/* 全局重置 & 基础通用样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    /* 基础字体缩放，所有设备统一基准 */
    font-size: 16px;
}

body {
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    background-color: #f0f4fa;
    color: #2d3748;
    line-height: 1.75;
}

/* 容器：多宽度分段适配大屏/笔记本/平板 */
.container {
    margin: 0 auto;
    padding: 0 24px;
    max-width: 1400px;
}
/* 超大显示器加宽 */
@media (min-width: 1440px) {
    .container {
        max-width: 1320px;
    }
}
/* 标准笔记本 */
@media (min-width: 1024px) and (max-width: 1439px) {
    .container {
        max-width: 1140px;
    }
}
/* 平板、手机统一左右留白 */
@media (max-width: 1023px) {
    .container {
        padding: 0 20px;
    }
}
@media (max-width: 576px) {
    .container {
        padding: 0 16px;
    }
}

/* 头部导航栏 */
.site-header {
    background-color: #ffffff;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    padding: 18px 0;
}
.site-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo img {
    height: 44px;
    width: auto;
    display: block;
}

.main-nav a {
    text-decoration: none;
    color: #4a5568;
    margin-left: 26px;
    font-size: 15px;
    transition: color 0.2s ease;
}
.main-nav a:hover {
    color: #3182ce;
}

/* 平板竖屏/手机：导航垂直居中换行 */
@media (max-width: 768px) {
    .site-header .container {
        flex-direction: column;
        gap: 16px;
    }
    .main-nav {
        text-align: center;
    }
    .main-nav a {
        margin: 0 10px;
    }
}
/* 小手机导航间距再缩小 */
@media (max-width: 576px) {
    .main-nav a {
        margin: 0 6px;
        font-size: 14px;
    }
}

/* 首屏横幅区域 */
.hero {
    text-align: center;
    padding: 70px 0 50px;
}
.hero h1 {
    font-size: 36px;
    color: #1a202c;
    margin-bottom: 18px;
    font-weight: 600;
}
.hero-desc {
    font-size: 18px;
    color: #718096;
    max-width: 780px;
    margin: 0 auto;
}
/* 平板 */
@media (max-width: 1023px) {
    .hero {
        padding: 55px 0 40px;
    }
    .hero h1 {
        font-size: 30px;
    }
}
/* 手机 */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 26px;
    }
    .hero-desc {
        font-size: 16px;
    }
}
@media (max-width: 576px) {
    .hero {
        padding: 40px 0 30px;
    }
    .hero h1 {
        font-size: 22px;
    }
}

/* 卡片容器：多栏自适应核心 */
.card-wrap {
    display: grid;
    gap: 28px;
    margin-bottom: 50px;
    /* 大屏默认三栏 */
    grid-template-columns: repeat(3, 1fr);
}
/* 平板横向：双栏布局 */
@media (max-width: 1023px) {
    .card-wrap {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }
}
/* 平板竖屏/手机：单列 */
@media (max-width: 768px) {
    .card-wrap {
        grid-template-columns: 1fr;
    }
}

/* 卡片通用样式 悬浮动效 */
.card-item {
    background: #fff;
    border-radius: 16px;
    padding: 36px 30px;
    box-shadow: 0 4px 12px rgba(49, 130, 206, 0.08);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.card-item:hover {
    transform: translateY(-6px);
    box-shadow: 0 10px 24px rgba(49, 130, 206, 0.12);
}
.card-item h2 {
    font-size: 22px;
    margin-bottom: 16px;
    color: #1a202c;
}
.card-item p {
    color: #606b7b;
    font-size: 15px;
    margin-bottom: 26px;
}
/* 小手机卡片内边距压缩 */
@media (max-width: 576px) {
    .card-item {
        padding: 26px 20px;
    }
    .card-item h2 {
        font-size: 20px;
    }
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 11px 24px;
    background-color: #3182ce;
    color: #fff;
    text-decoration: none;
    border-radius: 10px;
    font-size: 15px;
    transition: background 0.2s ease;
}
.btn:hover {
    background-color: #2b6cb0;
}
@media (max-width: 576px) {
    .btn {
        padding: 10px 20px;
        font-size: 14px;
    }
}

/* 关于本站模块 */
.about-box {
    background: #fff;
    border-radius: 16px;
    padding: 36px 30px;
    box-shadow: 0 4px 12px rgba(49, 130, 206, 0.08);
    margin-bottom: 70px;
}
.about-box h2 {
    font-size: 22px;
    margin-bottom: 14px;
}
.about-box p {
    color: #606b7b;
    font-size: 16px;
}
@media (max-width: 576px) {
    .about-box {
        padding: 26px 20px;
        margin-bottom: 50px;
    }
}

/* 页脚区域 */
.site-footer {
    background: #ffffff;
    padding: 40px 0;
    box-shadow: 0 -1px 3px rgba(0,0,0,0.05);
    text-align: center;
    color: #718096;
    font-size: 14px;
}
.icp {
    margin: 10px 0;
    color: #8892a0;
    font-style: normal;
}
.footer-links {
    margin-top: 14px;
}
.footer-links a {
    color: #3182ce;
    text-decoration: none;
    margin: 0 10px;
}
.footer-links a:hover {
    text-decoration: underline;
}
@media (max-width: 576px) {
    .site-footer {
        padding: 28px 0;
    }
    .footer-links a {
        margin: 0 6px;
        font-size: 13px;
    }
}