Add options for custom card header and overall card class

Author: adamrehn

README.md

@@ -160,7 +160,9 @@ The theme displays information as a series of grouped cards, which must be speci
       # (ONLY USED WHEN TYPE IS "custom": the HTML file from the `_include` directory that provides the card body contents)
       include: custom-card-body.html
 
-      # (OPTIONAL, AND ONLY USED WHEN TYPE IS "custom": a custom CSS class to add to the card body, defaults to no class)
+      # (OPTIONAL, AND ONLY USED WHEN TYPE IS "custom": CSS classes to add to the card, its header and its body, all default to no class)
+      card-class: my-custom-class
+      header-class: my-custom-class
       body-class: my-custom-class
 ```
 

_layouts/default.html

@@ -177,8 +177,8 @@ <h2 class="card-header">{{ card.name | escape }}</h2>
 
 								{% when "custom" %}
 
-									<div class="card">
-										<h2 class="card-header">{{ card.name | escape }}</h2>
+									<div class="card{% if card.card-class %} {{ card.card-class | escape }}{% endif %}">
+										<h2 class="card-header{% if card.header-class %} {{ card.header-class | escape }}{% endif %}">{{ card.name | escape }}</h2>
 										<div class="card-body{% if card.body-class %} {{ card.body-class | escape }}{% endif %}">
 											{% include {{ card.include }} %}
 										</div>