/* 全局重置与变量 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg: #f0f4fa;
    --text: #1a2a4a;
    --card: #fff;
    --shadow: 0 8px 32px rgba(0,0,0,0.08);
    --glass: rgba(255,255,255,0.6);
    --primary: #1a2a4a;
    --accent: #e94560;
    --grad: linear-gradient(135deg, #1a2a4a, #2d4a7a);
    --radius: 20px;
    --transition: 0.3s ease;
}

body.dark {
    --bg: #0f1a2e;
    --text: #e0e8f0;
    --card: #1a2a4a;
    --shadow: 0 8px 32px rgba(0,0,0,0.4);
    --glass: rgba(26,42,74,0.7);
    --primary: #e0e8f0;
    --grad: linear-gradient(135deg, #0f1a2e, #1a2a4a);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    transition: background var(--transition), color var(--transition);
}

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

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

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

h1 {
    font-size: 2.8rem;
    margin-bottom: 20px;
    font-weight: 800;
}

h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    font-weight: 700;
    position: relative;
}

h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--accent);
    margin-top: 10px;
    border-radius: 2px;
}

h3 {
    font-size: 1.4rem;
    margin-bottom: 12px;
    font-weight: 600;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    background: var(--accent);
    color: #fff;
    border-radius: 30px;
    font-weight: 600;
    transition: transform var(--transition), box-shadow var(--transition);
    border: none;
    cursor: pointer;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(233,69,96,0.3);
}

/* 头部 */
header {
    background: var(--glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 10px 0;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--accent);
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo svg {
    width: 40px;
    height: 40px;
}

nav {
    display: flex;
    gap: 30px;
    align-items: center;
}

nav a {
    color: var(--text);
    font-weight: 500;
    transition: color var(--transition);
    position: relative;
}

nav a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width var(--transition);
}

nav a:hover::after {
    width: 100%;
}

.mobile-menu {
    display: none;
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text);
    cursor: pointer;
}

/* Hero 区域 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--grad);
    color: #fff;
    text-align: center;
    padding: 120px 20px 80px;
    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(233,69,96,0.15), transparent 60%);
    animation: float 20s infinite ease-in-out;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(40px, -40px); }
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    text-shadow: 0 4px 20px rgba(0,0,0,0.2);
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero .btn {
    font-size: 1.1rem;
    padding: 16px 40px;
}

/* Banner 轮播 */
.banner-slider {
    position: relative;
    width: 100%;
    overflow: hidden;
    margin-top: 40px;
}

.banner-slide {
    display: none;
    animation: fade 0.6s ease;
}

.banner-slide.active {
    display: block;
}

.banner-slide img {
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    width: 100%;
}

@keyframes fade {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* 通用区块 */
.section {
    padding: 80px 0;
}

.section-alt {
    background: var(--card);
    border-radius: var(--radius);
    margin: 20px;
    padding: 60px 40px;
    box-shadow: var(--shadow);
}

/* 网格 */
.grid {
    display: grid;
    gap: 30px;
}

.grid-2 {
    grid-template-columns: repeat(2, 1fr);
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* 卡片 */
.card {
    background: var(--card);
    border-radius: var(--radius);
    padding: 30px;
    box-shadow: var(--shadow);
    transition: transform var(--transition), box-shadow var(--transition);
    border: 1px solid rgba(255,255,255,0.05);
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 60px rgba(0,0,0,0.12);
}

.card-icon {
    margin-bottom: 16px;
    width: 60px;
    height: 60px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--grad);
}

.stat-number {
    font-size: 3rem;
    font-weight: 800;
    color: var(--accent);
    line-height: 1.2;
}

.stat-label {
    font-size: 1rem;
    color: var(--text);
    opacity: 0.8;
}

/* FAQ */
.faq-item {
    border-bottom: 1px solid rgba(0,0,0,0.05);
    padding: 16px 0;
    cursor: pointer;
}

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

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
    padding-top: 0;
    color: var(--text);
    opacity: 0.8;
}

.faq-item.active .faq-answer {
    max-height: 500px;
    padding-top: 12px;
}

/* 页脚 */
footer {
    background: var(--grad);
    color: #fff;
    padding: 60px 20px 20px;
}

footer .grid-4 {
    gap: 40px;
}

footer a {
    color: rgba(255,255,255,0.7);
    transition: color var(--transition);
}

footer a:hover {
    color: #fff;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    margin-top: 40px;
    padding-top: 20px;
    text-align: center;
    font-size: 0.9rem;
    opacity: 0.8;
}

/* 返回顶部 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--accent);
    color: #fff;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(233,69,96,0.3);
    transition: transform var(--transition);
    display: none;
    z-index: 999;
}

.back-to-top.show {
    display: block;
}

.back-to-top:hover {
    transform: scale(1.1);
}

/* 暗黑切换按钮 */
.dark-toggle {
    background: none;
    border: 2px solid var(--text);
    border-radius: 30px;
    padding: 6px 16px;
    color: var(--text);
    cursor: pointer;
    font-size: 0.9rem;
    transition: all var(--transition);
}

/* 搜索框 */
.search-box {
    display: flex;
    gap: 10px;
    max-width: 400px;
    margin: 20px auto;
}

.search-box input {
    flex: 1;
    padding: 12px 20px;
    border: 2px solid rgba(0,0,0,0.1);
    border-radius: 30px;
    font-size: 1rem;
    background: var(--card);
    color: var(--text);
    outline: none;
}

.search-box button {
    padding: 12px 24px;
    border-radius: 30px;
    background: var(--accent);
    color: #fff;
    border: none;
    cursor: pointer;
}

/* 响应式 */
@media (max-width: 768px) {
    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .hero h1 { font-size: 2.2rem; }

    nav {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--card);
        padding: 20px;
        box-shadow: var(--shadow);
        border-radius: 0 0 var(--radius) var(--radius);
    }

    nav.open {
        display: flex;
    }

    .mobile-menu {
        display: block;
    }

    .section-alt {
        margin: 10px;
        padding: 30px 20px;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

/* 滚动动画（卡片初始状态由JS设置，这里定义过渡） */
.card {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.card.visible {
    opacity: 1;
    transform: translateY(0);
}