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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: #333;
    line-height: 1.6;
    background: #fff;
}

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

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

/* ===== 容器 ===== */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 导航栏 ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid #eee;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    font-size: 22px;
    font-weight: 700;
    color: #1a73e8;
    letter-spacing: 1px;
}

.nav {
    display: flex;
    gap: 32px;
}

.nav a {
    font-size: 15px;
    color: #555;
    transition: color 0.2s;
    position: relative;
}

.nav a:hover,
.nav a:focus {
    color: #1a73e8;
}

.nav a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: #1a73e8;
    transition: width 0.25s;
}

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

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: #333;
    padding: 4px;
}

/* ===== Hero 首屏 ===== */
.hero {
    padding: 160px 0 100px;
    background: linear-gradient(135deg, #1a73e8 0%, #0d47a1 100%);
    color: #fff;
    text-align: center;
}

.hero-content h1 {
    font-size: 40px;
    font-weight: 700;
    margin-bottom: 16px;
    letter-spacing: 2px;
}

.hero-subtitle {
    font-size: 22px;
    font-weight: 300;
    margin-bottom: 12px;
    opacity: 0.9;
}

.hero-desc {
    font-size: 16px;
    max-width: 600px;
    margin: 0 auto 40px;
    opacity: 0.8;
    line-height: 1.8;
}

.btn {
    display: inline-block;
    padding: 12px 40px;
    border: 2px solid #fff;
    border-radius: 6px;
    color: #fff;
    font-size: 16px;
    font-weight: 600;
    transition: background 0.3s, color 0.3s;
}

.btn:hover {
    background: #fff;
    color: #1a73e8;
}

/* ===== 通用 Section ===== */
.section {
    padding: 80px 0;
}

.section-alt {
    background: #f8f9fa;
}

.section-title {
    text-align: center;
    font-size: 30px;
    font-weight: 700;
    color: #222;
    margin-bottom: 16px;
}

.section-divider {
    width: 50px;
    height: 3px;
    background: #1a73e8;
    margin: 0 auto 40px;
    border-radius: 2px;
}

.section-desc {
    max-width: 700px;
    margin: 0 auto 60px;
    text-align: center;
    font-size: 16px;
    color: #666;
    line-height: 1.8;
}

/* ===== 特点卡片 ===== */
.features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.feature-card {
    text-align: center;
    padding: 40px 24px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
    transition: transform 0.25s, box-shadow 0.25s;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 40px;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: #222;
}

.feature-card p {
    font-size: 14px;
    color: #777;
    line-height: 1.7;
}

/* ===== 业务领域 ===== */
.services-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.service-card {
    padding: 32px 20px;
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.05);
    transition: transform 0.25s, box-shadow 0.25s;
    text-align: center;
}

.service-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 28px rgba(0, 0, 0, 0.08);
}

.service-card h3 {
    font-size: 18px;
    color: #222;
    margin-bottom: 12px;
}

.service-card p {
    font-size: 14px;
    color: #777;
    line-height: 1.7;
}

/* ===== 联系我们 ===== */
.contact-img {
    display: block;
    width: 200px;
    height: auto;
    border-radius: 12px;
    margin: 0 auto 40px;
}

.contact-info {
    max-width: 600px;
    margin: 0 auto;
}

.contact-item {
    display: flex;
    justify-content: space-between;
    padding: 16px 0;
    border-bottom: 1px solid #eee;
    font-size: 15px;
}

.contact-item:last-child {
    border-bottom: none;
}

.contact-label {
    font-weight: 600;
    color: #333;
    flex-shrink: 0;
    margin-right: 24px;
}

/* ===== 页脚 ===== */
.footer {
    background: #1a1a2e;
    color: #aaa;
    padding: 32px 0;
    text-align: center;
}

.footer-inner p {
    font-size: 14px;
    margin-bottom: 6px;
}

.footer-inner a {
    color: #aaa;
    transition: color 0.2s;
}

.footer-inner a:hover {
    color: #fff;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .nav {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: #fff;
        padding: 16px 24px;
        gap: 16px;
        box-shadow: 0 8px 16px rgba(0, 0, 0, 0.06);
        border-bottom: 1px solid #eee;
    }

    .nav-open {
        display: flex;
    }

    .menu-toggle {
        display: block;
    }

    .hero {
        padding: 120px 0 60px;
    }

    .hero-content h1 {
        font-size: 28px;
    }

    .hero-subtitle {
        font-size: 18px;
    }

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

    .section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 26px;
    }

    .contact-item {
        flex-direction: column;
        gap: 4px;
    }
}