/* css/style.css */

/* 1. 全局重置与基础变量 */
:root {
    --primary-color: #0056b3; /* 主色调：深蓝 */
    --secondary-color: #f4f4f4; /* 背景灰 */
    --text-color: #333;
    --white: #ffffff;
    --max-width: 1200px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--white);
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* 2. 导航栏 (响应式关键) */
header {
    background: var(--white);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: 20px;
}

.nav-links a {
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--primary-color);
}

/* 移动端菜单按钮 (默认隐藏) */
.menu-toggle {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* 3. 通用布局组件 */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 40px 20px;
}

.hero {
    background: linear-gradient(rgba(0,0,0,0.6), rgba(0,0,0,0.6)), url('../images/banner.jpg'); /* 记得放一张 banner.jpg 或者去掉背景图使用纯色 */
    background-color: var(--primary-color); /*  fallback */
    background-size: cover;
    background-position: center;
    color: var(--white);
    text-align: center;
    padding: 100px 20px;
}

.hero h1 { font-size: 2.5rem; margin-bottom: 20px; }
.btn {
    display: inline-block;
    background: var(--primary-color);
    color: var(--white);
    padding: 10px 25px;
    border-radius: 5px;
    margin-top: 20px;
    transition: background 0.3s;
}
.btn:hover { background: #004494; }

.section-title {
    text-align: center;
    margin-bottom: 40px;
    font-size: 2rem;
    color: var(--primary-color);
}

/* 网格布局 (用于产品和案例) */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.card {
    background: var(--white);
    border: 1px solid #ddd;
    border-radius: 8px;
    overflow: hidden;
    transition: transform 0.3s;
}

.card:hover { transform: translateY(-5px); box-shadow: 0 5px 15px rgba(0,0,0,0.1); }
.card img { width: 100%; height: 200px; object-fit: cover; }
.card-content { padding: 20px; }

/* 表单样式 */
.form-group { margin-bottom: 20px; }
.form-group label { display: block; margin-bottom: 5px; }
.form-group input, .form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

/* 页脚 */
footer {
    background: #333;
    color: var(--white);
    text-align: center;
    padding: 20px;
    margin-top: 50px;
}

/* 4. 媒体查询 (适配手机和平板) */
@media (max-width: 768px) {
    .menu-toggle { display: block; }
    
    .nav-links {
        display: none; /* 默认隐藏 */
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--white);
        padding: 20px;
        box-shadow: 0 5px 5px rgba(0,0,0,0.1);
    }

    .nav-links.active { display: flex; } /* 点击后显示 */
    
    .hero h1 { font-size: 1.8rem; }
}