.button {
    font-size: 1em;
    text-decoration: none;
    display: block;
    float: inherit;
    padding: 3px 5px 3px 20px;
    background-color: #FAFAFA;
    border-color: #DDD;
    border-style: solid;
    border-width: 1px;
    width: 100px;
}

.sub {
    font-size: 7px;
    display: block;
    float: left;
    padding: 2px 0 2px 0;
    color: #FFF;
    text-decoration: none;
    background-color: #90CAFF;
    border-color: #50AAFF;
    border-style: solid;
    border-width: 1px;
    margin-right: 3px;
    width: 15px;
    text-align: center;
}
<a class="sub">.sub</a> <a class="button">.button</a>