fix: Increase menu bar contrast (ietf-tools#6115)

Fixes ietf-tools#6112, ietf-tools#6113

Author: larseggert

ietf/templates/base.html

@@ -33,11 +33,11 @@
           data-group-menu-data-url="{% url 'ietf.group.views.group_menu_data' %}">
         {% analytical_body_top %}
         <a class="visually-hidden visually-hidden-focusable" href="#content">Skip to main content</a>
-        <nav class="navbar navbar-expand-lg {% if server_mode and server_mode != "production" %} bg-warning {% else %} bg-secondary {% endif %}  {% if navbar_mode %} {{ navbar_mode }} {% else %} fixed-top {% endif %}">
+        <nav class="navbar navbar-expand-lg {% if server_mode and server_mode != "production" %} bg-warning {% else %} bg-secondary-subtle {% endif %}  {% if navbar_mode %} {{ navbar_mode }} {% else %} fixed-top {% endif %}">
             <div class="container-fluid">
                 <a class="navbar-brand" href="/">
                     <img alt="IETF Logo" class="me-2"
-                        src="{% static 'ietf/images/ietf-logo-nor-white.svg' %}">
+                        src="{% static 'ietf/images/ietf-logo-nor.svg' %}">
                     Datatracker
                     {% if server_mode and server_mode != "production" %}
                         <span class="text-danger">&delta;</span>