Button hover CSS

**** HTML
<button type="submit" name="add-to-cart" class="single_add_to_cart_button">Mua hàng</button>

**** CSS
.single_add_to_cart_button {
    background-color: #333;
    color: #fff;
    display: inline-block;
    letter-spacing: 0.08px;
    line-height: 1;
    padding: 10px 35px;
    position: relative;
    text-transform: uppercase;
    z-index: 5;
    border-radius: 0;
    height: inherit;
    border: 1px solid transparent;
    width: 100%;
    font-size: 20px;
    margin-top: 15px;
}
.single_add_to_cart_button:before {
    background: #a8741a none repeat scroll 0 0;
    bottom: 0;
    content: "";
    left: 0;
    position: absolute;
    right: 0;
    top: 0;
    transform: scaleX(0);
    transform-origin: 0 50% 0;
    transition-duration: 0.3s;
    transition-property: transform;
    transition-timing-function: ease-out;
    z-index: -1;
    border:1px solid #a8741a;
}
.single_add_to_cart_button:hover:before {
    transform: scaleX(1);
}
.single_add_to_cart_button:focus,
.single_add_to_cart_button:hover {
    outline: none;
    border:1px solid #a8741a;
}