/* ==========================================================================
   MUJI Minimalist Clean Style (style.css)
   适用页面: index.html, about.html, projects.html (不包含 cv.html)
   ========================================================================== */

:root {
    /* --- 配色方案：自然、柔和 (Muji Style) --- */
    --bg-body: #FFFFFF;
    --bg-alt: #F7F8F9; /* 极淡的灰白，用于次要背景 */
    --bg-contact: #F5F8F9; /* 浅灰蓝，专门用于 Contact 区域 */
    
    --text-main: #2C2C2C; 
    --text-sub: #666666;
    
    /* 强调色：莫兰迪绿/灰绿 - 清新感 */
    --accent: #5A7D7C; 
    --accent-hover: #456362;
    
    --border: #E5E5E5;
    
    /* 间距与尺寸 */
    --nav-height: 70px;
    --container-width: 1000px;
    --radius: 4px;
}

/* =========================================
   1. 基础重置 & 通用设置
   ========================================= */
* { 
    box-sizing: border-box; 
    margin: 0; 
    padding: 0; 
}

body {
    font-family: 'Lato', 'Noto Sans SC', sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

a { 
    text-decoration: none; 
    color: inherit; 
    transition: color 0.3s; 
}

ul { 
    list-style: none; 
}

img {
    max-width: 100%;
    display: block;
}

/* =========================================
   2. 通用布局组件 (Utilities)
   ========================================= */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
}

.section {
    padding: 80px 0; 
}

.bg-alt { 
    background-color: var(--bg-alt); 
}

/* 标题样式 */
h3 { 
    font-weight: 500; 
    font-size: 1.3rem; 
    margin-top: 20px; 
    margin-bottom: 10px; 
}

.block-title { 
    font-weight: 700; 
    font-size: 1.1rem; 
    color: var(--text-main); 
    display: flex; 
    align-items: center; 
    gap: 8px; 
    margin-bottom: 15px; 
}

.block-title i { 
    color: var(--accent); 
}

/* 列表样式工具 */
.clean-list li { 
    margin-bottom: 15px; 
}

.clean-list-bullet li { 
    margin-left: 20px; 
    list-style: disc; 
    margin-bottom: 8px; 
    color: var(--text-sub); 
}

.clean-list-bullet li span.year { 
    font-weight: 300; 
    margin-left: 10px; 
    font-size: 0.9rem; 
    color: #999; 
}

.inline-list { 
    display: flex; 
    flex-wrap: wrap; 
    gap: 15px 30px; 
}

.mt-40 { margin-top: 40px; }

/* 按钮样式 */
.btn-clean {
    display: inline-block;
    padding: 10px 24px;
    border: 1px solid var(--text-main);
    border-radius: 2px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.3s;
}

.btn-clean:hover { 
    background: var(--text-main); 
    color: #FFF; 
}

/* =========================================
   3. 顶部导航 (Fixed Top)
   ========================================= */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--nav-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0,0,0,0.03);
    z-index: 1000;
    display: flex;
    align-items: center;
}

.header-inner {
    width: 100%;
    max-width: 1200px; 
    margin: 0 auto;
    padding: 0 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
    letter-spacing: 0.5px;
}

.nav-area { 
    display: flex; 
    align-items: center; 
    gap: 40px; 
}

.main-nav { 
    display: block; 
}

.nav-list { 
    display: flex; 
    gap: 20px; 
}

.nav-link {
    font-size: 0.95rem;
    color: var(--text-sub);
    font-weight: 500;
    position: relative;
}

.nav-link:hover, .nav-link.active { 
    color: var(--text-main); 
}

.nav-link::after {
    content: ''; 
    position: absolute; 
    bottom: -5px; 
    left: 0; 
    width: 0; 
    height: 1px;
    background: var(--text-main); 
    transition: width 0.3s;
}

.nav-link:hover::after { 
    width: 100%; 
}

/* 语言切换 */
.lang-selector {
    font-size: 0.85rem;
    color: var(--text-sub);
    font-family: 'Lato', sans-serif;
    display: flex;
    align-items: center;
    gap: 5px;
}

.lang-opt { 
    cursor: pointer; 
    transition: color 0.2s; 
}

.lang-opt:hover, .lang-opt.active { 
    color: var(--accent); 
    font-weight: 700; 
}

.divider { 
    color: #DDD; 
    font-size: 0.7rem; 
}

.menu-toggle { 
    display: none; 
    border: none; 
    background: none; 
    font-size: 1.2rem; 
    cursor: pointer; 
}

/* =========================================
   4. Hero Section (首页首屏)
   ========================================= */
.hero-section {
    margin-top: var(--nav-height); 
    min-height: 80vh; 
    display: flex;
    align-items: center;
}

.hero-layout {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr; 
    gap: 60px;
    align-items: center;
}

.hero-title { 
    font-size: 3rem; 
    font-weight: 300; 
    margin-bottom: 10px; 
    color: var(--text-main); 
}

.hero-role { 
    font-size: 1.1rem; 
    color: var(--text-sub); 
    font-weight: 300; 
    margin-bottom: 25px; 
}

.hero-divider { 
    width: 40px; 
    height: 2px; 
    background: var(--accent); 
    margin-bottom: 25px; 
}

.hero-desc { 
    font-size: 1.05rem; 
    margin-bottom: 30px; 
    max-width: 450px; 
    color: #555; 
}

.social-links { 
    margin-bottom: 35px; 
    display: flex; 
    gap: 20px; 
}

.social-links a { 
    font-size: 0.9rem; 
    color: var(--text-sub); 
    display: flex; 
    align-items: center; 
    gap: 6px; 
}

.social-links a:hover { 
    color: var(--accent); 
}

.profile-img {
    width: 100%;
    max-width: 320px;
    height: auto;
    border-radius: var(--radius);
    display: block;
    margin: 0 auto;
    object-fit: cover;
}

/* =========================================
   5. Research & Interests Section
   ========================================= */
.section-header { 
    margin-bottom: 50px; 
    text-align: left; 
}

.section-header h2 { 
    font-size: 2rem; 
    font-weight: 400; 
    margin-bottom: 8px; 
}

.section-subtitle { 
    font-family: 'Lato', sans-serif; 
    font-style: italic; 
    color: var(--accent); 
}

.research-intro { 
    margin-bottom: 40px; 
    font-size: 1.05rem; 
    max-width: 800px; 
}

.interests-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.interest-card {
    padding: 20px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    gap: 15px;
    font-weight: 500;
    color: var(--text-main);
    background-color: var(--bg-body);
    transition: all 0.3s ease;
}

.interest-card .icon {
    font-size: 1.2rem;
    color: var(--accent);
}

.interest-card:hover {
    border-color: var(--accent-hover);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
    transform: translateY(-2px);
}

/* =========================================
   6. Skills & Service Section
   ========================================= */
.skills-service-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}

.skills-category {
    margin-bottom: 30px;
}

.skills-category h3 {
    color: var(--accent-hover);
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.skills-category p {
    font-size: 0.95rem;
    color: var(--text-sub);
}

.review-summary {
    font-style: italic;
    margin-bottom: 25px;
}

.service-list-ul {
    padding-left: 0;
}

/* =========================================
   7. News & Funding Section
   ========================================= */
/* Talks List Style */
.talks-list-wrapper ul {
    list-style: none;
    padding: 0;
}

.talks-list-wrapper li {
    display: flex; 
    justify-content: space-between; 
    align-items: flex-start; 
    margin-bottom: 15px; 
    padding-bottom: 5px; 
    border-bottom: 1px solid rgba(0, 0, 0, 0.05); 
    gap: 20px; 
}

.talks-list-wrapper li:last-child {
    border-bottom: none; 
    margin-bottom: 0;
    padding-bottom: 0;
}

.talks-list-wrapper .date {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--accent);
    flex-shrink: 0; 
    width: 120px; 
    text-align: right;
}

.talks-list-wrapper .event {
    font-size: 1.0rem;
    color: var(--text-main);
    flex-grow: 1; 
    text-align: left;
}

/* Grants List Style */
.grants-list {
    list-style: none;
    padding: 0;
}

.grants-list li {
    display: flex; 
    flex-direction: column;
    padding-top: 10px;
    padding-bottom: 10px;
    margin-bottom: 5px; 
    border-bottom: 1px solid rgba(0, 0, 0, 0.05); 
}

.grants-list li:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.grants-list .role {
    display: inline-block; 
    font-size: 0.85rem; 
    font-weight: 700;
    color: var(--accent); 
    margin-right: 15px; 
}

.grants-list li > span:not(.role):not(.year) {
    font-size: 1.05rem;
    font-weight: 500;
    color: var(--text-main);
    display: block; 
    margin-top: 5px;
    margin-bottom: 5px;
}

.grants-list .year {
    display: inline-block;
    font-weight: 300;
    color: var(--text-sub);
    float: right;
    font-size: 0.9rem;
}

.grant-desc {
    font-size: 0.95rem;
    color: #555;
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px dashed var(--border); 
}

/* =========================================
   8. Teaching Section
   ========================================= */
.teaching-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.teaching-block {
    padding: 20px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background-color: var(--bg-body);
}

.course-list span {
    display: inline-block;
    padding: 4px 10px;
    background-color: var(--bg-alt);
    color: var(--text-main);
    border-radius: 15px;
    font-size: 0.9rem;
    margin-right: 5px;
    margin-bottom: 8px;
}

/* =========================================
   9. Contact Section (浅灰蓝背景)
   ========================================= */
#contact-section {
    background-color: var(--bg-contact); /* 应用 #F5F8F9 */
}

.contact-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.contact-quote {
    font-style: italic;
    color: var(--text-sub);
    margin-bottom: 30px;
}

.contact-items .c-item {
    margin-bottom: 15px;
}

.c-item .label {
    display: block;
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--accent);
    margin-bottom: 5px;
}

.c-item .val {
    font-size: 1rem;
    color: var(--text-main);
}

.contact-visual .visual-img {
    width: 100%;
    max-width: 400px;
    height: auto;
    border-radius: var(--radius);
    display: block;
    margin: 0 auto;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
}

/* =========================================
   10. Links Section (白色背景，灰色卡片)
   ========================================= */
#links {
    padding-top: 80px;
    padding-bottom: 80px;
    background-color: var(--bg-body); /* 白色 */
}

.link-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.link-category {
    background-color: var(--bg-alt); /* 浅灰背景 */
    padding: 25px;
    border-radius: var(--radius);
    border: 1px solid var(--border); 
    transition: box-shadow 0.3s;
}

.link-category:hover {
    border-color: var(--accent-hover);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05); 
}

.link-category h3 {
    font-size: 1.1rem;
    color: var(--accent);
    margin-bottom: 15px;
    font-weight: 700;
    border-bottom: 1px solid rgba(0,0,0,0.05);
    padding-bottom: 10px;
}

.link-category ul {
    list-style: none;
    padding: 0;
}

.link-category li {
    margin-bottom: 12px;
    font-size: 0.95rem;
    display: flex; 
    align-items: flex-start;
}

.link-category li::before {
    content: "\f054"; /* Font Awesome arrow */
    font-family: 'Font Awesome 6 Free';
    font-weight: 900;
    color: var(--accent);
    margin-right: 10px;
    font-size: 0.7rem;
    line-height: 1.5; 
    transform: translateY(2px); 
}

.link-category a {
    color: var(--text-sub);
    text-decoration: none;
    flex-grow: 1; 
}

.link-category a:hover {
    color: var(--text-main);
}

/* =========================================
   11. Footer
   ========================================= */
.site-footer {
    padding: 30px 0; 
    text-align: center;
    border-top: 1px solid var(--border); 
    background-color: var(--bg-alt); 
}

.site-footer p {
    font-size: 0.8rem;
    color: var(--text-sub);
    margin: 5px 0; 
}
.site-footer .copyright-text {
    margin-top: 0; 
}

/* =========================================
   12. 主站响应式设计 (不包含 CV)
   ========================================= */

@media (max-width: 900px) {
    .section { padding: 60px 0; }
    .hero-title { font-size: 2.5rem; }
    .hero-layout, .contact-layout {
        grid-template-columns: 1fr; 
        gap: 40px;
        text-align: center;
    }
    .hero-text { order: 2; } 
    .hero-image-wrapper { order: 1; }
    .hero-divider { margin: 20px auto; }
    .social-links { justify-content: center; }
    .skills-service-layout {
        grid-template-columns: 1fr; 
        gap: 40px;
    }
    .skills-block, .service-honors-block {
        text-align: left; 
    }
    .c-item { text-align: left; }
    .contact-info { order: 2; }
    .contact-visual { order: 1; }
    .link-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-area { gap: 15px; }
    .main-nav { 
        position: absolute; top: var(--nav-height); left: 0; width: 100%; 
        background: rgba(255, 255, 255, 0.98); 
        border-top: 1px solid var(--border);
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05);
        display: none; 
        max-height: calc(100vh - var(--nav-height));
        overflow-y: auto;
    }
    .main-nav.active { display: block; }
    .nav-list { flex-direction: column; padding: 15px 30px; }
    .nav-list li { margin-bottom: 10px; }
    .nav-link { font-size: 1.1rem; }
    .menu-toggle { display: block; }

    .talks-list-wrapper li {
        flex-direction: column;
        align-items: flex-start;
        gap: 0;
    }
    .talks-list-wrapper .date {
        width: auto;
        text-align: left;
        margin-bottom: 3px;
    }
}