AdminLTE/build/scss/_dropdown.scss

/*
 * Component: Dropdown menus
 * -------------------------
 */

// General Dropdown Rules
.dropdown-item {
  &:first-of-type {
    @include border-top-radius($border-radius);
  }
  &:last-of-type {
    @include border-bottom-radius($border-radius);
  }
}

.dropdown-item-title {
  font-size: $font-size-base;
  margin: 0;
}

// Dropdown Sizes
.dropdown-menu-lg {
  min-width: 280px;
  max-width: 300px;
  padding: 0;
  .dropdown-divider {
    margin: 0;
  }
  .dropdown-item {
    padding: $dropdown-padding-y $dropdown-item-padding-x;
  }
  p {
    white-space: normal;
    margin: 0;
  }
}

// Dropdown header and footer
.dropdown-footer,
.dropdown-header {
  text-align: center;
  display: block;
  padding: .5rem $dropdown-item-padding-x;
  font-size: $font-size-sm;
}

.dropdown-header {
  &:hover {
    background-color: $white;
    color: $gray-200;
  }
}

/* Add fade animation to dropdown menus by appending
 the class .animated-dropdown-menu to the .dropdown-menu ul (or ol)*/
.open:not(.dropup) > .animated-dropdown-menu {
  backface-visibility: visible !important;
  @include animation(flipInX .7s both);
}

@keyframes flipInX {
  0% {
    transform: perspective(400px) rotate3d(1, 0, 0, 90deg);
    transition-timing-function: ease-in;
    opacity: 0;
  }

  40% {
    transform: perspective(400px) rotate3d(1, 0, 0, -20deg);
    transition-timing-function: ease-in;
  }

  60% {
    transform: perspective(400px) rotate3d(1, 0, 0, 10deg);
    opacity: 1;
  }

  80% {
    transform: perspective(400px) rotate3d(1, 0, 0, -5deg);
  }

  100% {
    transform: perspective(400px);
  }
}

@-webkit-keyframes flipInX {
  0% {
    -webkit-transform: perspective(400px) rotate3d(1, 0, 0, 90deg);
    -webkit-transition-timing-function: ease-in;
    opacity: 0;
  }

  40% {
    -webkit-transform: perspective(400px) rotate3d(1, 0, 0, -20deg);
    -webkit-transition-timing-function: ease-in;
  }

  60% {
    -webkit-transform: perspective(400px) rotate3d(1, 0, 0, 10deg);
    opacity: 1;
  }

  80% {
    -webkit-transform: perspective(400px) rotate3d(1, 0, 0, -5deg);
  }

  100% {
    -webkit-transform: perspective(400px);
  }
}

/* Fix dropdown menu in navbars */
.navbar-custom-menu > .navbar-nav {
  > li {
    position: relative;
    > .dropdown-menu {
      position: absolute;
      right: 0;
      left: auto;
    }
  }
}

@include media-breakpoint-down(sm) {
  .navbar-custom-menu > .navbar-nav {
    float: right;
    > li {
      position: static;
      > .dropdown-menu {
        position: absolute;
        right: 5%;
        left: auto;
        border: 1px solid #ddd;
        background: $white;
      }
    }
  }
}