Newsletter sign up with success message

This is a solution to the Newsletter sign-up form with success message challenge on Frontend Mentor. The challenge was to build out the newsletter form and get it looking as close to the design as possible.
Users should be able to:
+ Add their email and submit the form
+ See a success message with their email after successfully submitting the form
+ See form validation messages if:
+ The field is left empty
+ The email address is not formatted correctly
+ View the optimal layout for the interface depending on their device's screen size