To check that you have specified the correct style sheet:
Choose Safari > Preferences.
Click Advanced and check the Style Sheet section. For information about the options, click the Help (question mark) button.
Safari uses the Cascading Style Sheet (CSS) you specify in addition to any style sheets specified by the page. A style sheet specified by the page may override your style sheet.
Choose Safari > Preferences.
Click Advanced and check the Style Sheet section. For information about the options, click the Help (question mark) button.