I'm doing the freecodecamp exercise of creating a portfolio. I am using Marterialize.css. The problem is this: when the hamburger menu is activated due to the size of the browser, the menu is displayed correctly, but it seems that the menu is located one layer below the gray background. I've been fingering the z-index, but even assigning them an index of 999 still looks like it's down. Any ideas? (I leave the example in CodePen)
p.d: the z-index 999 I added it inline in the html, to the classe side-nav