Creating ASP.NET Websites using CSS and Master Pages

I have some comments over the "Formatting Choices: HTML styles, Themes / Skins and CSS" and the four reasons against them.

You say: "Skins override CSS"

This is true, but not accurate. Any 'Appearance' property you set on a server control (not necessarily through the skin) is rendered in HTML as an inline style attribute, so if you set the ForeColor="Red" on a Label and you also have a CSS class for that same element saying you want it blue, you know by CSS specificity rules that any inline rule will win. So it is not the Skin to blame, but rather the way style properties are written into HTML.

Besides, the Skin overriding 'Appearance' properties on Controls actually depend on the way you apply the skin to the Page. There are two ways, one is setting the Theme through the  "theme" property, and the other through the "stylesheettheme" property. These you can set at the <%@ Page%> directive, or at the web.config  in the <pages> section. The "theme" way overrides any "appearance" property you set directly on a control, while the "stylesheettheme" way allows the theme to work as CSS cascade, where setting ForeColor directly on the control, overrides the ForeColor set on Theme.

I agree that setting "Appearance" properties through a Skin is not really a very good idea, because of repeated styles attributes all over your HTML, and because you can't override easily those inline properties, BUT... I think skins can be useful to set some "NonAppearence" general properties to SERVER controls and centralize those properties for easy changing them.

Take all <asp:Validators> for instance. They all have a Text property that define what mark to show when validation fails, if you set it through a Skin, not only your ASPX file will get rid of those properties, but you can easily change them from "*" to a "!" in a single place.

I also use skins to set CssClasses I want some controls to have by default. I usually have a class for rows and alternate rows in GridViews, so I place those CssClass in a GridView definition in the Skin and I can forget about them:

<asp:GridView runat="server" CssClass="tabularData" GridLines="None">
    <HeaderStyle CssClass="headerRow" />
    <RowStyle CssClass="row" />
    <AlternatingRowStyle CssClass="altRow" />
    <SelectedRowStyle CssClass="selRow" />
    <PagerStyle CssClass="pagerRow" />
    <EditRowStyle CssClass="editRow" />
    <FooterStyle CssClass="footerRow" />
    <EmptyDataRowStyle CssClass="emptyRow" />
</asp:GridView>

And if I apply my skin the "stylesheettheme" way I can alway re-declare 
the CssClass on a particular GridView to overwrite it.

I don't believe Skins are so evil to stop using them, I think it's better
to use them where CSS alone can't help you centralize the appearance.