/* 全局样式 */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    color: #333;
    line-height: 1.6;
}

header {
    background-color: #222;
    color: #fff;
    padding: 20px 0;
}

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

header nav ul {
    list-style: none;
    display: flex;
    margin: 0;
    padding: 0;
}

header nav ul li {
    margin-left: 20px;
}

header nav ul li a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
    transition: color 0.3s;
}

header nav ul li a:hover {
    color: #ff6347;
}

header .logo {
    font-size: 1.8em;
    font-weight: bold;
}

.banner {
    background: url('banner.jpg') no-repeat center center/cover;
    height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    text-align: center;
    position: relative;
}

.banner::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
}

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

.banner h1 {
    font-size: 3em;
    margin-bottom: 10px;
}

.banner p {
    font-size: 1.5em;
    margin-bottom: 20px;
}

section {
    padding: 60px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

h2 {
    font-size: 2.5em;
    margin-bottom: 20px;
    text-align: center;
    position: relative;
    z-index: 2;
}

.service-grid, .case-grid, .news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.service-item, .case-item, .news-item {
    background-color: #f4f4f4;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.service-item:hover, .case-item:hover, .news-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.2);
}

footer {
    background-color: #222;
    color: #fff;
    text-align: center;
    padding: 20px 0;
    margin-top: 40px;
}

footer p {
    margin: 5px 0;
}

/* 自适应布局 */
@media screen and (max-width: 768px) {
    header nav ul {
        flex-direction: column;
        text-align: center;
    }
    header nav ul li {
        margin: 10px 0;
    }
    .banner h1 {
        font-size: 2em;
    }
    .banner p {
        font-size: 1.2em;
    }
}