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.
What you want to do is make some CSS apply to two different types of elements, but allow them to have some differences as well. You can do this using some simple HTML:

```
<div class="base">
    <div class"inherited">
    </div>
</div>

```

And CSS:

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

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

```

This will add the shared properties to both types of `div`, but specific ones only to derived `div`s