.single-btn {
    font-weight: 500;
    letter-spacing: .5px;
    padding: 0px 10px;
    display: inline-block;
    margin: 15px;
    cursor: pointer;
    outline: none;
    position: relative;
    z-index: 1;
    transition: .8s;
    color: #252525;
    text-transform: uppercase;
    border-color: #fff;
    font-size: 15px;
}

.single-btn:hover:after {
    width: 100%;
    height: 0;
    right: 0;
    border-color: #fff;
}

.single-btn:after {
    position: absolute;
    content: '';
    display: block;
    width: 15px;
    height: 15px;
    border-width: 3px;
    border-style: solid;
    right: 1px;
    top: 1px;
    border-bottom: none;
    border-left: none;
    transition: .5s;
}

.single-btn:hover:before {
    width: 100%;
    height: 0;
    left: 0;
    border-color: #fff;
}

.single-btn:before {
    position: absolute;
    content: '';
    display: block;
    width: 15px;
    height: 15px;
    border-width: 3px;
    border-style: solid;
    left: 1px;
    bottom: 1px;
    border-top: none;
    border-right: none;
    transition: .5s;
}