i've noticed that when im trying to align a div with style sheets it doesnt align proplerly in the middle

its always to the side but when i select aligh text to middel only the content is centered

i want to do it like your site here where you have the main div align to the center

<p style="text-align:center;font-family:sans-serif;position: absolute;top: 50%;width:100%">Not Authorized</p>