/* 全局样式设置 */
body {
  margin: 0;
  font-family: 'Roboto', sans-serif; /* 使用无衬线字体 */
  background: linear-gradient(135deg, #1e3c72 70%, #2a5298 25%, #ff6f61 5%); /* 黄金比例配色，科技蓝与银灰色为主，亮橙点缀 */
  color: #ffffff;
  line-height: 1.6;
}

/* 导航栏样式 */
.navbar {
  position: fixed; /* 固定导航栏 */
  top: 0;
  width: 100%;
  background: rgba(30, 60, 114, 0.9); /* 半透明科技蓝背景 */
  padding: 20px 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 1000;
  box-shadow: 0 2px 4px rgba(0,0,0,0.2); /* 阴影效果 */
}

.navbar a {
  color: #ffffff;
  text-decoration: none;
  margin: 0 15px;
  font-size: 16px;
  transition: color 0.3s;
}

.navbar a:hover {
  color: #ff6f61; /* 点缀色在悬停时变化 */
}

/* 主内容区样式 */
.main {
  padding: 100px 20px 50px; /* 留出导航栏空间 */
  max-width: 1200px;
  margin: 0 auto;
}

/* 章节标题样式 */
h2 {
  font-size: 2em;
  margin-bottom: 20px;
  color: #ff6f61; /* 点缀色 */
  position: relative;
  padding-left: 10px;
}

h2::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 5px;
  height: 30px;
  background: #ff6f61;
  border-radius: 2px;
}

/* 段落样式 */
section p {
  font-size: 16px;
  margin-bottom: 20px;
  color: #f0f0f0;
}

/* 图片样式 */
img {
  width: 100%;
  max-width: 320px;
  border-radius: 10px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.2);
  transition: transform 0.3s, box-shadow 0.3s;
}

img:hover {
  transform: scale(1.05);
  box-shadow: 0 8px 16px rgba(0,0,0,0.3);
}

/* 代码块样式 */
pre {
  background: rgba(0,0,0,0.7);
  padding: 15px;
  border-radius: 8px;
  overflow-x: auto;
  margin-bottom: 20px;
}

code {
  color: #ff6f61;
  font-family: 'Courier New', Courier, monospace;
  font-size: 14px;
}

/* 按钮样式 */
.button {
  display: inline-block;
  background: linear-gradient(45deg, #ff7e5f, #feb47b);
  border: none;
  border-radius: 25px;
  color: #fff;
  padding: 12px 24px;
  font-size: 16px;
  cursor: pointer;
  transition: transform 0.2s, background 0.2s;
  text-decoration: none;
}

.button:hover {
  transform: scale(1.05);
  background: linear-gradient(45deg, #feb47b, #ff7e5f);
}

/* 卡片式设计 */
.card {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  padding: 20px;
  margin-bottom: 30px;
  transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: 0 10px 15px rgba(0,0,0,0.2);
}

/* 固定导航栏下方留白 */
.header-space {
  height: 80px; /* 导航栏高度 */
}

/* 响应式网格布局 */
.grid {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.grid-item {
  flex: 1 1 calc(33.333% - 20px);
}

@media (max-width: 768px) {
  .grid-item {
    flex: 1 1 calc(50% - 20px);
  }
}

@media (max-width: 480px) {
  .grid-item {
    flex: 1 1 100%;
  }
}

/* 动画效果 */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* 标题动效 */
@keyframes text-animate {
  0% { opacity: 0; transform: translateY(-20px); }
  100% { opacity: 1; transform: translateY(0); }
}

.title {
  font-size: 48px;
  color: #007BFF;
  animation: text-animate 1s ease-out forwards;
  margin-bottom: 40px;
}

/* 背景视频样式 */
.background-video {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -1;
  animation: fadeIn 3s ease-in-out;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* 成功案例卡片 */
.case-card {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  padding: 20px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s, box-shadow 0.3s;
}

.case-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 15px rgba(0, 0, 0, 0.2);
}

/* 导航系统 */
.nav-section {
  position: fixed;
  top: 80px;
  right: 20px;
  background: rgba(30, 60, 114, 0.8);
  padding: 10px 15px;
  border-radius: 8px;
}

.nav-section a {
  display: block;
  color: #ffffff;
  text-decoration: none;
  margin-bottom: 10px;
  font-size: 14px;
}

.nav-section a:hover {
  color: #ff6f61;
}

/* 章节分隔线 */
.section-divider {
  height: 2px;
  background: linear-gradient(90deg, #ff7e5f, #feb47b);
  margin: 40px 0;
  border: none;
}