Different version of theme on Mobile-platform

The theme looks as expected on desktop and tablet, but does not work on phone (ios): it looks as if another theme is operating… perhaps a “mobile-friendly” version?

It’s quite important the theme works on mobile (i anticipate this is how most people will view the Site).

I’m sure the theme worked on mobile when i first started working with it (about 2 months ago). I stopped looking at it on the phone and checked it on a tablet when it was being customised. Is it something in the css?

/* Hide Author*/

.entry-meta .byline {
  display: none;
}

/* TITLE VISIBLE on SCROLL and  WHite-Space mnipulation*/

.site-header {
	  
    position: fixed;
    top: 0;
    opacity: 1;
    z-index: 1;
    background-color: #FFFDFD;
    padding-bottom: 15px;
    
}

.site-branding {
margin-top: 25px;
}

.entry-header {
    padding-top: 50px;
}

/* Site Title Color */

.site-title a {
    color: #606666;
    opacity: 0.5;
}

/* Site Title Hover Color */

.site-title a:hover {
    color: #606666;
    opacity: 1;
    transition: .2s opacity ease-in-out;
}

/* Blog Page Post Title Hover Color */

.blog .entry-title a:hover {
    color: #606666;
    opacity: 1;
    transition: .2s opacity ease-in-out;
}

/* Blog Page Post Title Color */

.blog .entry-title a {
    color: #606666;
    opacity: 0.5;
}

/* HIDE MENU TOGGLE*/

.menu-toggle {
    display: none;
}

/* CENTER SITE-TITLE */

.site-branding {
    width: 100%;
    text-align: center;
		

}