CSS percentage behavior - html

Question

I'm having some strange behavior of the percentages.
I have layout which is 1366 pixels wide and I have one div which should be fluid.
Its 200px wide, which means it should be 14.64% wide.
When the layout is tested in 1366 pixels the div looks fine and there are no problems, but when I expand to 1920 the div is not wide enough.
Here is some samples of the code:
HTML:
<header>
<div class="top-bar">
<div class="fill"></div>
<div class="container">
<nav>
</nav>
</div>
</div>
<div class="bottom-bar">
</div>
</header>
And CSS
.container{
width: 1004px;
margin: 0px auto 0px auto;
}
header{
width: 100%;
height: 95px;
}
header div.top-bar{
background: #ffffff;
width: 100%;
height: 50px;
}
header div.fill{
background: #000000;
width: 14.64%;
height: 50px;
float: left;
}
nav{
height: 50px;
float: left;
}
header.main div.bottom-bar{
background: url("header-bottom.png") repeat-x;
width: 100%;
height: 45px;
}
I've coded liquid designs before, but never had problem like this, maybe my math is wrong or the problem is that everything else is hardcoded in pixels and this is liquid?

Answer 1

I'd guess the problem is because container has a pixel size while fill is in percentage. If all you want to achieve with the fill is to put a background color around container, you can do something like this (and remove the fill class css)
.container{
width: 1004px;
margin: 0px auto 0px auto;
background: #ffffff;
}
header div.top-bar{
width: 100%;
height: 50px;
background: #000000;
}
Now if you want to color only left side, and want to fit your 'fill' div nicely, then both container and fill have be either in percentage or in pixels (won't work properly in different screen sizes). There are different workarounds to make your fill work e.g. the following
header div.fill {
background: #000000;
width: 50%; /*make it wide enough*/
height: 50px;
float: left;
z-index: -1; /*put it behind container*/
position: relative;
}
header div.top-bar{
background: #ffffff;
width: 100%;
height: 50px;
z-index: -2; /*put it behind all*/
position: relative;
}

Answer 2

for managment layout use grid system css famework for example
Bootstrap
http://getbootstrap.com/
or
960 grid system
http://960.gs/