:root {
  --font-head: serif;
  --font-body: sans-serif;
  --font-mono: monospace;

  --page-width: 1500px;
  --page-margin: 30px;
  --columns: 3;
  --gutter: 20px;
  --sidebar-width: 325px;

  --text: hsl(54, 0%, 70%);
  --primary: hsl(178, 43%, 64%);
  --accent: hsl(38, 0.9em, 9%);
  --bg-page: hsl(30, 0%, 7%);
  --bg-content: hsl(38, 0%, 11%);
  --bg-accent: hsl(40, 0%, 23%);

  --grid-item: 100%;
}
@media (min-width: 1100px) {
  :root {
    --grid-item: calc(
      (99.9% / var(--columns)) - (var(--gutter) * (var(--columns) - 1)) /
        var(--columns)
    );
  }
}

:target {
  scroll-margin-block: 2ex;
}

html {
  background-position: center;
  background-attachment: fixed;
  background-size: cover;
  background-repeat: no-repeat;
  background-color: var(--bg-page);
  scroll-behavior: smooth;
  scrollbar-color: var(--bg-accent) var(--bg-page);
}

body {
  color: var(--text);
  font-family: var(--font-body);
  font-size: 1.1em;
  line-height: 1.3;
}

html,
body {
  overflow: visible;
}

main {
  max-width: var(--page-width);
  margin-inline: auto;
  padding-inline: 30px;
  margin-block: var(--page-margin);
}

main-divider {
  display: grid;
  gap: var(--gutter);
  align-items: start;
}
@media (min-width: 700px) {
  main-divider {
    grid-template-columns: var(--sidebar-width) auto;
  }
}

.gallery li {
  margin-bottom: var(--gutter);
}

hgroup {
  background-color: var(--bg-content);
  border: 1px solid var(--bg-accent);
  padding-inline: 26px;
  padding-block: 26px;
  scrollbar-color: var(--bg-accent) var(--bg-content);
  overflow-y: auto;
  max-height: 500px;
}
@media (min-width: 700px) {
  hgroup {
    max-height: calc(100svh - 2 * var(--page-margin));
    position: sticky;
    top: var(--page-margin);
    align-self: start;
  }
}

p {
  margin-block: 0.6rem;
  &:first-child {
    margin-top: 0;
  }
  &:last-child {
    margin-bottom: 0;
  }
}

b,
strong {
  font-weight: bold;
}
i,
em {
  font-style: italic;
}

a:not(a[data-img]) {
  color: var(--primary);
  text-decoration: underline dotted 1px;
  text-underline-offset: 3px;
  transition-property: color, box-shadow, text-decoration-color;
  transition-duration: 150ms;

  *:hover,
  *:focus {
    color: var(--text);
    text-decoration-color: var(--text);
    text-decoration-style: solid;
  }
  *:focus {
    outline: 1px dashed var(--primary);
    outline-offset: 1px;
  }
}

code {
  color: var(--code-text);
  border: 1px solid var(--bg-accent);
  border-radius: 2px;
  padding-inline: 2px;
  padding-block: 1px;
  font-family: var(--font-mono);
}

.filters {
  display: grid;
  gap: 10px;
}

.button-group {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.button {
  cursor: pointer;
  background: none;
  border: none;
  border: 1px solid var(--bg-accent);
  border-radius: 2px;
  color: var(--color);
  padding: 4px 8px;
  background-color: var(--accent);
  transition-property: color, background-color, text-decoration-color;
  transition-duration: 150ms;

  &:hover {
    color: var(--primary);
    border-style: solid;
    border-color: var(--primary);
  }
  &.is-checked {
    color: var(--bg-content);
    background-color: var(--primary);
  }
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-head);
  color: var(--primary);
}

h1 {
  font-size: 3em;
  margin-bottom: 1rem;
  line-height: 0.9;
}

img {
  display: block;
  object-fit: cover;
}

.entry {
  border: 1px solid var(--bg-accent);
}

.caption {
  padding: 12px 16px;
  padding-top: 10px;
  background-color: var(--bg-content);
}

figcaption {
  border-top: 1px dotted var(--bg-accent);
}

hr {
  border: none;
  border-top: 1px dotted var(--primary);
  margin-block: 16px;
}

details {
  margin-block: 12px;
  border: 1px solid var(--bg-accent);
  ul:not(.filters),
  ol {
    list-style-type: decimal;
    margin-left: 22px;
  }
  ol {
    margin-top: 6px;
    margin-bottom: 2px;
  }
  summary {
    cursor: pointer;
    color: var(--primary);
    font-weight: bold;
    padding: 4px 8px;
    background-color: var(--accent);
    transition-property: background-color, color, text-decoration-color,
      border-color;
    transition-duration: 150ms;
    &:hover {
      color: var(--text);
    }
  }
  details-content {
    padding: 10px;
    display: block;
  }
  &[open] {
    margin-bottom: 8px;
    summary {
      background-color: var(--primary);
      color: var(--bg-content);
      border-bottom: 1px solid var(--bg-accent);
    }
  }
}

.grid-item,
.grid-sizer {
  width: var(--grid-item);
}

.gutter-sizer {
  width: var(--gutter);
}

.responsive {
  width: 100%;
  height: auto;
}

html.bp-lock {
  overflow-y: visible;
}

#overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.85);
  display: none;
  padding: 30px;
  overflow-y: auto;
  z-index: 9999;
}

#overlay-content {
  max-width: 1000px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
  gap: 16px;
}

#overlay-content img {
  width: 100%;
  height: auto;
  border-radius: 8px;
}

#close {
  position: sticky;
  top: 10px;
  margin-bottom: 20px;
  padding: 8px 14px;
  font-size: 18px;
  cursor: pointer;
}

.thumb:hover {
    cursor: pointer;
}

.grid-item.thumb::after {
    content: '';
    position: absolute;
    top: 10px;
    right: 10px;
    width: 24px;
    height: 24px;
    background: url('../p/gallery/mult.svg') no-repeat center/contain;
    filter: drop-shadow(2px 2px 2px rgba(0,0,0,0.5));
    pointer-events: none;
}

#backbtn {
    display: inline-block; /* or block */
    margin-bottom: 20px; /* your desired spacing */
}