Hi there,
try this CSS:
.wp-block-button .wp-block-button__link,
a.button,
a.button:visited,
button,
html input[type=button],
input[type=reset],
input[type=submit] {
border-radius: 5px;
border-width: 4px;
border-bottom: 2px solid rgba(0, 0, 0, .2);
transition: color .1s ease-in-out, background-color .1s ease-in-out, border-color .1s ease-in-out, transform .2s ease-in-out;
transform: translateY(0);
}
.wp-block-button .wp-block-button__link:hover,
a.button:hover,
a.button:visited:hover,
button:hover,
html input[type=button]:hover,
input[type=reset]:hover,
input[type=submit]:hover {
transform: translateY(0);
box-shadow: 0 3px 7px 0 rgba(0, 0, 0, 0.4);
}