<!DOCTYPE html>
<style>
input[type="submit"] {
display: block;
width: 100px;
height: 100px;
background-color: green;
outline: none;
border: 5px solid magenta;
box-sizing: border-box;
}
</style>
<input type="submit" value="2" />
<input type="submit" value="3" />
<input type="submit" value="4" />