* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: #000;
  color: #fff;
  overflow-x: hidden;
  padding-top: 64px; /* 预留导航栏空间，避免内容被遮挡 */
}

/* 导航栏（默认显示，避免消失） */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  background: rgba(0,0,0,0.9);
  backdrop-filter: blur(10px);
  z-index: 999;
  /* 强制显示，取消初始隐藏 */
  transform: translateY(0);
  opacity: 1;
}
.nav-logo {
  font-weight: 600;
  font-size: 17px;
}
.nav-menu {
  display: flex;
  gap: 20px;
  align-items: center;
}
.nav-menu a {
  color: #fff;
  text-decoration: none;
  font-size: 15px;
  transition: color 0.2s;
}
.nav-menu a:hover {
  color: #0099ff;
}

/* 项目下拉框样式 */
.dropdown {
  position: relative;
  display: inline-block;
}
.dropdown-btn {
  color: #fff;
  font-size: 15px;
  cursor: pointer;
  transition: color 0.2s;
}
.dropdown-btn:hover {
  color: #0099ff;
}
.dropdown-menu {
  position: absolute;
  top: 100%;
  right: 0;
  background: #1a1a1a;
  border-radius: 10px;
  min-width: 120px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.3s ease;
  z-index: 9999;
}
.dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.dropdown-menu a {
  display: block;
  padding: 10px 16px;
  color: #fff;
  text-decoration: none;
  font-size: 14px;
  transition: background 0.2s;
}
.dropdown-menu a:hover {
  background: #2a2a2a;
  border-radius: 8px;
}

/* 手机端适配 */
@media (max-width: 768px) {
  .nav-menu { gap: 12px; }
  .nav-menu a, .dropdown-btn { font-size: 13px; }
  .nav-logo { font-size: 15px; }
  .dropdown-menu { min-width: 100px; }
  .dropdown-menu a { font-size: 12px; padding: 8px 12px; }
}

/* 首屏 LOGO 区 */
.hero {
  width: 100%;
  height: calc(100vh - 64px);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  background: radial-gradient(circle at center, #111 0%, #000 80%);
}
.hero-logo {
  width: 100px;
  height: 100px;
  object-fit: contain;
  /* 强制显示，取消初始透明 */
  opacity: 1;
  transform: scale(1);
  filter: drop-shadow(0 0 20px rgba(0,122,255,0.2));
}
.hero-text {
  margin-top: 16px;
  font-size: 20px;
  opacity: 1;
}

/* 卡片区域（强制显示，动画保留） */
.section {
  padding: 80px 20px;
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.card {
  max-width: 700px;
  width: 100%;
  background: #1a1a1a;
  border-radius: 20px;
  padding: 40px 30px;
  text-align: center;
  /* 强制显示，取消初始隐藏 */
  opacity: 1;
  transform: translateY(0);
  box-shadow: 0 0 30px rgba(0,122,255,0.08);
  transition: all 0.8s ease;
}
.card h2 {
  margin-bottom: 20px;
  font-size: 26px;
}
.card p {
  color: #ccc;
  line-height: 1.6;
  margin-bottom: 10px;
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 0 40px rgba(0,122,255,0.12);
}

/* 双卡片区域 */
.book {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  padding: 40px 20px;
  justify-content: center;
}
.book-page {
  width: 280px;
  background: #1a1a1a;
  border-radius: 20px;
  padding: 30px;
  text-align: center;
  /* 强制显示 */
  opacity: 1;
  transform: translateY(0);
  transition: all 0.8s ease;
}
.book-page h3 {
  margin-bottom: 10px;
  color: #0099ff;
}
.book-page:hover {
  transform: translateY(-5px) scale(1.02);
}

/* 联系方式 */
.contact-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
  margin-top: 20px;
}
.contact-item {
  width: 50px;
  text-align: center;
  transition: transform 0.2s;
}
.contact-item:hover {
  transform: translateY(-3px);
}
.contact-item img {
  width: 28px;
  height: 28px;
  object-fit: contain;
  margin-bottom: 4px;
}
.contact-item a {
  color: #fff;
  text-decoration: none;
  font-size: 12px;
}

/* 按钮样式 */
.license-btn {
  display: inline-block;
  margin-top: 16px;
  margin-right: 10px;
  padding: 10px 20px;
  background: #007aff;
  color: #fff;
  border-radius: 12px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: transform 0.2s;
}
.license-btn:hover {
  transform: scale(1.03);
}

/* QQ群切换样式 */
.qq-group {
  margin-top: 20px;
}
.qq-group img {
  width: 180px;
  margin: 10px 0;
  border-radius: 8px;
}