button{
position: relative;
outline: none;
cursor: pointer;
display: block;
border: 1px solid #52e0e2;
color: #52e0e2;
background-color: transparent;
padding: 1.5em 3em;
font-family: sans-serif;
font-size: 14px;
text-transform: uppercase;
letter-spacing: .5em;
line-height: 1;
transition: all .1s ease;
}
button:focus,
button:hover{
color: #000;
}
button:after{
content: "";
display: block;
position: absolute;
left: 0;
bottom: 0;
width: 100%;
height: 100%;
max-height: 0px;
background-color: #52e0e2;
transition: all .2s ease;
z-index: -1;
}
button:focus:after,
button:hover:after{
max-height: 100%;
}