Component Identification: Identify the components in your email template, such as headers, footers, buttons, and content blocks. Create Modules: Write separate CSS files for each component. For example, create a file for the header styles, another for the footer, and so on. Import CSS: Use the @import rule to import these CSS modules into a main stylesheet. Inline CSS: Since many email clients strip out external CSS, you may need to inline your CSS using tools like Premailer or Juice.