/* 全局变量 */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #2c3e50;
    --light-text: #ecf0f1;
    --dark-bg: #34495e;
    --light-bg: #f5f6fa;
    --nav-width: 280px;
    --transition: all 0.3s ease;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --card-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    --gradient: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: var(--light-bg);
    overflow-x: hidden;
}

/* 左侧导航栏 */
.side-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--nav-width);
    height: 100vh;
    background: var(--dark-bg);
    padding: 2rem;
    display: flex;
    flex-direction: column;
    z-index: 1000;
    transition: var(--transition);
}

.nav-brand {
    text-align: center;
    margin-bottom: 3rem;
}

.nav-brand h1 {
    color: var(--light-text);
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.nav-brand p {
    color: var(--secondary-color);
    font-size: 1rem;
}

.nav-menu {
    list-style: none;
    margin-bottom: auto;
}

.nav-item {
    margin-bottom: 1rem;
}

.nav-item a {
    display: flex;
    align-items: center;
    color: var(--light-text);
    text-decoration: none;
    padding: 1rem;
    border-radius: 8px;
    transition: var(--transition);
}

.nav-item a:hover,
.nav-item.active a {
    background: rgba(255, 255, 255, 0.1);
    transform: translateX(10px);
}

.nav-icon {
    margin-right: 1rem;
    font-size: 1.2rem;
}

.nav-footer {
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.social-link {
    color: var(--light-text);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 20px;
    font-size: 0.9rem;
    transition: var(--transition);
}

.social-link:hover {
    background: var(--secondary-color);
    border-color: var(--secondary-color);
}

/* 主内容区 */
.main-content {
    margin-left: var(--nav-width);
    min-height: 100vh;
}

.section {
    padding: 6rem 4rem;
    position: relative;
    overflow: hidden;
}

.section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, rgba(44, 62, 80, 0.05), rgba(52, 152, 219, 0.05));
    transform: skewY(-6deg);
    transform-origin: top left;
    z-index: -1;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.section-header p {
    color: var(--text-color);
    opacity: 0.8;
}

/* 首页区块 */
.section-home {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 4rem;
    background: var(--gradient);
    position: relative;
}

.hero-content {
    color: var(--light-text);
    max-width: 600px;
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-cta {
    display: flex;
    gap: 1rem;
}

.cta-button {
    display: inline-block;
    padding: 1rem 2rem;
    border-radius: 30px;
    text-decoration: none;
    font-weight: bold;
    transition: var(--transition);
}

.cta-button:first-child {
    background: var(--light-text);
    color: var(--primary-color);
}

.cta-button.outline {
    border: 2px solid var(--light-text);
    color: var(--light-text);
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.floating-cards {
    position: absolute;
    right: 4rem;
    display: flex;
    gap: 2rem;
    perspective: 1000px;
}

.tech-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    padding: 2rem;
    border-radius: 20px;
    color: var(--light-text);
    width: 250px;
    transform: rotateY(10deg);
    transition: var(--transition);
}

.tech-card:hover {
    transform: rotateY(0) translateY(-10px);
    background: rgba(255, 255, 255, 0.2);
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

/* 创新项目区块 */
.project-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.project-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
}

.project-card:hover {
    transform: translateY(-10px);
}

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

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.project-card:hover .project-image img {
    transform: scale(1.1);
}

.project-content {
    padding: 2rem;
}

.project-content h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.project-link {
    display: inline-block;
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: bold;
    margin-top: 1rem;
    transition: var(--transition);
}

.project-link:hover {
    color: var(--primary-color);
    transform: translateX(5px);
}

/* 研究领域区块 */
.research-showcase {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.research-item {
    display: flex;
    align-items: center;
    gap: 4rem;
    padding: 2rem;
    background: white;
    border-radius: 15px;
    box-shadow: var(--card-shadow);
}

.research-content {
    flex: 1;
}

.research-content h3 {
    color: var(--primary-color);
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
}

.research-list {
    list-style: none;
}

.research-list li {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
    position: relative;
}

.research-list li::before {
    content: '•';
    color: var(--secondary-color);
    position: absolute;
    left: 0;
    font-size: 1.5rem;
}

.research-visual {
    flex: 1;
    height: 300px;
    position: relative;
    overflow: hidden;
    border-radius: 10px;
}

.visual-element {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient);
    opacity: 0.1;
    transform: skewX(-15deg);
}

/* 团队介绍区块 */
.team-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.team-member {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
}

.team-member:hover {
    transform: translateY(-10px);
}

.member-avatar {
    height: 300px;
    overflow: hidden;
}

.member-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.member-info {
    padding: 2rem;
    text-align: center;
}

.member-info h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.member-title {
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.member-desc {
    opacity: 0.8;
}

/* 联系我们区块 */
.contact-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    max-width: 1200px;
    margin: 0 auto;
}

.contact-info h2 {
    color: var(--primary-color);
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.info-list {
    margin-top: 3rem;
}

.info-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: 2rem;
}

.info-icon {
    font-size: 1.5rem;
    margin-right: 1rem;
    color: var(--secondary-color);
}

.info-content h4 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.contact-form {
    background: white;
    padding: 3rem;
    border-radius: 15px;
    box-shadow: var(--card-shadow);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
    font-weight: bold;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 1rem;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--secondary-color);
    outline: none;
}

.form-group textarea {
    height: 150px;
    resize: vertical;
}

.submit-button {
    width: 100%;
    padding: 1rem;
    background: var(--gradient);
    color: var(--light-text);
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    transition: var(--transition);
}

.submit-button:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .project-grid,
    .team-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 992px) {
    :root {
        --nav-width: 80px;
    }

    .nav-brand h1,
    .nav-brand p,
    .nav-text {
        display: none;
    }

    .nav-icon {
        margin-right: 0;
        font-size: 1.5rem;
    }

    .social-links {
        flex-direction: column;
    }

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

@media (max-width: 768px) {
    .section {
        padding: 4rem 2rem;
    }

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

    .floating-cards {
        display: none;
    }

    .hero-title {
        font-size: 3rem;
    }

    .research-item {
        flex-direction: column;
        gap: 2rem;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fadeInUp {
    animation: fadeInUp 0.8s ease forwards;
}

@keyframes float {
    0% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
    100% {
        transform: translateY(0);
    }
}

.tech-card {
    animation: float 3s ease-in-out infinite;
}

.tech-card:nth-child(2) {
    animation-delay: 0.2s;
}

.tech-card:nth-child(3) {
    animation-delay: 0.4s;
}