Background image no longer fits to screen now that project is in php files

When my project was still coded as html files, the background images of my sections of my landing page fit the screen, but since changing it to php files to upload to wordpress these sections leave blank space on either side as well as above.

This is the CSS corresponding to it

#landing-section {

    padding-top: 0;
    margin-top: 0;
    background-image: url(images/landing-section-image.jpg);
    background-size: cover;
    background-position: center;
    height: 100vh;
    background-repeat: no-repeat;
}