/* ============================================================
   答题系统样式 - 现代化设计
   ============================================================ */
* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --purple: #8b5cf6;
  --bg: #f1f5f9;
  --card: #ffffff;
  --text: #1e293b;
  --text-light: #64748b;
  --border: #e2e8f0;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-lg: 0 10px 40px rgba(0,0,0,.12);
}
body {
  font-family: -apple-system, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 14px;
}

/* ---------- 登录页 ---------- */
.login-page {
  display: flex; align-items: center; justify-content: center;
  min-height: 100vh;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}
.login-card {
  background: #fff; border-radius: 16px; padding: 40px 36px;
  width: 380px; box-shadow: var(--shadow-lg);
}
.login-card h1 { font-size: 24px; text-align: center; color: var(--text); }
.login-card .subtitle { text-align: center; color: var(--text-light); margin: 8px 0 28px; }
.login-card form { display: flex; flex-direction: column; gap: 16px; }
.login-card label { display: flex; flex-direction: column; gap: 6px; font-size: 13px; color: var(--text-light); }
.login-card input {
  padding: 12px 14px; border: 1.5px solid var(--border); border-radius: 10px;
  font-size: 14px; outline: none; transition: all .2s;
}
.login-card input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(99,102,241,.15); }
.login-card button {
  margin-top: 8px; padding: 12px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: #fff; border: none; border-radius: 10px;
  font-size: 15px; font-weight: 600; cursor: pointer; transition: transform .15s, box-shadow .15s;
}
.login-card button:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(102,126,234,.4); }
.login-card button:disabled { opacity: .6; cursor: not-allowed; transform: none; }
.msg { min-height: 18px; font-size: 13px; text-align: center; }
.msg.error { color: var(--danger); }

/* ---------- 顶栏 ---------- */
.topbar {
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px 28px; background: #fff;
  box-shadow: 0 1px 4px rgba(0,0,0,.06);
  position: sticky; top: 0; z-index: 100;
}
.topbar-left, .topbar-right { display: flex; align-items: center; gap: 16px; }
.topbar .logo { font-size: 24px; }
.topbar h1 { font-size: 18px; font-weight: 700; color: var(--text); }
.conn-status {
  font-size: 12px; padding: 5px 12px; border-radius: 20px; font-weight: 600;
}
.conn-status.online { background: #d1fae5; color: #065f46; }
.conn-status.offline { background: #fee2e2; color: #991b1b; }
.conn-status.connecting { background: #fef3c7; color: #92400e; }

/* ---------- 布局 ---------- */
.container { max-width: 1440px; margin: 0 auto; padding: 20px; }
.panel {
  background: var(--card); border-radius: var(--radius);
  padding: 20px; box-shadow: var(--shadow); margin-bottom: 20px;
}
.section-title { display: flex; align-items: center; gap: 8px; margin-bottom: 16px; }
.section-title .icon { font-size: 20px; }
.section-title h2 { font-size: 16px; font-weight: 700; color: var(--text); }
.sub-title { font-size: 14px; color: var(--text-light); margin: 16px 0 8px; }

/* ---------- 顶栏面板 (班级+答案) ---------- */
.top-row { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.class-section, .answerkey-section { padding: 4px 0; }
.class-controls { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.class-controls select {
  padding: 8px 12px; border: 1.5px solid var(--border); border-radius: 8px;
  font-size: 13px; outline: none; min-width: 180px; background: #fff;
}
.class-controls select:focus { border-color: var(--primary); }
.class-info { margin-top: 10px; display: flex; gap: 16px; align-items: center; }
.class-count { font-size: 13px; color: var(--success); font-weight: 600; }
.current-class { font-size: 13px; color: var(--text-light); }
.answerkey-controls { display: flex; align-items: center; gap: 12px; }
.answerkey-info { font-size: 13px; color: var(--text-light); }

/* ---------- 控制面板+统计 ---------- */
.dashboard-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.control-group { padding: 12px 0; border-bottom: 1px dashed var(--border); }
.control-group:last-child { border-bottom: none; }
.control-group h3 { font-size: 14px; color: var(--text-light); margin-bottom: 10px; font-weight: 600; }
.row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.answer-row { gap: 8px; }
.row label { display: flex; align-items: center; gap: 6px; font-size: 13px; color: var(--text-light); }
.row input[type="number"], .row input[type="text"] {
  width: 80px; padding: 7px 10px; border: 1.5px solid var(--border);
  border-radius: 8px; font-size: 13px; outline: none; transition: border-color .2s;
}
.row input[type="text"] { width: 130px; }
.row input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(99,102,241,.12); }
.hint { font-size: 12px; color: var(--text-light); margin-top: 6px; }

/* ---------- 按钮 ---------- */
.btn {
  padding: 8px 16px; background: var(--primary); color: #fff;
  border: none; border-radius: 8px; font-size: 13px; font-weight: 500;
  cursor: pointer; transition: all .15s; white-space: nowrap;
}
.btn:hover { opacity: .9; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn-sm { padding: 5px 12px; font-size: 12px; }
.btn-primary { background: var(--primary); }
.btn-secondary { background: var(--text-light); }
.btn-ok { background: var(--success); }
.btn-warn { background: var(--warning); }
.btn-danger { background: var(--danger); }
.btn-success { background: var(--success); }
.btn-answer { background: var(--purple); min-width: 72px; padding: 8px 12px; }

/* ---------- 统计卡片 ---------- */
.stats-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.stat-card {
  background: #f8fafc; border-radius: 10px; padding: 16px; text-align: center;
  border-left: 4px solid var(--border); transition: transform .15s;
}
.stat-card:hover { transform: translateY(-2px); }
.stat-card.online { border-left-color: var(--success); }
.stat-card.answered { border-left-color: var(--primary); }
.stat-card.A { border-left-color: #ef4444; }
.stat-card.B { border-left-color: var(--warning); }
.stat-card.C { border-left-color: var(--success); }
.stat-card.D { border-left-color: var(--purple); }
.stat-num { font-size: 30px; font-weight: 700; color: var(--text); }
.stat-label { font-size: 12px; color: var(--text-light); margin-top: 4px; }

/* ---------- 正确率条 ---------- */
.accuracy-bar {
  background: #f1f5f9; border-radius: 8px; height: 26px;
  overflow: hidden; margin-top: 8px;
}
.accuracy-fill {
  height: 100%; background: linear-gradient(90deg, #10b981, #34d399);
  width: 0; transition: width .4s ease;
}
.accuracy-text { font-size: 13px; color: var(--text-light); margin-top: 6px; text-align: center; font-weight: 600; }

/* ---------- 表格 ---------- */
.table-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 14px; flex-wrap: wrap; gap: 12px; }
.table-actions { display: flex; gap: 10px; align-items: center; }
.table-actions input, .table-actions select {
  padding: 7px 12px; border: 1.5px solid var(--border); border-radius: 8px;
  font-size: 13px; outline: none;
}
.table-actions input:focus, .table-actions select:focus { border-color: var(--primary); }
.table-actions input { width: 180px; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; }
th, td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); font-size: 13px; }
th { background: #f8fafc; font-weight: 600; color: var(--text-light); position: sticky; top: 0; }
tbody tr { transition: background .15s; }
tbody tr:hover { background: #f8fafc; }
.empty { text-align: center; color: var(--text-light); padding: 30px; }

/* ---------- 徽章 ---------- */
.badge-ok { color: #065f46; background: #d1fae5; padding: 3px 10px; border-radius: 12px; font-size: 12px; font-weight: 500; }
.badge-err { color: #991b1b; background: #fee2e2; padding: 3px 10px; border-radius: 12px; font-size: 12px; font-weight: 500; }
.badge-gray { color: #475569; background: #e2e8f0; padding: 3px 10px; border-radius: 12px; font-size: 12px; font-weight: 500; }
.answer-badge {
  display: inline-block; width: 26px; height: 26px; line-height: 26px;
  text-align: center; border-radius: 50%; color: #fff; font-weight: 700; font-size: 13px;
}
.answer-badge.A { background: #ef4444; }
.answer-badge.B { background: var(--warning); }
.answer-badge.C { background: var(--success); }
.answer-badge.D { background: var(--purple); }

/* ---------- 弹窗 ---------- */
.modal {
  position: fixed; inset: 0; background: rgba(0,0,0,.5);
  display: flex; align-items: center; justify-content: center; z-index: 1000;
  backdrop-filter: blur(2px);
}
.modal.hidden { display: none; }
.modal-content {
  background: #fff; border-radius: 14px; width: 520px; max-width: 90vw;
  max-height: 85vh; overflow-y: auto; box-shadow: var(--shadow-lg);
  animation: modalIn .2s ease;
}
.modal-content.modal-wide { width: 720px; }
@keyframes modalIn { from { opacity: 0; transform: scale(.95); } to { opacity: 1; transform: scale(1); } }
.modal-header { display: flex; justify-content: space-between; align-items: center; padding: 18px 20px; border-bottom: 1px solid var(--border); }
.modal-header h3 { font-size: 16px; font-weight: 700; }
.modal-close { background: none; border: none; font-size: 20px; cursor: pointer; color: var(--text-light); padding: 4px 8px; border-radius: 6px; }
.modal-close:hover { background: #f1f5f9; }
.modal-body { padding: 20px; }
.modal-footer { display: flex; justify-content: flex-end; gap: 10px; padding: 16px 20px; border-top: 1px solid var(--border); }
.form-label { display: block; font-size: 13px; color: var(--text-light); margin-bottom: 6px; font-weight: 500; }
.form-input, .form-textarea {
  width: 100%; padding: 10px 12px; border: 1.5px solid var(--border);
  border-radius: 8px; font-size: 13px; outline: none; font-family: inherit;
}
.form-input:focus, .form-textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(99,102,241,.12); }
.form-textarea { resize: vertical; }

/* ---------- 答案录入网格 ---------- */
.answer-key-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 10px; max-height: 360px; overflow-y: auto; padding: 4px; }
.answer-key-item { display: flex; align-items: center; gap: 8px; }
.answer-key-item label { font-size: 13px; font-weight: 600; min-width: 50px; }
.answer-key-item select {
  flex: 1; padding: 6px 8px; border: 1.5px solid var(--border); border-radius: 6px;
  font-size: 13px; outline: none;
}
.answer-key-item select:focus { border-color: var(--primary); }

/* ---------- 班级名单编辑表格 ---------- */
.roster-table-wrap { max-height: 320px; overflow-y: auto; border: 1px solid var(--border); border-radius: 8px; }
.roster-table { width: 100%; border-collapse: collapse; }
.roster-table th { position: sticky; top: 0; background: #f8fafc; padding: 8px 10px; font-size: 12px; text-align: left; border-bottom: 1px solid var(--border); }
.roster-table td { padding: 4px 6px; border-bottom: 1px solid #f1f5f9; }
.roster-table input {
  width: 100%; padding: 5px 8px; border: 1px solid var(--border);
  border-radius: 5px; font-size: 13px; outline: none;
}
.roster-table input:focus { border-color: var(--primary); }
.roster-del { background: none; border: none; color: var(--danger); cursor: pointer; font-size: 16px; padding: 2px 6px; }
.roster-del:hover { background: #fee2e2; border-radius: 4px; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .dashboard-grid { grid-template-columns: 1fr; }
  .top-row { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}