refactor: improve styles

src/styles/style.scss

@@ -1,16 +1,14 @@
 // If you want to override variables do it here
 @import "variables";
 
-// Import CoreUI for React components library
+// Import styles
 @import "@coreui/coreui/scss/coreui";
 
-// Import Chart.js custom tooltips styles
-@import "@coreui/chartjs/scss/coreui-chartjs";
+// Vendors
+@import "vendors/simplebar";
 
-@import "layout";
+// Custom styles for this theme
+@import "theme";
 
-// Preview
-@import "examples";
-
-// If you want to add custom CSS you can put it here.
+// If you want to add custom CSS you can put it here
 @import "custom";