Orchard/src/Orchard.Web/Modules/Orchard.MultiTenancy/ResourceManifest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Orchard.UI.Resources;

namespace Orchard.MultiTenancy {
    public class ResourceManifest : IResourceManifestProvider {
        public void BuildManifests(ResourceManifestBuilder builder) {
            builder.Add().DefineStyle("MultiTenancyAdmin").SetUrl("admin.css");
        }
    }
}