Diaporama en arrière plan

Bonjour,
J'ai un diaporama issu d'un modèle, le problème c'est que en cliquant dessus, l'image devient fullscreen mais la têtière et le button_up reste en premier plan, ainsi que les 3 bulles d'un slider situé bien plus haut.
J'ai bien vérifier les z-index, c'est une histoire de fou !
Voici les CSS du diaporama :

.grid {
	position: relative;
	margin: 0 auto;
}

.js .grid::after {
	content: '';
	position: absolute;
	width: 100%;
	height: 100%;
	top: 0;
	left: 0;
	pointer-events: none;
	background: #252323 url(../img/loading.svg) no-repeat 50% 75px;
	background-size: 60px auto;
	-webkit-transition: opacity 0.3s;
	transition: opacity 0.3s;
}

.js .grid--loaded::after {
	opacity: 0;
}

.grid__item {
	width: 270px;
	padding: 10px;
}

.grid__item--current {
	opacity: 0 !important;
}

.img-wrap {
	display: block;
}

.img-wrap:focus,
.img-wrap:hover {
	outline: none;
}

.img-wrap img {
	display: block;
	max-width: 100%;
}

.preview {
	position: fixed;
	z-index: 1000;
	top: 0;
	left: 0;
	display: -webkit-flex;
	display: -ms-flex;
	display: flex;
	-ms-flex-pack: center;
	-webkit-justify-content: center;
	justify-content: center;
	-ms-flex-line-pack: center;
	-webkit-align-content: center;
	align-content: center;
	-ms-flex-align: center;
	-webkit-align-items: center;
	align-items: center;
	width: 100%;
	height: 100%;
	pointer-events: none;
}

.preview--open {
	pointer-events: auto;
}


/* circle overlay (generated SVG) */

.overlay {
	position: absolute;
	top: 0;
	left: 0;
	pointer-events: none;
}

.overlay circle {
	-webkit-transition: fill-opacity 0.3s, -webkit-transform 0s 0.3s;
	transition: fill-opacity 0.3s, transform 0s 0.3s;
	-webkit-transition-timing-function: ease-out;
	transition-timing-function: ease-out;
	-webkit-transform: scale3d(0, 0, 1);
	transform: scale3d(0, 0, 1);
	fill: #1f1d1d;
	fill-opacity: 0;
}

.preview--open .overlay circle {
	-webkit-transition: -webkit-transform 0.4s;
	transition: transform 0.4s;
	-webkit-transform: scale3d(1, 1, 1);
	transform: scale3d(1, 1, 1);
	fill-opacity: 1;
}

.clone {
	position: fixed;
	z-index: 110;
	-webkit-transition: -webkit-transform 0.6s cubic-bezier(0.5, 1, 0.2, 1);
	transition: transform 0.6s cubic-bezier(0.5, 1, 0.2, 1);
	-webkit-backface-visibility: hidden;
}

.original {
	position: relative;
	z-index: 120;
	display: block;
	object-fit: contain;
	-webkit-transition: opacity 0.2s;
	transition: opacity 0.2s;
	-webkit-backface-visibility: hidden;
}

.preview--open .animate {
	/* open */
	-webkit-transition: -webkit-transform 0.6s, opacity 0.2s;
	transition: transform 0.6s, opacity 0.2s;
}

.animate {
	/* close */
	-webkit-transition: -webkit-transform 0.3s, opacity 0.2s;
	transition: transform 0.3s, opacity 0.2s;
}

.description {
	color: #fff;
}

.js .description--grid {
	display: none;
}

.description--preview {
	position: fixed;
	z-index: 140;
	bottom: 0;
	left: 0;
	width: 100%;
	padding: 2em 1em;
	text-align: center;
	opacity: 0;
	background: linear-gradient(180deg, transparent, #1f1d1d);
	-webkit-transition: opacity 0.3s, -webkit-transform 0.3s;
	transition: opacity 0.3s, transform 0.3s;
	-webkit-transform: translate3d(0, 100%, 0);
	transform: translate3d(0, 100%, 0);
}

.preview--open .description--preview {
	opacity: 1;
	-webkit-transition-delay: 0.2s;
	transition-delay: 0.2s;
	-webkit-transform: translate3d(0, 0, 0);
	transform: translate3d(0, 0, 0);
}


/* Close button */

.action {
	font-size: 2em;
	margin-top: 300px;
	padding: 0;
	cursor: pointer;
	color: #6bd68a;
	border: none;
	background: none;
	z-index: 999999999999999;
}


.action:hover,
.action:focus {
	color: #6bd68a;
	outline: none;
}

.action--close {
	position: fixed;
	z-index: 99999999;
	top: 0;
	right: 0;
	padding: 1em;
	opacity: 0;
	-webkit-transition: opacity 0.3s, -webkit-transform 0.3s;
	transition: opacity 0.3s, transform 0.3s;
	-webkit-transform: scale3d(0.6, 0.6, 1);
	transform: scale3d(0.6, 0.6, 1);
}

.preview--image-loaded .action--close {
	opacity: 1;
	-webkit-transform: scale3d(1, 1, 1);
	transform: scale3d(1, 1, 1);
}

.text-hidden {
	position: absolute;
	display: block;
	overflow: hidden;
	width: 0;
	height: 0;
	color: transparent;
}

Comment faire pour que seul s'affiche la photo, la légende et le btn close ?
Merci pour votre aide,
E.