// here we are attemping to fool the browser and harness the power of GPU usage // using "transform: translate3d(0, 0, 0);" will use the Graphic Processor (GPU) and avoid the CSS transition using CPU... @include media-breakpoint-up(xl) { .page-sidebar { @include translate3d(0,0,0); } &.header-function-fixed, &.nav-function-fixed, &.header-function-fixed.nav-function-fixed { .page-wrapper, .page-sidebar { transform: none; -webkit-transform: none; -ms-transform: none; } } }