1. Create external style sheet and save it with the name portfoliostyles06 css

2. Add your name and the current date as a comment to the first line of the portfoliostyles06 css file.

3. In your HTML editor, open the files you created for your portfolio website and make sure your name and the current date are added as a comment to the first line of all files.

a. Update the HTML files to modify the link to the external style sheet to reference portfoliostyles06 css.

b. Apply a class named mobile to elements that should only be displayed on a mobile viewport, such as the telephone link.

c. Apply a class named desktop to elements that should only be displayed on a tablet or desktop viewport.

4. Update the CSS file to:

a. Create a media query for tablet and desktop viewports.

b. Create style rules for tablet and desktop viewports.

c. Hide the desktop class for the mobile layout.

d. Hide the mobile class for the desktop layout.

e. Refine your style sheet as desired.

f. Adjust viewport widths if necessary.

g. Add comments to note all changes and updates.

5. Save and test your files.

6. Validate and correct your HTML and CSS files