/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
}

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

ul {
    list-style: none;
}

/* 导航栏 */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 5%;
    background: #2c3e50;
    color: white;
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: background 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    background: #3498db;
}

/* 英雄区域 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 6rem 2rem;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* 按钮 */
.btn {
    display: inline-block;
    background: #3498db;
    color: white;
    padding: 0.8rem 2rem;
    border-radius: 5px;
    font-size: 1rem;
    transition: background 0.3s;
    border: none;
    cursor: pointer;
}

.btn:hover {
    background: #2980b9;
}

/* 特性卡片 */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    padding: 4rem 5%;
    background: #f5f5f5;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    text-align: center;
}

.feature-card h3 {
    color: #2c3e50;
    margin-bottom: 1rem;
}

.feature-card p {
    color: #666;
}

/* 页面头部 */
.page-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 4rem 2rem;
}

.page-header h1 {
    font-size: 2.5rem;
}

/* 内容区域 */
.content {
    padding: 3rem 5%;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

.content h2 {
    color: #2c3e50;
    margin: 2rem 0 1rem;
}

.content p {
    margin-bottom: 1rem;
    color: #555;
}

.content ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.content ul li {
    margin-bottom: 0.5rem;
    color: #555;
}

.content ul li::before {
    content: "•";
    color: #3498db;
    font-weight: bold;
    margin-right: 0.5rem;
}

/* 联系页面 */
.contact-info {
    background: #f5f5f5;
    padding: 2rem;
    border-radius: 10px;
    margin-bottom: 2rem;
}

.info-item {
    padding: 0.8rem 0;
    border-bottom: 1px solid #ddd;
}

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

.contact-form {
    background: #f5f5f5;
    padding: 2rem;
    border-radius: 10px;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: #2c3e50;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 1rem;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #3498db;
}

/* 页脚 */
footer {
    background: #2c3e50;
    color: white;
    text-align: center;
    padding: 2rem;
    margin-top: auto;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-links {
        gap: 1rem;
    }

    .hero h1 {
        font-size: 1.8rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .features {
        padding: 2rem 5%;
    }
}