Hi Duong Quoc,
Thank you for your inquiry.
For information on customizing the CSS classes in Syncfusion Blazor ComboBox, you can refer to the following documentation:
DropdownList CssClass Documentation: https://blazor.syncfusion.com/documentation/dropdown-list/style#cssclass
Regarding the Combobox, please note that we are currently actively working on updating the documentation. In the meantime, you can refer to the general guidance provided in the DropdownList documentation, as the CSS customization principles are similar. We will refresh the Combobox documentation in one of our upcoming releases.
Combobox Customization Documentation (Refer to DropdownList CssClass section): https://blazor.syncfusion.com/documentation/combobox/style#customizing-the-outline-themes-focus-color
We appreciate your understanding, and if you have any specific questions or need further assistance, feel free to let us know.
