Browsers incompatibility : Avoiding the need to press CTRL — to adjust the font

[manganime]

I have ran into some browser compatibility issues here. The problem is that whenever I use newer versions of browsers to open the page, it works great.But when I use browsers installed on college computers, which are relatively out of date, then css overflows. But if I press \[code\]CTRL --\[/code\], then the css is back to normal. Is there a way to fix that ? I mean the user doesn't need to present \[code\]CTRL --\[/code\] !