fix default theme

src/FileManagement.ts

@@ -136,7 +136,7 @@ export class AppSettings {
    */
 
   public vimMode: boolean = false;
-  public theme: string = "toposTheme";
+  public theme: string = "Dracula";
   public font: string = "IBM Plex Mono";
   public font_size: number = 24;
   public universes: Universes;

src/main.ts

@@ -210,7 +210,13 @@ export class Editor {
     loadUniverserFromUrl(this);
 
     // Set the color scheme for the application
+    let available_themes = Object.keys(colors);
+    if (this.settings.theme in available_themes) {
       this.readTheme(this.settings.theme);
+    } else {
+      this.settings.theme = "Dracula";
+      this.readTheme(this.settings.theme);
+    }
   }
 
   private getBuffer(type: string): any {