.container-3 a {
    position: relative;
    text-decoration: none;
    color: #337AB7;
    display: inline-block;
}
.container-3 a::before, 
.container-3 a::after {
    content: '';
    position: absolute;
    transition: transform .5s ease;
    left: -4px;
    top: 0;
    width: calc(100% + 8px);
    height: 100%;
    border-style: solid;
    border-color: #337AB7;
    box-sizing: border-box;
}
.container-3 a::before {
    border-width: 1px 0 1px 0;
    transform: scaleX(0);
}
.container-3 a::after {
    border-width: 0 1px 0 1px;
    transform: scaleY(0);
}
.container-3 a:hover::before, 
.container-3 a:hover::after {
    transform: scale(1, 1);
}