Introduce color for blog post background

Author: linkdotnet

LinkDotNet.Blog.Web/Pages/Index.razor.css

@@ -1,6 +1,5 @@
 .blogpost-cards {
-    /* TODO: Do not use the color directly, this will interfere with dark mode */
-    background-color: var(--big-stone);
+    background-color: var(--blog-post-background-color);
     margin: 1rem auto 1.6%;
 }
 

LinkDotNet.Blog.Web/wwwroot/css/basic.css

@@ -12,7 +12,7 @@
     --white: #ffffff;
     --wild-sand: #f4f4f4;    
 
-    /* Usages */
+    /* Usages - this colors have to be defined in every theme */
     --active-link: var(--big-stone);
     --disabled-link: var(--pewter);
     --link-hover: var(--tana);
@@ -37,6 +37,8 @@
     --button-secondary-color: var(--big-stone);
     --button-secondary-border-color: var(--big-stone);
 
+    --blog-post-background-color: var(--big-stone);
+
 }