Hardcoded inline styles are no-go obstacle for styling

[alex-ander-is]

Please consider to completely rework the concept of usage of hardcoded inline styles.
It's a no-go obstacle for a proper styling via classes.

https://github.com/custom-cards/button-card/blob/2562b84360114ab6b4e9305c91503d47b2693957/src/button-card.ts#L1161