button{
    outline: none;
    cursor: pointer;
    display: block;
    position: relative;
    text-align: center;
    border: none;
    background: #ff9e00;
    color: #253f43;
    padding: 1.25em 2em;
    font-family: serif;
    font-size: 16px;
    font-weight: 400;
    line-height: 1;
    text-transform: uppercase;
    letter-spacing: .5em;
    transition: padding .2s ease;
}

button:before{
    content: "";
    position: absolute;
    left: 50%;
    bottom: 1em;
    z-index: 2;
    border-bottom: 1px solid #253f43;
    width: 100%;
    max-width: 0;
    transform: translate(-55%,0);
    transition: max-width .2s ease;
}

button:focus,
button:hover{
    padding-top: 1em;
    padding-bottom: 1.5em;
}

button:focus:before,
button:hover:before{
    max-width: 40%;
}