Columns touching, Logo overlapping mobile menu, no mouesover on mobile devices

@Juergen:
1. Your calender is in table with fixed width of 200px and it’s not responsive. So, it’ showing like that. Either you need to make that table responsive or you need to adjust the width so that your sidebar is always more than 200px width. If you want to change the width then you can add the following css in “Appearance => Customize => Theme Options => Custom CSS Options” box:

@media screen and (max-width: 1280px) {
	#content_sidebar_wrap {
	    width: 830px;
	}
	#content_sidebar_wrap #main {
	    width: 490px;
	}	
	.sidebar-secondary {
	    width: 240px;
	}	
}	
@media screen and (max-width: 1152px) {
	#content_sidebar_wrap {
	    width: 770px;
	}
	#content_sidebar_wrap #main {
	    width: 470px;
	}	
	.sidebar-secondary {
	    width: 240px;
	}	
}
@media screen and (max-width: 1100px) {
	#content_sidebar_wrap {
	    width: 690px;
	}
	#content_sidebar_wrap #main {
	    width: 430px;
	}
	.sidebar-secondary {
	    width: 240px;
	}		
}

About menu is mobile devices, have you change or customize any code in catch-base theme folder. As it works on first click and after that it doesn’t. If you have change the code then please load the original theme. So, if you haven’t change the code then please try disabling plugin one by one to check conflicting plugin. IF all this fails then let me know it.

@Jürgen: Thanks for sharing info about this plugin conflict.