/* ====== 基础重置 ====== */
* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
  --primary: #4f46e5;
  --primary-light: #6366f1;
  --primary-dark: #4338ca;
  --primary-bg: #eef2ff;
  --success: #10b981;
  --success-bg: #ecfdf5;
  --danger: #ef4444;
  --danger-bg: #fef2f2;
  --warning: #f59e0b;
  --warning-bg: #fffbeb;
  --bg: #f3f4f6;
  --card: #ffffff;
  --text: #1f2937;
  --text-secondary: #4b5563;
  --text-hint: #9ca3af;
  --border: #e5e7eb;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
  --shadow-lg: 0 4px 6px rgba(0,0,0,.07), 0 2px 4px rgba(0,0,0,.04);
}
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg); color: var(--text); line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary); text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; }
input, select, textarea { font-family: inherit; font-size: 15px; }

/* ====== 布局 ====== */
.app-header {
  background: var(--primary); color: #fff; padding: 12px 16px;
  display: flex; align-items: center; gap: 12px;
  position: sticky; top: 0; z-index: 100; box-shadow: var(--shadow);
}
.app-header h1 { font-size: 18px; flex: 1; }
.app-header .header-btn {
  background: rgba(255,255,255,.15); color: #fff; border: none;
  padding: 6px 14px; border-radius: 8px; font-size: 14px; cursor: pointer;
}
.app-header .header-btn:hover { background: rgba(255,255,255,.25); }
.app-header .home-btn { font-size: 20px; }

.container { max-width: 960px; margin: 0 auto; padding: 16px; }
.container-wide { max-width: 1200px; margin: 0 auto; padding: 16px; }

/* ====== 卡片 ====== */
.card {
  background: var(--card); border-radius: var(--radius); padding: 16px;
  margin-bottom: 12px; box-shadow: var(--shadow);
}
.card-title { font-size: 16px; font-weight: 600; margin-bottom: 12px; color: var(--text); }

/* ====== 按钮 ====== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 10px 20px; border-radius: 8px; font-size: 15px; font-weight: 500;
  transition: all .15s; border: 1px solid transparent; white-space: nowrap;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #059669; }
.btn-outline { background: #fff; color: var(--primary); border-color: var(--primary); }
.btn-outline:hover { background: var(--primary-bg); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #dc2626; }
.btn-warning { background: var(--warning); color: #fff; }
.btn-warning:hover { background: #d97706; }
.btn-sm { padding: 6px 12px; font-size: 13px; border-radius: 6px; }
.btn-block { width: 100%; }
.btn-lg { padding: 14px 28px; font-size: 17px; }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-group { display: flex; gap: 8px; flex-wrap: wrap; }

/* ====== 表单 ====== */
.form-group { margin-bottom: 14px; }
.form-label { display: block; font-size: 14px; font-weight: 500; margin-bottom: 6px; color: var(--text-secondary); }
.form-input, .form-select, .form-textarea {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border);
  border-radius: 8px; font-size: 15px; background: #fff; transition: border-color .15s;
}
.form-input:focus, .form-select:focus, .form-textarea:focus {
  outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-bg);
}
.form-textarea { resize: vertical; min-height: 80px; }
.form-row { display: flex; gap: 12px; }
.form-row > * { flex: 1; }

/* ====== 首页 ====== */
.landing { min-height: 100vh; display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 20px; }
.landing-logo { font-size: 48px; margin-bottom: 8px; }
.landing-title { font-size: 24px; font-weight: 700; margin-bottom: 4px; text-align: center; }
.landing-subtitle { font-size: 15px; color: var(--text-hint); margin-bottom: 32px; text-align: center; }
.landing-cards { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; }
.landing-card {
  width: 260px; background: #fff; border-radius: 16px; padding: 28px 20px;
  text-align: center; cursor: pointer; transition: transform .15s, box-shadow .15s;
  box-shadow: var(--shadow); border: 2px solid transparent;
}
.landing-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.landing-card.admin { border-color: var(--primary); }
.landing-card.student { border-color: var(--success); }
.landing-card .icon { font-size: 48px; margin-bottom: 12px; }
.landing-card .title { font-size: 18px; font-weight: 600; margin-bottom: 6px; }
.landing-card .desc { font-size: 14px; color: var(--text-hint); }

/* ====== 导航标签 ====== */
.tabs { display: flex; gap: 4px; background: #fff; border-radius: 10px; padding: 4px; margin-bottom: 16px; box-shadow: var(--shadow); overflow-x: auto; }
.tab {
  flex: 1; padding: 10px 14px; text-align: center; font-size: 14px; font-weight: 500;
  border-radius: 8px; cursor: pointer; transition: all .15s; white-space: nowrap; color: var(--text-secondary);
}
.tab.active { background: var(--primary); color: #fff; }
.tab:hover:not(.active) { background: var(--primary-bg); }

/* ====== 统计卡片 ====== */
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 12px; margin-bottom: 16px; }
.stat-card {
  background: #fff; border-radius: 10px; padding: 16px; text-align: center; box-shadow: var(--shadow);
}
.stat-card .stat-value { font-size: 28px; font-weight: 700; color: var(--primary); }
.stat-card .stat-label { font-size: 13px; color: var(--text-hint); margin-top: 4px; }
.stat-card.success .stat-value { color: var(--success); }
.stat-card.danger .stat-value { color: var(--danger); }
.stat-card.warning .stat-value { color: var(--warning); }

/* ====== 列表项 ====== */
.list-item {
  display: flex; align-items: center; gap: 12px; padding: 12px;
  background: #fff; border-radius: 10px; margin-bottom: 8px; box-shadow: var(--shadow);
}
.list-item .item-main { flex: 1; min-width: 0; }
.list-item .item-title { font-size: 15px; font-weight: 500; }
.list-item .item-sub { font-size: 13px; color: var(--text-hint); margin-top: 2px; }
.list-item .item-badge {
  display: inline-block; padding: 2px 8px; border-radius: 4px; font-size: 12px; font-weight: 500;
}
.badge-active { background: var(--success-bg); color: var(--success); }
.badge-closed { background: var(--bg); color: var(--text-hint); }
.badge-important { background: var(--warning-bg); color: var(--warning); }
.badge-urgent { background: var(--danger-bg); color: var(--danger); }

/* ====== 表格 ====== */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; background: #fff; border-radius: 10px; overflow: hidden; box-shadow: var(--shadow); }
th { background: var(--primary-bg); color: var(--text-secondary); font-size: 13px; font-weight: 600; text-align: left; padding: 10px 12px; }
td { padding: 10px 12px; font-size: 14px; border-top: 1px solid var(--border); }
tr:hover { background: #fafafa; }
.text-center { text-align: center; }
.text-success { color: var(--success); }
.text-danger { color: var(--danger); }

/* ====== 签到码展示 ====== */
.code-display {
  background: #fff; border-radius: 16px; padding: 32px; text-align: center; box-shadow: var(--shadow-lg); margin-bottom: 16px;
}
.code-display .code-label { font-size: 14px; color: var(--text-hint); margin-bottom: 8px; }
.code-display .code-number {
  font-size: 56px; font-weight: 800; letter-spacing: 8px; color: var(--primary);
  font-family: 'Courier New', monospace; margin: 8px 0;
}
.code-display .code-title { font-size: 18px; font-weight: 600; margin-bottom: 4px; }
.code-display .code-info { font-size: 14px; color: var(--text-hint); }
.code-display img { margin: 16px auto; display: block; max-width: 240px; }

/* ====== 学员签到页 ====== */
.checkin-page { min-height: 100vh; display: flex; flex-direction: column; align-items: center; padding: 20px; }
.checkin-input {
  width: 100%; max-width: 320px; text-align: center; font-size: 32px; letter-spacing: 8px;
  padding: 16px; border: 2px solid var(--border); border-radius: 12px; margin-bottom: 16px;
}
.checkin-input:focus { border-color: var(--primary); outline: none; }
.student-search {
  width: 100%; max-width: 400px; padding: 12px 16px; font-size: 16px;
  border: 1px solid var(--border); border-radius: 10px; margin-bottom: 8px;
}
.student-list-search {
  max-height: 300px; overflow-y: auto; width: 100%; max-width: 400px;
}
.student-option {
  padding: 14px 16px; border-bottom: 1px solid var(--border); cursor: pointer;
  font-size: 15px; display: flex; align-items: center; gap: 8px;
}
.student-option:hover { background: var(--primary-bg); }
.student-option.selected { background: var(--primary-bg); border-left: 3px solid var(--primary); }

/* ====== 备忘录 ====== */
.memo-card {
  background: #fff; border-radius: 10px; padding: 16px; margin-bottom: 12px; box-shadow: var(--shadow);
  border-left: 4px solid var(--primary);
}
.memo-card.priority-important { border-left-color: var(--warning); }
.memo-card.priority-urgent { border-left-color: var(--danger); }
.memo-card.pinned { background: #fffbeb; }
.memo-header { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.memo-title { font-size: 16px; font-weight: 600; flex: 1; }
.memo-meta { font-size: 12px; color: var(--text-hint); }
.memo-content { font-size: 14px; color: var(--text-secondary); white-space: pre-wrap; margin-bottom: 8px; line-height: 1.7; }
.memo-footer { display: flex; align-items: center; gap: 8px; font-size: 13px; }
.memo-comments { margin-top: 8px; border-top: 1px solid var(--border); padding-top: 8px; }
.memo-comment { padding: 6px 0; font-size: 13px; border-bottom: 1px solid #f3f4f6; }
.memo-comment:last-child { border-bottom: none; }
.memo-comment .comment-author { font-weight: 500; color: var(--primary); }
.memo-comment .comment-time { color: var(--text-hint); font-size: 12px; }

/* ====== Toast ====== */
.toast {
  position: fixed; bottom: 20px; left: 50%; transform: translateX(-50%);
  background: #1f2937; color: #fff; padding: 12px 24px; border-radius: 8px;
  font-size: 14px; z-index: 9999; opacity: 0; transition: opacity .3s, transform .3s;
  pointer-events: none;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(-4px); }
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }

/* ====== 模态框 ====== */
.modal-overlay {
  position: fixed; top: 0; left: 0; width: 100%; height: 100%;
  background: rgba(0,0,0,.4); z-index: 200; display: flex; align-items: center; justify-content: center;
  padding: 20px;
}
.modal {
  background: #fff; border-radius: 16px; padding: 24px; max-width: 500px; width: 100%;
  max-height: 80vh; overflow-y: auto; box-shadow: 0 20px 60px rgba(0,0,0,.2);
}
.modal h2 { font-size: 20px; margin-bottom: 16px; }
.modal-close { float: right; font-size: 24px; color: var(--text-hint); cursor: pointer; background: none; border: none; }

/* ====== 进度条 ====== */
.progress-bar { width: 100%; height: 8px; background: var(--border); border-radius: 4px; overflow: hidden; margin: 8px 0; }
.progress-bar .fill { height: 100%; background: var(--success); border-radius: 4px; transition: width .3s; }

/* ====== 搜索栏 ====== */
.search-bar {
  display: flex; gap: 8px; margin-bottom: 12px; flex-wrap: wrap;
}
.search-bar input { flex: 1; min-width: 200px; }

/* ====== 空状态 ====== */
.empty-state { text-align: center; padding: 48px 20px; color: var(--text-hint); }
.empty-state .icon { font-size: 48px; margin-bottom: 12px; }

/* ====== 响应式 ====== */
@media (max-width: 640px) {
  .container, .container-wide { padding: 10px; }
  .app-header { padding: 10px 12px; }
  .app-header h1 { font-size: 16px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .code-display .code-number { font-size: 40px; letter-spacing: 4px; }
  .form-row { flex-direction: column; gap: 0; }
  .btn-group { flex-direction: column; }
  .btn-group .btn { width: 100%; }
  .landing-cards { flex-direction: column; }
  .landing-card { width: 100%; max-width: 300px; }
}

/* ====== 全屏签到展示 ====== */
.fullscreen-code {
  position: fixed; top: 0; left: 0; width: 100%; height: 100%;
  background: #fff; z-index: 999; display: flex; flex-direction: column;
  align-items: center; justify-content: center; padding: 20px;
}
.fullscreen-code .close-btn {
  position: absolute; top: 20px; right: 20px; font-size: 28px;
  background: none; border: none; cursor: pointer; color: var(--text-hint);
}
.fullscreen-code .code-label { font-size: 18px; color: var(--text-hint); margin-bottom: 8px; }
.fullscreen-code .code-number { font-size: 120px; font-weight: 800; letter-spacing: 16px; color: var(--primary); font-family: 'Courier New', monospace; }
.fullscreen-code .code-title { font-size: 24px; margin-top: 16px; }
.fullscreen-code img { max-width: 300px; margin-top: 24px; }

/* ====== 文件上传 ====== */
.file-upload {
  border: 2px dashed var(--border); border-radius: 12px; padding: 24px;
  text-align: center; cursor: pointer; transition: border-color .15s; background: #fafafa;
}
.file-upload:hover { border-color: var(--primary); }
.file-upload .icon { font-size: 36px; margin-bottom: 8px; }
.file-upload input[type=file] { display: none; }


@keyframes pulse-dot { 0%, 100% { opacity: 1; } 50% { opacity: 0.3; } }

/* 签到状态表格 - 粘性表头 */
#student-table thead th { position: sticky; top: 0; background: #fafbfc; z-index: 1; }
#student-table tbody tr { border-bottom: 1px solid var(--border); }

/* 状态徽章动画 */
.status-badge { transition: all 0.3s; }