Questions and answers on how to customize the default look of Foswiki for your own needs, using style sheets. For configuring page elements, see 
PatternSkinCustomization.
  First Read: How to modify PatternSkin styles 
PatternSkin uses 3 style sheets (attached to 
PatternSkinTheme): 
-  layout.css - the positioning of main page elements (blocks), widths and heights
-  style.css - fonts, sizes, margins and paddings
-  colors.css - border colors, text colors and background colors
When customizing your Foswiki installation, you can either choose to completely rewrite all css styles, or to selectively override some styles. The latter option is by far less time consuming, but all depends on your graphical wishes.
  When you need lots of graphic changes: Rewriting CSS 
  
   * Set FOSWIKI_LAYOUT_URL = %PUBURLPATH%/%SYSTEMWEB%/YourNewTopic/layout.css
   * Set FOSWIKI_STYLE_URL = %PUBURLPATH%/%SYSTEMWEB%/YourNewTopic/style.css
   * Set FOSWIKI_COLORS_URL = %PUBURLPATH%/%SYSTEMWEB%/YourNewTopic/colors.css
  When you need to make small adjustments: Adding to existing CSS 
With CSS you cannot remove already defined classes, you can only add to it, or override existing styles. 
Overriding default CSS is done with 3 
preference settings: 
USERLAYOUTURL, 
USERSTYLEURL, 
USERCOLORSURL. 
-  Create a new topic that will contain your new CSS files
-  Attach 1, 2 or 3 new style sheets to the topic, dependent on your CSS setup (if you don't change much, you might as well put everything in one CSS file, layout, margins and colors)
-  Point the CSS preference settings in DefaultPreferences or SitePreferences to your new files (below the USERXXXURLpreferences):
   * Set USERLAYOUTURL = %PUBURLPATH%/%SYSTEMWEB%/YourNewTopic/layout.css
   * Set USERSTYLEURL = %PUBURLPATH%/%SYSTEMWEB%/YourNewTopic/style.css
   * Set USERCOLORSURL = %PUBURLPATH%/%SYSTEMWEB%/YourNewTopic/colors.css
 
-  If you use only little CSS and you've only attached one file, write:
   * Set USERSTYLEURL = %PUBURLPATH%/%SYSTEMWEB%/YourNewTopic/style.css
Instead of setting these preferences in 
DefaultPreferences or 
SitePreferences, you can set these in your home topic, or in any other topic. Setting style URL preferences in: 
-  DefaultPreferences or SitePreferences: the style is visible for all users, site-wide
-  WebPreferences: the style is visible for all users in one web
-  Home topic: the style is visible for that one user when viewing the site
-  Some other topic: the style is only visible in that one topic
User styles are always loaded after Foswiki styles.
The rest of this topic shows examples of small CSS changes.
  Recipes 
  Hide the left bar 
See example at: 
PatternSkinCssCookbookNoLeftBar
  Toggle the left bar on small screen 
See example at: 
PatternSkinCssCookbookSidebarToggle
  Use different fonts 
See example at: 
PatternSkinCssCookbookFonts
  I want to change the height of the top bar 
This is the complete style definition to set the height of the top bar:
#patternTopBar,
#patternTopBarContents {
   height:75px; /* top bar height; make room for header columns */
   overflow:hidden;
}
Change the number from 75px to your value.
 
-  Create a new stylesheet (preferably a 'theme variant' file (see for instance https://mia.phsz.ch/pub/System/PatternSkinTheme/variant_foswiki_noframe.css with above definition in it)
-  Attach the file to a topic
-  Set the value of macro PATTERNSKIN_THEME_VARIANTto that topic attachment url using%PUBURL%/YourWebName/YourTopicName/your_theme_variant_file.css
Note: If using %WEBHEADERART% to customize the top bar, some 
#patternTopBarContents CSS is expanded inline from 
templates/css.pattern.tmpl. Override of some attributes, such as background color and repeat are not possible from the CSS files.
  No top bar 
See example
  Centered page 
See example
  Centered page (with a border around the page) 
See example
See example
  Setting EditTablePlugin styles 
See example
See example
  Style sheet documentation