/* =============================================================================
   基础样式与变量定义
   ============================================================================= */
:root {
    /* 明亮模式变量 */
    --bg-color: #f5f7fa;
    --text-color: #2c3e50;
    --card-bg: #ffffff;
    --card-border: #e1e4e8;
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    --card-hover-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
    --accent-color: #3498db;
    --subtitle-color: #7f8c8d;
    --desc-color: #95a5a6;
    --section-title-color: #34495e;
    --transition-speed: 0.3s;
}

[data-theme="dark"] {
    /* 暗色模式变量 */
    --bg-color: #1a1b1e;
    --text-color: #e0e0e0;
    --card-bg: #25262b;
    --card-border: #2c2e33;
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
    --card-hover-shadow: 0 10px 15px rgba(0, 0, 0, 0.4);
    --accent-color: #5dade2;
    --subtitle-color: #a0a0a0;
    --desc-color: #787878;
    --section-title-color: #ecf0f1;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color var(--transition-speed), color var(--transition-speed);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem;
}

/* =============================================================================
   布局组件
   ============================================================================= */
.container {
    width: 100%;
    max-width: 1000px;
    margin: 0 auto;
}

/* 头部样式 */
header {
    text-align: center;
    margin-bottom: 2rem;
    position: relative;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    letter-spacing: -0.5px;
}

.subtitle {
    color: var(--subtitle-color);
    font-size: 1.1rem;
    font-weight: 400;
}

/* 主题切换按钮 */
.theme-toggle {
    position: absolute;
    top: 0;
    right: 0;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-color);
    padding: 0.5rem;
    border-radius: 50%;
    transition: background-color 0.2s;
    line-height: 1;
}

.theme-toggle:hover {
    background-color: rgba(128, 128, 128, 0.1);
}

/* 分类区块样式 */
.section {
    margin-bottom: 3rem;
}

.section-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--section-title-color);
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--card-border);
    display: inline-block;
    padding-right: 1rem;
}

/* 网格布局 */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

/* 卡片样式 */
.card {
    background-color: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 12px;
    padding: 1.5rem;
    text-decoration: none;
    color: inherit;
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--card-hover-shadow);
    border-color: var(--accent-color);
}

.card-header {
    display: flex;
    align-items: center;
    margin-bottom: 0.75rem;
}

.card-icon {
    font-size: 2rem;
    margin-right: 1rem;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0;
}

.card-desc {
    color: var(--desc-color);
    font-size: 0.9rem;
    line-height: 1.5;
}

/* 底部版权 */
footer {
    margin-top: auto;
    padding-top: 2rem;
    color: var(--subtitle-color);
    font-size: 0.85rem;
    text-align: center;
}

/* 移动端适配 */
@media (max-width: 600px) {
    h1 {
        font-size: 2rem;
    }
    
    .theme-toggle {
        position: static;
        display: block;
        margin: 0 auto 1rem auto;
    }
    
    body {
        padding: 1.5rem;
    }
    
    .section-title {
        font-size: 1.3rem;
        margin-bottom: 1rem;
    }
}