:root {
  --color-primary: #1E88E5;
  --color-primary-dark: #1565C0;
  --color-primary-deep: #0D47A1;
  --color-primary-light: #E3F2FD;
  --color-primary-50: #F3F9FD;
  --color-primary-100: #BBDEFB;

  --color-text: #1F2A37;
  --color-text-secondary: #4B5563;
  --color-text-muted: #9CA3AF;
  --color-text-faint: #B0B7C0;

  --color-bg: #F5F7FA;
  --color-surface: #FFFFFF;
  --color-border: #E5E7EB;
  --color-border-light: #F0F2F5;
  --color-border-blue: #BBDEFB;

  --color-success: #2E7D32;
  --color-warning: #ED6C02;
  --color-danger: #D32F2F;

  --color-tag-bg: #E3F2FD;
  --color-tag-text: #1565C0;
  --color-tag-1-bg: #E3F2FD;  --color-tag-1-text: #1565C0;  /* 算法 */
  --color-tag-2-bg: #F3E5F5;  --color-tag-2-text: #6A1B9A;  /* 数据 */
  --color-tag-3-bg: #E8F5E9;  --color-tag-3-text: #2E7D32;  /* 应用 */
  --color-tag-4-bg: #FFF3E0;  --color-tag-4-text: #E65100;  /* 算力 */

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 2px 6px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 4px 16px rgba(15, 23, 42, 0.08);

  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 10px;

  --sidebar-w: 200px;
  --header-h: 60px;
}

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

html, body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei",
    "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: "tnum";
}

a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: 0; background: transparent; }
input, select { font-family: inherit; }

/* ============== Top Header ============== */
.app-header {
  height: var(--header-h);
  background: white;
  border-bottom: 1px solid var(--color-border-light);
  display: flex;
  align-items: center;
  padding: 0 24px;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: var(--sidebar-w);
}
.brand-logo {
  width: 36px; height: 36px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  color: white;
  font-size: 18px;
  position: relative;
  overflow: hidden;
}
.brand-logo::after {
  content: '';
  position: absolute; left: 0; top: 0; right: 0; bottom: 0;
  background: linear-gradient(180deg, transparent 40%, rgba(255,255,255,0.2));
  pointer-events: none;
}
.brand-text h1 {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text);
  letter-spacing: -0.3px;
  line-height: 1.2;
}
.brand-text p {
  font-size: 11px;
  color: var(--color-text-muted);
  margin-top: 2px;
}

.top-nav {
  flex: 1;
  display: flex;
  justify-content: center;
  gap: 48px;
}
.top-nav a {
  font-size: 14px;
  color: var(--color-text-secondary);
  padding: 0 4px;
  position: relative;
  height: var(--header-h);
  display: flex; align-items: center;
  transition: color 0.15s;
}
.top-nav a.active {
  color: var(--color-primary);
  font-weight: 500;
}
.top-nav a.active::after {
  content: '';
  position: absolute;
  bottom: 0; left: 50%; transform: translateX(-50%);
  width: 28px; height: 3px;
  background: var(--color-primary);
  border-radius: 2px 2px 0 0;
}

.user-zone {
  display: flex; align-items: center; gap: 10px;
  color: var(--color-text-secondary);
  font-size: 13px;
}
.user-avatar {
  width: 32px; height: 32px;
  background: var(--color-primary);
  color: white;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px;
  font-weight: 500;
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

/* ============== Body Layout ============== */
.app-body {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: calc(100vh - var(--header-h));
}

/* ============== Sidebar ============== */
.sidebar {
  background: white;
  border-right: 1px solid var(--color-border-light);
  padding: 16px 0;
}

.nav-group {
  margin-bottom: 8px;
}
.nav-group.has-active {
  background: var(--color-primary-50);
  border-left: 3px solid var(--color-primary);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 24px;
  cursor: pointer;
  color: var(--color-text-secondary);
  font-size: 14px;
  transition: all 0.15s;
  position: relative;
}
.nav-item:hover {
  background: var(--color-primary-50);
  color: var(--color-primary);
}
.nav-item .icon {
  width: 20px; height: 20px;
  display: flex; align-items: center; justify-content: center;
  color: var(--color-text-muted);
  flex-shrink: 0;
}
.nav-item:hover .icon,
.nav-item.active .icon {
  color: var(--color-primary);
}
.nav-item.active {
  background: var(--color-primary-50);
  color: var(--color-primary);
  font-weight: 500;
}

.nav-item .label-stack {
  flex: 1;
  display: flex; flex-direction: column;
  line-height: 1.4;
}
.nav-item .label-main { font-size: 14px; }
.nav-item .label-sub {
  font-size: 11px;
  color: var(--color-text-muted);
  margin-top: 1px;
}
.nav-item.active .label-sub { color: var(--color-primary); opacity: 0.7; }

.nav-item .arrow {
  color: var(--color-text-muted);
  font-size: 12px;
  transition: transform 0.2s;
}
.nav-item.expanded .arrow { transform: rotate(180deg); }

.badge-dot {
  background: var(--color-danger);
  color: white;
  font-size: 11px;
  font-weight: 600;
  border-radius: 999px;
  padding: 1px 7px;
  min-width: 18px;
  text-align: center;
}

.sub-nav {
  padding: 0 24px 8px 56px;
  display: none;
}
.nav-item.expanded + .sub-nav { display: block; }
.sub-nav a {
  display: block;
  font-size: 13px;
  color: var(--color-text-secondary);
  padding: 6px 0;
  transition: color 0.15s;
}
.sub-nav a:hover { color: var(--color-primary); }

/* ============== Main Content ============== */
.main {
  padding: 24px 32px 40px;
  overflow-x: auto;
}

.breadcrumb {
  font-size: 13px;
  color: var(--color-primary);
  margin-bottom: 8px;
}

.page-title {
  font-size: 24px;
  font-weight: 600;
  color: var(--color-text);
  letter-spacing: -0.5px;
  margin-bottom: 8px;
}

.page-desc {
  font-size: 13px;
  color: var(--color-text-muted);
  margin-bottom: 20px;
}

.divider {
  height: 1px;
  background: var(--color-border-light);
  margin-bottom: 20px;
}

/* ============== Stats Cards ============== */
.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}
.stat-card {
  background: white;
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  position: relative;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
  overflow: hidden;
}
.stat-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 32px; height: 3px;
  background: var(--color-primary);
  border-radius: 0 0 3px 0;
}
.stat-num {
  font-size: 36px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
  letter-spacing: -1px;
  font-variant-numeric: tabular-nums;
  margin-bottom: 8px;
}
.stat-label {
  font-size: 13px;
  color: var(--color-text-secondary);
}

/* ============== Filter Bar ============== */
.filter-bar {
  background: white;
  border-radius: var(--radius-lg);
  padding: 16px;
  margin-bottom: 16px;
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr auto;
  gap: 12px;
  align-items: center;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
}

.search-input,
.filter-select {
  height: 36px;
  padding: 0 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 13px;
  background: white;
  outline: none;
  transition: all 0.15s;
  width: 100%;
  color: var(--color-text);
}
.search-input:focus,
.filter-select:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(30, 136, 229, 0.12);
}
.search-input::placeholder { color: var(--color-text-muted); }
.filter-select {
  appearance: none;
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='none' stroke='%239CA3AF' stroke-width='1.5' d='M1 1.5L6 6.5L11 1.5'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 32px;
}

.count {
  font-size: 13px;
  color: var(--color-text-secondary);
  white-space: nowrap;
}
.count .num {
  color: var(--color-primary);
  font-weight: 600;
}

/* ============== Table ============== */
.table-wrap {
  background: white;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border-light);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}
thead th {
  background: #F8FAFC;
  color: var(--color-text-secondary);
  font-weight: 500;
  text-align: left;
  padding: 14px 16px;
  font-size: 13px;
  border-bottom: 1px solid var(--color-border-light);
  position: sticky;
  top: 0;
  z-index: 1;
}
thead th.col-num { width: 60px; text-align: center; }
thead th.col-year { width: 110px; }

tbody td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--color-border-light);
  color: var(--color-text);
  vertical-align: middle;
}
tbody td.col-num {
  text-align: center;
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
}
tbody tr {
  transition: background 0.1s;
}
tbody tr:hover { background: var(--color-primary-50); }
tbody tr:last-child td { border-bottom: 0; }

td.col-name {
  font-weight: 500;
  color: var(--color-text);
}
td.col-name .en {
  color: var(--color-text-muted);
  font-weight: 400;
  margin-left: 6px;
  font-size: 12px;
}
td.col-loc {
  color: var(--color-text-secondary);
}
td.col-year {
  color: var(--color-text-secondary);
  font-variant-numeric: tabular-nums;
}
td.col-cat .cat-tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 500;
  margin-right: 4px;
  margin-bottom: 4px;
  background: var(--color-tag-1-bg);
  color: var(--color-tag-1-text);
}
td.col-cat .cat-tag.lv1 { background: var(--color-tag-1-bg); color: var(--color-tag-1-text); }
td.col-cat .cat-tag.lv2 { background: var(--color-tag-2-bg); color: var(--color-tag-2-text); }
td.col-cat .cat-tag.lv3 { background: var(--color-tag-3-bg); color: var(--color-tag-3-text); }
td.col-cat .cat-tag.lv4 { background: var(--color-tag-4-bg); color: var(--color-tag-4-text); }
td.col-cat .arrow-mark {
  color: var(--color-text-faint);
  font-size: 11px;
  margin: 0 2px;
}

/* 分页 */
.pager {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 16px;
  background: white;
  border-top: 1px solid var(--color-border-light);
  font-size: 13px;
  color: var(--color-text-secondary);
}
.pager .pager-info { color: var(--color-text-muted); }
.pager .pager-controls {
  display: flex;
  gap: 4px;
}
.pager .pager-controls button {
  min-width: 32px;
  height: 32px;
  padding: 0 8px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--color-text-secondary);
  background: white;
  transition: all 0.15s;
}
.pager .pager-controls button:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}
.pager .pager-controls button.active {
  background: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}
.pager .pager-controls button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* ============== Responsive ============== */
@media (max-width: 1100px) {
  .filter-bar { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
  .app-body { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .stats { grid-template-columns: 1fr; }
  .top-nav { display: none; }
  .main { padding: 16px; }
  .stat-num { font-size: 28px; }
}