e="description" content="{{ .Site.Params.description }}">
  {{ end }}

  <!-- favicon -->
  <link rel="icon" href="{{ .Site.Params.favicon | absURL }}">

  <!-- keywords -->
  {{ if .Keywords }}
  <meta name="keywords" content="{{ range $key, $value := .Keywords }} {{ $value }} {{ end }}">
  {{ else }}
  <meta name="keywords" content="{{ range $key, $value := .Site.Params.keywords }} {{ $value }} {{ end }}">
  {{ end }}

  <!-- math -->
  {{ if cond (ne .Params.math nil) .Params.math .Site.Params.math.enabl