/* ===== 重置样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* ===== 根变量 - Pure Fluent Design ===== */
:root {
    /* 字体 - Fluent Design 无衬线字体，加粗显示 */
    --font-primary: 'Segoe UI', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', sans-serif;
    --font-secondary: 'Segoe UI', 'Noto Sans SC', sans-serif;
    --font-code: 'Cascadia Code', 'Consolas', 'Monaco', monospace;

    /* 字体粗细 - 比标准稍粗 */
    --font-weight-normal: 500;
    --font-weight-medium: 600;
    --font-weight-bold: 700;

    /* 颜色 - Fluent Design System */
    --color-primary: #0078d4;
    --color-primary-hover: #106ebe;
    --color-primary-pressed: #005a9e;
    --color-secondary: #605e5c;
    --color-accent-blue: #0078d4;
    --color-accent-gold: #f7630c;
    --color-accent-purple: #8764b8;
    --color-accent-green: #107c10;
    --color-text: #242424;
    --color-text-light: #605e5c;
    --color-text-secondary: #8a8886;
    --color-background: #ffffff;
    --color-background-light: #faf9f8;
    --color-background-hover: #f3f2f1;
    --color-border: #edebe9;
    --color-shadow: rgba(0, 0, 0, 0.08);
    --color-card-shadow: 0 2px 4px rgba(0, 0, 0, 0.08), 0 0 2px rgba(0, 0, 0, 0.04);
    --color-card-shadow-hover: 0 4px 8px rgba(0, 0, 0, 0.12), 0 0 2px rgba(0, 0, 0, 0.06);

    /* 间距 - Fluent Design 更大的留白 */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-xxl: 40px;
    --spacing-xxxl: 48px;
    --spacing-section: 64px;

    /* 圆角 - Fluent Design */
    --border-radius-sm: 2px;
    --border-radius: 4px;
    --border-radius-md: 6px;
    --border-radius-lg: 8px;
    --border-radius-xl: 12px;

    /* 其他 - Fluent Design */
    --transition: all 0.2s cubic-bezier(0.33, 0, 0.67, 1);
    --container-max-width: 1200px;
    --container-padding: 24px;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --color-primary: #4a9eff;
        --color-primary-hover: #6cb0ff;
        --color-primary-pressed: #2886de;
        --color-text: #ffffff;
        --color-text-light: #c8c6c4;
        --color-text-secondary: #a19f9d;
        --color-background: #1b1b1b;
        --color-background-light: #252525;
        --color-background-hover: #2f2f2f;
        --color-border: #3b3b3b;
        --color-shadow: rgba(0, 0, 0, 0.24);
        --color-card-shadow: 0 2px 4px rgba(0, 0, 0, 0.24), 0 0 2px rgba(0, 0, 0, 0.12);
        --color-card-shadow-hover: 0 4px 8px rgba(0, 0, 0, 0.36), 0 0 2px rgba(0, 0, 0, 0.18);
    }
}

/* ===== 基础样式 ===== */
html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background-light);
    font-weight: var(--font-weight-normal);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* ===== 排版 - Fluent Design ===== */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-primary);
    font-weight: var(--font-weight-bold);
    line-height: 1.3;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
    margin-top: 0;
}

h1 {
    font-size: 3rem;
    font-weight: 700;
}

h2 {
    font-size: 2.25rem;
}

h3 {
    font-size: 1.75rem;
}

p {
    margin-bottom: var(--spacing-sm);
}

a {
    color: var(--color-accent-blue);
    text-decoration: none;
    transition: var(--transition);
}

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

/* ===== 高亮文本 ===== */
.highlight {
    color: var(--color-accent-blue);
    font-weight: 500;
}

.highlight-gold {
    color: var(--color-accent-gold);
    font-weight: 500;
}

.highlight-purple {
    color: var(--color-accent-purple);
    font-weight: 500;
}

.highlight-green {
    color: var(--color-accent-green);
    font-weight: 500;
}

/* ===== 头部导航 ===== */
.header {
    background: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding-left: var(--spacing-md);
    padding-right: var(--spacing-md);
}

.nav-brand .logo {
    width: 50px;
    height: 50px;
    background: var(--color-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--color-primary);
}

.logo-text {
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
    font-family: var(--font-secondary);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav-link {
    font-family: var(--font-primary);
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--color-text);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.nav-link:hover,
.nav-link.active {
    background: var(--color-background-light);
    color: var(--color-primary);
    text-decoration: none;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--color-primary);
    margin: 3px 0;
    transition: var(--transition);
}

/* ===== 主要内容 ===== */
.main {
    margin-top: 80px;
}

/* ===== 英雄区域 ===== */
.hero {
    padding: var(--spacing-xxl) 0;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
}

.hero-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.hero-subtitle {
    font-size: 1.3rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    font-style: italic;
}

.hero-description {
    font-size: 1.1rem;
    line-height: 1.8;
}

.profile-image {
    width: 100%;
    max-width: 300px;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: 0 10px 30px var(--color-shadow);
}

.image-caption {
    font-size: 0.9rem;
    color: var(--color-text-light);
    text-align: center;
    margin-top: var(--spacing-sm);
    font-style: italic;
}

/* ===== 信息区域 ===== */
.info-section {
    padding: var(--spacing-xl) 0;
    background: var(--color-background);
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.info-card {
    background: var(--color-background-light);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--color-accent-blue);
}

.info-card h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    font-size: 1.25rem;
}

.chinese {
    color: var(--color-text-light);
    font-style: italic;
}

/* ===== 统计区域 ===== */
.stats-section {
    padding: var(--spacing-xxl) 0;
    background: var(--color-background-light);
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    font-size: 2.5rem;
    color: var(--color-primary);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

/* 扩展的项目卡片 */
.projects-expanded {
    grid-column: span 3;
}

.projects-content {
    /* 垂直排列各个分类 */
}

.project-category {
    margin-bottom: var(--spacing-xl);
}

.project-items-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.project-category h4 {
    color: var(--color-accent-blue);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.project-item {
    background: var(--color-background-light);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-sm);
    border-left: 3px solid var(--color-accent-blue);
    transition: var(--transition);
}

.project-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.project-title {
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
    font-size: 0.95rem;
}

.project-desc {
    color: var(--color-text-light);
    font-size: 0.9rem;
    line-height: 1.4;
    margin-bottom: var(--spacing-xs);
}

.project-tech {
    font-size: 0.8rem;
    color: var(--color-accent-gold);
    font-weight: 500;
}

@media (max-width: 1200px) {
    .projects-expanded {
        grid-column: span 2;
    }
}

@media (max-width: 768px) {
    .projects-expanded {
        grid-column: span 1;
    }
}

.stat-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    box-shadow: 0 5px 15px var(--color-shadow);
    transition: var(--transition);
    border-left: 4px solid var(--color-accent-blue);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px var(--color-shadow);
}

.stat-card.research {
    border-left-color: var(--color-accent-blue);
}

.stat-card.writing {
    border-left-color: var(--color-accent-green);
}

.stat-card.design {
    border-left-color: var(--color-accent-gold);
}

.stat-card.teaching {
    border-left-color: var(--color-accent-purple);
}

.stat-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
    display: block;
}

.stat-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
}

.stat-content {
    line-height: 1.6;
}

.stat-content strong {
    color: var(--color-primary);
    font-weight: 600;
}

.stat-content em {
    color: var(--color-accent-blue);
    font-style: italic;
}

/* ===== 研究兴趣区域 ===== */
.research-interests-section {
    padding: var(--spacing-xxl) 0;
    background: var(--color-background-light);
}

.research-content {
    margin-top: var(--spacing-lg);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.research-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    box-shadow: 0 5px 15px var(--color-shadow);
    border-left: 4px solid var(--color-accent-blue);
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px var(--color-shadow);
}

.research-card h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    font-size: 1.25rem;
}

.research-card ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.research-card li {
    padding: var(--spacing-xs) 0;
    line-height: 1.6;
    color: var(--color-text);
}

.research-card li strong {
    color: var(--color-primary);
}

.research-statement {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    box-shadow: 0 5px 15px var(--color-shadow);
    border: 2px solid var(--color-accent-gold);
}

.research-statement h3 {
    color: var(--color-primary);
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    text-align: center;
}

.research-statement p {
    line-height: 1.8;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
    text-align: justify;
}

.research-statement p:last-child {
    margin-bottom: 0;
}

/* ===== 社交链接区域 ===== */
.find-me-section {
    padding: var(--spacing-xl) 0;
    background: var(--color-background);
}

.social-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.social-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    background: var(--color-background-light);
    border-radius: var(--border-radius);
    transition: var(--transition);
    text-decoration: none;
    color: var(--color-text);
}

.social-link:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-2px);
    text-decoration: none;
}

.social-icon {
    font-size: 1.5rem;
}

/* ===== 页脚 ===== */
.footer {
    background: var(--color-primary);
    color: white;
    text-align: center;
    padding: var(--spacing-lg) 0;
}

/* ===== 作品集样式 ===== */
.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

.portfolio-card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: 0 5px 15px var(--color-shadow);
    overflow: hidden;
    transition: var(--transition);
    border-left: 4px solid var(--color-accent-blue);
}

.portfolio-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
}

.portfolio-image {
    height: 200px;
    overflow: hidden;
}

.image-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 3rem;
}

.marketing-placeholder {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.analysis-placeholder {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.innovation-placeholder {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

.design-placeholder {
    background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
}

.portfolio-content {
    padding: var(--spacing-lg);
}

.portfolio-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.3;
}

.portfolio-description {
    color: var(--color-text-light);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

.portfolio-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.portfolio-meta {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
}

.meta-item {
    font-size: 0.85rem;
    color: var(--color-text-light);
    background: var(--color-background-light);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 15px;
}

.portfolio-highlights {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border);
}

.highlight-item {
    margin-bottom: var(--spacing-sm);
    font-size: 0.9rem;
    line-height: 1.5;
}

.highlight-item strong {
    color: var(--color-accent-blue);
    font-weight: 600;
}

.filter-section {
    text-align: center;
}

.filter-buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.filter-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--color-background-light);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    color: var(--color-text);
    cursor: pointer;
    transition: var(--transition);
}

.filter-btn:hover,
.filter-btn.active {
    background: var(--color-accent-blue);
    color: white;
    border-color: var(--color-accent-blue);
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: var(--spacing-lg) 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .nav-toggle.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-lg);
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .social-links {
        grid-template-columns: 1fr;
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    .section-title {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }

    .hero {
        padding: var(--spacing-lg) 0;
    }

    .hero-title {
        font-size: 2rem;
    }

    .stats-section {
        padding: var(--spacing-lg) 0;
    }
}

/* ===== 通用页面样式 ===== */
.page-header {
    background: linear-gradient(135deg, rgba(127, 179, 213, 0.15) 0%, rgba(44, 62, 80, 0.08) 100%);
    color: var(--color-primary);
    padding: var(--spacing-xxl) 0 var(--spacing-xl) 0;
    text-align: center;
    margin-top: 80px;
    border-bottom: 1px solid var(--color-border);
}

.page-title {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
    font-weight: 700;
    color: var(--color-primary);
}

.page-subtitle {
    font-size: 1.3rem;
    color: var(--color-text-light);
    font-style: italic;
}

.page-content {
    padding: var(--spacing-xxl) 0;
}

/* ===== 卡片样式 - Fluent Design ===== */
.card {
    background: var(--color-background);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xxl);
    box-shadow: var(--color-card-shadow);
    margin-bottom: var(--spacing-lg);
    transition: var(--transition);
    border: 1px solid var(--color-border);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--color-card-shadow-hover);
}

.card-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.card-meta {
    color: var(--color-text-light);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.card-content {
    line-height: 1.6;
}

/* ===== 按钮样式 - Fluent Design ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 5px 12px;
    min-height: 32px;
    background: var(--color-primary);
    color: white;
    border: 1px solid transparent;
    border-radius: var(--border-radius);
    font-family: var(--font-primary);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.btn:hover {
    background: var(--color-primary-hover);
    color: white;
    text-decoration: none;
    transform: translateY(-1px);
}

.btn:active {
    background: var(--color-primary-pressed);
    transform: translateY(0);
}

.btn-secondary {
    background: var(--color-background-light);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* ===== 标签样式 ===== */
.tag {
    display: inline-block;
    background: var(--color-background-light);
    color: var(--color-text);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 20px;
    font-size: 0.8rem;
    margin: 0 var(--spacing-xs) var(--spacing-xs) 0;
    border: 1px solid var(--color-border);
}

.tag:hover {
    background: var(--color-accent-blue);
    color: white;
    border-color: var(--color-accent-blue);
}

.special-tag {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%) !important;
    color: white !important;
    border: none !important;
    font-weight: 600;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(255, 107, 107, 0.4);
    }

    70% {
        box-shadow: 0 0 0 10px rgba(255, 107, 107, 0);
    }

    100% {
        box-shadow: 0 0 0 0 rgba(255, 107, 107, 0);
    }
}

/* ===== 网格布局 ===== */
.grid {
    display: grid;
    gap: var(--spacing-lg);
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-4 {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

/* ===== 实用类 ===== */
.text-center {
    text-align: center;
}

.text-left {
    text-align: left;
}

.text-right {
    text-align: right;
}

.mb-sm {
    margin-bottom: var(--spacing-sm);
}

.mb-md {
    margin-bottom: var(--spacing-md);
}

.mb-lg {
    margin-bottom: var(--spacing-lg);
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.mt-md {
    margin-top: var(--spacing-md);
}

.mt-lg {
    margin-top: var(--spacing-lg);
}