Vertical Tabs Reloaded - Stylish - A way to modify the style

stylish.css

@import "resource://verticaltabsreloaded-at-go-dev-dot-de/data/template/basic/index.css"
@import "moz-extension://27c4f706-2646-481e-8da6-ce6af1eab0c9/data/template/basic/index.css";
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

/* Note: This is likely stop working with Firefox v57,
but I'm working on build-in customization, see https://github.com/Croydon/vertical-tabs-reloaded/issues/40 */

/* Another note: Use !important to overwrite the existing vars for sure;
also users should have set the Dark or Light theme in their VTR settings */

:root {
	/* Tabbrowser */
	--vtr-tabbrowser-background-color: purple !important;
	
	/* Tabbar, only used if no Firefox Theme installed */
	--vtr-tabbar-height: 48px;
	--vtr-tabbar-background-color: #f1f1f1; 
	
	/* Single tab */
	--vtr-tab-text-color: #fbfbfb;
	--vtr-tab-background: red !important;
	--vtr-tab-height: 28px; 
	--vtr-tab-min-height: 28px; 
	--vtr-tab-max-height: 28px; 
	--vtr-tab-border: 80px;
	--vtr-tab-border-radius: 0;
	--vtr-tab-border-left: 4px solid transparent;
	--vtr-tab-border-bottom: 1px solid #5E6972;
	
	/* Single tab selected */
	--vtr-tab-selected-text-color: #2296BD;
	--vtr-tab-selected-background: #2296BD;
	--vtr-tab-selected-font-weight: 600;
	--vtr-tab-selected-text-shadow: none;
	--vtr-tab-selected-border-left: 4px solid #ff9500;
	--vtr-tab-selected-border-radius: 0;
	
	/* Single tab pinned */
	--vtr-tab-pinned-text-color: #fbfbfb;
	--vtr-tab-pinned-background: #343F48;
	--vtr-tab-pinned-font-weight: 600;
	--vtr-tab-pinned-text-shadow: none;
	--vtr-tab-pinned-border-left: 4px solid #2292D0;
	--vtr-tab-pinned-border-radius: 0;	
	
	/* Single tab hover */
	--vtr-tab-hover-background: #5E6972;
	
	/* Splitter/Separation between tabbar and website */
	--vtr-splitter-background: red;
	--vtr-splitter-width: 3px;
	--vtr-splitter-border-left-size: 0;
	--vtr-splitter-border-left-color: red; 
	--vtr-splitter-border-right-size: 0;
	--vtr-splitter-border-right-color: red; 
}