/* 主色调变量定义 */
:root {
  --primary-color: #0D47A1; /* 深蓝色 */
  --secondary-color: #B0BEC5; /* 银灰色 */
  --accent-color-orange: #FF9800; /* 亮橙色 */
  --accent-color-green: #4CAF50; /* 亮绿色 */
  --background-gradient: linear-gradient(135deg, #0D47A1, #1976D2);
  --text-color: #ffffff;
  --body-bg-color: var(--secondary-color);
}

/* 全局样式 */
body {
  margin: 0;
  padding: 0;
  background-color: var(--body-bg-color);
  color: var(--text-color);
  font-family: 'Roboto', sans-serif;
  line-height: 1.6;
}

/* 导航栏样式 */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background-color: var(--primary-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 40px;
  z-index: 1000;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

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

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

/* 章节导航系统 */
.chapter-nav {
  position: fixed;
  top: 100px;
  right: 20px;
  background-color: rgba(13, 71, 161, 0.9);
  padding: 10px 20px;
  border-radius: 8px;
}

.chapter-nav a {
  display: block;
  color: #ffffff;
  margin: 10px 0;
  text-decoration: none;
  font-size: 16px;
  transition: color 0.3s ease;
}

.chapter-nav a:hover {
  color: var(--accent-color-orange);
}

/* 主内容区样式 */
.container {
  max-width: 1200px;
  margin: 120px auto 40px;
  padding: 20px;
}

/* 文章样式 */
article h2, article h3, article h4 {
  color: var(--primary-color);
}

article pre {
  background-color: #263238;
  padding: 15px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 20px 0;
}

article code {
  color: var(--accent-color-green);
  font-family: 'Courier New', Courier, monospace;
}

button {
  background-color: var(--accent-color-orange);
  color: #ffffff;
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.3s ease, transform 0.3s ease;
}

button:hover {
  background-color: #E65100;
  transform: scale(1.05);
}

/* 图片样式 */
.image-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 20px;
  margin: 40px 0;
}

.image-gallery img {
  width: 100%;
  height: auto;
  border-radius: 12px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

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

/* 背景渐变 */
.header {
  background: var(--background-gradient);
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
}

.header h1 {
  font-size: 48px;
  color: var(--text-color);
}

.header::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(13, 71, 161, 0.5);
}

/* 视差滚动 */
.parallax {
  background-image: url('https://images.gptkong.com/demo/sample1.png');
  height: 500px;
  background-attachment: fixed;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

/* 卡片式设计 */
.card {
  background-color: #ffffff;
  color: #000000;
  border-radius: 8px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  padding: 20px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

/* 折叠区域 */
.collapsible {
  background-color: var(--primary-color);
  color: var(--text-color);
  cursor: pointer;
  padding: 10px 20px;
  width: 100%;
  border: none;
  text-align: left;
  outline: none;
  font-size: 18px;
  border-radius: 4px;
  margin: 10px 0;
  transition: background-color 0.3s ease;
}

.collapsible:hover {
  background-color: var(--accent-color-orange);
}

.content {
  padding: 0 20px;
  display: none;
  overflow: hidden;
  background-color: #f1f1f1;
}

.content p {
  color: #000000;
}

.loader {
  width: 50px;
  height: 50px;
  border: 5px solid var(--secondary-color);
  border-top-color: var(--accent-color-green);
  border-radius: 50%;
  animation: spinner 1s linear infinite;
  margin: 20px auto;
}

@keyframes spinner {
  to { transform: rotate(360deg); }
}

/* 代码块样式 */
.code-example {
  background-color: #263238;
  padding: 15px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 20px 0;
}

.code-example code {
  color: var(--accent-color-green);
  font-family: 'Courier New', Courier, monospace;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .navbar {
    flex-direction: column;
    align-items: center;
    padding: 10px 20px;
  }
  
  .navbar a {
    margin: 10px 0;
  }
  
  .chapter-nav {
    position: static;
    margin: 20px 0;
  }
  
  .header h1 {
    font-size: 32px;
  }
  
  .image-gallery {
    grid-template-columns: 1fr;
  }
}