:root {
  --brand-blue: #2563EB;
  --brand-blue-dark: #1D4ED8;
  --brand-blue-light: #EFF6FF;
  --brand-green: #22C55E;
  --brand-green-dark: #16A34A;
  --text-primary: #0F172A;
  --text-secondary: #64748B;
  --text-muted: #94A3B8;
  --bg-page: #FFFFFF;
  --bg-subtle: #F8FAFC;
  --bg-footer: #0F172A;
  --border: #E2E8F0;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-md: 0 4px 20px rgba(15, 23, 42, 0.08);
  --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --container: 1600px;
  --header-h: 72px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: var(--bg-page);
  line-height: 1.6;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

.container { max-width: var(--container); margin: 0 auto; padding: 0 24px; }

.site-header {
  position: sticky; top: 0; z-index: 100;
  height: var(--header-h);
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.logo img, .logo svg { height: 44px; width: auto; }
.nav { display: flex; gap: 4px; }
.nav a {
  padding: 8px 14px; font-size: 15px; color: var(--text-secondary);
  border-radius: var(--radius-sm); transition: all 0.2s;
}
.nav a:hover, .nav a.active { color: var(--brand-blue); background: var(--brand-blue-light); }
.header-cta { display: flex; gap: 10px; align-items: center; }
.mobile-menu-btn { display: none; background: none; border: none; font-size: 22px; cursor: pointer; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 11px 22px; font-size: 15px; font-weight: 500;
  border-radius: var(--radius-md); border: none; cursor: pointer;
  transition: all 0.2s; font-family: inherit;
}
.btn-primary { background: var(--brand-blue); color: #fff; }
.btn-primary:hover { background: var(--brand-blue-dark); }
.btn-outline { background: transparent; color: var(--brand-blue); border: 1.5px solid var(--brand-blue); }
.btn-outline:hover { background: var(--brand-blue-light); }
.btn-lg { padding: 14px 30px; font-size: 16px; }
.btn-block { width: 100%; }

.section { padding: 80px 0; }
.section-subtle { background: var(--bg-subtle); }
.section-header { text-align: center; margin-bottom: 48px; }
.section-tag {
  display: inline-block; padding: 4px 12px; margin-bottom: 12px;
  background: var(--brand-blue-light); color: var(--brand-blue);
  font-size: 13px; font-weight: 500; border-radius: 20px;
}
.section-title { font-size: 32px; font-weight: 700; margin-bottom: 12px; }
.section-desc { font-size: 16px; color: var(--text-secondary); max-width: 560px; margin: 0 auto; }

.card {
  background: #fff; border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden;
  transition: box-shadow 0.2s, transform 0.2s;
}
.card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.card-body { padding: 24px; }

.tag {
  display: inline-block; padding: 4px 10px; font-size: 12px;
  border-radius: 4px; background: var(--bg-subtle); color: var(--text-secondary); margin-right: 6px;
}
.tag-blue { background: var(--brand-blue-light); color: var(--brand-blue); }
.tag-green { background: #F0FDF4; color: var(--brand-green-dark); }

.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }

.site-footer { background: var(--bg-footer); color: #94A3B8; padding: 64px 0 32px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 40px; }
.footer-brand img, .footer-brand svg { height: 40px; margin-bottom: 14px; }
.footer-brand p { font-size: 14px; line-height: 1.8; }
.footer-col h4 { color: #fff; font-size: 15px; margin-bottom: 14px; }
.footer-col a { display: block; font-size: 14px; padding: 5px 0; }
.footer-col a:hover { color: #fff; }
.footer-bottom {
  border-top: 1px solid #1E293B; padding-top: 20px;
  display: flex; justify-content: space-between; font-size: 13px; flex-wrap: wrap; gap: 8px;
}

.form-group { margin-bottom: 18px; }
.form-label { display: block; font-size: 14px; font-weight: 500; margin-bottom: 8px; }
.form-label .req { color: #EF4444; }
.form-input, .form-select, .form-textarea {
  width: 100%; padding: 12px 14px; font-size: 15px;
  border: 1px solid var(--border); border-radius: var(--radius-md); font-family: inherit;
}
.form-input:focus, .form-select:focus, .form-textarea:focus {
  outline: none; border-color: var(--brand-blue);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}
.form-textarea { min-height: 120px; resize: vertical; }

.filter-bar { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 28px; }
.filter-pill {
  padding: 8px 18px; font-size: 14px; border-radius: 20px;
  border: 1px solid var(--border); background: #fff; cursor: pointer;
}
.filter-pill.active { background: var(--brand-blue); color: #fff; border-color: var(--brand-blue); }

.page-header {
  padding: 48px 0; background: var(--bg-subtle); border-bottom: 1px solid var(--border);
}
.page-header h1 { font-size: 36px; font-weight: 700; margin-bottom: 8px; }
.page-header p { color: var(--text-secondary); }

.proto-toolbar {
  position: fixed; bottom: 20px; right: 20px; z-index: 300;
  display: flex; gap: 8px; align-items: center;
}
.proto-toolbar button, .proto-badge {
  background: #0F172A; color: #fff; border: none;
  padding: 8px 14px; border-radius: 20px; font-size: 12px; cursor: pointer;
}
.proto-toolbar a { background: var(--brand-blue); color: #fff; padding: 8px 14px; border-radius: 20px; font-size: 12px; }

@media (max-width: 1024px) {
  .grid-4, .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
  .nav, .header-cta .btn-outline { display: none; }
  .mobile-menu-btn { display: block; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .section { padding: 56px 0; }
  .section-title { font-size: 26px; }
  .footer-grid { grid-template-columns: 1fr; }
}