css/cssmodal--gallery.css
/*
 * CSS Modal Plugin for displaying an image gallery
 */
:root {
  --css-modal--gallery_iframe-size: 600px;
  --css-modal--gallery_min-size: 98px;
  --css-modal--gallery_thumb-size: 98px;
}

.css-modal_detail {
  position: relative;
  min-width: var(--css-modal--gallery_min-size);
  min-height: var(--css-modal--gallery_min-size);

  opacity: 0;
  width: 0;
  height: 0;
  transition: opacity 0s;
}

.css-modal_detail.is-active {
  opacity: 1;
  width: auto;
  height: auto;
  transition: opacity 0.2s ease-out;
}

/**
 * Styling for Iframe in modal
 */
.css-modal_detail > [data-iframe] {
  position: relative;
  float: left;
  width: var(--css-modal--gallery_iframe-size);
}

.css-modal_detail > [data-iframe]:after {
  float: left;
  content: '';
  padding-top: 56.25%;
}

.css-modal_detail iframe {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

@media (max-width: 30em) {
  .css-modal_detail > [data-iframe] {
    width: 411px;
  }
}

@media (max-width: 30em) {
  .css-modal_detail > [data-iframe] {
    width: 100%;
  }
}

.css-modal--gallery .css-modal_content-list {
  display: none;
  list-style: none;
  margin: 0.2em -0.2em -0.2em;
  padding: 0;
  overflow: hidden;
}

.css-modal--gallery .css-modal_content-list.is-active {
  display: block;
}

.css-modal--gallery .css-modal_content-list > li {
  float: left;
  padding: 0.2em;
}

.css-modal--gallery .css-modal_content-list img {
  display: block;
  border: 0;
}

.css-modal--gallery_navigation {
  list-style: none;
  margin: 0;
  padding: 0;
}

.css-modal--gallery_navigation a {
  position: absolute;
  top: 30%;
  bottom: 30%;
  width: 10em;
  max-width: 25%;
  font-family: arial, sans-serif;

  text-indent: -99em;
  overflow: hidden;
  text-decoration: none;
  text-shadow: 0 0 1px rgba(255, 255, 255, 0.5);
}

.css-modal--gallery_navigation img {
  max-width: var(--css-modal--gallery_thumb-size);
  max-height: var(--css-modal--gallery_thumb-size);
}

.css-modal--gallery_navigation_item::after {
  position: absolute;
  top: 50%;
  height: 32px;

  margin-top: -24px;
  line-height: 32px;
  padding: 0 8px;
  font-size: 64px;
  opacity: 0;
}

.css-modal--gallery_navigation_item:hover::after,
.css-modal--gallery_navigation_item:focus::after,
.css-modal--gallery_navigation_item:active::after {
  opacity: 1;
}

// Show on mobile
@media (max-width: 30em) {
  .css-modal--gallery_navigation_item:after {
    opacity: 1;
  }
}

.css-modal--gallery_navigation_item--prev {
  left: 0;
}

.css-modal--gallery_navigation_item--prev:after {
  content: '‹';
  left: 0;
  text-indent: 0;
}

.css-modal--gallery_navigation_item--next {
  right: 0;
}

.css-modal--gallery_navigation_item--next::after {
  content: '›';
  right: 0;
  text-indent: 0;
}

/**
 * Caption
 */
.css-modal--gallery_caption {
  border-bottom: 1px solid var(--css-modal_border-color);
}

.css-modal--gallery_caption p {
  margin: 1em 15px;
}
