Use either single or double quotes consistently throughout your feature files. This makes it clear to the reader where your strings and variables are.

Bad

Feature: logging in

  Scenario: logging in
    Given I have visited the website
    When I log in with "username" and 'password'
    Then I will see my account

Good

Feature: logging in

  Scenario: logging in
    Given I have visited the website
    When I log in with "username" and "password"
    Then I will see my account