sonarr: fixed dark theme modal colors

CSS/themes/sonarr/dark.css

@@ -15,7 +15,7 @@
 @import url(https://gilbn.github.io/theme.park/CSS/themes/sonarr/sonarr-base.css);
 :root {
   --main-bg-color: #1f1f1f;
-  --modal-bg-color: radial-gradient(ellipse at top, #F44336 0%, #0b3161 100%) center center/cover no-repeat fixed; 
+  --modal-bg-color: radial-gradient(ellipse at top, #1f1f1f 0%, #1f1f1f 100%) center center/cover no-repeat fixed; 
   --link-color: #FFEB3B; 
   --custom-buttons-color: radial-gradient(ellipse at center, #F44336 0%, #3F51B5 100%) center center/cover no-repeat fixed;
   --hompage-item-hover: radial-gradient(ellipse at center, rgba(0, 150, 136, 0.33) 0%, #b53f3f73 100%) center center/cover no-repeat fixed;