CSS - Círculos centralizados

/* =Reset default browser CSS. Baseado no trabalho de Eric Meyer: http://meyerweb.com/eric/tools/css/reset/index.html
-------------------------------------------------------------- */
html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, font, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
dl, dt, dd, ol,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td {
    border: 0;
    font-family: inherit;
    font-size: 100%;
    font-style: inherit;
    font-weight: inherit;
    margin: 0;
    outline: 0;
    padding: 0;
    vetical-align: baseline;
}
:focus {/* remember to define focus styles! */
    outline: 0;
}
body {
    line-height: 1;
    font-family: sans-serif;
}
.circulo_grande_ext{
    width: 150px;
    height: 150px;
    -webkit-border-radius: 100%;
    -moz-border-radius: 100%;
    border-radius: 100%;
    background-color: #efefef;
    vertical-align: middle;
    display: table-cell;
}
.circulo_grande_int{
    width: 120px;
    height: 120px;
    margin: 0 auto;
    -webkit-border-radius: 100%;
    -moz-border-radius: 100%;
    border-radius: 100%;
    background-color: #e0e0e0;
    color: #333333;
}
.conteudo_circulo{
    font-size: 60px;
    font-weight: bold;
    line-height: 12px;
    text-align: center;
    padding-top: 40%;
}
.minimo{
    font-size: 12px;
}