Change the color of the sold-out or disabled add to cart button
When using darker background color combinations, you might find the disabled (sold-out) button is difficult to read:
Example:

You can modify the code to improve the button appearance especially for these dark combinations.
Option 1 - Code to change text to white
Example:

Code to use:
/* -- code to change the sold-out button text -- */
.add-to-cart__wrapper .disabled {
color:#ffffff;
}
/* - end - */
Option 2 - Code to change background color and text
Example:

Code to use:
/* -- code to change sold-out button background color and text -- */
.add-to-cart__wrapper .disabled {
background-color: #dddddd;
border: 1px solid #dddddd;
color:#111111;
}
/* - end - */
Apply any valid hex color code to help with your shop:
http://www.colorhexa.com/web-safe-colors
Change the hover background color
Use this code in addition to the above options:
/* -- code a modify hover background color and text for sold-out button -- */
.add-to-cart__wrapper .disabled:hover {
background-color: #dddddd !important;
border: 1px solid #dddddd !important;
color: #111111 !important;
}
/* - end - */
Where do I add the code?
Use this link to learn where exactly to add this code snippet: