1. @mixin border-bottom {
    2.   position: relative;
    4.   &::after {
    5.     content: '';
    6.     position: absolute;
    7.     left: 0;
    8.     bottom: 0;
    9.     width: 100%;
    10.     height: 1px;
    11.     background: #e9e9e9;
    12.     transform: scaleY(0.5);
    13.   }
    14. }