/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
    background-color: #f9fafb;
    color: #1f2937;
    line-height: 1.6;
}

/* 字体 */
.font-serif-sc {
    font-family: "Noto Serif SC", "Songti SC", "SimSun", serif;
}

.font-sans-sc {
    font-family: "Noto Sans SC", "Microsoft YaHei", sans-serif;
}

/* 顶部固定邮箱栏 */
.fixed-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 50;
    background: linear-gradient(to right, #2563eb, #1d4ed8, #4338ca);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.header-content {
    max-width: 72rem;
    margin: 0 auto;
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.header-content span {
    color: white;
    font-size: 0.875rem;
}

.header-content a {
    margin-left: 0.5rem;
    color: white;
    font-weight: 500;
    text-decoration: none;
}

.header-content a:hover {
    color: #dbeafe;
    transition: color 0.2s ease;
}

/* 语言切换按钮 */
.lang-toggle {
    margin-left: 1rem;
    padding: 0.375rem 0.75rem;
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 0.375rem;
    font-size: 0.8125rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.lang-toggle:hover {
    background-color: rgba(255, 255, 255, 0.3);
    border-color: rgba(255, 255, 255, 0.5);
}

.lang-toggle:active {
    transform: scale(0.95);
}

/* 主内容区域 */
.main-content {
    max-width: 72rem;
    margin: 0 auto;
    padding: 4rem 1rem 3rem;
}

/* 页面标题 */
header {
    text-align: center;
    padding: 3rem 0 4rem;
}

header h1 {
    font-family: "Noto Serif SC", "Songti SC", "SimSun", serif;
    font-size: 2.5rem;
    font-weight: 700;
    color: #111827;
    margin-bottom: 1rem;
}

header p {
    color: #4b5563;
    font-size: 1.125rem;
    max-width: 42rem;
    margin: 0 auto;
}

/* 分类区域 */
section {
    margin-bottom: 4rem;
}

.section-header {
    display: flex;
    align-items: center;
    margin-bottom: 2rem;
}

.section-header .bar {
    width: 0.25rem;
    height: 2rem;
    border-radius: 0.25rem;
}

.section-header h2 {
    font-family: "Noto Serif SC", "Songti SC", "SimSun", serif;
    font-size: 2rem;
    font-weight: 700;
    color: #111827;
    margin-left: 0.75rem;
}

/* 网格布局 */
.grid {
    display: grid;
    gap: 1.5rem;
}

.grid-cols-1 {
    grid-template-columns: repeat(1, 1fr);
}

/* 品牌卡片 */
.brand-card {
    background-color: white;
    border-radius: 0.5rem;
    padding: 1.5rem;
    box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.brand-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.brand-card h3 {
    font-family: "Noto Serif SC", "Songti SC", "SimSun", serif;
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    white-space: nowrap;
}

.brand-card p {
    color: #4b5563;
    font-size: 0.875rem;
    line-height: 1.625;
}

/* 颜色标识 */
.blue-bar {
    background-color: #2563eb;
}

.blue-title {
    color: #1d4ed8;
}

.amber-bar {
    background-color: #d97706;
}

.amber-title {
    color: #b45309;
}

.green-bar {
    background-color: #059669;
}

.green-title {
    color: #047857;
}

/* 页脚 */
footer {
    text-align: center;
    padding: 2rem 0 1rem;
    border-top: 1px solid #e5e7eb;
}

footer p {
    color: #6b7280;
    font-size: 0.875rem;
}

/* 响应式设计 */
@media (min-width: 768px) {
    .header-content span {
        font-size: 1rem;
    }
    
    header h1 {
        font-size: 3rem;
    }
    
    .grid-cols-md-2 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .grid-cols-lg-4 {
        grid-template-columns: repeat(4, 1fr);
    }
}