The amount section is editable. If you click/tap on it, you can delete the current number and input whatever number you prefer. Perhaps find a way to bring this to your customers' attention?

@ja-socha please post your store URL so we can check where the code is.

The CSS that @MandasaTech wrote should have worked. Did you copy-paste it as is to the bottom of your base.css file? Can you send a screenshot of the pasted code?

Can you post the link to your store?