[4.0.0.-beta.6] ion-back-button color can not be changed

[RHinderiks]

Bug Report

Describe the Bug
Trying to overrride --ion-color-base to change the color of the ion-back-button since currently its the same color as our header background. However no color change is applied.

When overriding color with !important directly on ion-back-button it does work but this seems hacky

Expected Behavior
When overriding a variable i expect this value to be applied ?

[brandyscarney]

Thanks for the issue! Please do not override the --ion-color-base variable (see #14808). We are working on updating our components to include a --color and --background variable that can be used to override.

Please follow this issue to track which components still need to be updated: #14850

[ionitron-bot]

Thanks for the issue! This issue is being locked to prevent comments that are not relevant to the original issue. If this is still an issue with the latest version of Ionic, please create a new issue and ensure the template is fully filled out.