Add a nicer comment color in dark mode

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

assets/scss/code.scss

@@ -114,5 +114,5 @@ pre code {
 }
 
 .c, .c1, .cm {
-    color: $code-comment-color;
+    @include var(color, code-comment-color);
 }

assets/scss/modes.scss

@@ -17,6 +17,7 @@
         --code-color: #{$code-color-dark};
         --code-lineno-color: white;
         --code-keyword-color: #{$code-token-color-dark};
+        --code-comment-color: #{$code-comment-color-dark};
         --code-type-color: #{$code-token-color-dark};
         --code-highlight-color: #{$code-highlight-color-dark};
     }

assets/scss/variables.scss

@@ -31,6 +31,7 @@ $code-border-color: darken($code-color, 10%);
 $code-lineno-color: black;
 $code-lineno-spacing: 1rem;
 $code-comment-color: grey;
+$code-comment-color-dark: #68dcff;
 $code-border: $standard-border-width solid $code-border-color;
 
 $input-padding: 0.5rem;
@@ -57,6 +58,7 @@ $css-vars: (
     code-color: $code-color,
     code-lineno-color: $code-lineno-color,
     code-keyword-color: $code-token-color,
+    code-comment-color: $code-comment-color,
     code-type-color: $code-token-color,
     code-highlight-color: $code-highlight-color,
 );