VistaStyleBuilder

Some userChrome.css stuff I'm using on Firefox 131. Change colors to what you want.

/*Hide List All Tabs Button*/

#alltabs-button { display: none !important; }

/* hide tab bar if only one tab */
  #tabbrowser-tabs .tabbrowser-tab:only-of-type,
tab[first-visible-tab=true][last-visible-tab=true],
tab[first-visible-tab=true][last-visible-tab=true] + #tabbrowser-arrowscrollbox-periphery {
  visibility: collapse !important; }
#tabbrowser-tabs,
#tabbrowser-arrowscrollbox {
  min-height: 0 !important; }

/*Background Color of bookmarks bar*/
#PersonalToolbar {background-color: #ffffff !important;}

/* Hover background bookmarks bar*/
.bookmark-item:hover {
  background-color: #ced88b !important; }
 

#forward-button:hover {
  background-color: #bfcb6b !important; }

#back-button:hover {
  background-color: #bfcb6b !important; }


/*default colors for some right click context menus*/
menupopup {
  --panel-background: white !important;
  --panel-color: black !important;
}

/*default colors for some other right click context menu panels*/
panelview {
  --arrowpanel-background: white !important;
  color: black !important;
}

/*library toolbar and 3-bar menu right click context menu panel colors*/
#appMenu-libraryView, /*Library toolbar button*/
#appMenu-protonMainView {  /* 3-bar menu button */
  --arrowpanel-background: white !important;
  color: black !important;
}

/* This changes the color when hovering over items of some right click context menus */
menubar > menu[_moz-menuactive="true"],
menupopup > menu[_moz-menuactive="true"],
popup > menu[_moz-menuactive="true"],
menuitem[_moz-menuactive="true"]
{background-color: red !important; color: white !important}


/* Hover Background URLbar Buttons (Page Actions etc) */
.urlbar-icon:not([disabled]):hover,
.urlbar-icon-wrapper:not([disabled]):hover {
   background-color: #ced88b !important;
}
.urlbar-icon[open],
.urlbar-icon-wrapper[open],
.urlbar-icon:not([disabled]):hover:active,
.urlbar-icon-wrapper:hover:active {
   background-color: #ced88b !important;
}
.urlbar-icon-wrapper[open] > .urlbar-icon,
.urlbar-icon-wrapper > .urlbar-icon:hover,
.urlbar-icon-wrapper > .urlbar-icon:hover:active {
   background-color: #ced88b !important;  }


/* Background Color of First Tabs opened*/
#tabbrowser-tabs .tabbrowser-tab:hover:not([selected]) .tab-content {
background: linear-gradient(to bottom,#bfcb6b,#f2f2f2) !important; }

/* line on top of new tab color*/
.tab-line[selected="true"] {
    background-color: #bfcb6b !important;
}


/* Color of Dots on the left loading tabs animation*/
.tab-throbber::before {
fill: #bfcb6b !important;
opacity: 1 !important;
}

/* Color of background flash loading tabs animation*/
.tab-loading-burst[bursting]::before {
    fill: #bfcb6b !important;
}


.tab-close-button:hover{ background: #ced88b !important; }


/*More History URL Popup menu text and hover and selected background colors*/
  
#PopupAutoCompleteRichResult .autocomplete-richlistitem:not([selected=true]) {
    color: black !important;
}
#PopupAutoCompleteRichResult .autocomplete-richlistitem[selected=true] {
    color: black !important;
    background-color: #bfcb6b !important;
}

#PopupAutoCompleteRichResult .autocomplete-richlistitem:hover {
    color: black !important;
    background-color: #bfcb6b !important;}
#PopupAutoCompleteRichResult .search-one-offs:hover {
   color: black !important;
background-color: #bfcb6b !important;
}

/*hover color of url bar https links box*/

#identity-box:hover {
    background-color: #ced88b !important;}

/*** Tighten up drop-down/context/popup menu spacing ***/

menupopup > menuitem, menupopup > menu {
  padding-block: 4px !important;
}
:root {
  --arrowpanel-menuitem-padding: 4px 8px !important;}


/*url bar background color & border color and width*/

#urlbar-background{ border-color: #6bcbbf !important;
background-color: #ffffff !important;
border-width: 1px !important;}

/* Hide star button (bookmark) */

#star-button{
display:none;
}

/*Color of Icons when filling like Download Button circle etc.*/

:root {
    --lwt-toolbarbutton-icon-fill-attention: #6bcbbf !important;
}

/*Hover and Selected NavBar Toolbar Icons background color*/

.toolbarbutton-1 {
  --toolbarbutton-hover-background: transparent !important;
  --toolbarbutton-active-background: transparent !important;
   border: none !important;
   border-radius: 0px !important;
}

.toolbarbutton-1:hover {
    fill: #ffffff !important;
   fill-opacity: 1.0 !important;}

/*Prevents shadow around clicked URL Bar*/


#urlbar[breakout][breakout-extend], #urlbar-background,
#urlbar[breakout][breakout-extend] > #urlbar-input-container,
#urlbar[breakout] > #urlbar-input-container
{
   border: none !important;
   box-shadow: none !important;
}

/*Active tab background color and no border or shadow*/

.tab-background[selected="true"] {
    background-color: #ffffff !important;
    background-image: none !important;
    border: none !important;
    box-shadow: none !important;
  }

/*Remove gray backdrop from Clear History*/
#window-modal-dialog::backdrop {
  background-color: transparent !important;
}

/*Checkbox with transparent background, red checkmark & border*/
.checkbox-check{
  background-color: transparent !important;
  fill: red !important;
  border-color: #bf0000 !important;}
.checkbox-check[checked]{ border-color: #bf0000 !important }

/*Button with red border, black text when inactive & red background with white text when active*/
button {background-color: transparent !important;
color: #000000 !important;  box-shadow: 0 0 0 1px #bf0000 !important}

button:focus {background-color: #bf0000 !important;color: #ffffff !important; }

button:hover {background-color: #bf0000 !important;color: #ffffff !important; }

button:active {background-color: #bf0000 !important;color: #ffffff !important; }

/*Removes blue border, blue text highlight and shadow from focused URL Bar*/

#urlbar > #urlbar-background,
#urlbar[breakout][breakout-extend] > #urlbar-background,
#searchbar {
    border: 0px solid #ffffff !important;
    outline: none !important;
    border-radius: 0px !important;
    box-shadow: 0px !important;
}
#urlbar[breakout][breakout-extend] #urlbar-background {
    border-color: #ffffff !important;
}
#urlbar[breakout][breakout-extend], #urlbar-background,
#urlbar[breakout][breakout-extend] > #urlbar-input-container,
#urlbar[breakout] > #urlbar-input-container
{
   border: none !important;
   box-shadow: none !important;
}
#urlbar ::-moz-selection,
.searchbar-textbox ::-moz-selection {
background-color: #d9d9d9 !important;
color: black !important;}

/*Removes shadow from active tab and hover color from inactive tabs*/
.tab-background[selected]{ background: #f0f0f4 !important; box-shadow: none !important }
:root
.tab-background:not([selected]){
background-color: #f0f0f4 !important;}

/*Color of Tab bar*/
#TabsToolbar{ background-color: #ffffff !important; }

/*Hide Unified Extensions Button*/

#unified-extensions-button, #unified-extensions-button > .toolbarbutton-icon{
width: 0px !important;
padding: 0px !important;
}