/* === 基础重置 === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* === 基础样式 === */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

/* === 布局容器 === */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* === 头部样式 === */
header {
    background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    color: white;
    padding: 1rem 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

header h1 {
    font-size: 1.8rem;
    font-weight: 600;
}

/* === 导航菜单 === */
nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
}

nav a:hover,
nav a:focus {
    background: rgba(255,255,255,0.1);
    transform: translateY(-2px);
}

/* === 主要内容区 === */
main {
    min-height: calc(100vh - 200px);
    padding: 2rem 0;
}

/* === 英雄区域 === */
.hero {
    text-align: center;
    padding: 4rem 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    margin-bottom: 3rem;
    border-radius: 0 0 20px 20px;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
}

/* === 内容区域 === */
.content {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

.content h1,
.content h2 {
    color: #2c3e50;
    margin-bottom: 1.5rem;
}

.content h1 {
    font-size: 2.5rem;
}

.content h2 {
    font-size: 2rem;
    margin-top: 2rem;
}

.content p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
}

.content ul,
.content ol {
    margin-left: 2rem;
    margin-bottom: 1.5rem;
}

.content li {
    margin-bottom: 0.5rem;
}

/* === 文章网格 === */
.articles-grid {
    display: grid;
    gap: 2rem;
    margin: 2rem 0;
}

.article-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

.article-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.article-card h3 {
    margin-bottom: 1rem;
}

.article-card h3 a {
    color: #2c3e50;
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: 600;
    transition: color 0.3s ease;
}

.article-card h3 a:hover {
    color: #3498db;
}

.article-meta {
    display: flex;
    gap: 1.5rem;
    font-size: 0.9rem;
    color: #7f8c8d;
    margin: 1rem 0;
}

/* === 表单样式 === */
form div {
    margin: 1.5rem 0;
}

form label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #2c3e50;
}

form input,
form textarea {
    width: 100%;
    padding: 0.8rem;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-family: inherit;
    font-size: 1rem;
    transition: all 0.3s ease;
}

form input:focus,
form textarea:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

form button {
    background: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    color: white;
    padding: 1rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

form button:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
}

/* === 链接样式 === */
a {
    color: #3498db;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #2980b9;
    text-decoration: underline;
}

/* === 页脚样式 === */
footer {
    background: #2c3e50;
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

footer p {
    opacity: 0.8;
}

/* === 响应式设计 === */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    nav ul {
        flex-direction: column;
        gap: 1rem;
        width: 100%;
    }
    
    .article-meta {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .container {
        padding: 0 15px;
    }
    
    .content {
        padding: 0 15px;
    }
    
    .article-card {
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    header .container {
        flex-direction: column;
        text-align: center;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .hero h1 {
        font-size: 1.8rem;
    }
    
    main {
        padding: 1rem 0;
    }
}

/* === 工具类 === */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

/* === 动画效果 === */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.6s ease-out;
}

/* === 卡片悬停效果 === */
.hover-lift {
    transition: all 0.3s ease;
}

.hover-lift:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.15);
}