/* 
 * index.css - 当发网主页样式表
 * 版本：3.5
 * 描述：Web开发技术分享平台的主页样式，提供响应式设计、可访问性优化和打印样式
 * 作者：当发网
 * 版权所有：Dangfa.com
 */

/* 
 * ============================================
 * CSS重置与基础样式
 * ============================================
 */

/* 全局盒模型重置 */
*,
*::before,
*::after {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

/* 元素边距与默认样式重置 */
html,
body,
div,
span,
h1,
h2,
h3,
h4,
p,
a,
img,
ul,
li,
footer,
header,
nav,
main,
section {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}

/* 现代HTML5元素显示重置 */
footer,
header,
nav,
main,
section {
    display: block;
}

/* ============================================
 * CSS变量定义
 * ============================================
 */

:root {
    /* 颜色系统 - 语义化命名 */
    --color-primary: #82255E;
    --color-primary-dark: #5a1840;
    --color-secondary: #B83B6A;
    --color-accent: #E8D8B0;
    --color-dark: #2A101B;
    --color-light: #F0E6DC;
    --color-white: #FFFFFF;

    /* 中性色调 */
    --color-gray-light: #f5f5f5;
    --color-gray-medium: #e0e0e0;

    /* 文本颜色系统 */
    --color-text-primary: #333333;
    --color-text-secondary: #595959;
    --color-text-on-primary: var(--color-white);
    --color-text-on-dark: var(--color-light);
    --color-link: var(--color-light);
    --color-link-hover: var(--color-primary-dark);

    /* 卡片专用颜色（浅色模式） */
    --color-card-bg: var(--color-accent);
    --color-card-text: var(--color-text-primary);
    --color-card-title: var(--color-primary);
    --color-card-border: rgba(130, 37, 94, 0.1);

    /* 排版系统 */
    --font-family: "微软雅黑", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    --border-radius: 10px;

    /* 交互效果 */
    --transition-default: all 0.3s ease;
    --shadow-default: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 8px 15px rgba(0, 0, 0, 0.15);
    --focus-outline: 3px solid var(--color-accent);
    --focus-outline-offset: 2px;

    /* Flexbox回退布局专用变量 */
    --flex-gap: 1rem;
}

/* 深色模式变量 */
@media (prefers-color-scheme: dark) {
    :root {
        --color-primary: #6a1e4c;
        --color-primary-dark: #4d1838;
        --color-secondary: #8f2d5b;
        --color-accent: #e6d9b8;
        --color-dark: #1a0d13;
        --color-light: #f0e6d8;
        --color-gray-light: #2d2d2d;
        --color-gray-medium: #404040;

        /* 深色模式文本调整 */
        --color-text-primary: #f0f0f0;
        --color-text-secondary: #b3b3b3;
        --color-text-on-dark: var(--color-light);
        --color-link: var(--color-accent);
        --color-link-hover: var(--color-light);

        /* 深色模式卡片专用颜色 */
        --color-card-bg: #2a1a25;
        --color-card-text: #f0e6dc;
        --color-card-title: #e6d9b8;
        --color-card-border: rgba(230, 217, 184, 0.2);

        --shadow-default: 0 4px 6px rgba(0, 0, 0, 0.4);
        --shadow-hover: 0 8px 15px rgba(0, 0, 0, 0.5);
    }
}

/* 高对比度模式 */
@media (prefers-contrast: more) {
    :root {
        --color-primary: #5a1840;
        --color-primary-dark: #000000;
        --color-secondary: #333333;
        --color-accent: #000000;
        --color-dark: #000000;
        --color-light: #ffffff;
        --color-gray-light: #ffffff;
        --color-gray-medium: #cccccc;

        /* 高对比度文本 */
        --color-text-primary: #000000;
        --color-text-secondary: #333333;
        --color-text-on-primary: #ffffff;
        --color-text-on-dark: #ffffff;

        /* 高对比度卡片专用颜色 */
        --color-card-bg: #ffffff;
        --color-card-text: #000000;
        --color-card-title: #000000;
        --color-card-border: #000000;

        --color-high-contrast-yellow: #FFFF00;
        --focus-outline: 3px solid var(--color-high-contrast-yellow);
    }
}

/* ============================================
 * 基础元素样式
 * ============================================
 */

html {
    font-size: 16px;
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--color-text-primary);
    background-color: var(--color-gray-light);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 全局文本颜色设置 */
p,
h1,
h2,
h3,
h4,
h5,
h6,
li {
    color: var(--color-text-primary);
}

/* 链接基础样式 */
a {
    color: var(--color-link);
    text-decoration: none;
    transition: var(--transition-default);
}

/* 容器布局 */
.container {
    width: 100%;
    max-width: 100%;
    margin: 0 auto;
    padding: 0 15px;
}

/* 文本选择样式 */
::selection {
    background-color: var(--color-primary);
    color: var(--color-white);
}

::-moz-selection {
    background-color: var(--color-primary);
    color: var(--color-white);
}

/* ============================================
 * 可访问性组件
 * ============================================
 */

/* 跳过链接 */
.skip-link {
    position: absolute;
    top: -44px;
    left: 6px;
    background: var(--color-primary);
    color: var(--color-white);
    padding: 8px 12px;
    border-radius: var(--border-radius);
    text-decoration: none;
    z-index: 1000;
    -webkit-transition: var(--transition-default);
    -moz-transition: var(--transition-default);
    transition: var(--transition-default);
    font-weight: bold;
}

.skip-link:focus {
    top: 6px;
    outline: var(--focus-outline);
    outline-offset: var(--focus-outline-offset);
}

/* 屏幕阅读器专用类 */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ============================================
 * 头部与导航
 * ============================================
 */

header {
    background-color: var(--color-primary);
    color: var(--color-accent);
    text-align: center;
    padding: 1.5rem 1rem 0;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
    position: relative;
    overflow: hidden;
    -webkit-box-shadow: var(--shadow-default);
    -moz-box-shadow: var(--shadow-default);
    box-shadow: var(--shadow-default);
}

header h1 {
    position: relative;
    z-index: 1;
    margin: 0;
    color: var(--color-text-on-primary);
}

/* Logo样式 */
.logo-container {
    position: relative;
    display: inline-block;
}

.logo {
    max-width: 260px;
    height: auto;
    display: block;
    margin: 0 auto;
}

/* Logo描述文本 - 仅供屏幕阅读器使用 */
.logo-description {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* 主导航 */
.main-nav {
    margin-top: 1.5rem;
    background-color: var(--color-primary-dark);
    border-radius: var(--border-radius) var(--border-radius) 0 0;
}

.nav-list {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    list-style: none;
    padding: 0.75rem 0;
    margin: 0;
}

.nav-item {
    margin: 0.25rem;
}

.nav-link {
    display: block;
    padding: 0.5rem 1rem;
    color: var(--color-text-on-dark);
    text-decoration: none;
    border-radius: 20px;
    -webkit-transition: var(--transition-default);
    -moz-transition: var(--transition-default);
    transition: var(--transition-default);
    font-size: 0.9rem;
    font-weight: 500;
    text-align: center;
}

.nav-link:hover,
.nav-link:focus {
    background-color: var(--color-accent);
    color: var(--color-primary-dark);
    outline: none;
}

.nav-link:focus {
    outline: var(--focus-outline);
    outline-offset: var(--focus-outline-offset);
}

@supports selector(:focus-visible) {
    .nav-link:focus {
        outline: none;
    }

    .nav-link:focus-visible {
        outline: var(--focus-outline);
        outline-offset: var(--focus-outline-offset);
    }
}

/* 高对比度模式下导航链接边框 */
@media (prefers-contrast: more) {
    .nav-link {
        border: 1px solid var(--color-light);
    }
}

/* ============================================
 * 主要内容区域
 * ============================================
 */

main {
    background-color: var(--color-secondary);
    padding: 1.5rem 1rem;
    -webkit-box-flex: 1;
    -ms-flex-positive: 1;
    flex-grow: 1;
}

/* ============================================
 * 技术卡片组件
 * ============================================
 */

/* 卡片容器布局 */
.tech-cards {
    /* Flexbox作为Grid的兼容性回退 */
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    gap: var(--flex-gap);
    justify-items: center;
    align-items: stretch;

    /* 性能优化 */
    content-visibility: auto;
}

/* 支持Grid的浏览器使用Grid布局 */
@supports (display: grid) {
    .tech-cards {
        display: grid;
        grid-template-columns: 1fr;
        gap: var(--flex-gap);
        justify-items: center;
        align-items: stretch;
    }
}

/* 卡片基础样式 */
.tech-card {
    background-color: var(--color-card-bg);
    border-radius: var(--border-radius);
    overflow: hidden;
    -webkit-transition: var(--transition-default);
    -moz-transition: var(--transition-default);
    transition: var(--transition-default);
    -webkit-box-shadow: var(--shadow-default);
    -moz-box-shadow: var(--shadow-default);
    box-shadow: var(--shadow-default);
    position: relative;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    flex-direction: column;
    width: 100%;
    max-width: 400px;
    border: 1px solid var(--color-card-border);

    /* 动画性能优化 */
    will-change: transform, box-shadow;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    -webkit-transform: translateZ(0);
    transform: translateZ(0);
}

/* Flexbox回退布局基础样式 - 单列布局 */
.tech-card {
    width: calc(100% - var(--flex-gap));
    margin: 0 calc(var(--flex-gap) / 2) var(--flex-gap);
}

/* 卡片顶部装饰条 */
.tech-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--color-primary);
    -webkit-transform: scaleX(0);
    -moz-transform: scaleX(0);
    -ms-transform: scaleX(0);
    -o-transform: scaleX(0);
    transform: scaleX(0);
    -webkit-transition: -webkit-transform 0.3s ease;
    transition: -webkit-transform 0.3s ease;
    -moz-transition: transform 0.3s ease, -moz-transform 0.3s ease;
    transition: transform 0.3s ease;
    transition: transform 0.3s ease, -webkit-transform 0.3s ease, -moz-transform 0.3s ease;
    will-change: transform;
}

/* 卡片链接样式 */
.tech-card a {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    flex-direction: column;
    padding: 1.25rem;
    color: var(--color-card-text);
    text-decoration: none;
    height: 100%;
    -webkit-box-flex: 1;
    flex-grow: 1;
}

.tech-card a:focus {
    outline: none;
}

.tech-card a:focus {
    border-radius: var(--border-radius);
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* 卡片标题 */
.tech-card h4 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 1rem;
    display: inline-block;
    font-style: italic;
    border-bottom: 2px solid var(--color-card-title);
    text-align: center;
    width: 100%;
    padding-bottom: 0.5rem;
    color: var(--color-card-title);
}

/* 卡片描述 */
.tech-card p {
    margin-bottom: 1rem;
    text-align: justify;
    line-height: 1.7;
    font-size: 0.95rem;
    color: var(--color-card-text);
}

/* 描述区域布局 */
.tech-card .description {
    -webkit-box-flex: 1;
    flex-grow: 1;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    flex-direction: column;
}

/* 阅读更多区域 */
.read-more-container {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: end;
    justify-content: flex-end;
    margin-top: auto;
    padding-top: 1rem;
}

.tech-card .read-more {
    display: -webkit-inline-box;
    display: -ms-inline-flexbox;
    display: inline-flex;
    -webkit-box-align: center;
    align-items: center;
    font-weight: bold;
    color: var(--color-dark);
    -webkit-transition: var(--transition-default);
    -moz-transition: var(--transition-default);
    transition: var(--transition-default);
    gap: 0.25rem;
    font-size: 0.9rem;
}

.arrow {
    font-weight: bold;
    margin-left: 0.25rem;
}

/* 卡片交互状态 */
.tech-card:hover::before,
.tech-card:focus-within::before {
    -webkit-transform: scaleX(1);
    -moz-transform: scaleX(1);
    -ms-transform: scaleX(1);
    -o-transform: scaleX(1);
    transform: scaleX(1);
}

.tech-card:hover,
.tech-card:focus-within {
    -webkit-transform: translateY(5px);
    -moz-transform: translateY(5px);
    -ms-transform: translateY(5px);
    -o-transform: translateY(5px);
    transform: translateY(5px);
    -webkit-box-shadow: var(--shadow-hover);
    -moz-box-shadow: var(--shadow-hover);
    box-shadow: var(--shadow-hover);
}

.tech-card:hover .read-more,
.tech-card:focus-within .read-more {
    -webkit-transform: translateX(5px);
    -moz-transform: translateX(5px);
    -ms-transform: translateX(5px);
    -o-transform: translateX(5px);
    transform: translateX(5px);
    color: var(--color-primary-dark);
}

.tech-card:focus-within {
    -webkit-transform: translateY(5px);
    -moz-transform: translateY(5px);
    -ms-transform: translateY(5px);
    -o-transform: translateY(5px);
    transform: translateY(5px);
    -webkit-box-shadow: 0 0 0 3px var(--color-primary), var(--shadow-hover);
    -moz-box-shadow: 0 0 0 3px var(--color-primary), var(--shadow-hover);
    box-shadow: 0 0 0 3px var(--color-primary), var(--shadow-hover);
    position: relative;
    z-index: 10;
}

/* 深色模式下卡片样式优化 */
@media (prefers-color-scheme: dark) {
    .tech-card .read-more {
        color: var(--color-card-title);
    }

    .tech-card:hover .read-more,
    .tech-card:focus-within .read-more {
        color: var(--color-light);
    }
}

/* 现代焦点管理 */
@supports selector(:focus-visible) {
    .tech-card a:focus {
        outline: none;
    }

    .tech-card a:focus-visible {
        border-radius: var(--border-radius);
        outline: 2px solid var(--color-primary);
        outline-offset: 2px;
    }
}

/* 高对比度模式下的卡片样式 */
@media (prefers-contrast: more) {
    .tech-card {
        border: 2px solid #000;
    }

    .tech-card h4 {
        border-bottom: 2px solid #000;
    }

    .tech-card .read-more {
        color: #000;
    }

    .tech-card a {
        color: #0000EE;
        /* 标准链接蓝色 */
    }

    .tech-card:focus-within {
        -webkit-box-shadow: 0 0 0 4px var(--color-high-contrast-yellow), 0 4px 8px rgba(0, 0, 0, 0.3);
        -moz-box-shadow: 0 0 0 4px var(--color-high-contrast-yellow), 0 4px 8px rgba(0, 0, 0, 0.3);
        box-shadow: 0 0 0 4px var(--color-high-contrast-yellow), 0 4px 8px rgba(0, 0, 0, 0.3);
        border: 2px solid var(--color-high-contrast-yellow);
    }
}

/* ============================================
 * 页脚样式
 * ============================================
 */

footer {
    background-color: var(--color-dark);
    color: var(--color-light);
    text-align: center;
    padding: 1.25rem 1rem;
    border-radius: 0 0 var(--border-radius) var(--border-radius);
    -webkit-box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
    -moz-box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
}

footer p {
    margin: 0.5rem 0;
    font-size: 0.9rem;
    color: var(--color-text-on-dark);
}

footer a {
    color: var(--color-link);
    text-decoration: none;
    -webkit-transition: var(--transition-default);
    -moz-transition: var(--transition-default);
    transition: var(--transition-default);
}

footer a:hover {
    text-decoration: underline;
    color: var(--color-accent);
}

/* ============================================
 * 响应式设计 - 移动设备优化 (< 400px)
 * ============================================
 */

@media (max-width: 399.98px) {
    .container {
        padding: 0 10px;
    }

    header {
        padding: 1.25rem 0.5rem 0;
    }

    .logo {
        max-width: 220px;
    }

    /* 导航调整为垂直布局 */
    .nav-list {
        display: flex;
        flex-direction: column;
        align-items: stretch;
        width: 100%;
    }

    .nav-item {
        margin: 0;
        width: 100%;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

    .nav-item:first-child {
        border-top: 1px solid rgba(255, 255, 255, 0.1);
    }

    .nav-link {
        text-align: center;
        border-radius: var(--border-radius);
        padding: 0.75rem 1rem;
        min-height: 44px;
        /* 可访问性最小高度 */
    }

    /* 卡片内边距调整 */
    .tech-card a {
        padding: 1rem;
    }

    .tech-card h4 {
        font-size: 1.3rem;
    }

    /* 焦点状态调整 */
    .tech-card:focus-within {
        -webkit-transform: translateY(-3px);
        -moz-transform: translateY(-3px);
        -ms-transform: translateY(-3px);
        -o-transform: translateY(-3px);
        transform: translateY(-3px);
        -webkit-box-shadow: 0 0 0 2px var(--color-primary), var(--shadow-hover);
        -moz-box-shadow: 0 0 0 2px var(--color-primary), var(--shadow-hover);
        box-shadow: 0 0 0 2px var(--color-primary), var(--shadow-hover);
    }
}

/* ============================================
 * 响应式设计 - 小屏幕 (400px - 576px)
 * ============================================
 */

@media (min-width: 400px) and (max-width: 575.98px) {
    .nav-list {
        max-width: 100%;
    }

    .nav-item {
        width: calc(50% - 0.5rem);
        margin: 0.25rem;
    }

    .nav-link {
        text-align: center;
        padding: 0.6rem 0.5rem;
        font-size: 0.9rem;
    }

    /* Flexbox回退布局：单列 */
    .tech-card {
        width: calc(100% - var(--flex-gap));
        margin: 0 calc(var(--flex-gap) / 2) var(--flex-gap);
    }

    /* Grid布局覆盖 - 单列 */
    @supports (display: grid) {
        .tech-cards {
            grid-template-columns: repeat(1, 1fr);
            gap: var(--flex-gap);
        }

        .tech-card {
            width: 100%;
            margin: 0;
        }
    }
}

/* ============================================
 * 响应式设计 - 小型设备 (576px - 767px)
 * ============================================
 */

@media (min-width: 576px) and (max-width: 767.98px) {
    .container {
        max-width: 540px;
        padding: 0 15px;
    }

    header {
        padding: 1.75rem 1rem 0;
    }

    .logo {
        max-width: 280px;
    }

    main {
        padding: 1.75rem 1rem;
    }

    .tech-cards {
        --flex-gap: 1.25rem;
        gap: var(--flex-gap);
    }

    /* Flexbox回退布局：单列 */
    .tech-card {
        width: calc(100% - var(--flex-gap));
        margin: 0 calc(var(--flex-gap) / 2) var(--flex-gap);
    }

    /* Grid布局覆盖 - 单列 */
    @supports (display: grid) {
        .tech-cards {
            grid-template-columns: repeat(1, 1fr);
        }

        .tech-card {
            width: 100%;
            margin: 0;
        }
    }

    .tech-card a {
        padding: 1.5rem;
    }

    .tech-card h4 {
        font-size: 1.5rem;
    }

    footer {
        padding: 1.5rem 1rem;
    }

    /* 导航样式 - 三列布局 */
    .nav-list {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 0.5rem;
        justify-items: center;
    }

    .nav-item {
        margin: 0;
        width: 100%;
        max-width: 160px;
    }

    .nav-link {
        padding: 0.5rem 0.75rem;
        font-size: 0.9rem;
        text-align: center;
        border-radius: var(--border-radius);
        width: 100%;
    }
}

/* ============================================
 * 响应式设计 - 中等设备 (768px - 991px)
 * ============================================
 */

@media (min-width: 768px) and (max-width: 991.98px) {
    .container {
        max-width: 720px;
    }

    header {
        padding: 2rem 1rem 0;
    }

    .logo {
        max-width: 300px;
    }

    main {
        padding: 2rem 1rem;
    }

    .tech-cards {
        --flex-gap: 1.5rem;
        gap: var(--flex-gap);
    }

    /* Flexbox回退布局：两列布局 */
    .tech-card {
        width: calc(50% - (var(--flex-gap) * 0.5));
        margin: 0 calc(var(--flex-gap) / 2) var(--flex-gap);
    }

    /* 清除每行第二个卡片的右边距 */
    .tech-card:nth-child(2n) {
        margin-right: 0;
    }

    /* Grid布局 - 两列 */
    @supports (display: grid) {
        .tech-cards {
            grid-template-columns: repeat(2, 1fr);
        }

        .tech-card {
            max-width: none;
            width: 100%;
            margin: 0;
        }
    }

    .tech-card h4 {
        font-size: 1.5rem;
    }

    .tech-card p {
        font-size: 1rem;
    }

    /* 导航样式 - 两行三列布局 */
    .nav-list {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        grid-template-rows: repeat(2, auto);
        gap: 0.5rem;
        justify-items: center;
    }

    .nav-item {
        margin: 0;
        width: 100%;
        max-width: 180px;
    }

    .nav-link {
        padding: 0.6rem 1rem;
        font-size: 0.95rem;
        text-align: center;
        border-radius: var(--border-radius);
        width: 100%;
    }
}

/* ============================================
 * 响应式设计 - 大型设备 (≥ 992px)
 * ============================================
 */

@media (min-width: 992px) {
    .container {
        max-width: 960px;
        padding: 0 15px;
    }

    header {
        padding: 2.5rem 1rem 0;
    }

    .logo {
        max-width: 320px;
    }

    main {
        padding: 2.5rem 1rem;
    }

    .tech-cards {
        --flex-gap: 1.75rem;
        gap: var(--flex-gap);
    }

    /* Flexbox回退布局：两列布局 */
    .tech-card {
        width: calc(50% - (var(--flex-gap) * 0.5));
        margin: 0 calc(var(--flex-gap) / 2) var(--flex-gap);
    }

    /* 清除每行第二个卡片的右边距 */
    .tech-card:nth-child(2n) {
        margin-right: 0;
    }

    /* Grid布局覆盖 - 两列 */
    @supports (display: grid) {
        .tech-cards {
            grid-template-columns: repeat(2, 1fr);
        }

        .tech-card {
            width: 100%;
            margin: 0;
        }
    }

    .tech-card a {
        padding: 1.75rem;
    }

    .nav-list {
        padding: 1.25rem 0;
        display: flex;
        flex-wrap: nowrap;
        justify-content: center;
    }

    .nav-item {
        margin: 0.25rem;
        width: auto;
        max-width: none;
    }

    .nav-link {
        padding: 0.6rem 1.5rem;
        font-size: 1rem;
    }
}

/* ============================================
 * 响应式设计 - 超大设备 (≥ 1200px)
 * ============================================
 */

@media (min-width: 1200px) {
    .container {
        max-width: 1140px;
    }

    .logo {
        max-width: 340px;
    }

    .tech-cards {
        --flex-gap: 2rem;
        gap: var(--flex-gap);
    }

    /* Flexbox回退布局：三列布局 */
    .tech-card {
        width: calc(33.333% - (var(--flex-gap) * 0.667));
        margin: 0 calc(var(--flex-gap) / 2) var(--flex-gap);
    }

    /* 清除每行第三个卡片的右边距 */
    .tech-card:nth-child(3n) {
        margin-right: 0;
    }

    /* Grid布局 - 三列 */
    @supports (display: grid) {
        .tech-cards {
            grid-template-columns: repeat(3, 1fr);
        }

        .tech-card {
            width: 100%;
            margin: 0;
        }
    }

    .tech-card a {
        padding: 2rem;
    }
}

/* ============================================
 * 响应式设计 - 特大设备 (≥ 1400px)
 * ============================================
 */

@media (min-width: 1400px) {
    .container {
        max-width: 1320px;
    }

    header {
        padding: 3rem 1rem 0;
    }

    .logo {
        max-width: 360px;
    }

    .tech-cards {
        --flex-gap: 2.25rem;
        gap: var(--flex-gap);
    }

    /* Flexbox回退布局：三列布局 */
    .tech-card {
        width: calc(33.333% - (var(--flex-gap) * 0.667));
        margin: 0 calc(var(--flex-gap) / 2) var(--flex-gap);
    }

    /* 清除每行第三个卡片的右边距 */
    .tech-card:nth-child(3n) {
        margin-right: 0;
    }

    /* Grid布局覆盖 */
    @supports (display: grid) {
        .tech-card {
            width: 100%;
            margin: 0;
        }
    }
}

/* ============================================
 * 无障碍优化 - 减少运动
 * ============================================
 */

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    .skip-link {
        -webkit-transition: none;
        -moz-transition: none;
        transition: none;
    }

    .tech-card:hover,
    .tech-card:focus-within {
        -webkit-transform: none;
        -moz-transform: none;
        -ms-transform: none;
        -o-transform: none;
        transform: none;
        will-change: auto;
    }

    .tech-card:focus-within {
        -webkit-box-shadow: 0 0 0 4px var(--color-primary), 0 2px 4px rgba(0, 0, 0, 0.2);
        -moz-box-shadow: 0 0 0 4px var(--color-primary), 0 2px 4px rgba(0, 0, 0, 0.2);
        box-shadow: 0 0 0 4px var(--color-primary), 0 2px 4px rgba(0, 0, 0, 0.2);
    }

    .tech-card:hover .read-more,
    .tech-card:focus-within .read-more {
        -webkit-transform: none;
        -moz-transform: none;
        -ms-transform: none;
        -o-transform: none;
        transform: none;
    }

    .tech-card::before {
        will-change: auto;
    }
}

/* ============================================
 * 打印样式
 * ============================================
 */

@media print {
    * {
        background: transparent !important;
        color: black !important;
        -webkit-box-shadow: none !important;
        -moz-box-shadow: none !important;
        box-shadow: none !important;
        text-shadow: none !important;
    }

    body {
        color: #000;
    }

    p,
    h1,
    h2,
    h3,
    h4,
    h5,
    h6,
    li {
        color: #000;
    }

    .tech-card {
        border: 1px solid #000;
        page-break-inside: avoid;
        margin-bottom: 1rem;
        will-change: auto;
        background-color: white !important;
    }

    .tech-card h4 {
        color: #000;
        border-bottom: 1px solid #000;
    }

    .tech-card p {
        color: #000;
    }

    .tech-card:focus-within {
        border: 2px solid #000;
        -webkit-box-shadow: none;
        -moz-box-shadow: none;
        box-shadow: none;
    }

    /* 打印时显示链接URL */
    a[href]:after {
        content: " (" attr(href) ")";
        color: #000;
    }

    /* 隐藏非必要元素 */
    header,
    footer {
        background: white !important;
        color: black !important;
    }

    .read-more-container,
    .main-nav,
    .skip-link {
        display: none;
    }
}