Modify your Master Page to display the top level web description

1) Create a new Web Control

The web control shall retrieve the description from your top level site.

In your Visual Studio project, right click and choose Add > New Item... In the New Item dialogue select Module. Give the new module a name (SiteDescription) and click OK.
Remove the txt file.
Add a class (Add > Class...), give it a name (SiteDescription) and click Add.
The source code of your class will look something like this:

namespace NameSpace.SiteDescription
{
    /// <summary>
    /// SiteDescription class is used to displayes the description of the top level web.
    /// </summary>
    [ToolboxData("<{0}:SiteDescription runat=server></{0}:SiteDescription>")]
    public class SiteDescription : WebControl
    {
        private string _alt = "- default description of site";
        /// <summary>
        /// override so that the surrounding tag is a div insteadof a span
        /// </summary>
        protected override HtmlTextWriterTag TagKey
        {
            get { return HtmlTextWriterTag.Div; }
        }
        /// <summary>
        /// Add the description as an em tag
        /// </summary>
        /// <param name="writer"></param>
        [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust"
            )]
        protected override void AddAttributesToRender(HtmlTextWriter writer)
        {
            writer.RenderBeginTag(HtmlTextWriterTag.Em);
            writer.WriteEncodedText(_alt);
            writer.RenderEndTag();
        }
        private void InitiateDescription()
        {
            try
            {
                var webApp = SPContext.Current.Site.WebApplication;
                SPWeb siteToUse = SPContext.Current.Web;
                foreach (SPSite site in webApp.Sites)
                {
                    if (site.RootWeb.Title.Equals("Title")) /* your title...*/
                    {
                        siteToUse = site.RootWeb;
                        break;
                    }
                }
                if (!String.IsNullOrEmpty(siteToUse.Description))
                {
                    _alt = siteToUse.Description;
                }
              
            }
            catch (Exception e)
            {
                /*error handling*/
            }
        }
        /// <summary>
        /// Create new web control
        /// </summary>
        public BannerDescription()
        {
            InitiateDescription();
        }
    }
}

Edit the Elements.xml file of your new Web Control:

<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Control
   Id="SiteDescription"
   Sequence="24"
   ControlClass="Namespace.SiteDescription.SiteDescription"
    ControlAssembly="Namespace, Version=1.0.0.0, Culture=neutral, PublicKeyToken=xxx">
  </Control>
</Elements>

2) Use your description web control in your master page

<NameSpace:SiteDescription ID="SiteDescriptionWebControl" runat="server"/>

Visual Studio will prompt you with the right import statements.

Adding your custom styles in your SharePoint 2010 Rich Html Editor

This blog post describes how to add a custom styles in your Rich Html Editors.

The new style will appear when editing e.g. a wiki or site page in the Markup-Style dropdown:

 

 

Or in the Table-Style drop down:

 

1: Create the style
Add CSS file to managed folder /layouts/Namespace/wiki.css

Example headings (Markup-Style dropdown):

H1.ms-rteElement-MyH1
{
    /* This name will be displayed in the drop down */
    -ms-name: "My heading 1";
}
.ms-rteElement-MyH1
{
    background-color: #597087;
    color: #ffffff;
}

Example tables (Table-Style drop down) - Table with coloured header row and zebra stripes:

.ms-rteTable-10,
.ms-rteTableHeaderFirstCol-10,
.ms-rteTableHeaderLastCol-10,
.ms-rteTableHeaderOddCol-10,
.ms-rteTableHeaderEvenCol-10,
.ms-rteTableFirstCol-10,
.ms-rteTableLastCol-10,
.ms-rteTableOddCol-10,
.ms-rteTableEvenCol-10,
.ms-rteTableFooterFirstCol-10,
.ms-rteTableFooterLastCol-10,
.ms-rteTableFooterOddCol-10,
.ms-rteTableFooterEvenCol-10,
TD.ms-rteTable-10,
TH.ms-rteTable-10,
.ms-rtetablecells
{
    /* This name is displayed in the drop down */
    -ms-name:"Table Style 4 - Zebra stripes";
    border-left: none;
    border-right: none;
    text-align:left;
    line-height:2;
    vertical-align: top;
    padding:2px;
    padding-left: 5px;
}
.ms-rteTableHeaderFirstCol-10,
.ms-rteTableHeaderLastCol-10,
.ms-rteTableHeaderOddCol-10,
.ms-rteTableHeaderEvenCol-10
{
    background-color: #b5c1ce;
    color: white;
    border-top: solid #D5DCE3 1px; 
    border-bottom: solid #D5DCE3 1px;
}
.ms-rteTableFooterFirstCol-10,
.ms-rteTableFooterLastCol-10,
.ms-rteTableFooterOddCol-10,
.ms-rteTableFooterEvenCol-10
{
    font-weight: bold;
    border-top: solid #D5DCE3 2px; 
    border-bottom: solid #D5DCE3 2px;
}
.ms-rteTableFirstCol-10, 
.ms-rteTableLastCol-10
{
    font-weight: bold;
}
.ms-rteTable-10 tr.ms-rteTableOddRow-10 {
 background-color: #eee;
}
.ms-rteTable-10 tr.ms-rteTableEvenRow-10 {
 background-color: #fff;
}

2: Add Css to master page or default page layout

<SharePoint:CssRegistration ID="CssRegistrationWiki" 
   name="/_layouts/Namespace/wiki.css"  After="corev4.css" runat="server"/>3: 

It is not possible to remove any existing table or heading styles. You can change existing style or add new styles, but not delete. Also, it is not possible to change the name of an existing style.

A common thing you would like to do is change the default table style, this can be done by using "-default" instead of "-10" in the style selectors in the example above. But remember that the name of the default table style will never be changed.

There is a way to do this but it requires you to add a parameter every place the "PublishingWebControls:RichHtmlField" field is used, see this blog post at sharepoint blues.