hugo-snap-gallery/static/css/snap-gallery.css

/*
  SPDX-FileCopyrightText: 2020 Max Mehl <mail@mehl.mx>
  SPDX-License-Identifier: MIT
*/

/** GENERAL FIGURE LAYOUT **/

figure {
  max-width: 90%;
  margin: 30px auto 40px;
  display: block;
  text-align: center;
}

/* make box with box-shadow only as large as image */
.snap-wrapper {
  box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2),0 6px 20px 0 rgba(0,0,0,0.19);
  display: inline-block;
}

figure a:hover {
  text-decoration: none;
}

figure img {
  max-width: 100%;
  max-height: 100%;
}

figure.small img {
  max-height: 150px;
}

figure.medium img {
  max-height: 225px;
}

figure.pull-right {
  padding: 10px 0 10px 10px;
}

figure.pull-left {
  padding: 10px 10px 10px 0;
}

figure figcaption {
  background-color: rgba(0, 0, 0, 0.5);
  display: block;
  font-size: .8em;
  padding: 1px;
  position: static;
  text-align: center;
  bottom: 0;
  left: 0;
  right: 0;
  color: #FFF;
}

/** GALLERY MARKUP **/
.snap-gallery {
  margin: 10px;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}

/* avoid sick effects of inline-block on gallery elements */
.snap-gallery .snap-wrapper {
  display: block;
} 

.snap-gallery figure {
  position: relative;
  width: 30%;
  padding-bottom: 30%;
  margin: 1%;
  text-align: left;
  box-shadow: 0 1px 2px 0 rgba(0,0,0,0.2),0 2px 4px 0 rgba(0,0,0,0.19);
}

.snap-gallery figcaption {
  position: absolute;
}

.snap-gallery img.snap-thumb {
  position: absolute;
  object-fit: cover;
  object-position: center;
  height: 100%;
  width: 100%;
}

.snap-gallery figure img.snap-thumb:hover {
  transform: scale(1.02);
  -webkit-transition: all 0.3s ease-in-out;
  -moz-transition: all 0.3s ease-in-out;
  -o-transition: all 0.3s ease-in-out;
  transition: all 0.3s ease-in-out;
}

@media screen and (max-width: 767px) {
  .snap-gallery figure {
    width: 45%;
    padding-bottom: 45%;
    margin: 2%
  }
}
@media screen and (max-width: 479px) {
  .snap-gallery figure {
    width: 90%;
    padding-bottom: 90%;
    margin: 3%;
  }
}

/** LIGHTBOX MARKUP **/

.snap-lightbox {
  /** Default lightbox to hidden */
  display: none;

  /** Position and style */
  position: fixed;
  z-index: 999;
  width: 100%;
  height: 100%;
  text-align: center;
  white-space: nowrap;
  top: 0;
  left: 0;
  background: rgba(0,0,0,0.8);
}

/* effects when "activating" the figure */ 
.snap-lightbox:target {
  /** Remove default browser outline */
  outline: none;

  /** Unhide lightbox **/
  display: block;
}

/* Click on the complete background closes the lightbox */
/* Exception: arrow in gallery, they have higher z-index */
a.snap-lightbox-close {
  position: fixed;
  z-index: 800;
  width: 100%;
  height: 100%;
  text-align: center;
  white-space: nowrap;
  top: 0;
  left: 0;
}

/* keep lightbox in middle. TODO: hacky, and not realibly in middle */
.snap-lightbox::before {
  content: "";
  display: inline-block;
  vertical-align: middle;
  width: 0;
  /* adjust for white space between pseudo element and next sibling */
  margin-right: -.25em;
  /* stretch line height */
  height: 100%;
}

/* Container for image */
.snap-lightbox-inner {
  display: inline-block;
  vertical-align: middle;
  white-space: normal;
  max-width: 90%;
  max-height: 80%;
  height: 100%;
}

.snap-lightbox-inner p {
  color: #fff;
  z-index: 810;
  position: relative;
}

/* prev/next arrows & close button */

.snap-lightbox-close-button {
  position: fixed;
  z-index: 950;
  width: 5%;
  height: calc(5vw); /* ~5% width */
  right: 0;
  top: 0;
}

.snap-lightbox-x::after {
  content: "\00d7"; /* This will render the 'X' */
  font-size: 3em;
  font-style: normal;
  font-weight: 700;
  color: #000;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
}

.snap-lightbox-close-button:hover .snap-lightbox-x::after {
  color: #fff;
  transition: all 0.25s ease;
}

.snap-lightbox-prev, .snap-lightbox-next  {
  position: fixed;
  z-index: 800;
  width: 5%;
  height: 100%;
  text-align: center;
  top: 0;
}

.snap-lightbox-prev {
  left: 0;
}

.snap-lightbox-next {
  right: 0;
}

.snap-lightbox-arrow {
  display: inline-block;
  position: fixed;
  top: 50%;
  z-index: 900;
  border: solid #000;
  border-width: 0 7px 7px 0;
  display: inline-block;
  padding: 1%;
}

span .snap-lightbox-arrow {
  border-color: #5e5e5e;
}

.snap-lightbox-prev .snap-lightbox-arrow {
  left: 2%;
  transform: rotate(135deg);
  -webkit-transform: rotate(135deg);
}

.snap-lightbox-next .snap-lightbox-arrow {
  right: 2%;
  transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg);
}

a.snap-lightbox-prev:hover > .snap-lightbox-arrow,
a.snap-lightbox-next:hover > .snap-lightbox-arrow {
  border-color: #fff;
  transition: all 0.25s ease;
}

@media screen and (max-width: 767px) {
  .snap-lightbox-inner {
    max-width: 80%;
  }
  .snap-lightbox-prev, .snap-lightbox-next {
    width: 10%;
  }
  .snap-lightbox-close-button {
    width: 10%;
    height: calc(10vw); /* ~10% width */
  }
}