/* ========== 全局重置 & 基础 ========== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: #f4f6f9;
    color: #1a1a2e;
    line-height: 1.6;
    transition: background .3s, color .3s;
    min-height: 100vh;
}

body.dark {
    background: #0d1117;
    color: #e6edf3;
}

a {
    color: inherit;
    text-decoration: none;
}

img {
    display: block;
    max-width: 100%;
    height: auto;
}

ul, ol {
    list-style: none;
}

/* ========== 容器 ========== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ========== 辅助类 ========== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* ========== 头部导航 ========== */
header {
    background: linear-gradient(135deg, #0d1117 0%, #1f2937 100%);
    color: #fff;
    padding: 16px 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
}

.logo {
    font-size: 1.6rem;
    font-weight: 800;
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    white-space: nowrap;
}

.logo span {
    font-weight: 300;
    color: #94a3b8;
    -webkit-text-fill-color: #94a3b8;
}

.nav-links {
    display: flex;
    gap: 24px;
    list-style: none;
    flex-wrap: wrap;
}

.nav-links a {
    font-size: .95rem;
    padding: 6px 0;
    border-bottom: 2px solid transparent;
    transition: border .2s, color .2s;
    color: rgba(255,255,255,.85);
}

.nav-links a:hover,
.nav-links a.active {
    border-bottom-color: #f59e0b;
    color: #fff;
}

.dark-toggle {
    background: rgba(255,255,255,.1);
    border: 1px solid rgba(255,255,255,.2);
    color: #fff;
    padding: 8px 16px;
    border-radius: 30px;
    cursor: pointer;
    font-size: .85rem;
    transition: all .2s;
    white-space: nowrap;
}

.dark-toggle:hover {
    background: #f59e0b;
    border-color: #f59e0b;
}

.mobile-nav {
    display: none;
    background: none;
    border: none;
    color: #fff;
    font-size: 1.8rem;
    cursor: pointer;
    padding: 4px 8px;
}

/* ========== Hero 区域 ========== */
.hero {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
    color: #fff;
    padding: 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 50%, rgba(245,158,11,.08) 0%, transparent 60%);
    animation: heroGlow 8s infinite alternate;
    pointer-events: none;
}

@keyframes heroGlow {
    0% { transform: translate(0, 0); }
    100% { transform: translate(10%, 10%); }
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero h1 {
    font-size: 2.8rem;
    font-weight: 800;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #fbbf24, #ef4444);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto 32px;
    color: #cbd5e1;
}

.hero .btn-group {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 28px;
}

.hero .btn {
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    color: #fff;
    padding: 14px 36px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1rem;
    transition: transform .2s, box-shadow .2s;
    display: inline-block;
    border: none;
    cursor: pointer;
}

.hero .btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 30px rgba(245,158,11,.35);
}

.hero .btn-outline {
    background: transparent;
    border: 2px solid rgba(255,255,255,.3);
    color: #fff;
}

.hero .btn-outline:hover {
    background: rgba(255,255,255,.05);
    border-color: #f59e0b;
}

/* ========== 搜索模拟 ========== */
.search-sim {
    display: flex;
    max-width: 500px;
    margin: 0 auto;
    border-radius: 50px;
    overflow: hidden;
    border: 1px solid rgba(255,255,255,.2);
}

.search-sim input {
    flex: 1;
    padding: 14px 20px;
    border: none;
    background: rgba(255,255,255,.08);
    color: #fff;
    font-size: 1rem;
    outline: none;
}

.search-sim input::placeholder {
    color: #94a3b8;
}

.search-sim button {
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    border: none;
    padding: 14px 28px;
    color: #fff;
    font-weight: 600;
    cursor: pointer;
    transition: opacity .2s;
}

.search-sim button:hover {
    opacity: .9;
}

/* ========== 通用区块 ========== */
.section {
    padding: 70px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
}

.section-title h2 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-title p {
    color: #64748b;
    max-width: 600px;
    margin: 0 auto;
    font-size: 1.05rem;
}

.dark .section-title p {
    color: #94a3b8;
}

/* ========== 网格布局 ========== */
.grid-3,
.grid-4 {
    display: grid;
    gap: 28px;
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-4 {
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

/* ========== 卡片 ========== */
.card {
    background: #fff;
    border-radius: 20px;
    padding: 28px 24px;
    box-shadow: 0 4px 20px rgba(0,0,0,.05);
    transition: transform .3s, box-shadow .3s;
    border: 1px solid rgba(0,0,0,.04);
}

.card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 40px rgba(0,0,0,.1);
}

.dark .card {
    background: #161b22;
    border-color: #30363d;
    box-shadow: 0 4px 20px rgba(0,0,0,.3);
}

.card .icon {
    width: 48px;
    height: 48px;
    margin-bottom: 16px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(245,158,11,.15), rgba(239,68,68,.1));
}

.card h3 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    font-weight: 600;
}

.card p {
    color: #64748b;
    font-size: .95rem;
}

.dark .card p {
    color: #8b949e;
}

/* ========== 毛玻璃卡片 ========== */
.glass {
    background: rgba(255,255,255,.6);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255,255,255,.2);
}

.dark .glass {
    background: rgba(22,27,34,.7);
    border-color: rgba(48,54,61,.5);
}

/* ========== 统计数据 ========== */
.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 24px;
    text-align: center;
}

.stat-item {
    padding: 30px 16px;
    background: linear-gradient(135deg, #0f172a, #1e293b);
    border-radius: 20px;
    color: #fff;
}

.stat-item .number {
    font-size: 2.8rem;
    font-weight: 800;
    background: linear-gradient(135deg, #fbbf24, #ef4444);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-item p {
    color: #94a3b8;
    margin-top: 6px;
}

/* ========== Banner 轮播 ========== */
.banner-slider {
    position: relative;
    overflow: hidden;
    border-radius: 24px;
    height: 400px;
    background: #0f172a;
}

.banner-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    padding: 40px;
    color: #fff;
    opacity: 0;
    transition: opacity .8s ease;
    text-align: center;
}

.banner-slide.active {
    opacity: 1;
}

.banner-slide h2 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 12px;
}

.banner-slide p {
    font-size: 1.1rem;
    max-width: 600px;
    color: #cbd5e1;
}

.banner-dots {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 10px;
}

.banner-dots span {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255,255,255,.3);
    cursor: pointer;
    transition: all .3s;
}

.banner-dots span.active {
    background: #f59e0b;
    width: 32px;
    border-radius: 6px;
}

/* ========== FAQ ========== */
.faq-item {
    border-bottom: 1px solid #e2e8f0;
    padding: 18px 0;
    cursor: pointer;
}

.dark .faq-item {
    border-color: #30363d;
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 1.05rem;
}

.faq-question span {
    font-size: 1.4rem;
    transition: transform .3s;
}

.faq-item.open .faq-question span {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height .4s ease;
    color: #64748b;
    font-size: .95rem;
    padding-top: 0;
}

.faq-item.open .faq-answer {
    max-height: 300px;
    padding-top: 14px;
}

.dark .faq-answer {
    color: #8b949e;
}

/* ========== 步骤 ========== */
.howto-step {
    display: flex;
    gap: 20px;
    align-items: flex-start;
    margin-bottom: 28px;
}

.howto-step .step-num {
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    color: #fff;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.howto-step h4 {
    font-weight: 600;
    margin-bottom: 4px;
}

.howto-step p {
    color: #64748b;
    font-size: .95rem;
}

.dark .howto-step p {
    color: #8b949e;
}

/* ========== 联系卡片 ========== */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
}

.contact-card {
    background: linear-gradient(135deg, #0f172a, #1e293b);
    color: #fff;
    padding: 28px;
    border-radius: 20px;
    text-align: center;
}

.contact-card h4 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: #fbbf24;
}

.contact-card p {
    color: #cbd5e1;
    font-size: .95rem;
}

/* ========== 页脚 ========== */
footer {
    background: #0d1117;
    color: #cbd5e1;
    padding: 50px 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 30px;
    margin-bottom: 30px;
}

.footer-grid h4 {
    color: #fff;
    margin-bottom: 14px;
    font-size: 1rem;
}

.footer-grid a {
    display: block;
    font-size: .9rem;
    padding: 4px 0;
    opacity: .7;
    transition: opacity .2s;
}

.footer-grid a:hover {
    opacity: 1;
}

.footer-bottom {
    border-top: 1px solid #1f2937;
    padding-top: 20px;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    font-size: .85rem;
    gap: 12px;
}

.footer-bottom a {
    opacity: .7;
}

.footer-bottom a:hover {
    opacity: 1;
}

/* ========== 返回顶部 ========== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: linear-gradient(135deg, #f59e0b, #ef4444);
    color: #fff;
    border: none;
    font-size: 1.4rem;
    cursor: pointer;
    opacity: 0;
    transform: translateY(20px);
    transition: all .3s;
    z-index: 99;
    box-shadow: 0 4px 16px rgba(245,158,11,.3);
}

.back-to-top.visible {
    opacity: 1;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
}

/* ========== 滚动动画 ========== */
.scroll-animate {
    opacity: 0;
    transform: translateY(24px);
    transition: all .6s ease;
}

.scroll-animate.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        gap: 12px;
        padding: 16px 0;
    }

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

    .mobile-nav {
        display: block;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .section-title h2 {
        font-size: 1.8rem;
    }

    .banner-slider {
        height: 320px;
    }

    .banner-slide h2 {
        font-size: 1.6rem;
    }
}

@media (max-width: 600px) {
    .hero h1 {
        font-size: 1.6rem;
    }

    .section-title h2 {
        font-size: 1.6rem;
    }

    .banner-slider {
        height: 280px;
    }

    .banner-slide h2 {
        font-size: 1.4rem;
    }

    .stat-item .number {
        font-size: 2.2rem;
    }

    .contact-grid {
        grid-template-columns: 1fr;
    }
}

/* ========== 暗色模式额外微调 ========== */
.dark .stat-item {
    background: linear-gradient(135deg, #0d1117, #161b22);
}

.dark .hero::before {
    background: radial-gradient(circle at 30% 50%, rgba(245,158,11,.05) 0%, transparent 60%);
}

.dark .search-sim input {
    background: rgba(255,255,255,.06);
}

/* ========== 打印样式 ========== */
@media print {
    header,
    .back-to-top,
    .dark-toggle,
    .mobile-nav {
        display: none !important;
    }

    body {
        background: #fff;
        color: #000;
    }

    .card {
        box-shadow: none;
        border: 1px solid #ddd;
    }
}