{%- macro render_logo(src, classname='') -%}
  {%- if src and src.startswith(('https://', 'http://')) -%}
    <img class="{{ classname }}" src="{{ src }}" alt="{{ project }}" />
  {%- elif src -%}
    <img class="{{ classname }}" src="{{ pathto('_static/' + src, 1) }}" alt="{{ project }}" />
  {%- elif logo_url -%}
    <img class="{{ classname }}" src="{{ logo_url }}" alt="{{ project }}" />
  {%- endif -%}
{%- endmacro -%}

<a class="bz-header-brand" href="{{ pathto(master_doc) }}">
  {{ render_logo(theme_light_logo, 'only-light') }}
  {{ render_logo(theme_dark_logo, 'only-dark') }}
  <span>{{ docstitle if docstitle else project }}</span>
</a>