@font-face {
  font-family: "OPPOSans-Regular";
  src: url("fonts/OPPOSans-Regular.woff2") format("woff2"),
       url("fonts/OPPOSans-Regular.woff") format("woff");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

:root {
  --primary-color: #0363ef;
  --text-color: #2d2d2d;
  --muted-color: #6f6f6f;
  --bg-light: #f9f9f9;
  --border-color: #6f6f6f;
  --card-bg: #f4f4f4;
  --radius: 8px;
  --spacing: 20px;
  --max-width: 1200px;
}

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

body {
  font-family: "OPPOSans-Regular", Helvetica, sans-serif;
  color: var(--text-color);
  line-height: 1.6;
  background-color: #fff;
}

h1, h2, h3, h4, h5, h6 {
  font-family: "OPPOSans-Medium", Helvetica, sans-serif;
}

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

/* 容器 */
.container {
  max-width: var(--max-width);
  margin: auto;
  padding: 1rem;
}

/* 通用卡片样式 */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: var(--spacing);
}

/* 导航栏 */
.navbar {
  background: #fff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  position: sticky;
  top: 0;
  z-index: 2000;
}

.nav-container {
  margin: auto;
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-links a {
  font-weight: 500;
  color: var(--text-color);
  text-decoration: none;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--primary-color);
}

.nav-links a.active {
  color: var(--primary-color);
  font-weight: bold;    
  pointer-events: none; 
  border-bottom: 2px solid var(--primary-color);
  padding-bottom: 2px;
}

.logo-link {
  display: inline-block;
  transition: transform 0.3s, box-shadow 0.3s;
}

.logo-link:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.logo {
  height: 50px;
  display: block;
}

/* Hero Section */
.contact-hero {
    padding: 80px 0 40px;
}

.hero-title {
    font-weight: 900;
    font-size: 36px;
    margin-bottom: 20px;
}

.hero-subtitle {
    color: rgba(111, 111, 111, 1);
    font-weight: 700;
    font-size: 24px;
}

/* Section Styles */
.cooperation-section,
.teaching-section,
.admission-section {
    padding: 60px 0;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    border-bottom: 1.5px solid #ccc;
    padding-bottom: 0.5rem; 
}

/* Cooperation Section */
.cooperation-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.cooperation-card {
    position: relative;
    height: 268px;
    border-radius: 8px;
    overflow: hidden;
}

.card-image {
    width: 100%;
    height: 100%;
    background: #f0f0f0;
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
}

.card-overlay {
    position: absolute;
    top: 60px;
    left: 0;
    width: 100%;
    height: 147px;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
}

.card-overlay h3 {
    color: #fff;
    font-weight: 700;
    font-size: 20px;
    text-align: center;
    line-height: 1.4;
}

.more {
  color: var(--muted-color);
  text-decoration: none;
  font-size: 1rem;
}

.more:hover {
  color: var(--primary-color);
}

.qrcode-cards {
    display: flex;
    justify-content: center; /* 水平居中 */
    margin-top: 20px;        /* 和标题留点间距 */
}

.qrcode-size {
    width: 300px;   /* 控制二维码大小 */
    height: auto;   /* 按比例缩放 */
}

/* Teaching Section */
.teaching-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.teaching-card {
    position: relative;
    height: 268px;
    border-radius: 8px;
    overflow: hidden;
}

/* Admission Section */
.admission-content {
    display: grid;
    gap: 20px;
    margin: 0 auto;
}

.admission-text {
    max-width: 100%;
}

.lab-intro p {
    font-size: 16px;
    color: #494949;
    margin-bottom: 25px;
    line-height: 1.8;
}

.research-direction {
    margin-bottom: 30px;
}

.research-direction h3 {
    font-size: 18px;
    color: #000;
    margin-bottom: 10px;
    font-weight: 700;
}

.research-direction p {
    font-size: 16px;
    color: #494949;
    margin-bottom: 15px;
    line-height: 1.6;
}

.research-direction ul {
    padding-left: 20px;
    margin-bottom: 20px;
}

.research-direction li {
    font-size: 16px;
    color: #494949;
    margin-bottom: 10px;
    line-height: 1.6;
}

.admission-requirements {
    margin-top: 60px;
}

.admission-requirements h3 {
    font-size: 20px;
    color: #000;
    margin-bottom: 30px;
    font-weight: 700;
}

.requirement-item {
    margin-bottom: 40px;
}

.requirement-item h4 {
    font-size: 18px;
    color: #000;
    margin-bottom: 15px;
    font-weight: 700;
}

.requirement-item h5 {
    font-size: 16px;
    color: #000;
    margin: 20px 0 15px;
    font-weight: 700;
}

.requirement-item p {
    font-size: 16px;
    color: #494949;
    margin-bottom: 15px;
    line-height: 1.6;
}

.requirement-item ol,
.requirement-item ul {
    padding-left: 20px;
    margin-bottom: 20px;
}

.requirement-item li {
    font-size: 16px;
    color: #494949;
    margin-bottom: 10px;
    line-height: 1.6;
}

.note {
    font-style: italic;
    color: #666;
}
/* Footer */
.footer {
  background: #f1f1f1;
  padding: 2rem 0;
  margin-top: 4rem;
  --max-width: 1200px;
  font-size: 14px;
  color: #707070;
  line-height: 2;
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 0;
}

.footer-images {
  display: flex;
  gap: 1rem;          
  align-items: center;  
}

.footer-logo {
  height: 60px;
  margin-top: 0.5rem;  
}

.qrcode {
  width: 60px;
  margin-top: 0.5rem;  
  margin-left: 0;      
}

/* 响应式 */
@media (max-width: 768px) {
  .nav-links {
    flex-direction: column;
    gap: 0.7rem;
  }
  .hero {
    height: 250px;
  }
  .hero h1 {
    font-size: 1.5rem;
  }
}