Selam :)

portfolio page is adjusted to be 5 columns in wide screens. But your columns size should always be in even numbers since you are using 2x sizes. So open js/main.js in a text editor and find line : 345-360, you will see this code lines;

var viewports = [ {
					width : 1200,
					columns : 5
				}, {
					width : 900,
					columns : 4
				}, {
					width : 500,
					columns : 3
				}, { 
					width : 320,
					columns : 2
				}, { 
					width : 0,
					columns : 2
				} ];

change it as ;

var viewports = [ {
					width : 768,
					columns : 4
				}, {
					width : 320,
					columns : 2
				}, { 
					width : 0,
					columns : 1
				} ];