In ionic if you want to work with color.
For example,
- want to change the primary color.
- want to change the warning color
- add a new color name
I will go one by one to further explanation
Change the primary color
After creating your app. You change your mind about applying the primary color of your app from blue to yellow or green. To do that. Ionic has a tool to support generating color variables for the whole app. You can play around and see the result in preview mode
https://ionicframework.com/docs/theming/color-generator
You also can change the warning color or danger color if you want.
Add a new color name
Moreover, If you want to add a new color name to make your app more fancy. You can access the link below to add your favorite color. For example: I want to add “btn-gold” to my button
https://ionicframework.com/docs/theming/colors

Add the generated code above to your variable.css. and then use it in your HTML page
<ion-button color="btn-gold">YOUR BUTTON</ion-button>