:root {
    --color-primary: #2a3b52;
    --color-primary-dark: #1c2938;
    --color-accent: #4d8ee6;
    --color-surface: #e8edf3;
    --color-text: #1f2a36;
    --rgb-primary: 42,59,82;
    --rgb-accent: 77,142,230;
    --radius-sm: 2px;
    --radius-md: 3px;
    --radius-lg: 5px;
    --radius-xl: 6px;
    --shadow-sm: 0 1px 2px rgba(15,23,42,0.05);
    --shadow-md: 0 2px 4px rgba(15,23,42,0.06), 0 1px 3px rgba(15,23,42,0.04);
    --shadow-lg: 0 6px 12px rgba(15,23,42,0.1), 0 4px 8px rgba(15,23,42,0.08);
    --space-section: 2.75rem;
    --space-card: 1rem;
    --space-gap: 0.9rem;
    --transition: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
    --heading-weight: 800;
    --body-line-height: 1.6;
}

body { color: var(--color-text); line-height: var(--body-line-height); background: var(--color-surface); }
h1, h2, h3, h4 { font-weight: var(--heading-weight); color: var(--color-primary-dark); }
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: #ffffff; }
.btn, button[class*="btn"], a[class*="btn"] { border-radius: var(--radius-md); transition: var(--transition); background: var(--color-accent); color: #ffffff; box-shadow: var(--shadow-sm); }
a:not([class]) { color: var(--color-primary); transition: var(--transition); }

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

/* news: featured-top */
/* 首篇横跨全宽 */
.news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-gap); }
.news-grid > *:first-child { grid-column: span 3; }

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

/* hero: centered */
.hero-content { text-align: center; max-width: 800px; margin: 0 auto; }

/* testimonials: stacked */
/* 垂直堆叠 */
.testimonial-list { display: flex; flex-direction: column; gap: var(--space-gap); max-width: 720px; margin: 0 auto; }

/* partners: grid-4 */
.partner-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: calc(var(--space-gap) * 1.5); align-items: center; }

/* faq: with-sidebar */
/* FAQ 左 + 联系信息右 */
.faq-wrapper { display: grid; grid-template-columns: 2fr 1fr; gap: 1.75rem; }

/* stats: big-number */
/* 大数字居中 */
.stats-grid { display: flex; flex-wrap: wrap; justify-content: center; gap: 1.75rem; }
.stats-grid .stat-value { font-size: 3rem; color: var(--color-primary); }

/* cta: split */
.cta-inner { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 1.75rem; }

/* Page Layout: full-width */
/* 无侧边栏, 全宽 */
.page-main { max-width: 1200px; margin: 0 auto; }

/* 条件性装饰 */
.card:hover, [class*="card"]:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); background: #ffffff; }
a:not([class]):hover { color: var(--color-accent); }
header, .header, .navbar { background: #252e3a; color: #eef2f6; box-shadow: 0 4px 12px rgba(13,21,34,0.18), 0 2px 4px rgba(13,21,34,0.12); }

/* 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: 0.85rem; --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; }
}