/* 导航栏样式 */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  padding: 15px 0;
  background: transparent;
  transition: all 0.5s ease;
  z-index: 1000;
}

.header.scrolled {
  background: rgba(0, 0, 0, 0.9);
  box-shadow: 0 2px 15px rgba(0, 0, 0, 0.1);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo img {
  max-height: 40px;
  transition: var(--transition);
}

.logo:hover img {
  opacity: 0.8;
}

/* 导航菜单 */
.nav-menu ul {
  display: flex;
  gap: 35px;
}

.nav-menu a {
  color: #fff;
  font-weight: 600;
  font-size: 15px;
  position: relative;
}

.nav-menu a::after {
  content: "";
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary-color);
  transition: width 0.3s ease;
}

.nav-menu a:hover::after,
.nav-menu a.active::after {
  width: 100%;
}

.nav-menu a:hover,
.nav-menu a.active {
  color: var(--primary-color);
}

/* 移动端导航切换按钮 */
.mobile-nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 1001;
  position: relative;
  -webkit-tap-highlight-color: transparent;
}

.mobile-nav-toggle span {
  display: block;
  width: 28px;
  height: 3px;
  background: #fff;
  transition: all 0.3s ease;
  border-radius: 2px;
}

.mobile-nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(8px, 8px);
  background: var(--primary-color);
}

.mobile-nav-toggle.active span:nth-child(2) {
  opacity: 0;
  transform: translateX(-20px);
}

.mobile-nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(8px, -8px);
  background: var(--primary-color);
}

/* 移动端菜单遮罩层 */
.mobile-nav-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  z-index: 998;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.mobile-nav-overlay.active {
  display: block;
  opacity: 1;
}

/* 移动端导航菜单 */
@media (max-width: 768px) {
  .header {
    padding: 10px 0;
  }

  .nav-menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 75vw;
    max-width: 320px;
    height: 100vh;
    background: #fff;
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.2);
    transition: right 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 999;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding-top: 80px;
  }

  .nav-menu.active {
    right: 0;
  }

  .nav-menu ul {
    flex-direction: column;
    gap: 0;
    padding: 0;
  }

  .nav-menu a {
    display: block;
    padding: 18px 30px;
    color: var(--dark-bg);
    border-bottom: 1px solid var(--border-color);
    font-size: 16px;
    transition: all 0.2s ease;
    -webkit-tap-highlight-color: transparent;
    position: relative;
  }

  .nav-menu a:active {
    background: rgba(255, 196, 81, 0.1);
  }

  .nav-menu a:hover,
  .nav-menu a.active {
    background: var(--primary-color);
    color: var(--dark-bg);
    padding-left: 35px;
  }

  .nav-menu a.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: var(--dark-bg);
  }

  .nav-menu a::after {
    display: none;
  }

  .mobile-nav-toggle {
    display: flex;
  }

  /* 移动端显示"了解我们"按钮，但样式更小更紧凑 */
  .btn-primary {
    display: inline-block;
    padding: 3px 9px;
    font-size: 12px;
    border-width: 1px;
    white-space: nowrap;
    border-radius: 3px;
  }

  .logo img {
    max-height: 32px;
  }
}