.presentation-nav{position:fixed;right:22px;bottom:22px;z-index:60;display:grid;grid-template-columns:42px minmax(68px,auto) 42px;align-items:center;padding:6px;border:1px solid rgba(116,212,255,.3);border-radius:999px;background:rgba(7,21,37,.92);box-shadow:0 12px 35px rgba(0,0,0,.28);backdrop-filter:blur(14px)}
.presentation-nav button{width:42px;height:42px;border:0;border-radius:50%;background:transparent;color:#fff;font-size:20px;font-weight:900;cursor:pointer}
.presentation-nav button:hover:not(:disabled){background:#1b77ff}
.presentation-nav button:disabled{opacity:.28;cursor:default}
.presentation-nav span{padding:0 9px;color:#bcd0e0;text-align:center;font-size:12px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;white-space:nowrap}
main>section{scroll-margin-top:76px}
@media(max-width:650px){.presentation-nav{right:12px;bottom:12px;grid-template-columns:38px minmax(58px,auto) 38px}.presentation-nav button{width:38px;height:38px}.presentation-nav span{font-size:11px;padding:0 6px}}