Follow these steps to create a Theme:

• Open Microsoft PowerPoint 2010.
• Go to Design Tab.
• Click the drop down arrow in colors.
• Click on "Create New Theme Colors".

•  Choose the Theme colors as per your requirement.
• · Enter the Name and click on Save.

• Go to File =>Save As type. 
• Enter File Name as MyTheme. 
• Choose Office Theme in Save As Type.
• Click on Save.

• Open the SharePoint Site.
• Go to Site Actions =>Site Settings => Galleries => Themes.

·         Click Add new item and browse your theme and add the theme file that we have created.

After adding a theme you have to apply it in the SharePoint Server:

·         Go to Site Actions => Site Settings => Look and Feel => Site Theme.

·         Select the theme which we have created and Click on Apply to apply the theme in the SharePoint Server.

The sites look like the following:

Now you have to apply the theme programmatically in the SharePoint Site:

1)    Open Visual Studio and create a Console Application.

Write the below code in the Program.cs file:

using System;

using System.Text;

using Microsoft.SharePoint;

using Microsoft.SharePoint.Utilities;

using System.Collections.ObjectModel;

 

namespace ApplyThemeinSharePoint

{

    class Program

    {

        static void Main(string[] args)

        {

            using (SPSite objSite = new SPSite("http://rohit:34143/"))

            {

                using (SPWeb objWeb = objSite.OpenWeb())

                {

                    ReadOnlyCollection<ThmxTheme> objThemeList;

                    objThemeList = ThmxTheme.GetManagedThemes(objSite);

                    foreach(ThmxTheme objThmx in objThemeList)

                    {

                        if (objThmx.Name == "Berry")

                        {

                            ThmxTheme.SetThemeUrlForWeb(objWeb, 

                                                        objThmx.ServerRelativeUrl);

                            break;

                        }

                    }

                }

            }

            Console.WriteLine("Berry Theme applied in the SharePoint Site");

        }

    }

}

  Output:

Now you can see in your SharePoint site Berry Theme is applied. Now the site looks like the following:

Thanks for reading this article. After reading this article you can easily create the theme with help of PowerPoint and can also apply the theme in the SharePoint site.