How to make fade transition slower

Site URL: https://brm-designs.com

Hello, 

I added custom css to slow the transition of the fade on my homepage gallery, however it does not consistently work and im unsure why. It's hard to pinpoint why exactly it isnt working due to the randomness of its occurance...

here is the code i have added (found from a different forum post, not my own):

.gallery-fullscreen-slideshow-item-img {
	transition: opacity 2300ms ease-in-out !important;
	-webkit-transition: opacity 2300ms ease-in-out !important;
	-ms-transition: opacity 2300ms ease-in-out !important;
	-moz-transition: opacity 2300ms ease-in-out !important;
	-o-transition: opacity 2300ms ease-in-out !important;
}

.gallery-fullscreen-slideshow[data-transition="fade"] .gallery-fullscreen-slideshow-item[data-active="true"] .gallery-fullscreen-slideshow-item-src {
	transition: opacity 1400ms ease-in-out !important;
	-webkit-transition: opacity 1400ms ease-in-out !important;
	-ms-transition: opacity 1400ms ease-in-out !important;
	-moz-transition: opacity 1400ms ease-in-out !important;
	-o-transition: opacity 1400ms ease-in-out !important;
}

Any help would be really appreciated

password to site is BRM123