Add modal colors (#338)

Author: janfaracik

src/main/frontend/main.scss

@@ -83,6 +83,14 @@
                          0 0 1px 1px rgba(0, 0, 20, 0.025),
                          0 10px 20px rgba(0, 0, 20, 0.3);
 
+  /* Modals */
+  --modal-backdrop-background: hsla(240, 6%, 3%, 0.9);
+  --modal-backdrop-filter: contrast(0.85) saturate(2) brightness(0.7) blur(20px);
+  --modal-box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05),
+                      0 0 8px 2px rgba(0, 0, 30, 0.05),
+                      0 0 1px 1px rgba(0, 0, 20, 0.025),
+                      0 10px 20px rgba(0, 0, 20, 0.3);
+  
   /* Links */
   --link-color: #53c1ff;
   --link-visited-color: #53c1ff;