:root {
    --primary-color: #e0e0e0;
    --secondary-color: #6ab0f3;
    --accent-color: #4ecdc4;
    --background-color: #121212;
    --card-bg: #1e1e1e;
    --text-primary: #e0e0e0;
    --text-secondary: #a0a0a0;
    --border-radius: 8px;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

body {
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    padding: 20px;
    transition: var(--transition);
}

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

/* 页面标题区域 */
.page-header {
    text-align: center;
    margin-bottom: 50px;
    padding: 30px;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    border: 1px solid #333;
}

.page-title {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: var(--primary-color);
}

.page-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto;
}

/* 卡片网格布局 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 25px;
    margin-bottom: 50px;
}

/* 卡片样式 - 黑夜模式优化 */
.card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 25px;
    transition: var(--transition);
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    height: 100%;
    border-left: 4px solid var(--secondary-color);
    position: relative;
    overflow: hidden;
    border: 1px solid #333;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.4);
    border-color: #444;
}

.card-icon {
    font-size: 2.2rem;
    color: var(--secondary-color);
    margin-bottom: 15px;
}

.card-title {
    font-size: 1.4rem;
    margin-bottom: 12px;
    color: var(--primary-color);
}

.card-description {
    color: var(--text-secondary);
    margin-bottom: 20px;
    flex-grow: 1;
}

.card-footer {
    margin-top: auto;
}

/* 按钮样式 - 黑夜模式优化 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--secondary-color);
    color: white;
    padding: 10px 20px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    border: none;
    box-shadow: 0 3px 5px rgba(0, 0, 0, 0.3);
    gap: 8px;
}

.btn:hover {
    background: var(--accent-color);
    transform: translateY(-2px);
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.4);
}

.btn i {
    font-size: 0.9rem;
}

/* 页脚样式 */
.footer {
    text-align: center;
    padding: 30px;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-top: 50px;
    border: 1px solid #333;
}

.copyright {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .card-grid {
        grid-template-columns: 1fr;
    }
    
    .page-title {
        font-size: 2rem;
    }
}

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

.card {
    animation: fadeIn 0.5s ease forwards;
}

.card:nth-child(1) { animation-delay: 0.1s; }
.card:nth-child(2) { animation-delay: 0.2s; }
.card:nth-child(3) { animation-delay: 0.3s; }
.card:nth-child(4) { animation-delay: 0.4s; }
.card:nth-child(5) { animation-delay: 0.5s; }
.card:nth-child(6) { animation-delay: 0.6s; }

/* 装饰性背景元素 */
.bg-decoration {
    position: fixed;
    z-index: -1;
    opacity: 0.03;
    pointer-events: none;
}

.bg-circle {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    background: var(--secondary-color);
    top: 10%;
    right: 10%;
}

.bg-square {
    width: 200px;
    height: 200px;
    border-radius: 20px;
    background: var(--accent-color);
    bottom: 10%;
    left: 10%;
    transform: rotate(45deg);
}