:root {
    --color-primary: #334155;
    --color-primary-dark: #0f172a;
    --color-accent: #3b82f6;
    --color-surface: #f8fafc;
    --color-text: #0b1220;
    --rgb-primary: 51,65,85;
    --rgb-accent: 59,130,246;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 18px;
    --radius-xl: 22px;
    --shadow-sm: 0 1px 0 rgba(15, 23, 42, 0.06), 0 10px 18px rgba(2, 6, 23, 0.05);
    --shadow-md: 0 4px 10px rgba(2, 6, 23, 0.08), 0 16px 36px rgba(2, 6, 23, 0.10);
    --shadow-lg: 0 10px 24px rgba(2, 6, 23, 0.10), 0 30px 60px rgba(2, 6, 23, 0.14);
    --space-section: 5rem;
    --space-card: 2rem;
    --space-gap: 1.5rem;
    --transition: 0.36s cubic-bezier(0.16, 1, 0.3, 1);
    --heading-weight: 650;
    --body-line-height: 1.7;
}

body { color: var(--color-text); line-height: var(--body-line-height); background: var(--color-surface); }
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:
        0 2px 0 rgba(59,130,246,0.06),
        0 6px 16px rgba(2,6,23,0.08),
        0 22px 48px -18px rgba(2,6,23,0.18);
    padding: var(--space-card);
    transition:
        var(--transition),
        box-shadow 0.45s cubic-bezier(0.16, 1, 0.3, 1),
        transform 0.45s cubic-bezier(0.16, 1, 0.3, 1),
        border-color 0.45s cubic-bezier(0.16, 1, 0.3, 1);
    background: rgba(248,250,252,0.92);
    border: 1px solid rgba(15,23,42,0.08);
}
.btn, button[class*="btn"], a[class*="btn"] {
    border-radius: var(--radius-md);
    transition:
        var(--transition),
        background-color 0.45s cubic-bezier(0.16, 1, 0.3, 1),
        box-shadow 0.45s cubic-bezier(0.16, 1, 0.3, 1),
        transform 0.45s cubic-bezier(0.16, 1, 0.3, 1);
}
a:not([class]) {
    color: var(--color-primary);
    transition:
        var(--transition),
        color 0.45s cubic-bezier(0.16, 1, 0.3, 1),
        text-shadow 0.45s cubic-bezier(0.16, 1, 0.3, 1);
    text-shadow: 0 1px 0 rgba(255,255,255,0.6);
}

/* ========== 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: centered */
/* 居中大卡片 */
                .feature-list { display: flex; flex-direction: column; align-items: center; gap: calc(var(--space-gap) * 2); max-width: 720px; margin: 0 auto; }

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

/* testimonials: masonry */
.testimonial-list { column-count: 2; column-gap: var(--space-gap); }
                .testimonial-list > * { break-inside: avoid; margin-bottom: var(--space-gap); }

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

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

/* stats: grid-3 */
.stats-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-gap); text-align: center; }

/* cta: split */
.cta-inner { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 2rem; }

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

/* 条件性装饰 */
.hero, [class*="hero"], section:first-of-type {
    background:
        radial-gradient(1200px 420px at 20% -10%, rgba(59,130,246,0.25) 0%, rgba(59,130,246,0.05) 38%, rgba(2,6,23,0) 65%),
        radial-gradient(900px 420px at 90% 0%, rgba(148,163,184,0.22) 0%, rgba(148,163,184,0.06) 40%, rgba(2,6,23,0) 70%),
        linear-gradient(135deg, #334155 0%, #0f172a 55%, #0b1220 100%);
    border-radius: var(--radius-xl);
}
.card { border: 1px solid rgba(51,65,85, .14); }
header, .header, .navbar {
    box-shadow:
        0 1px 0 rgba(59,130,246,0.10),
        0 8px 20px rgba(2,6,23,0.10),
        0 28px 60px -28px rgba(2,6,23,0.22);
    border-bottom: 1px solid rgba(15,23,42,0.08);
}

/* 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; }
}