<STYLE>
.boxlink BUTTON{
    background-color: transparent; color: blue;
    width: 100px; height: 30px;
    border-style: width; border-style: solid; border-color: blue;
}
.boxlink:hover BUTTON{
    color: red; border-color: red; font-size: 105%;
}
</STYLE>

<A class="boxlink" href="someURL">
    <BUTTON onclick="navigate(this.parentElement.href)">В сад!</BUTTON>
</A>