.container {
  width: 1200px;
  margin: 0 auto;
}
.category-nav {
  z-index: 3;
  background-color: rgba(255, 255, 255, 0.7);
  position: absolute;
  left: 0px;
  top: 0;
}
.category-nav a {
  color: red;
}
.category-nav li {
  height: 40px;
  line-height: 40px;
  padding: 2rem;
  box-sizing: border-box;
  border-bottom: 1px solid #d6d6d6;
}
.category-nav li:hover {
  background-color: rgba(195, 195, 195, 0.2);
}
.category-nav .category-menu {
  width: 10rem;
  height: 400px;
  background-color: rgba(255, 255, 255, 0.7);
  position: relative;
  left: 0px;
  top: 0px;
}
.category-nav .category-menu .category_sub_menu {
  overflow: hidden;
  width: 0;
  height: 400px;
  background-color: rgba(238, 238, 238, 0.7);
  position: absolute;
  left: 10rem;
  top: 0px;
  transition: all 500ms;
}