:root {
    --color-primary: #3b82f6;
    --color-primary-dark: #1e40af;
    --color-accent: #60a5fa;
    --color-surface: #f8fafc;
    --color-text: #1e293b;
    --rgb-primary: 59,130,246;
    --rgb-accent: 96,165,250;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --shadow-sm: 0 1px 2px rgba(15,23,42,.06), 0 1px 3px rgba(15,23,42,.04);
    --shadow-md: 0 2px 4px rgba(15,23,42,.06), 0 4px 12px -2px rgba(15,23,42,.08), 0 0 0 1px rgba(255,255,255,.5) inset;
    --shadow-lg: 0 8px 16px -4px rgba(15,23,42,.12), 0 4px 8px rgba(15,23,42,.06), 0 0 0 1px rgba(255,255,255,.6) inset;
    --space-section: 3rem;
    --space-card: 1.25rem;
    --space-gap: 1rem;
    --transition: 0.5s cubic-bezier(0.22, 1, 0.36, 1);
    --heading-weight: 600;
    --body-line-height: 1.7;
    accent-color: var(--color-primary);
}

/* 基础覆盖 */
body {
    color: var(--color-text);
    line-height: var(--body-line-height);
    background: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 50%, #cbd5e1 100%);
    caret-color: var(--color-primary);
}
h1, h2, h3, h4 { font-weight: var(--heading-weight); }
section, .section { padding-top: var(--space-section); padding-bottom: var(--space-section); }
.card, [class*="card"] {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: var(--space-card);
    transition: var(--transition);
    background: linear-gradient(145deg, #ffffff 0%, #f8fafc 100%);
}
.btn, button[class*="btn"], a[class*="btn"] {
    border-radius: var(--radius-md);
    transition: var(--transition);
    background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
    color: #ffffff;
    box-shadow: 0 4px 12px -2px rgba(37,99,235,.35), 0 2px 4px rgba(15,23,42,.08);
}
a:not([class]) { color: var(--color-primary); transition: var(--transition); }

/* ========== Section Layout Variants ========== */

/* news: masonry-2 */
.news-grid { column-count: 2; column-gap: var(--space-gap); }
.news-grid .card { break-inside: avoid; margin-bottom: var(--space-gap); }

/* features: grid-4 */
.feature-list { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-gap); }

/* hero: overlay */
.hero { position: relative; min-height: 70vh; display: flex; align-items: center; }
.hero-content { position: relative; z-index: 1; }

/* testimonials: carousel */
.testimonial-list { display: flex; overflow: hidden; }
.testimonial-list > * { flex: 0 0 100%; }

/* partners: centered */
.partner-grid { display: flex; flex-wrap: wrap; justify-content: center; gap: 2rem; }

/* faq: single-column */
.faq-list { max-width: 800px; margin: 0 auto; }

/* stats: grid-4 */
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-gap); text-align: center; }

/* cta: card-style */
.cta-inner {
    background: linear-gradient(145deg, #ffffff 0%, #eff6ff 100%);
    border-radius: var(--radius-xl);
    padding: 3rem;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

/* Page Layout: wide */
.page-main { max-width: 1400px; margin: 0 auto; }

/* 条件性装饰 */
a:not([class]):hover { color: var(--color-accent); }
.hero, [class*="hero"], section:first-of-type {
    background: radial-gradient(circle at 85% 20%, rgba(59,130,246,.35) 0%, transparent 60%), linear-gradient(135deg, #0f172a 0%, #1e293b 35%, #334155 70%, #3b82f6 140%);
    color: #f8fafc;
}
.card {
    border: 1px solid transparent;
    border-image: linear-gradient(135deg, rgba(var(--rgb-primary), .45) 0%, rgba(var(--rgb-accent), .15) 100%) 1;
}
header, .header, .navbar {
    box-shadow: 0 4px 12px -2px rgba(15,23,42,.08), 0 2px 4px rgba(15,23,42,.04);
    background: rgba(255,255,255,.85);
    backdrop-filter: blur(8px);
}

/* Responsive */
@media (max-width: 1024px) {
    .news-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .feature-list { grid-template-columns: repeat(2, 1fr) !important; }
    .partner-grid { grid-template-columns: repeat(3, 1fr) !important; }
    .stats-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .hero-inner { grid-template-columns: 1fr !important; }
}
@media (max-width: 640px) {
    :root { --space-section: 2rem; --space-card: 1rem; --space-gap: 0.75rem; }
    .news-grid { grid-template-columns: 1fr !important; }
    .feature-list { grid-template-columns: 1fr !important; }
    .faq-list { grid-template-columns: 1fr !important; }
    .testimonial-list { column-count: 1 !important; }
    .partner-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .stats-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .cta-inner { grid-template-columns: 1fr !important; }
}