Theme development

I have been trying to make changes in the theme which my developers made for me.
Here is the source code of the page I have been trying to change : http://pastebin.com/h5V1967r
In the HTML.tpl.php file I changed the manual links to print $styles , added the main style sheets in the .info file of the theme too.
Now here is the new source code of the page : http://pastebin.com/6E7yVJBH

Hello all,

I'm working on a site where I want to include a really easy to use dashboard for managing articles. My goal is to create a view of nodes in a grid layout. So to have all the articles listed in a table with links and info - almost exactly like the one you find in admin/content.

I use Gallery style to display artwork uploaded by users in my website. The total numbers of items to display in one page can be defined in "Items per page" in views. However, this seems awkward, because users might use different devices to browse the site, from smartphone, iPad, to wide screen... so the numbers of items in one row could vary from two to six. Although I have tried to use a number that is divisible by as many numbers as possible, such as 12, or 24, there still cases that the last row could not be fully filled (e.g.

I just installed a new theme and then I selected the set theme as default.
But I can't access my website anymore. It shows a fatal error message. How can I fix this?
Thanks!!!

I use gallery style to create views to display image and some other attributes, such as title and author, of an artwork node in my website. The views display fine in Firefox and IE. But in Chrome, the additional fields (title, author etc) are overlapped by the image of the next row, like this. Does anyone know how to fix it?

Hi,
I am developing my theme and using a menu_tree on 3 levels.
As I want to be able to choose a different color for each menu option, i would like to use the menu id as part of the CSS class name.
I found an easy way to do that, i added the line
$class[] = $data['link']['mlid'];
in the function menu_tree_output of the file \includes\menu.inc

I know I am not supposed to do that, so I created instead a function named mythemename_menu_tree_output in my template.php file but it doesn't work.