Why is the dropdown content is in transparent color?

Question

Please help. Which property should I add so that the dropdown would not be transparent?
https://code.sololearn.com/WRGg74rDoBIT/?ref=app

Answer 1

*Already answered in the comments*

The z-index property specifies the stack order of an element, setting this property as "-1" you putted that menu behind all other things, this is why you see a transparent menu. :3

Answer 2

@Maz Thanks a lot. 🙂