/* 基础样式 */
:root {
  /* 主色调 */
  --primary-color: #005FCC;
  --secondary-color: #212121;
  --tertiary-color: #9a9a9a;
  --accent-color: #00CC66;
  --accent-color-alt: #FF6600;
  --light-color: #FFFFFF;
  --light-gray: #F5F5F5;
  --mid-gray: #DDDDDD;
  --dark-gray: #666666;

  /* 字体 */
  --heading-font: 'Noto Sans SC', Arial, sans-serif;
  --body-font: 'Noto Sans SC', Arial, sans-serif;

  /* 尺寸 */
  --container-width: 1200px;
  --header-height: 90px;
  --section-spacing: 80px;
  --card-radius: 8px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  font-family: var(--body-font);
  line-height: 1.6;
  color: var(--secondary-color);
  background-color: var(--light-color);
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: all 0.3s ease;
}

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

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

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--heading-font);
  margin-top: 0;
  line-height: 1.3;
  color: var(--secondary-color);
}

p {
  margin: 0 0 1rem;
}

ul {
  padding-left: 1.2rem;
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 15px;
}

.section-title {
  text-align: center;
  margin-bottom: 2.5rem;
  font-size: 2rem;
  font-weight: 700;
  position: relative;
  padding-bottom: 1rem;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 80px;
  height: 3px;
  background-color: var(--primary-color);
  transform: translateX(-50%);
}

.btn {
  display: inline-block;
  padding: 0.8rem 1.8rem;
  background-color: var(--primary-color);
  color: var(--light-color);
  border: none;
  border-radius: 4px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: center;
}

.btn:hover {
  background-color: var(--secondary-color);
  color: var(--light-color);
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.btn-outline {
  background-color: transparent;
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
}

.btn-outline:hover {
  background-color: var(--primary-color);
  color: var(--light-color);
}

/* 导航栏样式 */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background-color: var(--light-color);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  z-index: 1000;
  transition: all 0.3s ease;
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  font-size: 1.2rem;
  font-weight: 700;
  flex-shrink: 0;
  max-width: 70%;
}

.logo a {
  color: var(--secondary-color);
}

.logo h1 {
  margin: 0;
  font-size: 1.8rem;
  letter-spacing: 1px;
  color: var(--primary-color);
  font-weight: 700;
}

/* 导航栏右侧内容容器 */
.nav-right {
  display: flex;
  align-items: center;
  margin-left: auto;
}

.main-nav ul {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
}

.main-nav li {
  margin-left: 35px;
}

.main-nav a {
  color: var(--secondary-color);
  font-weight: 500;
  padding: 12px 0;
  position: relative;
  font-size: 1.05rem;
}

.main-nav a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background-color: var(--primary-color);
  transition: width 0.3s ease;
}

.main-nav a:hover::after,
.main-nav a.active::after {
  width: 100%;
}

.menu-toggle {
  display: none;
  font-size: 1.5rem;
  cursor: pointer;
}

.search-box {
  display: flex;
  align-items: center;
  margin-left: 25px;
}

.search-box input {
  padding: 8px 12px;
  border: 1px solid var(--mid-gray);
  border-radius: 4px 0 0 4px;
  width: 140px;
  font-size: 0.9rem;
}

.search-box button {
  background-color: var(--primary-color);
  color: var(--light-color);
  border: none;
  padding: 8px 12px;
  border-radius: 0 4px 4px 0;
  cursor: pointer;
  font-size: 0.9rem;
}

/* 焦点区域 - 轮播图 */
.hero {
  padding-top: var(--header-height);
  background-color: var(--light-gray);
  position: relative;
}

.hero-slider {
  position: relative;
  overflow: hidden;
  height: 500px;
  padding: 0 30px;
}

.slide {
  display: none;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  padding: 40px 0;
  opacity: 0;
  transform: translateX(50px);
  transition: opacity 0.8s ease, transform 0.8s ease;
  z-index: 1;
}

.slide.active {
  display: flex;
  justify-content: space-between;
  align-items: center;
  opacity: 1;
  transform: translateX(0);
  z-index: 2;
}

/* 添加轮播图切换动画，从右侧进入 */
.slide.active-next {
  display: flex;
  opacity: 0;
  transform: translateX(50px);
}

/* 添加轮播图切换动画，从左侧进入 */
.slide.active-prev {
  display: flex;
  opacity: 0;
  transform: translateX(-50px);
}

/* 添加轮播图切换动画，向左退出 */
.slide.inactive-next {
  display: flex;
  opacity: 0;
  transform: translateX(-50px);
  z-index: 1;
}

/* 添加轮播图切换动画，向右退出 */
.slide.inactive-prev {
  display: flex;
  opacity: 0;
  transform: translateX(50px);
  z-index: 1;
}

.slide-content {
  flex: 1;
  max-width: 500px;
  padding-right: 40px;
  transition: transform 0.8s ease, opacity 0.8s ease;
  -webkit-transition: transform 0.8s ease, opacity 0.8s ease;
  -moz-transition: transform 0.8s ease, opacity 0.8s ease;
  -ms-transition: transform 0.8s ease, opacity 0.8s ease;
  -o-transition: transform 0.8s ease, opacity 0.8s ease;
}

/* 激活状态下的内容进入动画 */
.slide.active .slide-content {
  opacity: 1;
  transform: translateY(0);
}

/* 未激活状态下的内容起始位置 */
.slide:not(.active) .slide-content {
  opacity: 0;
  transform: translateY(20px);
}

.slide-content h2 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
  font-weight: 700;
  position: relative;
  padding-bottom: 15px;
  margin-bottom: 20px;
}

.slide-content h2::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 80px;
  height: 3px;
  background-color: var(--primary-color);
}

.slide-content p {
  font-size: 1.1rem;
  margin-bottom: 2rem;
  color: var(--dark-gray);
}

.slide-image {
  flex: 1;
  text-align: right;
  transition: transform 0.8s ease 0.2s, opacity 0.8s ease 0.2s;
  /* 延迟执行，形成连贯效果 */
}

/* 激活状态下的图片进入动画 */
.slide.active .slide-image {
  opacity: 1;
  transform: translateX(0);
}

/* 未激活状态下的图片起始位置 */
.slide:not(.active) .slide-image {
  opacity: 0;
  transform: translateX(30px);
}

.slide-image img {
  max-width: 100%;
  max-height: 400px;
  border-radius: var(--card-radius);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  transition: transform 0.5s ease, box-shadow 0.5s ease, border 0.5s ease;
}

.slider-controls {
  position: absolute;
  bottom: 30px;
  left: 0;
  right: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 15px;
  z-index: 10;
}

.control {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background-color: var(--mid-gray);
  cursor: pointer;
  transition: all 0.3s ease;
}

.control:hover {
  background-color: var(--dark-gray);
}

.control.active {
  width: 30px;
  border-radius: 10px;
  background-color: var(--primary-color);
}

/* 轮播图左右切换按钮 */
.slider-prev,
.slider-next {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 50px;
  height: 50px;
  background-color: rgba(255, 255, 255, 0.8);
  border: none;
  border-radius: 50%;
  font-size: 1.2rem;
  color: var(--secondary-color);
  cursor: pointer;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  z-index: 10;
  transition: all 0.5s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
}

.slider-prev {
  left: -100px;
}

.slider-next {
  right: -100px;
}

.hero-slider:hover .slider-prev {
  left: 10px;
  opacity: 1;
}

.hero-slider:hover .slider-next {
  right: 10px;
  opacity: 1;
}

.slider-prev:hover,
.slider-next:hover {
  background-color: var(--primary-color);
  color: white;
  transform: translateY(-50%) scale(1.1);
}

.slider-prev:focus,
.slider-next:focus {
  outline: none;
}

/* 轮播图美化：为当前激活的轮播图添加阴影和边框效果 */
.slide.active .slide-image img {
  transform: scale(1.02);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
  border: 5px solid white;
}

/* 改善轮播图文字内容的视觉效果 */
.slide-content h2 {
  position: relative;
  padding-bottom: 15px;
  margin-bottom: 20px;
}

.slide-content h2::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 80px;
  height: 3px;
  background-color: var(--primary-color);
}

/* 最新动态 */
.latest-news {
  padding: var(--section-spacing) 0;
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 30px;
  margin-bottom: 40px;
}

.news-item {
  border-radius: var(--card-radius);
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  transition: all 0.3s ease;
  background-color: var(--light-color);
}

.news-item:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.news-image {
  position: relative;
  height: 200px;
  overflow: hidden;
}

.news-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.news-item:hover .news-image img {
  transform: scale(1.05);
}

.news-date {
  position: absolute;
  bottom: 0;
  left: 0;
  background-color: var(--primary-color);
  color: var(--light-color);
  padding: 10px 15px;
  text-align: center;
  line-height: 1.2;
}

.news-date .day {
  display: block;
  font-size: 1.5rem;
  font-weight: 700;
}

.news-date .month,
.news-date .year {
  display: block;
  font-size: 0.8rem;
}

.news-content {
  padding: 20px;
}

.badge {
  display: inline-block;
  padding: 5px 10px;
  font-size: 0.75rem;
  background-color: var(--accent-color);
  color: var(--light-color);
  border-radius: 20px;
  margin-bottom: 10px;
}

.news-content h3 {
  font-size: 1.2rem;
  margin-bottom: 10px;
}

.news-content p {
  color: var(--dark-gray);
  margin-bottom: 15px;
}

.read-more {
  font-weight: 500;
  color: var(--primary-color);
}

.read-more i {
  margin-left: 5px;
  transition: transform 0.3s ease;
}

.read-more:hover i {
  transform: translateX(5px);
}

.view-all-container {
  text-align: center;
}

/* 研究方向 */
.research-areas {
  padding: var(--section-spacing) 0;
  background-color: var(--light-gray);
}

.areas-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 30px;
}

.area-card {
  background-color: var(--light-color);
  padding: 30px;
  border-radius: var(--card-radius);
  text-align: center;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  transition: all 0.3s ease;
}

.area-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.area-icon {
  font-size: 2.5rem;
  color: var(--primary-color);
  margin-bottom: 20px;
}

.area-card h3 {
  font-size: 1.3rem;
  margin-bottom: 15px;
}

.area-card p {
  color: var(--dark-gray);
  margin-bottom: 20px;
}

/* 学术成果 */
.publications-highlight {
  padding: var(--section-spacing) 0;
}

.publication-tabs {
  background-color: var(--light-color);
  border-radius: var(--card-radius);
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.tab-headers {
  display: flex;
  background-color: var(--light-gray);
  border-bottom: 1px solid var(--mid-gray);
}

.tab {
  padding: 15px 25px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
}

.tab.active {
  background-color: var(--light-color);
  color: var(--primary-color);
  border-bottom: 3px solid var(--primary-color);
}

.tab-pane {
  display: none;
  padding: 30px;
}

.tab-pane.active {
  display: block;
}

.publication-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.publication-list li {
  padding: 20px;
  border-bottom: 1px solid var(--mid-gray);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.publication-list li:last-child {
  border-bottom: none;
}

.pub-info {
  flex: 1;
}

.pub-venue {
  display: inline-block;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 8px;
}

.pub-info h4 {
  margin-bottom: 8px;
  font-size: 1.1rem;
}

.pub-authors {
  color: var(--dark-gray);
  font-size: 0.9rem;
  margin-bottom: 10px;
}

.pub-links {
  display: flex;
  gap: 15px;
}

.pub-link {
  font-size: 0.9rem;
  color: var(--primary-color);
}

.pub-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-left: 20px;
}

.tag {
  display: inline-block;
  padding: 5px 10px;
  background-color: var(--light-gray);
  color: var(--dark-gray);
  border-radius: 20px;
  font-size: 0.8rem;
}

/* 团队成员 */
.team-preview {
  padding: var(--section-spacing) 0;
  background-color: var(--light-gray);
}

.team-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(250px, 320px));
  gap: 30px;
  margin-bottom: 40px;
  justify-content: center;
  max-width: 1080px;
  margin-left: auto;
  margin-right: auto;
}

.team-member {
  background-color: var(--light-color);
  border-radius: var(--card-radius);
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
  transition: all 0.3s ease;
}

.team-member:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.member-photo {
  height: 250px;
  overflow: hidden;
  background-color: white;
  display: flex;
  align-items: center;
  justify-content: center;
}

.member-photo img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  transition: transform 0.5s ease;
}

.team-member:hover .member-photo img {
  transform: scale(1.05);
}

.member-info {
  padding: 20px;
  text-align: center;
}

.member-info h3 {
  font-size: 1.3rem;
  margin-bottom: 5px;
}

.member-title {
  color: var(--primary-color);
  font-weight: 500;
  margin-bottom: 8px;
}

.member-research {
  color: var(--dark-gray);
  font-size: 0.8rem;
  margin-bottom: 15px;
}

.member-social {
  display: flex;
  justify-content: center;
  gap: 15px;
}

.member-social a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background-color: var(--light-gray);
  color: var(--secondary-color);
  border-radius: 50%;
  transition: all 0.3s ease;
}

.member-social a:hover {
  background-color: var(--primary-color);
  color: var(--light-color);
}

/* 联系我们 */
.contact-preview {
  padding: var(--section-spacing) 0;
}

.contact-card {
  display: flex;
  background-color: var(--light-color);
  border-radius: var(--card-radius);
  overflow: hidden;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.contact-info {
  flex: 1;
  padding: 40px;
}

.contact-info h2 {
  margin-bottom: 15px;
}

.contact-info p {
  color: var(--dark-gray);
  margin-bottom: 30px;
}

.contact-list {
  list-style: none;
  padding: 0;
  margin-bottom: 30px;
}

.contact-list li {
  display: flex;
  align-items: center;
  margin-bottom: 15px;
  color: var(--secondary-color);
}

.contact-list i {
  width: 20px;
  margin-right: 15px;
  color: var(--primary-color);
}

.social-links {
  display: flex;
  gap: 15px;
}

.social-links a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background-color: var(--light-gray);
  color: var(--secondary-color);
  border-radius: 50%;
  transition: all 0.3s ease;
}

.social-links a:hover {
  background-color: var(--primary-color);
  color: var(--light-color);
}

.contact-map {
  flex: 1;
  min-height: 400px;
}

.contact-map img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* 页脚 */
.footer {
  background-color: var(--secondary-color);
  color: var(--light-gray);
  padding: 60px 0 0;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-column h3 {
  color: var(--light-color);
  font-size: 1.2rem;
  margin-bottom: 20px;
  position: relative;
  padding-bottom: 10px;
}

.footer-column h3::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 40px;
  height: 2px;
  background-color: var(--primary-color);
}

.footer-column p {
  color: var(--mid-gray);
  margin-bottom: 20px;
}

.footer-column ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-column ul li {
  margin-bottom: 10px;
}

.footer-column ul a {
  color: var(--mid-gray);
  transition: all 0.3s ease;
}

.footer-column ul a:hover {
  color: var(--light-color);
  padding-left: 5px;
}

.subscribe-form {
  display: flex;
  margin-top: 15px;
}

.subscribe-form input {
  flex: 1;
  padding: 10px;
  border: 1px solid var(--dark-gray);
  background-color: rgba(255, 255, 255, 0.1);
  color: var(--light-color);
  border-radius: 4px 0 0 4px;
}

.subscribe-form button {
  padding: 10px 15px;
  background-color: var(--primary-color);
  color: var(--light-color);
  border: none;
  border-radius: 0 4px 4px 0;
  cursor: pointer;
}

.subscribe-form button:hover {
  background-color: var(--accent-color);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 20px 0;
  text-align: center;
}

.footer-bottom p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--mid-gray);
}

/* 响应式设计 */
@media (max-width: 1200px) {
  :root {
    --section-spacing: 60px;
  }
}

@media (max-width: 992px) {
  :root {
    --header-height: 70px;
  }

  .slide-content h2 {
    font-size: 2rem;
  }

  .hero-slider {
    height: 450px;
  }

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

  .contact-card {
    flex-direction: column;
  }

  .contact-map {
    min-height: 300px;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 60px;
    --section-spacing: 50px;
  }

  .logo {
    max-width: 65%;
  }

  .logo h1 {
    font-size: 1.3rem;
    letter-spacing: 0.3px;
    line-height: 1.2;
    word-break: keep-all;
    overflow-wrap: break-word;
  }

  .main-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    height: calc(100vh - var(--header-height));
    background-color: var(--light-color);
    padding: 20px;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    z-index: 999;
  }

  .main-nav.active {
    transform: translateX(0);
  }

  .main-nav ul {
    flex-direction: column;
  }

  .main-nav li {
    margin-left: 0;
    margin-bottom: 15px;
  }

  .menu-toggle {
    display: block;
  }

  .search-box {
    display: none;
  }

  .hero-slider {
    height: auto;
    min-height: 550px;
    padding: 0 20px;
  }

  .slide {
    position: relative;
    padding: 40px 0;
    height: auto;
    min-height: 550px;
  }

  .slide.active {
    flex-direction: column;
  }

  .slide-content {
    order: 1;
    padding-right: 0;
    text-align: center;
    margin-bottom: 30px;
    max-width: 100%;
  }

  .slide-content h2::after {
    left: 50%;
    transform: translateX(-50%);
  }

  .slide-image {
    order: 2;
    text-align: center;
  }

  .slider-prev,
  .slider-next {
    width: 40px;
    height: 40px;
    font-size: 1rem;
    opacity: 0.7;
  }

  .slider-prev {
    left: -25px;
  }

  .slider-next {
    right: -25px;
  }

  .hero-slider:hover .slider-prev {
    left: -10px;
  }

  .hero-slider:hover .slider-next {
    right: -10px;
  }

  .control {
    width: 10px;
    height: 10px;
  }

  .control.active {
    width: 25px;
  }

  .publication-list li {
    flex-direction: column;
    align-items: flex-start;
  }

  .pub-tags {
    margin-left: 0;
    margin-top: 10px;
  }

  .footer-content {
    grid-template-columns: 1fr;
    gap: 30px;
  }
}

/* 中等屏幕调整 */
@media (max-width: 1024px) and (min-width: 769px) {
  .team-grid {
    grid-template-columns: repeat(3, minmax(220px, 280px));
    gap: 25px;
  }
}

@media (max-width: 576px) {
  :root {
    --section-spacing: 40px;
  }

  .logo {
    max-width: 70%;
  }

  .logo h1 {
    font-size: 1.1rem;
    letter-spacing: 0.2px;
    line-height: 1.2;
  }

  .section-title {
    font-size: 1.6rem;
  }

  .slide-content h2 {
    font-size: 1.6rem;
  }

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

  .tab {
    padding: 12px 15px;
    font-size: 0.9rem;
  }

  .contact-info {
    padding: 30px 20px;
  }
}

/* 超小屏幕优化 */
@media (max-width: 480px) {
  .logo {
    max-width: 75%;
  }

  .logo h1 {
    font-size: 1rem;
    letter-spacing: 0.1px;
    line-height: 1.1;
  }
}

@media (max-width: 360px) {
  .logo {
    max-width: 80%;
  }

  .logo h1 {
    font-size: 0.9rem;
    letter-spacing: 0.05px;
    line-height: 1.1;
  }
}