// ==UserScript==
// @name           Design css
// @namespace       
// @include        http://www.example.com/*
// ==/UserScript==

var css = "@import url(http://localhost/your_css);"; 

if (typeof GM_addStyle != "undefined") {
	GM_addStyle(css);
} else if (typeof addStyle != "undefined") {
	addStyle(css);
} else {
	var heads = document.getElementsByTagName("head");
	if (heads.length > 0) {
		var node = document.createElement("style");
		node.type = "text/css";
		node.innerHTML = css;
		heads[0].appendChild(node); 
	}
}

greaseMonkey - Ajouter votre css personnelle sur vos pages - Add your owner css in your html's code

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