Rocket.Chat/app/theme/client/vendor/photoswipe.css

.pswp__button {
	position: relative;

	display: block;
	float: right;
	overflow: visible;

	width: 44px;
	height: 44px;
	margin: 0;
	padding: 0;

	cursor: pointer;
	transition: opacity 0.2s;

	opacity: 0.75;
	border: 0;
	background: none;
	box-shadow: none;
	appearance: none;

	&:focus,
	&:hover {
		opacity: 1;
	}

	&:active {
		opacity: 0.9;
		outline: none;
	}

	&::-moz-focus-inner {
		padding: 0;

		border: 0;
	}
}

.pswp__ui--over-close .pswp__button--close {
	opacity: 1;
}

.pswp__button,
.pswp__button--arrow--left::before,
.pswp__button--arrow--right::before {
	width: 44px;
	height: 44px;

	background: url(/images/gallery-skin.svg) 0 0 no-repeat;
	background-size: 264px 88px;
}

@media (-webkit-min-device-pixel-ratio: 1.1),
	(-webkit-min-device-pixel-ratio: 1.09375),
	(min-resolution: 105dpi),
	(min-resolution: 1.1dppx) {
	.pswp--svg .pswp__button--arrow--left,
	.pswp--svg .pswp__button--arrow--right {
		background: none;
	}
}

.pswp__button--close {
	background-position: 0 -44px;
}

.pswp__button--share {
	background-position: -44px -44px;
}

.pswp__button--fs {
	display: none;
}

.pswp--supports-fs .pswp__button--fs {
	display: block;
}

.pswp--fs .pswp__button--fs {
	background-position: -44px 0;
}

.pswp__button--zoom {
	display: none;

	background-position: -88px 0;
}

.pswp--zoom-allowed .pswp__button--zoom {
	display: block;
}

.pswp--zoomed-in .pswp__button--zoom {
	background-position: -132px 0;
}

.pswp--touch .pswp__button--arrow--left,
.pswp--touch .pswp__button--arrow--right {
	visibility: hidden;
}

.pswp__button--arrow--left,
.pswp__button--arrow--right {
	position: absolute;
	top: 50%;

	width: 70px;
	height: 100px;
	margin-top: -50px;

	background: none;
}

.pswp__button--arrow--left {
	left: 0;
}

.pswp__button--arrow--right {
	right: 0;
}

.pswp__button--arrow--left::before,
.pswp__button--arrow--right::before {
	position: absolute;
	top: 35px;

	width: 32px;
	height: 30px;

	content: '';

	background-color: rgba(0, 0, 0, 0.3);
}

.pswp__button--arrow--left::before {
	left: 6px;

	background-position: -138px -44px;
}

.pswp__button--arrow--right::before {
	right: 6px;

	background-position: -94px -44px;
}

/*

	4. Caption

 */
.pswp__caption {
	position: absolute;
	bottom: 0;
	left: 0;

	width: 100%;
	min-height: 44px;

	& small {
		color: #bbbbbb;

		font-size: 11px;
	}
}

.pswp__caption__center {
	max-width: 420px;
	margin: 0 auto;
	padding: 10px;

	text-align: left;

	color: #cccccc;

	font-size: 13px;
	line-height: 20px;
}

.pswp__caption--empty {
	display: none;
}

/* Fake caption element, used to calculate height of next/prev image */
.pswp__caption--fake {
	visibility: hidden;
}

/*

	5. Loading indicator (preloader)

	You can play with it here - http://codepen.io/dimsemenov/pen/yyBWoR

 */
.pswp__preloader {
	position: absolute;
	top: 0;
	left: 50%;

	width: 44px;
	height: 44px;
	margin-left: -22px;

	transition: opacity 0.25s ease-out;

	opacity: 0;
	direction: ltr;
	will-change: opacity;
}

.pswp__preloader__icn {
	width: 20px;
	height: 20px;
	margin: 12px;
}

.pswp__preloader--active {
	opacity: 1;
}

.pswp--css_animation {
	& .pswp__preloader--active {
		opacity: 1;

		& .pswp__preloader__icn {
			position: absolute;
			top: 15px;
			left: 15px;

			width: 14px;
			height: 14px;
			margin: 0;

			animation: clockwise 500ms linear infinite;

			opacity: 0.75;
			background: none;
		}

		& .pswp__preloader__donut {
			position: absolute;
			top: 0;
			left: 0;

			box-sizing: border-box;
			width: 14px;
			height: 14px;
			margin: 0;

			animation: donut-rotate 1000ms cubic-bezier(0.4, 0, 0.22, 1) infinite;

			border: 2px solid #ffffff;
			border-bottom-color: transparent;
			border-left-color: transparent;
			border-radius: 50%;
			background: none;
		}

		& .pswp__preloader__cut {
			/*
					The idea of animating inner circle is based on Polymer ("material") loading indicator
					by Keanu Lee https://blog.keanulee.com/2014/10/20/the-tale-of-three-spinners.html
				*/
			position: relative;

			overflow: hidden;

			width: 7px;
			height: 14px;
		}
	}
}

@media screen and (max-width: 1024px) {
	.pswp__preloader {
		position: relative;
		top: auto;
		left: auto;

		float: right;

		margin: 0;
	}
}

@-webkit-keyframes clockwise {
	0% {
		transform: rotate(0deg);
	}

	100% {
		transform: rotate(360deg);
	}
}

@keyframes clockwise {
	0% {
		transform: rotate(0deg);
	}

	100% {
		transform: rotate(360deg);
	}
}

@-webkit-keyframes donut-rotate {
	0% {
		transform: rotate(0);
	}

	50% {
		transform: rotate(-140deg);
	}

	100% {
		transform: rotate(0);
	}
}

@keyframes donut-rotate {
	0% {
		transform: rotate(0);
	}

	50% {
		transform: rotate(-140deg);
	}

	100% {
		transform: rotate(0);
	}
}

/*

	6. Additional styles

 */

/* root element of UI */
.pswp__ui {
	z-index: 1550;

	visibility: visible;

	opacity: 1;
	-webkit-font-smoothing: auto;
}

/* top black bar with buttons and "1 of X" indicator */
.pswp__top-bar {
	position: absolute;
	top: 0;
	left: 0;

	width: 100%;
	height: 44px;
}

.pswp__caption,
.pswp__top-bar,
.pswp--has_mouse .pswp__button--arrow--left,
.pswp--has_mouse .pswp__button--arrow--right {
	transition: opacity 333ms cubic-bezier(0.4, 0, 0.22, 1);
	-webkit-backface-visibility: hidden;
	will-change: opacity;
}

/* pswp--has_mouse class is added only when two subsequent mousemove events occur */
.pswp--has_mouse .pswp__button--arrow--left,
.pswp--has_mouse .pswp__button--arrow--right {
	visibility: visible;
}

.pswp__top-bar,
.pswp__caption {
	background-color: rgba(0, 0, 0, 0.5);
}

/* pswp__ui--fit class is added when main image "fits" between top bar and bottom bar (caption) */
.pswp__ui--fit .pswp__top-bar,
.pswp__ui--fit .pswp__caption {
	background-color: rgba(0, 0, 0, 0.3);
}

/* pswp__ui--idle class is added when mouse isn't moving for several seconds (JS option timeToIdle) */
.pswp__ui--idle .pswp__top-bar {
	opacity: 0;
}

.pswp__ui--idle .pswp__button--arrow--left,
.pswp__ui--idle .pswp__button--arrow--right {
	opacity: 0;
}

/*
	pswp__ui--hidden class is added when controls are hidden
	e.g. when user taps to toggle visibility of controls
*/
.pswp__ui--hidden .pswp__top-bar,
.pswp__ui--hidden .pswp__caption,
.pswp__ui--hidden .pswp__button--arrow--left,
.pswp__ui--hidden .pswp__button--arrow--right {
	/* Force paint & create composition layer for controls. */
	opacity: 0.001;
}

/* pswp__ui--one-slide class is added when there is just one item in gallery */
.pswp__ui--one-slide .pswp__button--arrow--left,
.pswp__ui--one-slide .pswp__button--arrow--right,
.pswp__ui--one-slide .pswp__counter {
	display: none;
}

.pswp__element--disabled {
	display: none !important;
}

.pswp--minimal--dark .pswp__top-bar {
	background: none;
}