/* 全局基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

/* 灰白主配色 */
body {
    background-color: #f8f9fa; /* 浅灰背景 */
    color: #333333; /* 主文字色 */
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* 标题样式 - 不换行 + 黑色 */
h1, h2, h3, h4 {
    color: #212529; /* 标题黑 */
    white-space: nowrap; /* 强制标题不换行 */
    font-weight: 600;
}

h1 {
    font-size: 2.2rem;
}

h2 {
    font-size: 1.8rem;
}

h3 {
    font-size: 1.4rem;
}

/* 导航栏样式 */
header {
    background-color: #ffffff; /* 白色导航栏 */
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    padding: 1.2rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.6rem;
    font-weight: 700;
    color: #212529;
}

.nav-links {
    display: flex;
    gap: 1.8rem;
    flex-wrap: wrap;
}

.nav-links a {
    text-decoration: none;
    color: #333333;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover, .nav-links a.active {
    color: #000000; /* 选中/hover为纯黑 */
    font-weight: 600;
}

/* 按钮样式 */
.cta-btn {
    display: inline-block;
    background-color: #333333; /* 黑色按钮 */
    color: #ffffff !important;
    padding: 0.7rem 1.4rem;
    border-radius: 4px;
    text-decoration: none;
    transition: background-color 0.3s;
}

.cta-btn:hover {
    background-color: #000000;
}

/* 页面通用样式 */
.page-header {
    text-align: center;
    margin: 3rem 0;
}

.section {
    padding: 4rem 0;
    background-color: #ffffff; /* 白色内容区 */
    margin-bottom: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.03);
}

/* 图标样式 - 黑色 */
.icon {
    color: #000000;
    font-size: 1.2rem;
    margin-right: 0.5rem;
}

/* 页脚样式 */
footer {
    background-color: #ffffff;
    padding: 3rem 0 1.5rem;
    margin-top: 3rem;
    border-top: 1px solid #e9ecef;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-brand {
    flex: 1;
    min-width: 250px;
}

.footer-contact {
    flex: 1;
    min-width: 250px;
}

.footer-social {
    flex: 1;
    min-width: 250px;
}

.social-links a {
    display: inline-block;
    margin-right: 1rem;
    color: #000000; /* 社交图标黑色 */
    font-size: 1.5rem;
    transition: transform 0.3s;
}

.social-links a:hover {
    transform: translateY(-3px);
}

.copyright {
    text-align: center;
    padding-top: 1.5rem;
    border-top: 1px solid #e9ecef;
    color: #6c757d;
    font-size: 0.9rem;
}

/* 响应式适配 */
@media (max-width: 768px) {
    .nav-links {
        gap: 1rem;
    }
    h1 {
        font-size: 1.8rem;
    }
    h2 {
        font-size: 1.5rem;
    }
    .footer-content {
        flex-direction: column;
    }
}

/* 产品/优势卡片样式 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.card {
    padding: 1.8rem;
    background-color: #f8f9fa; /* 浅灰卡片 */
    border-radius: 6px;
    border: 1px solid #e9ecef;
}

.card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 4px;
    margin-bottom: 1.2rem;
}

.card h3 {
    margin-bottom: 0.8rem;
}

.card p {
    color: #6c757d;
    line-height: 1.5;
}