feat: apply code block background and foreground color

src/themes.rs

@@ -262,24 +262,36 @@ fn style_declarations(style: &Style) -> String {
 }
 
 fn generate_css(scopes: &[&str], theme: &Theme) -> String {
+    let mut rules = Vec::new();
+
+    // The theme's editor foreground/background colour the code block itself.
+    let mut block_style = Vec::new();
+    if let Some(Color(hex)) = &theme.foreground {
+        block_style.push(format!("color:{hex}"));
+    }
+    if let Some(Color(hex)) = &theme.background {
+        block_style.push(format!("background:{hex}"));
+    }
+    if !block_style.is_empty() {
+        rules.push(format!(".code-block{{{}}}", block_style.join(";")));
+    }
+
     let mut groups: HashMap<&Style, Vec<&str>> = HashMap::new();
     for &scope in scopes {
         if let Some(style) = theme.styles.get(scope) {
             groups.entry(style).or_default().push(scope);
         }
     }
-    groups
-        .iter()
-        .map(|(style, scopes)| {
+    rules.extend(groups.iter().map(|(style, scopes)| {
         let selectors = scopes
             .iter()
             .map(|s| scope_to_selector(s))
             .collect::<Vec<_>>()
             .join(",");
         format!("{}{{{}}}", selectors, style_declarations(style))
-        })
-        .collect::<Vec<_>>()
-        .join("\n")
+    }));
+
+    rules.join("\n")
 }
 
 #[func]