/* ===== 全局样式 ===== */
:root {
  --primary: #1e88e5;
  --secondary: #ff5722;
  --light: #f0f9ff;
  --dark: #38bdf8;
  --dark-hover: #0ea5e9;
  --text: #333;
  --border-radius: 8px;
}

* { 
  box-sizing: border-box; 
  margin: 0; 
  padding: 0; 
}

body {
  font-family: 'Microsoft YaHei', Arial, sans-serif;
  line-height: 1.7;
  color: var(--text);
  background: white;
}

/* ===== 导航栏 ===== */
nav {
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark-hover) 100%);
  padding: 15px 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 10px rgba(56, 189, 248, 0.3);
}

nav ul {
  display: flex;
  justify-content: center;
  list-style: none;
  gap: 30px;
  flex-wrap: wrap;
}

nav a {
  color: white;
  text-decoration: none;
  font-weight: bold;
  text-transform: uppercase;
  font-size: 14px;
  letter-spacing: 1px;
  padding: 5px 0;
  transition: all 0.3s;
}

nav a:hover,
nav a.active {
  color: #ffeb3b;
  border-bottom: 2px solid #ffeb3b;
}

/* ===== 容器与布局 ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  padding: 80px 0;
}

.section-title {
  text-align: center;
  font-size: 2.2em;
  color: var(--primary);
  margin-bottom: 50px;
  position: relative;
  padding-bottom: 15px;
}

.section-title::after {
  content: "";
  display: block;
  width: 80px;
  height: 3px;
  background: linear-gradient(to right, var(--primary), var(--dark));
  margin: 15px auto 0;
  border-radius: 2px;
}

/* ===== 关于我们 ===== */
.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

/* ===== 特点展示 ===== */
.features {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
  margin-top: 40px;
}

.feature {
  flex-basis: 28%;
  text-align: center;
  margin-bottom: 30px;
  padding: 30px 20px;
  border-radius: var(--border-radius);
  background: white;
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
  transition: transform 0.3s;
}

.feature:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(56, 189, 248, 0.1);
}

.feature-icon {
  font-size: 48px;
  color: var(--dark);
  margin-bottom: 15px;
}

.feature h3 {
  color: var(--primary);
  margin-bottom: 10px;
}

/* ===== 产品中心 ===== */
.products {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
}

.product-card {
  border: 1px solid #e0e0e0;
  border-radius: var(--border-radius);
  overflow: hidden;
  transition: transform 0.3s, box-shadow 0.3s;
  background: white;
}

.product-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 30px rgba(0,0,0,0.1);
  border-color: var(--dark);
}

.product-img {
  height: 200px;
  background: var(--light);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

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

.product-card:hover .product-img img {
  transform: scale(1.05);
}

.product-info {
  padding: 20px;
}

.product-info h3 {
  color: var(--primary);
  margin: 0 0 10px;
}

/* ===== 视频展示 ===== */
.video-section {
  background: var(--light);
}

.video-container {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
}

video {
  width: 100%;
  border-radius: var(--border-radius);
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

/* ===== 资料下载 ===== */
.downloads {
  text-align: center;
}

.download-btn {
  display: inline-block;
  background: linear-gradient(135deg, var(--primary) 0%, var(--dark) 100%);
  color: white;
  padding: 12px 30px;
  margin: 10px;
  border-radius: 4px;
  text-decoration: none;
  font-weight: bold;
  transition: all 0.3s;
}

.download-btn:hover {
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark-hover) 100%);
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(56, 189, 248, 0.4);
}

/* ===== 联系我们 ===== */
#contact {
  background: linear-gradient(135deg, var(--primary) 0%, var(--dark) 100%);
  color: white;
}

#contact .section-title {
  color: white;
}

#contact .section-title::after {
  background: #ffeb3b;
}

.contact-form {
  max-width: 600px;
  margin: 0 auto;
  background: rgba(255, 255, 255, 0.1);
  padding: 30px;
  border-radius: var(--border-radius);
  backdrop-filter: blur(5px);
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  color: white;
  font-weight: bold;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.9);
  font-size: 14px;
  transition: all 0.3s;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  background: white;
  box-shadow: 0 0 0 2px rgba(255, 235, 59, 0.5);
}

.btn-submit {
  background: linear-gradient(135deg, #ff5722 0%, #ff9800 100%);
  color: white;
  padding: 12px 30px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 16px;
  width: 100%;
  font-weight: bold;
  transition: all 0.3s;
}

.btn-submit:hover {
  background: linear-gradient(135deg, #e64a19 0%, #f57c00 100%);
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(255, 87, 34, 0.4);
}

/* ===== 页脚 ===== */
footer {
  text-align: center;
  padding: 40px 20px;
  background: linear-gradient(135deg, var(--dark) 0%, #0284c7 100%);
  color: white;
}

footer a {
  color: #ffeb3b;
  text-decoration: none;
  transition: color 0.3s;
}

footer a:hover {
  color: white;
  text-decoration: underline;
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
  .section-title { 
    font-size: 1.8em; 
    margin-bottom: 30px;
  }
  
  nav ul { 
    gap: 15px; 
  }
  
  nav a {
    font-size: 13px;
  }
  
  section {
    padding: 60px 0;
  }
  
  .about-content {
    grid-template-columns: 1fr;
  }
  
  .feature {
    flex-basis: 100%;
    max-width: 300px;
    margin: 0 auto 30px;
  }
  
  .features {
    justify-content: center;
  }
}