.tool-block {
    height: 120px;
    transition: all 0.3s ease;
}
.tool-block:hover {
    transform: translateY(-5px);
}

:root {
  --color-primary: #2563EB;
  --color-primary-dark: #1D4ED8;
  --color-bg: #F8F9FB;
  --color-card: #FFFFFF;
  --color-text: #1F2937;
  --color-text-muted: #6B7280;
  --color-border: #E5E7EB;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.06);
  --shadow-md: 0 4px 12px rgba(15,23,42,.08);

  /* 分类辅助色（低饱和，仅小面积点缀） */
  --cat-visual:   #2563EB;
  --cat-speech:   #0891B2;
  --cat-ml:       #7C3AED;
  --cat-api_call: #D97706;
  --cat-ai_tools: #059669;
  --cat-hardware: #64748B;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
}

/* Header */
.site-header {
  background: var(--color-card);
  border-bottom: 1px solid var(--color-border);
}

.brand-link { color: var(--color-text); }
.brand-icon {
  width: 44px; height: 44px;
  border-radius: 12px;
  background: rgba(37,99,235,.12);
  color: var(--color-primary);
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 22px;
}
.site-title {
  font-size: 20px; font-weight: 700; line-height: 1.2;
}
.site-subtitle {
  font-size: 13px; color: var(--color-text-muted); margin-top: 3px;
}
.btn-icon { border-radius: 10px; }

/* Search panel */
.search-panel {
  background: var(--color-card);
  border-bottom: 1px solid var(--color-border);
  border-top: 1px solid var(--color-border);
}
.search-panel .form-control { border-color: var(--color-border); }
.search-panel .input-group-text { border-color: var(--color-border); }
.search-panel .input-group { max-width: 640px; }
.filter-row .category-btn {
  padding: .28rem .75rem;
  font-size: .875rem;
}
.filter-row .category-btn,
.category-btn.active {
  border-radius: 999px;
  padding: .32rem .85rem;
  font-size: .9rem;
  transition: all .2s ease;
}
.filter-row .category-btn {
  background: var(--color-card);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}
.filter-row .category-btn:hover { border-color: var(--color-primary); color: var(--color-primary); }
.category-btn.active {
  background: var(--color-primary) !important;
  border-color: var(--color-primary) !important;
  color: #fff !important;
}

.qr-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-card);
  padding: .45rem .65rem;
}
.qr-placeholder {
  width: 52px; height: 52px;
  display: inline-flex; align-items: center; justify-content: center;
  border: 1px dashed var(--color-border);
  border-radius: 8px;
  font-size: 30px;
  color: var(--color-text);
}

/* Category section */
.category-section {
  position: relative;
  padding-left: 14px;
}
.category-section::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 4px;
  border-radius: 999px;
  background: var(--color-primary);
}
.category-section[data-category="speech"]::before   { background: var(--cat-speech); }
.category-section[data-category="ml"]::before       { background: var(--cat-ml); }
.category-section[data-category="api_call"]::before { background: var(--cat-api_call); }
.category-section[data-category="ai_tools"]::before { background: var(--cat-ai_tools); }
.category-section[data-category="hardware"]::before { background: var(--cat-hardware); }

.section-head h2 {
  font-size: 20px; font-weight: 700;
}
.section-count { font-weight: 500; }
.category-icon {
  width: 40px; height: 40px;
  border-radius: 11px;
  background: rgba(37,99,235,.10);
  color: var(--cat-visual);
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 19px;
}
.category-icon.cat-speech   { background: rgba(8,145,178,.10);   color: var(--cat-speech); }
.category-icon.cat-ml       { background: rgba(124,58,237,.10);  color: var(--cat-ml); }
.category-icon.cat-api_call { background: rgba(217,119,6,.12);   color: var(--cat-api_call); }
.category-icon.cat-ai_tools { background: rgba(5,150,105,.10);   color: var(--cat-ai_tools); }
.category-icon.cat-hardware { background: rgba(100,116,139,.12); color: var(--cat-hardware); }

/* Tool cards */
.tool-card {
  height: auto;
  min-height: 168px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-card);
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
  text-decoration: none;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}
a.tool-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: rgba(37,99,235,.35);
  color: inherit;
}
.tool-card-disabled {
  background: #FAFAFA;
  color: var(--color-text-muted);
  cursor: default;
}
.tool-card-more {
  background: rgba(248,249,251,.75);
  border-style: dashed;
  color: var(--color-text-muted);
  cursor: pointer;
}
.tool-icon {
  width: 42px; height: 42px;
  border-radius: 11px;
  background: rgba(37,99,235,.10);
  color: var(--color-primary);
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 21px;
}
.tool-title { font-size: 15px; }
.level-badge {
  font-size: .72rem;
  font-weight: 600;
  border-radius: 999px;
  padding: .18rem .5rem;
}
.level-1 { background: #EAF2FE; color: #2563EB; }
.level-2 { background: #E8F6EE; color: #15803D; }
.level-3 { background: #FFF4E2; color: #B45309; }
.level-4 { background: #FDECEC; color: #B91C1C; }
.soon-badge {
  background: #F3F4F6;
  color: #6B7280;
  font-weight: 600;
  font-size: .72rem;
  border-radius: 999px;
  padding: .18rem .55rem;
}
.tool-col { margin-bottom: 1rem; }

/* Focus visibility */
a.tool-card:focus-visible,
.btn:focus-visible,
.form-control:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Footer */
.site-footer {
  background: var(--color-card);
  color: var(--color-text-muted);
  font-size: 14px;
  border-top: 1px solid var(--color-border);
}
.footer-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: .75rem;
}
.footer-links li + li { margin-top: .4rem; }
.footer-links a {
  color: var(--color-text-muted);
  text-decoration: none;
}
.footer-links a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}
.footer-qr {
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 3px;
  background: #fff;
}

/* Nav QR hover popover */
.nav-qr-wrap { position: relative; }
.nav-qr-popover {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  z-index: 1050;
  display: none;
  background: var(--color-card, #fff);
  border: 1px solid var(--color-border, #E5E7EB);
  border-radius: var(--radius-md, 10px);
  padding: .75rem;
  box-shadow: 0 8px 24px rgba(15,23,42,.15);
  white-space: nowrap;
}
.nav-qr-wrap:hover .nav-qr-popover { display: block; }
.nav-qr-card { display: flex; align-items: center; gap: .75rem; }
.nav-qr-img {
  width: 110px; height: 110px;
  border-radius: 8px;
  border: 1px solid var(--color-border, #E5E7EB);
}
.nav-qr-text { line-height: 1.4; }