CSS Can only style elements with pixels, not percents - html

Question

i'm having a bit of a brain melting problem. I have a master div thats pretty much the body (don't ask me why, i was getting desperate), and within that div is a head div, and within that div is the navigation bar. It's a clear hierarchy. The problem is, whenever i try to use percents to adjust the height and width of the navigation bar or the head div, nothing happens. Zip, zero, nada. I've tried changing the positions to absolute, relative, even static. I've removed the Master Div, i've reordered the hierarchy, but nothing seems to work. Eventually i got to the point where i figured out that when i used pixels, i got the change wanted. (Obviously had to do a bit of conversion). My first thought was hierarchy, but again, it's clear, with no missing ending tags, no weird parents or children.
HTML
<div id="master_div">
<div id="head_div">
<div id="title_div">
<p id="title">A Challenging Sew</p>
<p id="subtitle">A sewing room, Venti Starbucks and a iPod classic....with a weekly Monday update to keep me on task....lets see what happens....</p>
</div>
<div id="nav_bar">
<ul>
<li><a class="nav_bar_links" href="/home">Home</a></li>
<li><a class="nav_bar_links" href="/about">About</a></li>
<li><a class="nav_bar_links" href="/projects/2013">Projects for 2013/2014</a></li>
<li><a class="nav_bar_links" href="http://www.flickr.com/photos/91959855#N02/collections/72157632507621761/">Completed</a></li>
<li><a class="nav_bar_links" href="/archive">Archives</a></li>
<li><a class="nav_bar_links" href="/subscribe">Subscribe</a></li>
<li><a class="nav_bar_links" id="sign_in" href="#">Sign In</a></li>
</ul>
</div>
</div>
</div>
CSS
body
{
font-family: 'Lato', Helvetica, Arial, sans-serif;
font-size: 15px;
padding:0 !important;
}
#master_div
{
position:relative;
width:100%;
height:100%;
margin:0;
padding:0;
}
/* Navigation Page */
#scary_tree
{
position:absolute;
right:40%;
top:25%;
}
/* Home */
/* TODO: Make Responsive Home Page */
#head_div
{
background-color:whitesmoke;
position:absolute;
height:63px;
width:100%;
margin:0;
padding:0;
}
/* A Challenging Sew + A sewing room, Venti Starbucks and a iPod classic..*/
#title_div
{
background-color:white;
opacity: .7;
position:relative;
height:30px;
width:100%;
top:15px;
border-top: solid 1px #e7e7e7;
border-bottom: solid 1px #e7e7e7;
}
#title
{
position:absolute;
left:3%;
top:-9%;
font-size:100%;
margin:0;
padding:0;
}
#subtitle
{
position:absolute;
left:3%;
top:50%;
padding:0;
margin:0;
font-size:40%;
line-height: 1.2;
}
#nav_bar
{
position:absolute;
top:100%;
height:15%;
width:100%;
background-color:whitesmoke;
border-top: solid 1px #e7e7e7;
border-bottom: solid 1px #e7e7e7;
margin:0;
padding:0;
}
#nav_bar ul {
margin:0;
padding:0;
position:relative;
height:20px;
top:-8px;
}
#nav_bar li {
display:inline;
}
#nav_bar a:link,a:visited {
margin:0;
padding-left:5px;
text-decoration: none;
color: black;
font-size:50%;
}
#nav_bar #sign_in
{
position:absolute;
right:2%;
top:3px;
margin:0;
padding:0;
}
Note: I am using a reset file. However, i still have margin and padding :0 in there because it doesn't really seem to be taking hold.
Feel free to critique me on my coding style, still learning!

Answer 1

You might wan to try
min-height: 100%;
min-width: 100%;
position: absolute;

Answer 2

Found the cause, setting my master div's position to relative was the issue. Have no idea why but hey. It works now. Sort of.