Get custom theme colors working

Introduces _theme-colors.scss with generated palettes and integrates them into custom-theme.scss for both light and dark themes. Removes stepper icon styles from performance-info.component.css and moves them to custom-theme.scss for better maintainability and consistency.

src/app/performance-info/performance-info.component.css

@@ -1,14 +1,3 @@
 .info-box {
   color: var(--mat-sys-on-surface);
 }
-
-::ng-deep .mat-step-header .mat-step-icon {
-  background-color: #ccc;
-  color: white;
-}
-
-
-::ng-deep .mat-step-header .mat-step-icon-selected,
-::ng-deep .mat-step-icon-state-edit {
-  background-color: var(--color-indigo-500) !important;
-}