Update index page (ezsystems#34)

Be more precise on what are the U.I. guidelines and where we are in their development.

ui-guidelines/index.html

@@ -56,10 +56,11 @@ <h2>UI Guidelines</h2>
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-						<h1>eZ System's User Interface Guidelines</h1>
-						<p class="header top-low">This is a resource for designers, product managers, and developers, providing a unified language. We use it to simplify the way people interact with content, offering a consistent interface across our CMS.</p>
+						<h1>eZ Platform's User Interface Guidelines</h1>
+						<p class="header top-low">This is a resource for designers, product managers, and developers, providing a unified language to build and customize eZ Platform admin user interface (aka Platform UI). We use it to simplify how we can build and offer a consistent interface across our content management platform.</p>
 						<p class="header top-low">eZ’s UI Guidelines provides a simplified and recognizable experience; increases our productivity, enabling us to evolve faster; and it allows us to develop collectively.</p>
-						<p class="header top-low bottom-half-extra">This is an open source project, you can directly impact its evolution by filling issues and submitting pull requests. This is as much your tool as it is ours, and we look forward to collaborating with developers and partners on making it even better.</p>
+						<p class="header top-low bottom-half-extra">This is an open source project, you can directly contribute to it by filling issues and submitting pull requests. This is as much your tool as it is ours, and we look forward to collaborating with developers and partners on making it even better.</p>
+						<p class="header top-low bottom-half-extra">Note: this is a work in progress, is only very partially used on eZ Platform version 1.x. Our goal is to embrace those guidelines as we will build eZ Platform version 2.x.</p>
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