Theme not displaying fully on mobile

My site had a problem displaying on mobile as it would load to the left side of the page leaving a small blank part down the right side on the page. Alex had me insert this code: @media only screen and (max-width: 480px:wink: {
.plain-text-container {
width: 100%;
to the Global CSS. Now the site on mobile has is only 3/4 width. Support access has already been granted. Please assist.