Remove the dark header from light theme

RIGS/templates/event_table.html

@@ -1,7 +1,7 @@
 <div class="d-none d-md-block">
     <div class="table-responsive">
         <table class="table mb-0">
-            <thead class="thead-dark">
+            <thead>
                 <tr>
                     <th scope="col">#</th>
                     <th scope="col">Event Date</th>

RIGS/templates/invoice_list.html

@@ -11,7 +11,7 @@
         {% block search %}{% endblock %}
         <div class="table-responsive col-sm-12">
             <table class="table table-hover">
-                <thead class="thead-dark">
+                <thead>
                     <tr>
                         <th scope="col">Invoice #</th>
                         <th scope="col">Event</th>

RIGS/templates/invoice_list_waiting.html

@@ -19,7 +19,7 @@
         <p>These events have happened, but paperwork has not yet been sent to treasury</p>
         <div class="table-responsive col-sm-12">
             <table class="table table-hover">
-                <thead class="thead-dark">
+                <thead>
                     <tr>
                         <th scope="col">Event #</th>
                         <th scope="col">Start Date</th>

RIGS/templates/risk_assessment_table.html

@@ -15,7 +15,7 @@
         <div class="col-sm-12">
             <div class="table-responsive">
                 <table class="table mb-0">
-                    <thead class="thead-dark">
+                    <thead>
                         <tr>
                             <th scope="col">Event</th>
                             <th scope="col" class="">{{ object_list.0|verbose_name:'nonstandard_equipment'|title }}</th>

templates/partials/generic_list.html

@@ -16,7 +16,7 @@
     <div class="d-none d-md-block">
         <div class="table-responsive">
             <table class="table table-striped">
-                <thead class="thead-dark">
+                <thead>
                     <tr>
                         <th scope="col">#</th>
                         <th scope="col">Name<a href="?{% orderby request 'orderBy' 'name' %}"><span class="caret"></span></a></td>