Firefox displays header wrong

[farfromunique]

h2 {
    text-align: center;
    -webkit-margin-after: 5px;
    -webkit-margin-before: 5px;
    font-size: 1.8rem;
}

set -webkit-margin-after: and -webkit-margin-before: to use more standard margin-top and margin-bottom

[farfromunique]

Also applies to IE and Edge