button{
outline: none;
cursor: pointer;
display: block;
position: relative;
text-align: center;
border: none;
background-color: transparent;
color: #000;
padding: 1em 2em;
font-family: monospace;
font-size: 18px;
line-height: 1;
text-transform: uppercase;
letter-spacing: .2em;
transition: all .3s ease;
}
button:before,
button:after{
content: "";
position: absolute;
z-index: -1;
transition: all .3s ease;
}
button:before{
top: -1px;
left: -1px;
width: 100%;
height: 100%;
border-top: 1px solid #000;
border-left: 1px solid #000;
max-width: 15%;
max-height: 35%;
}
button:after{
bottom: 0;
right: 0;
width: 100%;
height: 100%;
border-bottom: 1px solid #000;
border-right: 1px solid #000;
max-width: 15%;
max-height: 35%;
}
button:hover:before,
button:focus:before,
button:hover:after,
button:focus:after{
max-width: 100%;
max-height: 100%;
}