Product page - variants & quantities

This is my first time asking Qs in the forum. I've got zero CSS knowledge, I don't even know what CSS is. If possible, I would like some push-button easy-to-follow instructions so my old unskilled brain can cope. Please.

I recently tweaked some colours for something elsewhere and now I can't figure out how to change the background colour of my variants, I used to have a grey box with black text. Now, the grey box only appears when hovering. Also, when I click a variant, it turns solid black and stays like that. The black is ok but I'd like the text to show up after selecting, like it does on the Add to Cart button.

Then there's the quantity box... on products where I have variants, there is only one item of each variant available but a quantity box is present and seems to make the items unlimited. Although, if you select multiples of a variant by upping the quantity, then click add to cart, a pop-up says that there's only one available but, I'd rather have no quantity box. How can I remove the quantity box from products that shouldn't have it? 

Just noticed that it's my second post, don't remember the first. And, this post is in a Customize with Code section but I don't want code. Would appreciate a nudge in the right direction, I'll get the hang of using the forum one day!

You can share link to this product, we can check problem easier

https://www.peaseaart.com/online-shop/p/pinch-bowl-kowhai

Thanks for your reply

On 4/5/2024 at 2:28 PM, dingdong said:

https://www.peaseaart.com/online-shop/p/pinch-bowl-kowhai

Thanks for your reply

You can use this to Website > Website Tools > Custom CSS

input:checked + label {
    color: #fff !important;
}