Make the webpage content larger: Choose View > Zoom In, press Command (⌘)–Plus Sign (+), or pinch open on your trackpad. To make only text larger, choose View > Zoom Text Only before you zoom in.
Set a minimum font size for webpages: Choose Safari > Preferences, click Advanced, then select “Never use font sizes smaller than.” Click the pop-up menu and choose the minimum font size you want.
Expand to full-screen view: Click the green full-screen button 
in the top-left corner of the browser window, or press Control-Command (⌘)-F. To return to standard view, move the pointer to the top-left corner of the screen, then click the green full-screen button again, or press Control-Command (⌘)-F.