Question: Is it possible to create an operating system that loads a web browser without menu bars, tabs etc. and that is all it loads.

I do not mean like Chrome OS but I mean all it loads is a html page which can be interacted with like an ordinary web page e.g. google.com, youtube.com.

Also, if this is possible, I would prefer it to be a Linux based OS and Webkit based browser.

Answer: 
The easiest is to add your someInheritedDiv element to the first rule like this.

```css
div.someBaseDiv,
#someInheritedDiv
{
    margin-top:3px;
    margin-left:auto;
    margin-right:auto;
    margin-bottom:0px;
}

```

This will tell your #someInheritedDiv to apply the same styles as div.someBaseDiv has. Then you *extend* this set of styles with more specific to your #someInheritedDiv:

```css
#someInheritedDiv
{
    background-image:url("images/worldsource/customBackground.gif");
    background-repeat:no-repeat;
    width:950px;
    height:572px;
}

```

This is how **specificity** in CSS works.
Use both classes and combine them like so:

```
.baseClass
{
    margin-top:3px;
    margin-left:auto;
    margin-right:auto;
    margin-bottom:0px;
}

.baseClass.otherClass /* this means the element has both baseClass and otherClass */
{
    background-image:url("images/worldsource/customBackground.gif");
    background-repeat:no-repeat;
    width:950px;
    height:572px;
}

```

The markup is as follows:

```
<div class="baseClass otherClass"></div>

```

Now, in this fashion you can override baseClass if necessary... and since you don't have to keep adding your new class names to the baseClass definition, it's a bit cleaner.