main button,.button{
    display: block;
    width: min(100%,38ch);
    border: none;
    margin-right:auto;
    margin-left: auto;
    padding: 0;
    text-align: center;
    font-size: inherit;
    line-height: 2.618;
    font-weight: 400;
    border-radius:var(--small)}

.primary.button{
    color: #fff;
    background:linear-gradient(to bottom, #07f 0%,#05e 100%);
    box-shadow:0 0 1.618rem rgba(0,153,255,.13),0 .09rem .146rem rgba(0,0,102,.3),.09rem .146rem .236rem rgba(0,0,102,.2),.146rem .236rem .382rem rgba(0,34,136,.14),.236rem .382rem .618rem rgba(0,34,136,.13),.382rem .618rem 1rem rgba(0,34,136,.1)}

main button.secondary,.secondary.button{
    background-color: rgba(0,0,0,0);
    height: 2.618em;
    line-height: calc(2.618em - 4px);
    color: #06f;
    border: 2px solid #06f}

/*CENTER UNDER ELEMENT WITH 62ch MAX-WIDTH*/
:where(main>*>*>*):not(header,hgroup,h1,.h1,h2,.h2,h3,.h3,hgroup p,figcaption,small)+button,.button{
    margin-right:min((100% - 38ch)/2,12ch);
    margin-left:min((100% - 38ch)/2,12ch)}