Your product designer is remarkable, however, it's just the start and I am stuck up somewhere.
I added a product and on designer page when I enter quantity it's white coloured and nothing is seen. When I highlight the quantity entered then only text can be seen. May be due to the theme I am using.
Please tell me what code should I use in customer CSS as !important that the CSS overrides the theme and text in quantity text field is shown perfectly in black colour.
Welcome to our forum.
Please send me your designer page url, i will check it and send you custom CSS.