The iOS ButtonGroup styling was based on a single linear gradient which you need to change it to change the color. However I've just changed it to be based on a background color, to allow easier styling. I've pushed an internal build which you can download and use just
.km-root .km-ios .km-buttongroup .km-button
to change the color of the whole ButtonGroup.
Or, you can use our Mobile ThemeBuilder
to control both the background color and the gradient (the ButtonGroup is on the My Account page).
All the best,
the Telerik team
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