/* Set font size and family for dialogs
 * and other miscellaneous text
 */
window {
  font-size: 3.5mm !important;
  font-family: helvetica !important;
}

/* Place the sidebar on the right edge of the window
   Side effect: also moves the mail folder to the right side 
(Bug 226926)

 */
window > hbox {
  direction:rtl;
}
window > hbox > * {
  direction:ltr;
}

/* PERSONAL TOOLBAR */
/*
 * Note: Rules affecting icons on the PT do not apply to folder contents.
 * Those are governed by "Bookmarks menu" rules.
 */

/* Kill bookmark icons in the Personal Toolbar */
toolbarbutton.bookmark-item > .toolbarbutton-icon {
  display: none;
}

/* Alternatives: */
/* Select only bookmark folder icons */
/*
.bookmark-item[type="menu"] > .toolbarbutton-icon {
  do something...
}
 */

/* Select only tab group icons */
/*
.bookmark-item.bookmark-group > .toolbarbutton-icon {
  do something...
}
 */

/* Example: only kill icons on normal bookmarks */
/*
.bookmark-item:not(.bookmark-group):not([type="menu"]) > .toolbarbutton-icon {
  display: none;
}
 */

/* Visual aids for no-icons operation */

/* Make tab group bookmarks italic and brown */
.bookmark-group > .toolbarbutton-text {
   font-style: italic;
   color: brown;
}

/* Make bookmark folders bold and navy blue */
.bookmark-item[type="menu"] > .toolbarbutton-text {
   font-weight: 900;
   color: navy;
}

/* BOOKMARKS MENU */

/* Kill "normal" bookmark icons in the bookmarks menu */
menuitem.bookmark-item > .menu-iconic-left {
  display: none;
}

/* Other examples: */

/* kill icons for bookmark folders in Bookmarks menu */
menu.bookmark-item > .menu-iconic-left {
  display: none;
}

/* kill icons for bookmark groups in Bookmarks menu */
menuitem.bookmark-group > .menu-iconic-left {
  display: none;
}

/* Style the now-iconless bookmark menu items (mimicking the PT styles) */
/* bookmark folders */
menu.bookmark-item {
  color: navy !important;
  font-weight: 900 !important;
}

/* tab group bookmarks */
menuitem.bookmark-group {
   color: brown !important;
   font-style: italic !important;
}

/* You could select normal bookmarks this way */
/*
menuitem.bookmark-item {
  do something...
}
*/

/* TABBROWSER TABS */

/* Kill tabbrowser icons */
/* Note: this leaves some empty vertical space in the tab strip in some themes */

/* Kill all tab icons, no matter what */
/*
.tabbrowser-tabs .tab-icon {
  display: none;
}
 */

/* Alternatively, kill only default tabbrowser icons (no site icon) */
.tabbrowser-tabs *|tab:not([image]) .tab-icon {
  display: none;
}

/* Show icons (no matter what) when hovering over the tab */
/*
.tabbrowser-tabs *|tab:hover .tab-icon {
  display: -moz-box;
}
 */

/* Show tab loading indicator while the tab is loading */
/*
.tabbrowser-tabs *|tab[busy] .tab-icon {
  display:-moz-box;
}
*/

/* Shrink tab titles by 10% */
.tabbrowser-tabs .tab-text {
  font-size: 90%;
}

/* Turn off the great big icons on editor/mail toolbars (bugs 78843/94581) */
.toolbar-primary-icon {
    visibility: collapse;
}

/* Make menus big, pretty and readable (like the old SGI look):
 * menubar isn't used after 12/19 builds, but is needed for NS6;
 * the rest are for post-12/19
 */
menubar, menubutton, menulist, menu, menuitem {
  font-family: helvetica !important;
  font-style: italic !important;
  font-weight: bold !important;
  font-size: 4mm !important;
}

/* Next two don't work as either "slider" or "scrollbar".
 * Apparently scrollbar size is controlled by images
 * used for the up/down/left/right arrows.
slider {
   height: 20px !important;
}
slider[align="vertical"] {
   width: 20px !important;
}
*/

/* Single line text fields */
input {
  /* Set font size and family of text fields */
  font-family: clean !important;
  font-size: 13px !important;

  /* Set background color to something a little prettier */
  background-color: rgb(200, 255, 220) !important;

  /* Add some key bindings.
   * For an explanation of how to do this,
   * see below under "Custom key bindings".
   */
  -moz-binding: url("resource:///res/builtin/myHTMLBindings.xml#myInputFields") !important;
}

/* Multi-line textareas */
textarea {
  background-color: rgb(200, 255, 220) !important;
}

/* The  dropdown address and autocomplete windows are grey.
 * To make them match better with the URL field and look more like 4.x:
 */

/*  URL dropdown box  */
#ubhist-popup
  {
    background            : white !important;
    border                : 1px solid black !important;
    padding               : 0px !important;            
  }

/*  autocomplete text field  */
.textfield-popup
  {
    background            : white !important;
    border                : 1px solid black !important;
  }

#ubhist-popup > .popup-internal-box, .textfield-popup > .popup-internal-box
  {
    border-left           : 1px solid white !important;
    border-top            : 1px solid white !important;
    border-right          : 1px solid white !important;
    border-bottom         : 1px solid white !important;
  }

/* 3. Add a border (line of 1px) to the tooltips. */
.tooltip-label
   {
     border                : 1px solid !important;
   }

/* MAIL
 *
 * For other things you can change in mail windows,
 * see the files in the source tree under themes/modern/messenger
 */

/* Specify the font used for the subject in the message pane
 * (it was bold, fixed-width and too wide).
 */
.subjectvalue {
  font-family; helvetica !important;
  font-weight: normal !important;
}

/* Make the thread and folder panes readable. */
treechildren {
  font-size: 14px !important;
}

/* Change the background colour of the messages (top right hand
 * pane in 3-pane view) of Mail/News from gray to white.
 */
outliner {
     background-color : white !important;
}
userContent.css
Here are some samples of things you can change via userContent.css:

/* Obviate need to zoom on many sites. */
html>body {
  font-size: 100% !important;
  line-height: normal !important;
}

/*
 * Disable the deprecated HTML <font> tag. (Like above,
 * reduces need to zoom.)
 */
font {
  font-family: inherit !important;
  font-size: inherit !important;
  color: inherit !important;
}

/* Put a thin black border around all dropdown forms like NS4.x */
:-moz-dropdown-list {
  border: 1px solid black !important;
  border-top-style: solid !important;
}

/* Disable marquee display */
marquee {
  -moz-binding: none; display: block; height: auto !important;
  /* This is better than just display:none !important;
   * because you can still see the text in the marquee,
   * but without scrolling.
   */
}

/*
 * Until bug 105547 is fixed, a helpful workaround to
 * highlight some links which would pop up a new window:
 */
:link:hover[target="_blank"],:visited:hover[target="_blank"] {
  color: white !important; background: red !important;
}
:link:hover[target="_new"],:visited:hover[target="_new"] {
  color: white !important; background: red !important;
}

/*
 * Many input forms have typing areas so small it's hard to use
 * them. On many of them, this sets a minimum width of about 50
 * characters, and a miniumum height of about 12 characters.
 */
textarea {
  min-width: 50ex !important;
  min-height: 12em !important;
}

/* Improve scroll performance on slow machines on some sites. */
* {
  background-attachment: scroll !important;
}

/*
 * Ignore user-specified style in mail messages.
 * See http://bugzilla.mozilla.org/show_bug.cgi?id=18427 for details.
 */
.moz-text-html font, .moz-text-html div, .moz-text-html body {
  font-size: inherit !important;
  font-family: inherit !important;
  color: inherit !important;
  background-color: inherit !important;
  background-image: inherit !important;
  text-align: inherit !important;
  text-indent: inherit !important;
}

/*
 * These are for chatzilla:
 */

/* defaults for anything in the chatzilla content area */
.output-window {
    background: #555 !important;
    color: white !important;
    font-weight: bold !important;

    /* for testing CSS syntax:
    border-style: solid;
    border-width: thick;
    border-color: #0f0 !important;
     */
}

/* messages I type */
.msg[msg-user$="ME!"] .msg-data {
    color: orange !important;
    background: #555 !important;
}

/* every other message can have a different color,
 * to make it easier to follow conversations
 */
.msg[mark="odd"] .msg-data {
    color: white !important;
    background: #666 !important;
}

/* messages directed to me */
.msg[important] .msg-data {
    color: yellow !important;
    /* background: gray !important; */
}

/* messages when people leave the channel */
.msg[msg-type="QUIT"] .msg-data {
    background: #444 !important;
    color: yellow !important;
}

BODY {
PADDING-RIGHT: 0px; 
PADDING-LEFT: 0px; 
FONT-SIZE: 12px; 
BACKGROUND: #b6b8b1;
PADDING-BOTTOM: 0px;
MARGIN: 0px;
COLOR: #111;
LINE-HEIGHT: 145%;
PADDING-TOP: 0px;
FONT-FAMILY: arial,'trebuchet ms',helvetica,sans-serif;
TEXT-ALIGN: center
} 


#wrap1 {
BACKGROUND: url(/community/graphics/users/2/wrap1.gif) #acaea7 repeat-y left top;
MARGIN: 0px auto;
max-width: 882px
}

#wrap2 {
BACKGROUND: url(/community/graphics/users/2/wrap2.gif) repeat-y right top
}

#topbar {
BACKGROUND: #fff;
MARGIN: 0px -10px;
OVERFLOW: hidden;
LINE-HEIGHT: 23px;
HEIGHT: 28px;
max-width: 852px
}

#content {
CLEAR: both;
BACKGROUND: #fff;
MARGIN: 0px auto;
POSITION: relative;
TEXT-ALIGN: left;
max-width: 812px;
min-width: 739px
}

#footer {
CLEAR: both;
BACKGROUND: #fff;
MARGIN: 0px auto;
POSITION: relative;
TEXT-ALIGN: left;
max-width: 812px;
min-width: 739px
}