I think the ideal is to use CSS purely for the layout and presentation, and HTML for the content. But let's say, the company wants to change a "Related articles" box from the bottom of the page to the top of the page. In such case, won't using CSS alone be not an ideal solution, but is better to alter the HTML as well? So as things are right now, HTML still takes a role in the page layout and presentation? Thanks.
Things still appear in the same order as they are in the html - it's not as restrictive as that as we can use absolute and relative positions, but those are undesirable - it's better to use to dom flow to handle placement, and that means yes, you should move the node in the html.
As Jason said, CSS is for styling the content, the content itself and its order is defined by the data (html), as order is necessary for the context of information, so it lies firmly in the 'data' part of what we do rather than the 'display'
EDIT: I should say this: If you want your data to be totally independent of the display, you should consider defining your pages as xml only and using xsl to define the layout. xsl combines with css to completely abstract the display away from the data.
HTML divides your page in logical sections. CSS then applies a certain look/feel/style to those sections.
If you want to change your page layout to include a section inside another one, you have no choice but to modify your HTML because HTML has a role on page layout.
You can actually move blocks around using nothing but CSS. The compromise always boils down to how good your CSS skills are and how much compatibility with older browsers you're after or care about. There are limits to what CSS can do, so yes, HTML definitely still has a role to play.
it is possible to change the "source order" of divs or use css to change positions. But if its more practical to just change the html, then there's no other way round it. At the end of the day, if its more important content then the source should reflect it for semantic reasons.
It does on two levels:
Firstly, the order of elements is still important. CSS floats are used a lot for layout but they also require elements to be in a certain order to get things in the right place. For example, lets say you have two buttons:
<input type="button" value="Click Me">
<input type="button" value="No, Click Me!">
These are next to each other. Lets say someone asks you to move the second button to the far right. This is how you do it:
<input type="button" value="No, Click Me!" style="float: right">
<input type="button" value="Click Me">
If you don't do this, the second (floated) button will appear below the other.
The second way HTML is still important is that there are still things that you need HTML tables for that can't be done in pure CSS at all, in a browser-compatible way (meaning IE6 support generally) or easily. This isn't something the pure CSS zealots like to hear but, like it or not, in the real world it's still true.
This is especially true with HTML emails. If you thought browser support for CSS was bad, mail program support is so much worse. Generally speaking you avoid CSS altogether with HTML emails and just pretend like its still 1999.