have a questions about slider

I have made slider for my company's website. the reference of the code is demo-real-estate-2.
It works well with full height from the screen but I wanted to make the height 75% from the top. I dunno how to do it.
please help me out.
following is the code.

		 
			

				
					
						
							
							
						
					
				

				
					
						
							Daeyeon Corporation
							provides world class automatic machines, systems and solutions for BGMS and Test Kit Manufacturing.
								DAEYEON ENG's superior technologies contributes to productivity improvement, high quality maintenance and profit maximization.