#main_nav {
  width: 100%;
  position: relative;
  z-index: 1000; /* 确保整个导航层级最高 */
}

/* 导航头部固定在顶部 */
#main_nav {
  position: fixed; /* 固定定位，滚动时保持在顶部 */
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000; /* 最高层级，确保覆盖其他内容 */
  background-color: #fff; /* 不透明背景，防止内容穿透 */
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05); /* 增加阴影增强层次感 */
  height: 130px;
}

/* 为页面主体添加顶部间距，避免内容被固定导航遮挡 */
#main_nav + * {
  margin-top: 130px; /* 导航总高度（一级菜单4rem + 二级菜单~1.5rem） */
}

/* 其他原有样式保持不变 */
#main_nav .custom-scrollbar {
  scrollbar-width: thin;
}
#main_nav .custom-scrollbar::-webkit-scrollbar {
  width: 5px;
  height: 5px;
}
#main_nav .custom-scrollbar::-webkit-scrollbar-track {
  background: #f1f1f1;
  border-radius: 3px;
}
#main_nav .custom-scrollbar::-webkit-scrollbar-thumb {
  background: #ddd;
  border-radius: 3px;
}
#main_nav .custom-scrollbar::-webkit-scrollbar-thumb:hover {
  background: #ccc;
}

/* 三级菜单动画和样式 */
#main_nav .submenu-enter {
  opacity: 0;
  transform: translateX(5px);
}
#main_nav .submenu-enter-active {
  opacity: 1;
  transform: translateX(0);
  transition: opacity 200ms ease-out, transform 200ms ease-out;
}
#main_nav .submenu-exit {
  opacity: 1;
}
#main_nav .submenu-exit-active {
  opacity: 0;
  transform: translateX(5px);
  transition: opacity 150ms ease-in, transform 150ms ease-in;
}

/* 其他样式保持不变... */
#main_nav .bg-white {
  background-color: #fff;
}
#main_nav .border-gray-100 {
  border-color: #f3f4f6;
}
#main_nav .container {
  width: 100%;
  margin-right: auto;
  margin-left: auto;
  padding-right: 1rem;
  padding-left: 1rem;
}
#main_nav .flex {
  display: flex;
}
#main_nav .items-center {
  align-items: center;
}
#main_nav .justify-between {
  justify-content: space-between;
}
#main_nav .h-16 {
  height: 4rem;
}
#main_nav .border-b {
  border-bottom-width: 1px;
}
#main_nav .space-x-2 > :not([hidden]) ~ :not([hidden]) {
  --tw-space-x-reverse: 0;
  margin-right: calc(0.5rem * var(--tw-space-x-reverse));
  margin-left: calc(0.5rem * calc(1 - var(--tw-space-x-reverse)));
}
#main_nav .text-2xl {
  font-size: 1.5rem;
  line-height: 2rem;
}
#main_nav .text-xl {
  font-size: 1.25rem;
  line-height: 1.75rem;
}
#main_nav .font-bold {
  font-weight: 700;
}
#main_nav ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
}
#main_nav .space-x-1 > :not([hidden]) ~ :not([hidden]) {
  --tw-space-x-reverse: 0;
  margin-right: calc(0.25rem * var(--tw-space-x-reverse));
  margin-left: calc(0.25rem * calc(1 - var(--tw-space-x-reverse)));
}
#main_nav .py-3 {
  padding-top: 0.75rem;
  padding-bottom: 0.75rem;
}
#main_nav .overflow-x-auto {
  overflow-x: auto;
}
#main_nav .min-w-max {
  min-width: max-content;
}
#main_nav .absolute {
  position: absolute;
}
#main_nav .shadow-lg {
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}
#main_nav .rounded-md {
  border-radius: 0.375rem;
}
#main_nav .z-50 {
  z-index: 50;
}
#main_nav .px-4 {
  padding-right: 1rem;
  padding-left: 1rem;
}
#main_nav .max-h-80 {
  max-height: 20rem;
}
#main_nav .overflow-y-auto {
  overflow-y: auto;
}
#main_nav .min-w-[300px] {
  min-width: 300px;
}
#main_nav .hidden {
  display: none;
}
#main_nav .grid {
  display: grid;
}
#main_nav .grid-cols-1 {
  grid-template-columns: repeat(1, minmax(0, 1fr));
}
#main_nav .sm\:grid-cols-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
#main_nav .gap-1 > :not([hidden]) ~ :not([hidden]) {
  --tw-space-y-reverse: 0;
  margin-top: calc(0.25rem * calc(1 - var(--tw-space-y-reverse)));
  margin-bottom: calc(0.25rem * var(--tw-space-y-reverse));
}
#main_nav .px-3 {
  padding-right: 0.75rem;
  padding-left: 0.75rem;
}
#main_nav .py-2 {
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;
}
#main_nav .text-sm {
  font-size: 0.875rem;
  line-height: 1.25rem;
}
#main_nav .font-medium {
  font-weight: 500;
}
#main_nav .text-gray-700 {
  --tw-text-opacity: 1;
  color: rgba(55, 65, 81, var(--tw-text-opacity));
}
#main_nav .hover\:bg-hover:hover {
  background-color: #f5f5f5;
}
#main_nav .mr-2 {
  margin-right: 0.5rem;
}
#main_nav .whitespace-nowrap {
  white-space: nowrap;
}
#main_nav .block {
  display: block;
}
#main_nav .text-gray-600 {
  --tw-text-opacity: 1;
  color: rgba(75, 85, 99, var(--tw-text-opacity));
}
#main_nav .rounded-md {
  border-radius: 0.375rem;
}
#main_nav .bg-active {
  background-color: #f0f0f0;
}
#main_nav .text-black {
  --tw-text-opacity: 1;
  color: rgba(0, 0, 0, var(--tw-text-opacity));
}
#main_nav .font-semibold {
  font-weight: 600;
}
#main_nav .menu-transition {
  transition-all: all 300ms ease-in-out;
}

/* 三级菜单容器基础样式 */
#main_nav #level3-container {
  position: fixed; /* 确保相对于视口定位 */
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

#main_nav .logo {
    display: flex;
    align-items: center;
    gap: 1px;
    text-decoration: none;
    padding: 5px;
}

#main_nav .logo-code {
    color: #1D2129;
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

#main_nav .logo-json {
    color: #165DFF;
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

#main_nav .logo-domain {
    color: #722ED1;
    font-size: 1rem;
    letter-spacing: -0.01em;
}