:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1e40af;
    --color-accent: #3b82f6;
    --color-surface: #f1f5f9;
    --color-text: #1e293b;
    --rgb-primary: 37,99,235;
    --rgb-accent: 59,130,246;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 14px;
    --radius-xl: 20px;
    --shadow-sm: 0 1px 2px rgba(15,23,42,.05), 0 1px 3px rgba(15,23,42,.06);
    --shadow-md: 0 1px 2px rgba(15,23,42,.04), 0 8px 20px -8px rgba(15,23,42,.12), inset 0 1px 0 rgba(255,255,255,.7);
    --shadow-lg: 0 2px 4px rgba(15,23,42,.05), 0 16px 36px -12px rgba(15,23,42,.16), 0 8px 16px -8px rgba(37,99,235,.14), inset 0 1px 0 rgba(255,255,255,.8);
    --space-section: 2.75rem;
    --space-card: 1.125rem;
    --space-gap: .875rem;
    --transition: .55s cubic-bezier(.22, 1, .36, 1);
    --heading-weight: 600;
    --body-line-height: 1.75;
}

body {
    color: var(--color-text);
    line-height: var(--body-line-height);
    background:
        radial-gradient(900px 420px at 85% -10%, rgba(59,130,246,.14), transparent 60%),
        radial-gradient(700px 360px at -5% 10%, rgba(14,165,233,.08), transparent 55%),
        linear-gradient(180deg, #f8fafc 0%, #eef2f7 100%);
    background-attachment: fixed;
}

h1, h2, h3, h4 { font-weight: var(--heading-weight); }

section, .section {
    padding-top: var(--space-section);
    padding-bottom: var(--space-section);
    background: linear-gradient(180deg, rgba(255,255,255,.32), rgba(148,163,184,0) 70%);
}

.card, [class*="card"] {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: var(--space-card);
    color: var(--color-text);
    background:
        radial-gradient(560px 180px at 90% -20%, rgba(59,130,246,.08), transparent 55%),
        linear-gradient(145deg, #ffffff 0%, #f8fafc 100%);
    transition: var(--transition);
}

.btn, button[class*="btn"], a[class*="btn"] {
    border-radius: var(--radius-md);
    transition: var(--transition);
    background: linear-gradient(135deg, #60a5fa 0%, #2563eb 55%, #1e40af 100%);
    box-shadow: 0 8px 20px -8px rgba(37,99,235,.55), inset 0 1px 0 rgba(255,255,255,.25);
    color: #ffffff;
    text-shadow: 0 1px 1px rgba(15,23,42,.18);
}

a:not([class]) {
    color: var(--color-primary);
    transition: var(--transition);
}

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

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

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

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

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

/* partners: scroll */
.partner-grid {
    display: flex;
    gap: 1.75rem;
    overflow: hidden;
    animation: partnerScroll 20s linear infinite;
}
@keyframes partnerScroll {
    0% { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

/* 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: 1.75rem;
}

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

/* 条件性装饰 */
.card:hover, [class*="card"]:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    background:
        radial-gradient(560px 180px at 90% -20%, rgba(59,130,246,.12), transparent 55%),
        linear-gradient(145deg, #ffffff 0%, #f1f5f9 100%);
}

a:not([class]):hover { color: var(--color-accent); }

.card {
    border-left: 3px solid var(--color-primary);
    border-image: linear-gradient(180deg, #60a5fa, #1e40af) 1;
}

header, .header, .navbar {
    background: linear-gradient(180deg, rgba(255,255,255,.78), rgba(255,255,255,.18) 65%, transparent);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
}

/* 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: 1.75rem;
        --space-card: .9375rem;
        --space-gap: .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; }
}