*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial,"Helvetica Neue";
  background:#222; /* dark gray background requested */
  display:flex;
  align-items:center;
  justify-content:center;
  text-align:center;
  padding:2rem;
}
.wrap{
  width:100%;
  max-width:1200px;
  padding:1rem;
  background:transparent;
  border-radius:0;
}
.hero{
  width:100%;
  height:auto;
  display:block;
  margin:0 auto;
  max-width:100%;
}
@media(min-width:900px){.wrap{padding:1.5rem}}