* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    background: #f5f7fb;
    color: #222;
}

/* ===== 顶部导航 ===== */
header {
    position: sticky;
    top: 0;
    background: #111;
    color: #fff;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 30px;
    z-index: 999;
}

.logo {
    font-size: 20px;
    font-weight: bold;
    letter-spacing: 2px;
}

nav a {
    color: #fff;
    margin-left: 20px;
    text-decoration: none;
    transition: 0.3s;
}

nav a:hover {
    color: #00c3ff;
}

/* ===== HERO 轮播区 ===== */
.hero {
    position: relative;
    height: 420px;
    overflow: hidden;
}

.hero img {
    width: 100%;
    height: 420px;
    object-fit: cover;
    filter: brightness(0.6);
}

.hero-title {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #fff;
    text-align: center;
}

.hero-title h1 {
    font-size: 36px;
}

.hero-title p {
    margin-top: 10px;
}

/* ===== 通用布局 ===== */
.container {
    width: 90%;
    max-width: 1100px;
    margin: auto;
}

/* ===== section ===== */
.section {
    padding: 60px 0;
}

.section h2 {
    text-align: center;
    margin-bottom: 30px;
    font-size: 26px;
}

/* ===== 卡片 ===== */
.row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.card {
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0,0,0,0.08);
    transition: 0.3s;
}

.card:hover {
    transform: translateY(-8px);
}

.card img {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.card h3 {
    padding: 10px;
}

.card p {
    padding: 0 10px 15px;
    color: #00aaff;
    font-weight: bold;
}

/* ===== 深色区块 ===== */
.dark {
    background: #0f172a;
    color: #fff;
}

/* ===== 关于 ===== */
.about {
    background: #fff;
    padding: 60px 0;
    text-align: center;
}

.about p {
    max-width: 800px;
    margin: auto;
    line-height: 1.8;
}

/* ===== 联系 ===== */
.contact-box {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-top: 20px;
}

.contact-item {
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 10px 20px rgba(0,0,0,0.05);
}

.form-box {
    margin-top: 40px;
    background: #fff;
    padding: 20px;
    border-radius: 10px;
}

form input,
form textarea {
    width: 100%;
    margin-top: 10px;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 6px;
}

form button {
    margin-top: 10px;
    background: #00aaff;
    color: #fff;
    border: none;
    padding: 10px 20px;
    cursor: pointer;
}

/* ===== footer ===== */
footer {
    text-align: center;
    padding: 20px;
    background: #111;
    color: #fff;
    margin-top: 40px;
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
    .row {
        grid-template-columns: repeat(2, 1fr);
    }

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

@media (max-width: 500px) {
    .row {
        grid-template-columns: 1fr;
    }

    .hero-title h1 {
        font-size: 24px;
    }
}