Practice/_src/admin/scss/common/_layout.scss

body {
  height:100vh;
}
$header-height : 50px;
$nav-height : 59px;

#header {
  position:relative;
  @include display-flex();
  height:$header-height;
  background: #5399ea; /* Old browsers */
  background: -moz-linear-gradient(left, #5399ea 0%, #5ec0cc 100%); /* FF3.6-15 */
  background: -webkit-linear-gradient(left, #5399ea 0%,#5ec0cc 100%); /* Chrome10-25,Safari5.1-6 */
  background: linear-gradient(to right, #5399ea 0%,#5ec0cc 100%); /* W3C, IE10+, FF16+, Chrome26+, Opera12+, Safari7+ */
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#5399ea', endColorstr='#5ec0cc',GradientType=1 ); /* IE6-9 */
  padding:0 30px;
  z-index:101;
  align-items: center;

  .logo {
    display:block;
    color:#fff;
    font-size:19px;
  }

  .top-navs {
    -ms-flex:1;
    -webkit-flex:1;
    flex:1;
  }


  .btn-top-action {
    padding:14px;
    cursor:pointer;
    background:transparent;
    position:relative;
    color:#fff;
    border:0 none;
    outline:none !important;
    font-size:13px;

    i {
      font-size:20px;
      vertical-align: middle;
    }
  }

  .btn-user {
    display:inline-block;

    .btn-top-action {

      &:after {
        content:"\f107";
        font-family:'Font Awesome 5 Pro';
        position:absolute;
        right:0px;
        top:50%;
        -webkit-transform: translateY(-50%);
        -moz-transform: translateY(-50%);
        -ms-transform: translateY(-50%);
        -o-transform: translateY(-50%);
        transform: translateY(-50%);
      }
    }
  }
}

#nav {
  position:relative;
  z-index: 100;
  width: 100%;
  height: $nav-height;
  background-color: #ffffff;
  border-bottom: 1px solid #e6e6e6;
  padding:0 30px;

  .main-navigation {
    @include display-flex();
    height:$nav-height;
    padding:0;
    margin:0;
    list-style:none;
    flex-wrap:wrap;

    > li {
      display:block;
      position:relative;
      margin-right:30px;

      > a {
        @include display-flex();
        height:$nav-height;
        justify-content: center;
        align-items: center;
        color:#979797;
        font-size:0;
        font-weight:500;
        padding-left:0;
        padding-right:45px;
        position:relative;

        &:after {
          content:"\f107";
          font-family:'Font Awesome 5 Pro';
          position:absolute;
          font-size:15px;
          right:15px;
          top:50%;
          -webkit-transform: translateY(-50%);
          -moz-transform: translateY(-50%);
          -ms-transform: translateY(-50%);
          -o-transform: translateY(-50%);
          transform: translateY(-50%);
        }

        i, span {
          font-size:15px;
        }

        i + span {
          margin-left:6px;
        }
      }

      &.active {
        > a {
          color:#282828;
        }
      }

      > ul {
        height:0;
        visibility: hidden;
        opacity:0;
        z-index:101;
        position:absolute;
        top:100%;
        left:0;
        width:130px;
        background:#fff;
        list-style:none;
        padding:0;
        margin:0;
        border:1px solid #767676;

        li {
          display:block;

          a {
            display:block;
            padding:12px 15px;
            font-size:13px;
            color:#282828;
            cursor:pointer;

            &:hover {
              background-color:#f4f8f9;
            }
          }

          &.active {
            a {
              background-color:#f4f8f9;
              color:$color-primary;
            }
          }
        }
      }

      &:hover {
        > a {
          color:#282828;
        }

        > ul {
          height:auto;
          visibility: visible;
          opacity:1;
          -webkit-transition: visibility .3s, opacity .3s;
          -moz-transition: visibility .3s, opacity .3s;
          -ms-transition: visibility .3s, opacity .3s;
          -o-transition: visibility .3s, opacity .3s;
          transition: visibility .3s, opacity .3s;
        }
      }
    }
  }
}

#contents {
  padding:30px;
  height: calc(100vh - #{$header-height} - #{$nav-height});
  overflow-y:auto;
}

.page-header {
  margin-bottom:30px;

  .page-title {
    font-size:23px;
    font-weight:500;
    color:#282828;

    small {
      color:#767676;
      font-size:12px;
      margin-left:15px;
    }
  }
}