  color: var(--muted);
  background: #fff;
  border: 1px solid var(--border);
}
.filter-link.active { background: var(--primary); color: #fff; border-color: var(--primary); }

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  margin-top: 14px;
  flex-wrap: wrap;
}

/* 空状态 */
.empty { color: var(--muted); text-align: center; padding: 14px; }
.empty-card h2.empty { font-size: 40px; margin-bottom: 0; }

/* ---------- 管理员登录 ---------- */
.auth-wrap { display: flex; justify-content: center; padding-top: 8vh; }
.auth-card { width: 100%; max-width: 380px; text-align: center; }
.auth-card form { text-align: left; margin-top: 16px; }

/* ---------- 题目编辑 ---------- */
.option-edit-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}
.option-edit-row .input { flex: 1; }
.answer-radio, .answer-check { width: 18px; height: 18px; flex-shrink: 0; accent-color: var(--primary); }
.add-option { margin-bottom: 8px; }

/* 批改 */
.grade-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--border);
  flex-wrap: wrap;
}
.grade-label { font-size: 14px; font-weight: 600; }
.grade-input { width: 130px; }

/* 记录详情元信息 */
.attempt-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
}
.meta-label {
  display: block;
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 2px;
}

/* ---------- 移动端适配 ---------- */
@media (max-width: 768px) {
  .container { padding: 16px 12px 40px; }
  .hero h1 { font-size: 22px; }
  .result-grid { grid-template-columns: repeat(3, 1fr); gap: 6px; }
  .result-num { font-size: 22px; }
  .stat-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .form-row-2col { grid-template-columns: 1fr; gap: 14px; }
  .topbar-inner { padding: 10px 12px; }
  .brand { font-size: 16px; }
  .nav a { padding: 5px 8px; font-size: 13px; }
  .btn-lg { padding: 13px 18px; font-size: 16px; }
  .option-row { padding: 12px 12px; }
}