/* 全局设计系统 — 企业品牌风格 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --brand-primary: #0b1a2f;
    --brand-accent: #f0b429;
    --brand-accent2: #e89e2e;
    --glass-bg: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.15);
    --shadow-card: 0 12px 30px rgba(0, 0, 0, 0.2);
    --radius-card: 24px;
    --radius-btn: 40px;
    --text-light: #f5f7fa;
    --text-dark: #e0e4ec;
    --bg-dark: #0a1424;
    --bg-card: rgba(20, 32, 52, 0.75);
    --transition: 0.3s cubic-bezier(0.2, 0.9, 0.3, 1);
}

body {
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background: var(--bg-dark);
    color: var(--text-light);
    line-height: 1.6;
    scroll-behavior: smooth;
    transition: background 0.2s, color 0.2s;
}

a {
    color: var(--brand-accent);
    text-decoration: none;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* 玻璃效果卡片 */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-card);
    transition: transform 0.2s, box-shadow 0.3s;
}

.glass-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

/* 渐变banner */
.gradient-bg {
    background: linear-gradient(145deg, #0f1f35 0%, #182b4a 60%, #2a3f5e 100%);
}

.btn-accent {
    background: var(--brand-accent);
    color: #0b1a2f;
    font-weight: 600;
    padding: 14px 34px;
    border-radius: var(--radius-btn);
    border: none;
    cursor: pointer;
    transition: 0.2s;
    display: inline-block;
}

.btn-accent:hover {
    background: #f5c542;
    transform: scale(1.02);
    box-shadow: 0 8px 20px rgba(240, 180, 41, 0.3);
}

/* 导航吸顶 */
.sticky-header {
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(14px);
    background: rgba(10, 20, 36, 0.8);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 0;
}

.logo svg {
    height: 44px;
    width: auto;
    display: block;
}

.nav-menu {
    display: flex;
    gap: 28px;
    list-style: none;
    font-weight: 500;
}

.nav-menu li a {
    color: #dfe7f0;
    padding: 8px 0;
    border-bottom: 2px solid transparent;
    transition: 0.2s;
}

.nav-menu li a:hover,
.nav-menu li.active a {
    color: var(--brand-accent);
    border-bottom-color: var(--brand-accent);
}

.menu-toggle {
    display: none;
    background: transparent;
    border: none;
    color: white;
    font-size: 28px;
    cursor: pointer;
}

.dark-toggle {
    background: rgba(255, 255, 255, 0.1);
    border: none;
    color: white;
    padding: 8px 16px;
    border-radius: 40px;
    font-size: 16px;
    cursor: pointer;
    backdrop-filter: blur(4px);
}

/* hero */
.hero {
    padding: 80px 0 100px;
    text-align: center;
}

.hero h1 {
    font-size: 3.2rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    max-width: 900px;
    margin: 0 auto 24px;
}

.hero .highlight {
    color: var(--brand-accent);
}

.hero-desc {
    font-size: 1.3rem;
    max-width: 700px;
    margin: 0 auto 40px;
    opacity: 0.85;
}

.hero-banner-slot {
    background: rgba(255, 255, 255, 0.03);
    border-radius: 48px;
    padding: 20px;
    margin-top: 40px;
}

.carousel-place {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.carousel-item {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 24px;
    padding: 30px 20px;
    min-width: 180px;
    flex: 1 0 200px;
    backdrop-filter: blur(4px);
    border: 1px solid rgba(255, 255, 255, 0.06);
    transition: opacity 0.3s;
}

/* 通用section */
section {
    padding: 70px 0;
}

.section-title {
    font-size: 2.4rem;
    margin-bottom: 16px;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.section-sub {
    opacity: 0.8;
    margin-bottom: 50px;
    font-size: 1.1rem;
}

.grid-3,
.grid-4 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 28px;
}

.grid-2 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 28px;
}

.card {
    background: var(--bg-card);
    backdrop-filter: blur(4px);
    border-radius: var(--radius-card);
    padding: 28px 22px;
    border: 1px solid rgba(255, 255, 255, 0.06);
    transition: 0.25s;
}

.card:hover {
    background: rgba(30, 48, 72, 0.7);
    transform: translateY(-6px);
}

.stat-number {
    font-size: 2.8rem;
    font-weight: 700;
    color: var(--brand-accent);
}

.faq-item,
.howto-step {
    background: rgba(255, 255, 255, 0.03);
    border-radius: 20px;
    padding: 20px 24px;
    margin-bottom: 16px;
    border-left: 4px solid var(--brand-accent);
    cursor: pointer;
}

.faq-question {
    font-weight: 600;
    font-size: 1.2rem;
    display: flex;
    justify-content: space-between;
}

.faq-answer {
    margin-top: 12px;
    opacity: 0.9;
    display: none;
}

.faq-item.open .faq-answer {
    display: block;
}

.article-card {
    padding: 24px;
}

.article-card time {
    opacity: 0.6;
    font-size: 0.9rem;
}

.footer {
    background: #050d1a;
    padding: 48px 0 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    font-size: 0.95rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 24px;
}

.footer a {
    opacity: 0.7;
}

.footer a:hover {
    opacity: 1;
}

.scroll-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--brand-accent);
    color: #0b1a2f;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    cursor: pointer;
    opacity: 0;
    transition: 0.2s;
    pointer-events: none;
    border: none;
}

.scroll-top.visible {
    opacity: 1;
    pointer-events: auto;
}

/* 移动响应 */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        flex-direction: column;
        background: rgba(10, 20, 36, 0.98);
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        padding: 20px 30px;
        border-radius: 0 0 30px 30px;
    }

    .nav-menu.open {
        display: flex;
    }

    .menu-toggle {
        display: block;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

    .section-title {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.8rem;
    }
}

/* 动画辅助 */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

.lazy-svg {
    background: transparent;
}