Breadcrumb links disappear on hover because foreground becomes same as background.

[kfogel]

See the two attached screenshots. My mouse pointer wasn't captured by the screenshot, unfortunately, but in the first screenshot, imagine it right underneath the "Home" breadcrumb link in the upper left corner -- underneath, not actually on the link yet:

In the next screenshot, my mouse pointer is on the "Home" link, which has now disappeared, presumably because its foreground become the same (or close to the same) as the background color:

At first I thought this could be a bug in our custom appearance settings, but looking at those settings, I don't think so:

--- streetcrm/templates/admin/base_site.html
+++ streetcrm/templates/admin/base_site.html
@@ -8,11 +8,7 @@
 {% block branding %}
 {% load staticfiles %}
   <a id="logo-wrapper" href="{% url 'admin:index' %}" >
-    {% if logo %}
-        <img src="{% static "images/logo.png" %}" alt="organization's logo" height="50">
-    {% else %}
-        <img src="{% static "images/streetcrm-logo.png" %}" alt="streetcrm logo" height="50">
-    {% endif %}
+        <img src="{% static "images/logo.png" %}" alt="SWOP logo" height="50">
   </a>
 <a href="{% url 'admin:index' %}" class="navbar-brand">{% trans "Contacts" %}</a>
 <div id="top-right-wrapper">
@@ -37,7 +33,7 @@
     {% if user.is_active %}
     <div id="user-menu-link">
       <!-- three-lines icon from https://www.iconfinder.com/icons/134216/hamburger_lines_menu_icon -->
-      <img src="{% static "images/three_lines_default.png" %}">
+      <img src="{% static "images/three_lines_purple.png" %}">
       <div class="clearblock"></div>
       <ul id="user-menu">
         {% if user.has_usable_password and perms.auth.can_change_password %}

Oh, wait, I think I see where the problem is! In /var/www/.config/streetcrm/config.ini, we have this option set:

theme_color = "#5F1F7F"

But do we offer a corresponding option for foreground colors (assuming that theme_color in practice sets background colors in most places)?

Anyway, for now my hypothesis is that this is a combination of local configuration bug (the setting of theme_color) and a more general bug that we don't offer sufficient customization ability so that sites can set the foreground too when they set the background.