vb.org Archive - Fluid header with fixed navbar and background

Hi. For few days now I'm looking for the solution of my problem with postion of my header, navbar and background. I want to make my header width for all screen, navbar stays normal like in fixed style and my background to be fixed, but when I would scroll the page down, the background would change into some color.
English is not my national language and its really hard for me to explain this for you and I'm sure its way too harder for you to understand what I have writen here as well, but at least I tried. ;)

Simple put - I want to get something like this - xboxforum.pl I'm not sure, but probably I shouldnt put here this link, but otherwise I cant explain correct what exactly I need to do with the background. So sorry in advance for that.

Sorry for my english. Any help will be greatly appreciate.

I'm using vB 4.1.7 and my style is breezefixed - https://vborg.vbsupport.ru/showthread.php?t=233455

X vBulletin 3.8.12 by vBS Debug Information
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X vBulletin 3.8.12 by vBS Debug Information

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Memory Usage 1,709KB
Queries Executed 10 (?)

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Template Usage:

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Hooks Called:

init_startup
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X vBulletin 3.8.12 by vBS Debug Information
Page Generation 0.00984 seconds Memory Usage 1,709KB Queries Executed 10 (?)
More Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (2)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
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