If you want to target a specific instance and wrapping it in a div with a particular class/id does not suffice for you, you may want to vote for this feature: https://feedback.telerik.com/blazor/1433654-component-specific-css-classes-and-ability-to-set-classes-per-instance. For the time being you can use the ".k-calendar" and ".k-datepicker" classes as root selectors for, respectively the calendar (both the popup one in the pickers, and the standalone one) and for the main input+button.