/* ===================
   全局设置
   =================== */
body {
  margin: 0;
  background: #121212; /* 深色背景，呼应“黑神话”主题 */
  color: #e0e0e0;      /* 文字为浅色 */
  font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
}

a {
  text-decoration: none;
  color: inherit;
}

/* ===================
   顶部导航
   =================== */
.header-topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  /* 让导航稍微更宽松一点，你可再加大 */
  padding: 1rem 1.5rem;
  background-color: #1e1e1e;  
  box-shadow: 0 1px 5px rgba(0,0,0,0.3);
}

.left-section {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* 校徽图片 */
.logo-img {
  width: 60px;
  height: 60px;
  object-fit: contain;
}

/* 课程标题 */
.course-info h1 {
  margin: 0;
  font-size: 1.4rem;
  color: #ffc107; /* 金色 */
}

.course-info p {
  margin: 2px 0 0 0;
  font-size: 0.85rem;
  color: #ccc;
}

/* 导航菜单 */
.nav ul {
  display: flex;
  gap: 1rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav ul li a {
  position: relative;
  display: block;
  padding: 0.4rem 0.8rem;
  border-radius: 4px;
  transition: background-color 0.2s ease;
  font-weight: 500;
  color: #e0e0e0;
}
.nav ul li a:hover {
  background-color: rgba(255, 193, 7, 0.2);
}
.active-link {
  background-color: rgba(255, 193, 7, 0.3);
  color: #fff;
}

/* ===================
   Hero Banner (第一张图)
   =================== */
.hero-banner {
  /* 这里使用 hero_banner.jpg，给顶部做大背景 */
  background: linear-gradient(to right, rgba(255,193,7,0.3), rgba(0,0,0,0.5)), 
              url('banner.jpg') center/cover no-repeat;

  min-height: 45vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: #fff;
}

.hero-text {
  max-width: 600px;
  margin: 0 1rem;
}
.hero-text h2 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: #ffc107;
}
.hero-text p {
  font-size: 1rem;
  line-height: 1.6;
  margin-bottom: 1rem;
  color: #f8f8f8;
}

/* 按钮风格 */
.btn-gold {
  display: inline-block;
  padding: 0.6rem 1.2rem;
  border-radius: 4px;
  background-color: #ffc107;
  color: #222;
  font-weight: 600;
  transition: background-color 0.2s ease;
}
.btn-gold:hover {
  background-color: #ffca2c;
}

/* ===================
   主内容区（第二张图可以在这里 <img src="wukong_banner.jpg">）
   =================== */
.main-content {
  max-width: 900px;
  margin: 2rem auto;
  background: #1d1d1d;
  border-radius: 8px;
  padding: 1.5rem 2rem;
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.main-content h2 {
  margin-top: 0.5rem;
  font-size: 1.6rem;
  color: #ffc107;
  border-bottom: 1px solid #444;
  padding-bottom: 0.3rem;
}

.main-content p {
  line-height: 1.7;
  margin: 0.8rem 0;
  color: #ddd;
}

/* 额外区块，用来排版正文内容 */
.content-section {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1.5rem;
}

/* 图片自适应宽度 */
.img-responsive {
  max-width: 100%;
  border-radius: 4px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.4);
}

/* ===================
   页脚
   =================== */
footer {
  text-align: center;
  padding: 1rem 0;
  background-color: #1e1e1e;
  border-top: 1px solid #333;
  font-size: 0.9rem;
  color: #ccc;
  margin-top: 2rem;
}