element/packages/theme-chalk/src/menu.scss

@import "mixins/mixins";
@import "common/var";

@mixin menu-item {
  height: 56px;
  line-height: 56px;
  font-size: 14px;
  color: $--menu-item-color;
  padding: 0 20px;
  cursor: pointer;
  position: relative;
  transition: border-color .3s, background-color .3s, color .3s;
  box-sizing: border-box;
  white-space: nowrap;
}

@include b(menu) {
  border-radius: 2px;
  list-style: none;
  position: relative;
  margin: 0;
  padding-left: 0;
  background-color: $--menu-item-fill;
  @include utils-clearfix;

  & li {
    list-style: none;
  }

  @include m(dark) {
    background-color: $--dark-menu-item-fill;

    & .el-menu-item,
    & .el-submenu__title {
      color: $--color-black;

      &:hover {
        background-color: $--color-black;
      }
    }

    & .el-submenu .el-menu {
      background-color: $--color-black;

      & .el-menu-item:hover {
        background-color: $--color-black;
      }
    }
  }
  @include m(horizontal) {
    & .el-menu-item {
      float: left;
      height: 60px;
      line-height: 60px;
      margin: 0;
      cursor: pointer;
      position: relative;
      box-sizing: border-box;
      border-bottom: 5px solid transparent;

      a,
      a:hover {
        color: inherit;
      }

      &:hover {
        background-color: $--menu-item-hover-fill;
      }
    }
    & .el-submenu {
      float: left;
      position: relative;

      > .el-menu {
        position: absolute;
        top: 65px;
        left: 0;
        border:1px solid $--color-black;
        padding: 5px 0;
        background-color: $--color-white;
        z-index: 100;
        min-width: 100%;
        box-shadow: 0 2px 4px 0 rgba(0,0,0,0.12), 0 0 6px 0 rgba(0,0,0,0.04);
      }

      & .el-submenu__title {
        height: 60px;
        line-height: 60px;
        border-bottom: 5px solid transparent;
      }

      & .el-menu-item {
        background-color: $--color-white;
        float: none;
        height: 36px;
        line-height: 36px;
        padding: 0 10px;
      }

      & .el-submenu__icon-arrow {
        position: static;
        vertical-align: middle;
        margin-left: 5px;
        color: $--color-black;
        margin-top: -3px;
      }
    }
    & .el-menu-item:hover,
    & .el-submenu__title:hover {
      background-color: $--menu-item-fill;
    }
    & > .el-menu-item:hover,
    & > .el-submenu:hover .el-submenu__title,
    & > .el-submenu.is-active .el-submenu__title {
      border-bottom: 5px solid $--color-primary;
    }

    &.el-menu--dark {
      & .el-menu-item:hover,
      & .el-submenu__title:hover {
        background-color: $--dark-menu-item-fill;
      }

      & .el-submenu {
        .el-menu-item,
        .el-submenu-title {
          color: $--color-black;

          &:hover {
            background-color: $--color-black;
          }
        }
        .el-menu-item.is-active {
          color: $--color-primary;
        }
      }
    }
  }
  @include m(collapse) {
    width: 64px;

    > .el-menu-item,
    > .el-submenu > .el-submenu__title {
      [class^="el-icon-"] {
        margin: 0;
        vertical-align: middle;
        width: 24px;
        text-align: center;
      }
      .el-submenu__icon-arrow {
        display: none;
      }
      span {
        height: 0;
        width: 0;
        overflow: hidden;
        visibility: hidden;
        display: inline-block;
      }
    }

    .el-submenu {
      position: relative;
      & .el-menu {
        position: absolute;
        margin-left: 5px;
        top: 0;
        left: 100%;
        z-index: 10;
      }

      &.is-opened {
        > .el-submenu__title .el-submenu__icon-arrow {
          transform: none;
        }
      }
    }
  }
}
@include b(menu-item) {
  @include menu-item;

  & [class^="el-icon-"] {
    margin-right: 5px;
    width: 24px;
    text-align: center;
  }
  & * {
    vertical-align: middle;
  }
  &:first-child {
    margin-left: 0;
  }
  &:last-child {
    margin-right: 0;
  }
  &:hover {
    background-color: $--color-black;
  }
  @include when(active) {
    color: $--color-primary;
  }
}
  
@include b(submenu) {
  @include e(title) {
    position: relative;
    @include menu-item;

    &:hover {
      background-color: $--color-black;
    }

    & * {
      vertical-align: middle;
    }
  }
  & .el-menu {
    background-color: $--color-black;
  }
  & .el-menu-item {
    height: 50px;
    line-height: 50px;
    padding: 0 45px;
    min-width: 200px;

    &:hover {
      background-color: $--color-black;
    }
  }
  @include e(icon-arrow) {
    position: absolute;
    top: 50%;
    right: 20px;
    margin-top: -7px;
    transition: transform .3s;
    font-size: 12px;
  }
  @include when(active) {
    .el-submenu__title {
      border-bottom-color: $--color-primary;
    }
  }
  @include when(opened) {
    > .el-submenu__title .el-submenu__icon-arrow {
      transform: rotateZ(180deg);
    }
  }
  [class^="el-icon-"] {
    vertical-align: middle;
    margin-right: 5px;
    width: 24px;
    text-align: center;
  }
}

@include b(menu-item-group) {
  > ul {
    padding: 0;
  }
  @include e(title) {
    padding-top: 15px;
    line-height: normal;
    font-size: 14px;
    padding-left: 20px;
    color: $--color-black;
  }
}

.horizontal-collapse-transition .el-submenu__title .el-submenu__icon-arrow {
  transition: .2s;
  opacity: 0;
}