Aligning Div inside another Div - css

Question

You can visit the site I am working on here. Currently, I am working on making the site relative. I am adjusting the CSS for a resolution with a width less than 820px. This involves adjusting the menu from this
to this . As you can see, I have outlined my divs with a red border to demonstrate the problem. I want to the menu bar to sink to the bottom of its parent div. However, setting it to bottom: 0 nothing changes. How can I get the div class="nav" to sink to the bottom of div class="header" at a resolution of less than 820px?
Here is my HTML
<div class="header">
<div id="narrow-logo"><img src="Images/pantry logo.png" width="536" height="348"></div>
<div class="nav">
<ul>
<li class="link">HOME</li>
<li class="link">MENU</li>
<li id="logo"><img src="Images/pantry logo.png" width="536" height="348"></li>
<li class="link">CONTACT</li>
<li class="link">ABOUT</li>
</ul>
</div>
</div>
And my CSS
.header {
width: 960px;
height: 150px;
margin: 0 auto;
text-align: center;
position: relative;
padding: 100px 0px 0px 0px;
}
.header div#narrow-logo {
display: none;
}
.nav ul li {
display: inline-block;
vertical-align: middle;
margin-right: 70px;
}
#logo a img {
max-width: 250px;
height: auto;
position: absolute;
top: 50%;
left: 50%;
-webkit-transform: translate(-50%,-50%);
transform: translate(-50%,-50%);
}
#logo {
width: 250px;
position: relative;
}
#media screen and (max-width: 1080px) {
.header {
width: 700px;
height: 125px;
padding: 75px 0px 0px 0px;
}
#logo a img {
max-width: 180px;
}
#logo {
width: 180px;
}
#media screen and (max-width: 820px) {
.header {
border: 2px solid red;
width: 475px;
padding: 0;
margin-top: 40px;
height: 200px;
}
.header div#narrow-logo {
border: 2px solid red;
display: inherit;
position: absolute;
left: 50%;
-webkit-transform: translate(-50%);
transform: translate(-50%);
}
.header div#narrow-logo a img {
width: 200px;
height: auto;
}
.nav {
border: 2px solid red;
bottom: 0px;
}
.nav ul li {
margin-right: 25px;
}
.nav ul li:nth-child(3) {
display: none;
}
#logo a img {
display: none;
}
#logo {
width: 0;
}
I know that is a lot of code and I apologize. I just wanted to make sure I included all positioning attributes that could be causing my issue. Let me know if I can clarify anything, and I appreciate your time and advice.

Answer 1

For bottom:0 to work, you need the element that it's being applied to to be absolutely positioned. You also need, in this case, to have it's parent relatively positioned. Try this:
.nav ul li {
display: inline-block;
margin-right: 70px;
position:absolute;
bottom:0;
}

Answer 2

Adding position value will resolve your issue.Please update your css in the following section.
#media screen and (max-width: 820px) {
.nav {
border: 2px solid red;
bottom: 0px;
position:absolute;
left:16%;
}
}

Answer 3

For bottom:0; to work, your class="nav" has to have absolute positioning.
CSS:
.nav {
position: absolute;
bottom: 0;