How to use StyleSheet?

Step 1. Right-click on Solution Explorer - Add New Item - Add StyleSheet.css.

Step 2. In the body class of StyleSheet.css just give the property which has to be set for any page in the project.

Source code: StyleSheet.css

body {
    background-color: Silver;
}

Step 3. Drag and drop StyleSheet.css from Solution Explorer.

Solution Explorer

Step 4. Write the classes defining the style that has to be applied.

Example. textbox background color has to be the same in all the pages so we define a class .txtbox with the background color.

Source code: StyleSheet.css

body {
    background-color: Silver;
}

.txtbox {
    width: 20;
    height: 10;
    background-color: Aqua;
}

.Dropdownlist {
    width: auto;
    background-color: Lime;
}

Step 5. Drag a textbox and give a textbox class as a CSS class in the property.

CSS Class

Source code: Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>  
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head runat="server">  
    <title>Untitled Page</title>  
    <link href="StyleSheet.css" rel="stylesheet" type="text/css" />  
</head>  
<body>  
    <form id="form1" runat="server">  
        <div>  
            <!-- Content can be added here -->  
        </div>  
        <br />  
        <br />  
        <asp:TextBox ID="TextBox1" runat="server" CssClass="txtbox"></asp:TextBox>  
    </form>  
</body>  
</html>

Step 6. Add a new form and the same StyleSheet.css can be used for any textbox placed in the project.