<a href="#" class="mali_oglas_kategorija">Kategorija</a>

.mali_oglas_kategorija {
        position: relative;
        display: inline-block;
    font-weight: bold;
        width: 100px;
    padding: 6px 20px 6px 40px;
    margin: 10px 10px 10px -18px;
        color: #e5e5e5 !important;
    background-color: #760000;
    -webkit-box-shadow: 0px 2px 4px rgba(0,0,0,.5);
    -moz-box-shadow: 0px 2px 4px rgba(0,0,0,.5);
    box-shadow: 0px 2px 4px rgba(0,0,0,.5);}
.mali_oglas_kategorija:after{
        content: ' ';
    position: absolute;
    width: 0;
    height: 0;
    left: 0px;
    top: 100%;
    border-width: 5px 10px;
    border-style: solid;
    border-color: #470000 #470000 transparent transparent;
}

<a href="#" class="mali_oglas_kategorija">Kategorija<b></b></a>