Can't make a div overlap another specific div - html

Question

I have two elements a nav div and a slide controller div, but I just cannot make the nav div overlap the slide controller div. Here is my code (1. Nav code 2. Slide controller code):
nav {
position: absolute;
width: 200px;
height: 100vh;
background-color: white;
margin-top: -20px;
z-index: 1;
}
nav ol {
margin-top: 100px;
width: 190px;
}
nav li{
display: block;
margin: 0px;
padding: 15px;
position: relative;
width: 170px;
border-bottom: 1px solid #bfbebe
}
nav a {
color: black;
}
#Slider_Control {
position: absolute;
z-index: 2;
width: 210px;
height: 40px;
background-color: #d51200;
margin-left: 50%;
transform: translate(-50%);
-webkit-transform: translate(-50%);
-ms-transform: translate(-50%);
margin-top: 574px;
}
.CircleControl {
width: 10px;
height: 10px;
display: inline-block;
background: white;
border-radius: 100%;
margin-right: 5px;
margin-left: 5px;
}
#Circles {
text-align: center;
height: 40px;
line-height: 40px;
}
#Arrow_1, #Arrow_2 {
position: absolute;
width: 20px;
height: 0 auto;
margin-top: -40px;
padding: 10px;
background: #ed1602
}
#Arrow_2 {
margin-left: 170px;
transform: rotate(180deg);
}
#Triangle_1 {
width: 0;
height: 0;
border-bottom: 14px solid transparent;
border-left: 20px solid #7d0b00;
margin-left: 210px;
margin-top: -14px;
}
#Triangle_2 {
position: absolute;
width: 0;
height: 0;
border-bottom: 14px solid transparent;
border-right:20px solid #7d0b00;
margin-top: -14px;
margin-left: -20px;
}
I hope someone could solve this problem that the slider controller keeps overlapping the nav div, which sould be the other way around.
(Let me now if you need some more information)

Answer 1

Well from what i'm seeing, if you want the nav tag to overlap #Slider_Control, since they both have position:absolute, all you have to do is put an higher z-index on your nav tag. Right now your nav is at 1 and your Slider_Control is at 2, so the Slider_Control will always be on top.
But again, I could be wrong, providing the html context of this would help.