/* =============================================
   个人学术主页 - 样式表
   重庆大学 · 物理学院
   ============================================= */

/* ----- CSS 变量 (可在此处自定义主题色) ----- */
:root {
    --primary:       #1a56db;      /* 主色调 - 重大蓝 */
    --primary-dark:  #1243af;
    --primary-light: #e8f0fe;
    --accent:        #f59e0b;      /* 强调色 - 暖金色 */
    --accent-light:  #fef3c7;
    --bg:            #ffffff;
    --bg-alt:        #f8fafc;
    --text:          #1e293b;
    --text-light:    #64748b;
    --text-lighter:  #94a3b8;
    --border:        #e2e8f0;
    --shadow:        0 4px 24px rgba(0,0,0,0.06);
    --shadow-hover:  0 8px 40px rgba(0,0,0,0.10);
    --radius:        12px;
    --radius-sm:     8px;
    --transition:    0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --max-width:     1100px;
    --font-cn:       'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-en:       'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ----- Reset & Base ----- */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: var(--font-cn);
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition);
}
a:hover { color: var(--primary-dark); }

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* ----- 导航栏 ----- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text);
}
.nav-logo:hover { color: var(--primary); }

.nav-menu {
    display: flex;
    list-style: none;
    gap: 4px;
}

.nav-link {
    display: block;
    padding: 8px 16px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-light);
    border-radius: var(--radius-sm);
    transition: var(--transition);
}
.nav-link:hover {
    color: var(--primary);
    background: var(--primary-light);
}

/* 移动端菜单按钮 */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}
.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: var(--transition);
}

/* ----- Hero 首屏 ----- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 120px 24px 80px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(26,86,219,0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(245,158,11,0.06) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, rgba(26,86,219,0.04) 0%, transparent 50%);
    z-index: 0;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 740px;
}

.hero-avatar {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    overflow: hidden;
    margin: 0 auto 24px;
    border: 4px solid var(--primary-light);
    box-shadow: 0 8px 32px rgba(26,86,219,0.15);
}
.hero-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-name {
    font-size: 2.8rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-title {
    font-size: 1.15rem;
    color: var(--text-light);
    font-weight: 500;
    margin-bottom: 4px;
}

.hero-subtitle {
    font-size: 0.95rem;
    color: var(--text-lighter);
    font-weight: 400;
    margin-bottom: 20px;
}

.hero-tags {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin-bottom: 28px;
}

.tag {
    display: inline-block;
    padding: 6px 18px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--primary);
    background: var(--primary-light);
    border-radius: 20px;
    transition: var(--transition);
}
.tag:hover {
    background: var(--primary);
    color: #fff;
    transform: translateY(-2px);
}

.hero-actions {
    display: flex;
    gap: 12px;
    justify-content: center;
    margin-bottom: 28px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    font-size: 0.95rem;
    font-weight: 500;
    font-family: var(--font-cn);
    border-radius: 30px;
    border: 2px solid transparent;
    cursor: pointer;
    transition: var(--transition);
}
.btn-primary {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}
.btn-primary:hover {
    background: var(--primary-dark);
    border-color: var(--primary-dark);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(26,86,219,0.25);
}
.btn-outline {
    background: transparent;
    color: var(--primary);
    border-color: var(--primary);
}
.btn-outline:hover {
    background: var(--primary);
    color: #fff;
    transform: translateY(-2px);
}

.hero-social {
    display: flex;
    justify-content: center;
    gap: 16px;
}
.hero-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    font-size: 1.25rem;
    color: var(--text-light);
    background: var(--bg-alt);
    border: 1px solid var(--border);
    transition: var(--transition);
}
.hero-social a:hover {
    color: #fff;
    background: var(--primary);
    border-color: var(--primary);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(26,86,219,0.25);
}

/* ----- 通用 Section ----- */
.section {
    padding: 90px 0;
}
.section-alt {
    background: var(--bg-alt);
}

.section-title {
    text-align: center;
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.section-divider {
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 2px;
    margin: 0 auto 48px;
}

/* ----- 关于我 ----- */
.about-content {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 48px;
    align-items: start;
}

.about-text p {
    margin-bottom: 16px;
    font-size: 1.05rem;
    color: var(--text);
    line-height: 1.8;
}

.info-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow);
}

.info-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
}
.info-item:last-child { border-bottom: none; }

.info-label {
    display: flex;
    align-items: center;
    gap: 6px;
    min-width: 100px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-light);
}
.info-label i {
    width: 18px;
    color: var(--primary);
}
.info-value {
    font-size: 0.95rem;
    color: var(--text);
}

/* ----- 教育经历 Timeline ----- */
.timeline {
    position: relative;
    max-width: 680px;
    margin: 0 auto;
    padding-left: 32px;
}
.timeline::before {
    content: '';
    position: absolute;
    left: 8px;
    top: 8px;
    bottom: 8px;
    width: 2px;
    background: var(--border);
}

.timeline-item {
    position: relative;
    padding: 0 0 40px 24px;
}
.timeline-item:last-child { padding-bottom: 0; }

.timeline-dot {
    position: absolute;
    left: -28px;
    top: 6px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--primary);
    border: 3px solid var(--primary-light);
}
.timeline-content {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}
.timeline-content:hover {
    box-shadow: var(--shadow-hover);
    transform: translateX(4px);
}

.timeline-date {
    display: inline-block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary);
    background: var(--primary-light);
    padding: 4px 14px;
    border-radius: 20px;
    margin-bottom: 8px;
}
.timeline-content h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 4px;
}
.timeline-sub {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 8px;
}

/* ----- 研究方向 ----- */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 28px;
}

.research-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px 28px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
}
.research-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-light);
}

.research-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    color: var(--primary);
    background: var(--primary-light);
    border-radius: 16px;
    transition: var(--transition);
}
.research-card:hover .research-icon {
    background: var(--primary);
    color: #fff;
    transform: rotate(-6deg) scale(1.05);
}

.research-card h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 10px;
}
.research-card p {
    font-size: 0.92rem;
    color: var(--text-light);
    line-height: 1.7;
}

/* ----- 发表论文 ----- */
.pub-list {
    max-width: 800px;
    margin: 0 auto;
}

.pub-item {
    display: flex;
    gap: 16px;
    padding: 20px 0;
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}
.pub-item:hover {
    padding-left: 12px;
}
.pub-item:last-child { border-bottom: none; }

.pub-num {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary);
    min-width: 36px;
    padding-top: 2px;
}

.pub-content {
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.pub-authors { font-size: 0.95rem; }
.pub-title {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text);
}
.pub-journal { font-size: 0.88rem; color: var(--text-light); }
.pub-links {
    font-size: 0.85rem;
    display: flex;
    gap: 6px;
}

.placeholder-text {
    text-align: center;
    color: var(--text-lighter);
    font-size: 1.05rem;
    padding: 40px 0;
}

/* ----- 科研项目 ----- */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.project-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}
.project-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

.project-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}
.project-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.project-tag {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 3px 12px;
    border-radius: 20px;
    background: #fef3c7;
    color: #b45309;
    white-space: nowrap;
}
.tag-blue { background: #dbeafe; color: #1d4ed8; }
.tag-green { background: #d1fae5; color: #047857; }

.project-desc {
    font-size: 0.92rem;
    color: var(--text-light);
    line-height: 1.7;
    margin-bottom: 16px;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}
.project-tech span {
    display: inline-block;
    font-size: 0.78rem;
    font-weight: 500;
    padding: 4px 12px;
    border-radius: 20px;
    background: var(--bg-alt);
    color: var(--text-light);
    border: 1px solid var(--border);
}

/* ----- 荣誉奖项 ----- */
.honors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 16px;
    max-width: 800px;
    margin: 0 auto;
}

.honor-item {
    display: flex;
    align-items: center;
    gap: 16px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 24px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}
.honor-item:hover {
    transform: translateX(6px);
    border-color: var(--primary-light);
    box-shadow: var(--shadow-hover);
}
.honor-item i {
    font-size: 1.6rem;
    color: var(--accent);
    min-width: 40px;
    text-align: center;
}
.honor-item h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 2px;
}
.honor-item p {
    font-size: 0.85rem;
    color: var(--text-light);
}

/* ----- 联系方式 ----- */
.contact-intro {
    text-align: center;
    font-size: 1.05rem;
    color: var(--text-light);
    margin-bottom: 36px;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    max-width: 800px;
    margin: 0 auto;
}

.contact-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 8px;
    padding: 28px 20px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
    color: var(--text);
    cursor: default;
}
.contact-card[target="_blank"] { cursor: pointer; }
.contact-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-light);
}
.contact-card i {
    font-size: 2rem;
    color: var(--primary);
    transition: var(--transition);
}
.contact-card:hover i {
    transform: scale(1.15);
}
.contact-card h4 {
    font-size: 0.95rem;
    font-weight: 600;
}
.contact-card p {
    font-size: 0.85rem;
    color: var(--text-light);
    word-break: break-all;
}

/* ----- 页脚 ----- */
.footer {
    background: var(--text);
    color: var(--text-lighter);
    padding: 36px 0;
    text-align: center;
}
.footer-content p {
    font-size: 0.88rem;
    margin-bottom: 4px;
}
.footer-motto {
    font-weight: 500;
    color: var(--text-light);
}
.footer-built i {
    color: #ef4444;
    margin: 0 2px;
}
.footer-built i:last-child {
    color: var(--accent);
}

/* ----- 返回顶部按钮 ----- */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--primary);
    color: #fff;
    border: none;
    font-size: 1.1rem;
    cursor: pointer;
    box-shadow: 0 4px 16px rgba(26,86,219,0.3);
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: var(--transition);
    z-index: 999;
}
.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
    box-shadow: 0 6px 24px rgba(26,86,219,0.4);
}

/* =============================================
   响应式设计 Responsive
   ============================================= */

/* 平板 */
@media (max-width: 900px) {
    .about-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .hero-name { font-size: 2.2rem; }
}

/* 手机 */
@media (max-width: 640px) {
    .nav-menu {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: rgba(255,255,255,0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 16px 24px;
        gap: 4px;
        border-bottom: 1px solid var(--border);
        transform: translateY(-110%);
        opacity: 0;
        transition: var(--transition);
        pointer-events: none;
    }
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }
    .nav-toggle {
        display: flex;
    }
    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    .hero {
        padding: 100px 20px 60px;
        min-height: auto;
    }
    .hero-name { font-size: 1.8rem; }
    .hero-title { font-size: 1rem; }
    .hero-avatar {
        width: 100px;
        height: 100px;
    }
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }

    .section { padding: 60px 0; }
    .section-title { font-size: 1.6rem; }

    .research-grid,
    .project-grid {
        grid-template-columns: 1fr;
    }

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

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

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        font-size: 1rem;
    }
}

@media (max-width: 400px) {
    .contact-grid { grid-template-columns: 1fr; }
}

/* =============================================
   动画 Animations
   ============================================= */

/* 淡入上移 */
@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section {
    animation: fadeUp 0.6s ease-out both;
}

/* 滚动入场 (由 IntersectionObserver 控制) */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}