/* 通用学习卡组样式 */
:root {
  --primary-color: #3a86ff;
  --secondary-color: #8338ec;
  --success-color: #38b000;
  --danger-color: #e63946;
  --warning-color: #ffbe0b;
  --bg-color: #f6f8fb;
  --card-color: #ffffff;
  --text-color: #1f2937;
  --muted-color: #6b7280;
  --border-color: #e5e7eb;
  --border-radius: 12px;
  --box-shadow: 0 2px 12px rgba(15, 23, 42, .06);
  --transition: all .2s ease;
}
body.dark-mode {
  --bg-color: #0f172a;
  --card-color: #1e293b;
  --text-color: #e2e8f0;
  --muted-color: #94a3b8;
  --border-color: #334155;
  --box-shadow: 0 2px 12px rgba(0, 0, 0, .4);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg-color); color: var(--text-color); line-height: 1.6;
  transition: background .25s ease, color .25s ease;
}
.container { max-width: 1400px; margin: 0 auto; padding: 0 20px; }

/* 头部 */
.header {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: #fff; padding: 38px 30px; border-radius: 0 0 var(--border-radius) var(--border-radius);
  margin-bottom: 26px;
}
.header h1 { font-size: 2rem; margin-bottom: 8px; font-weight: 800; }
.header .subtitle { opacity: .9; font-size: .98rem; }

/* 布局 */
.layout { display: grid; grid-template-columns: 260px 1fr; gap: 24px; align-items: start; }
@media (max-width: 900px) { .layout { grid-template-columns: 1fr; } }

/* 侧栏 */
.sidebar { position: sticky; top: 20px; display: flex; flex-direction: column; gap: 18px; }
@media (max-width: 900px) { .sidebar { position: static; } }
.sidebar-section {
  background: var(--card-color); border-radius: var(--border-radius);
  box-shadow: var(--box-shadow); padding: 18px;
}
.sidebar-section h3 { font-size: .95rem; margin-bottom: 12px; color: var(--muted-color); display: flex; align-items: center; gap: 8px; }
.group-filters { display: flex; flex-direction: column; gap: 4px; }
.group-filter {
  display: flex; align-items: center; gap: 10px; padding: 9px 10px;
  border-radius: 8px; cursor: pointer; font-size: .92rem; transition: var(--transition);
  border: 1px solid transparent;
}
.group-filter:hover { background: var(--bg-color); }
.group-filter.active { background: rgba(58, 134, 255, .1); border-color: rgba(58, 134, 255, .3); font-weight: 600; }
.group-color { width: 10px; height: 10px; border-radius: 50%; flex: none; }
.group-name { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.group-count { font-size: .8rem; color: var(--muted-color); }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; text-align: center; }
.stat { display: flex; flex-direction: column; gap: 2px; }
.stat-value { font-size: 1.25rem; font-weight: 800; color: var(--primary-color); }
.stat-label { font-size: .78rem; color: var(--muted-color); }
.sidebar-actions { display: flex; flex-direction: column; gap: 8px; }
.action-btn {
  display: flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 12px; border-radius: 8px; border: none; cursor: pointer;
  background: var(--primary-color); color: #fff; text-decoration: none;
  font-size: .92rem; transition: var(--transition); width: 100%;
}
.action-btn:hover { filter: brightness(1.08); }
.action-btn.secondary { background: var(--bg-color); color: var(--text-color); border: 1px solid var(--border-color); }

/* 工具栏 */
.toolbar { display: flex; flex-direction: column; gap: 12px; margin-bottom: 22px; }
.search-box { position: relative; }
.search-icon { position: absolute; left: 14px; top: 50%; transform: translateY(-50%); color: var(--muted-color); }
.search-box input {
  width: 100%; padding: 13px 42px; border-radius: var(--border-radius);
  border: 1px solid var(--border-color); background: var(--card-color); color: var(--text-color);
  font-size: .98rem; transition: var(--transition);
}
.search-box input:focus { outline: none; border-color: var(--primary-color); box-shadow: 0 0 0 3px rgba(58, 134, 255, .12); }
.clear-btn {
  position: absolute; right: 10px; top: 50%; transform: translateY(-50%);
  border: none; background: transparent; color: var(--muted-color); cursor: pointer;
  padding: 4px 8px; border-radius: 6px; display: none;
}
.search-box input:not(:placeholder-shown) + .clear-btn { display: block; }
.toolbar-row { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; }
.filter-buttons { display: flex; gap: 8px; }
.filter-btn {
  padding: 8px 16px; border-radius: 20px; border: 1px solid var(--border-color);
  background: var(--card-color); color: var(--text-color); cursor: pointer;
  font-size: .9rem; transition: var(--transition);
}
.filter-btn.active { background: var(--primary-color); color: #fff; border-color: var(--primary-color); }
.sort-box { display: flex; align-items: center; gap: 6px; font-size: .9rem; color: var(--muted-color); }
.sort-box select {
  padding: 7px 10px; border-radius: 8px; border: 1px solid var(--border-color);
  background: var(--card-color); color: var(--text-color);
}

/* 内容头 */
.content-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.content-header h2 { font-size: 1.2rem; }
.count-badge { background: var(--primary-color); color: #fff; font-size: .78rem; padding: 2px 9px; border-radius: 12px; vertical-align: middle; }
.view-controls { display: flex; gap: 6px; }
.view-btn {
  width: 36px; height: 36px; border-radius: 8px; border: 1px solid var(--border-color);
  background: var(--card-color); color: var(--muted-color); cursor: pointer;
}
.view-btn.active { background: var(--primary-color); color: #fff; border-color: var(--primary-color); }

/* 卡片 */
.items-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.item-card {
  background: var(--card-color); border-radius: var(--border-radius); box-shadow: var(--box-shadow);
  padding: 16px; cursor: pointer; transition: var(--transition); border: 1px solid transparent;
  display: flex; flex-direction: column; gap: 6px; min-height: 150px;
}
.item-card:hover { transform: translateY(-3px); border-color: rgba(58, 134, 255, .35); }
.item-card-header { display: flex; justify-content: space-between; align-items: center; }
.item-card-id { font-size: .78rem; color: var(--muted-color); font-weight: 600; }
.item-card-favorite, .table-favorite {
  border: none; background: transparent; color: var(--muted-color); cursor: pointer;
  font-size: .95rem; padding: 2px 4px; border-radius: 6px;
}
.item-card-favorite.active, .table-favorite.active { color: var(--warning-color); }
.item-card-front { font-size: 1.35rem; font-weight: 800; word-break: break-word; }
.item-card-sub { font-size: .88rem; color: var(--secondary-color); }
.item-card-back { font-size: .92rem; color: var(--muted-color); display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.item-card-footer { margin-top: auto; display: flex; justify-content: space-between; align-items: center; font-size: .78rem; color: var(--muted-color); padding-top: 8px; }
.item-card-group { background: var(--bg-color); padding: 2px 8px; border-radius: 10px; }
.item-card-extra { color: var(--primary-color); font-weight: 600; }

/* 列表 */
.items-list { display: flex; flex-direction: column; gap: 8px; }
.item-row {
  display: flex; align-items: flex-start; gap: 14px; background: var(--card-color);
  border-radius: var(--border-radius); box-shadow: var(--box-shadow); padding: 14px 18px;
  cursor: pointer; transition: var(--transition);
}
.item-row:hover { border-left: 3px solid var(--primary-color); padding-left: 15px; }
.item-row-id { font-size: .8rem; color: var(--muted-color); font-weight: 600; min-width: 44px; padding-top: 3px; }
.item-row-content { flex: 1; }
.item-row-front { font-size: 1.08rem; font-weight: 700; display: flex; align-items: center; gap: 8px; }
.item-row-sub { font-size: .85rem; color: var(--secondary-color); }
.item-row-back { font-size: .9rem; color: var(--muted-color); margin-top: 2px; }
.item-row-group { font-size: .78rem; color: var(--muted-color); white-space: nowrap; }

/* 表格 */
.items-table { width: 100%; border-collapse: collapse; background: var(--card-color); border-radius: var(--border-radius); overflow: hidden; box-shadow: var(--box-shadow); }
.items-table th, .items-table td { padding: 11px 14px; text-align: left; border-bottom: 1px solid var(--border-color); font-size: .9rem; }
.items-table th { background: var(--bg-color); color: var(--muted-color); font-weight: 600; white-space: nowrap; }
.items-table tbody tr { cursor: pointer; }
.items-table tbody tr:hover { background: rgba(58, 134, 255, .06); }

/* 分页 */
.pagination { display: flex; justify-content: center; align-items: center; gap: 6px; flex-wrap: wrap; margin: 26px 0 10px; }
.pagination-btn {
  min-width: 38px; padding: 7px 11px; border-radius: 8px; border: 1px solid var(--border-color);
  background: var(--card-color); color: var(--text-color); cursor: pointer; font-size: .9rem;
}
.pagination-btn.active { background: var(--primary-color); color: #fff; border-color: var(--primary-color); }
.pagination-btn.disabled { opacity: .45; cursor: not-allowed; }
.pagination-info { color: var(--muted-color); font-size: .85rem; padding: 0 8px; }

/* 空状态 */
.no-results { text-align: center; padding: 70px 20px; color: var(--muted-color); }
.no-results i { font-size: 2.4rem; margin-bottom: 14px; opacity: .5; }
.no-results h3 { color: var(--text-color); margin-bottom: 8px; }

/* 弹窗 */
.modal {
  position: fixed; inset: 0; background: rgba(15, 23, 42, .55); backdrop-filter: blur(3px);
  display: none; align-items: center; justify-content: center; z-index: 1000; padding: 20px;
}
.modal.active { display: flex; }
.modal-content {
  background: var(--card-color); border-radius: 18px; max-width: 680px; width: 100%;
  max-height: 88vh; overflow-y: auto; padding: 30px; position: relative;
  box-shadow: 0 24px 70px rgba(0, 0, 0, .3); animation: modalIn .22s ease;
}
@keyframes modalIn { from { opacity: 0; transform: translateY(14px) scale(.98); } to { opacity: 1; transform: none; } }
.modal-close {
  position: absolute; top: 16px; right: 16px; border: none; background: var(--bg-color);
  color: var(--muted-color); width: 34px; height: 34px; border-radius: 50%; cursor: pointer;
}
.modal-header { margin-bottom: 18px; padding-right: 40px; }
.modal-header h3 { font-size: 1rem; color: var(--muted-color); font-weight: 500; }
.modal-meta { display: flex; gap: 10px; margin-top: 6px; font-size: .8rem; color: var(--muted-color); }
.modal-group { background: var(--bg-color); padding: 2px 10px; border-radius: 10px; }
.modal-front { font-size: 2rem; font-weight: 800; line-height: 1.3; word-break: break-word; }
.modal-sub { font-size: 1.05rem; color: var(--secondary-color); margin-top: 4px; }
.modal-back { font-size: 1.1rem; margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--border-color); }
.modal-details { margin-top: 16px; display: flex; flex-direction: column; gap: 10px; }
.modal-detail-row { display: flex; gap: 12px; font-size: .95rem; }
.modal-detail-label { color: var(--muted-color); min-width: 74px; flex: none; }
.modal-detail-value { flex: 1; }
.modal-actions { display: flex; gap: 8px; margin-top: 24px; flex-wrap: wrap; }
.modal-action-btn {
  padding: 9px 14px; border-radius: 8px; border: 1px solid var(--border-color);
  background: var(--bg-color); color: var(--text-color); cursor: pointer; font-size: .88rem;
  display: inline-flex; align-items: center; gap: 6px;
}
.modal-action-btn.active { color: var(--warning-color); border-color: var(--warning-color); }

/* 页脚 */
footer { margin: 48px 0 30px; border-top: 1px solid var(--border-color); padding-top: 22px; }
.footer-content { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; color: var(--muted-color); font-size: .88rem; }
.footer-links { display: flex; gap: 16px; }
.footer-links a { color: var(--muted-color); text-decoration: none; display: inline-flex; align-items: center; gap: 6px; }
.footer-links a:hover { color: var(--primary-color); }