github.css

.branch-name,
.commit-ref,
.commit .sha-block,
.commit .sha,
.commit-desc pre,
.commit-tease-sha,
.blob-num,
.blob-code-inner,
.gollum-editor .gollum-editor-body,
.gollum-editor .expanded textarea,
kbd,
.default-label .sha,
.file-info,
.hook-delivery-guid,
.hook-delivery-response-status,
.news .alert .branch-link,
.export-phrase pre,
.tag-references>li.commit,
.uploaded-files .filename,
.oauth-app-info-container dl.keys dd,
.two-factor-recovery-codes,
.two-factor-secret,
.branch-name,
.commit-ref {
  font-family: "Meslo LG L";
}

gitter.css

.gist .blob-num,
.gist .blob-code-inner,
.gist .highlight,
.gist pre,
.gist code,
.gist .gist-file {
  font-family: "Meslo LG L";
}