how to center (V,H) div inside div - css

Question

My problem is that I wanted to have split page by two divs side by side (50% width). Inside of them I wanted to place another divs and make them aligned vertically and horizontally at the same time.
I think that it is possible to make it without JS, but I'm not able to do that.
Can anybody make my two circles placed in the center (V,H) of their parent DIV, which are 50% of width and 100% of height so that when I will resize my window the circles will always be in center (and side by side as is now)?
Here is my code:
<div id="container">
<div class="left">
<div class="kolo1">
sometext1
</div>
</div>
<div class="right">
<div class="kolo2">
sometext 2
</div>
</div>
</div>
And a JSFiddle for that: http://jsfiddle.net/m5LCx/
Thanks in advance in solving my quest :)

Answer 1

It's actually quite simple, all you need to do is to simulate a table-like behaviour:
HTML markup:
<div id="container">
<div>
<div class="half left">
<div class="circle">hello</div>
</div>
<div class="half right">
<div class="circle">world</div>
</div>
</div>
</div>
CSS styles:
html, body {
width: 100%;
height: 100%;
margin: 0;
padding: 0;
}
#container {
display: table;
width: 100%;
height: 100%;
}
#container > div {
display: table-row;
}
.half {
display: table-cell;
width: 50%;
text-align: center;
vertical-align: middle;
}
.half.left {
background: red;
}
.half.right {
background: blue;
}
.circle {
display: inline-block;
padding: 50px;
border-radius: 50%;
}
.half.left .circle {
background: blue;
}
.half.right .circle {
background: red;
}
Final result http://jsfiddle.net/m5LCx/11/:

Answer 2

Working here http://jsfiddle.net/3KmbV/
add position: relative in .left and .right class and than add margin: auto; position: absolute; top: 0; left: 0; right: 0; bottom: 0; in .kolo1 and .kolo2 class. and remove top position from .left class
try it
body {
background-color: #006666;
margin: 0 auto;
height: 100%;
width: 100%;
font-size: 62.5%;
}
#container {
width: 100%;
min-height: 100%;
height: 100%;
position: absolute;
}
.left {
width: 50%;
min-height: 100%;
float: left;
top: 0;
background-color: #660066;
position: relative;
}
.right {
width: 50%;
min-height: 100%;
float: right;
min-height: 100%;
background-color: #003366;
position: relative;
}
.kolo1 {
background-color: #0f0;
width: 10em;
height: 10em;
border-radius: 5em;
line-height: 10em;
text-align: center;
margin: auto;
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 0;
}
.kolo2 {
background-color: #00f;
width: 10em;
height: 10em;
border-radius: 5em;
line-height: 10em;
text-align: center;
margin: auto;
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 0;
}

Answer 3

you can give postion: relative to .left and .right.
and give below CSS for to .kolo1 and .kolo2
margin: -5em 0 0 -5em;
position: absolute;
left: 50%;
top: 50%;
Updated demo

Answer 4

Another fiddle. This one uses absolute positioning with negative margins to ensure the circles are always in the centre. CSS looks like this
.kolo1 {
position: absolute;
top: 50%;
left: 50%;
margin-left: -5em; /* this must be half of the width */
margin-top: -5em; /* this must be half of the height */
}
As #Tushar points out, you need to set the position of the parent element to relative also.

Answer 5

Working Fiddle
.kolo1 {
background-color: #0f0;
width: 10em;
height: 10em;
border-radius: 5em;
line-height: 10em;
text-align: center;
margin: 50% auto 0 auto;
}
.kolo2 {
background-color: #00f;
width: 10em;
height: 10em;
border-radius: 5em;
line-height: 10em;
text-align: center;
margin: 50% auto 0 auto;
}

Answer 6

Try adding padding-top:50% for parent divs (having class left and right)