:root {
  --bg: #f5f6f8;
  --card: #ffffff;
  --text: #1f2933;
  --muted: #6b7785;
  --border: #dde1e6;
  --accent: #2563eb;
  --code-bg: #f0f2f5;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14181d;
    --card: #1d232a;
    --text: #e6e9ed;
    --muted: #97a3b0;
    --border: #2f3842;
    --accent: #6ea0ff;
    --code-bg: #262d35;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 2rem 1rem;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

main {
  max-width: 52rem;
  margin: 0 auto;
}

main.wide { max-width: 68rem; }

header { margin-bottom: 1.5rem; }

.topnav {
  margin-bottom: 1rem;
  font-size: 0.85rem;
}

.label {
  margin: 0;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

h1 {
  margin: 0.1rem 0 0;
  font-size: 1.5rem;
  font-weight: 600;
  overflow-wrap: anywhere;
}

h2 {
  margin: 0 0 0.75rem;
  font-size: 1.1rem;
  font-weight: 600;
}

.card h2 + table,
.card h2 + p { margin-top: 0; }
.card table + h2,
.card .smiles + h2,
.card p + h2 { margin-top: 2rem; }

.description { margin: 0.25rem 0 0; }

.intro { margin: 0 0 1.5rem; }

.card {
  padding: 1.5rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
}

a { color: var(--accent); }

.muted, .note { color: var(--muted); }

.note { margin: 1.5rem 0 0; font-size: 0.9rem; }

/* The front page: three polymers next to each other. */
.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

@media (max-width: 52rem) {
  .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 34rem) {
  .grid { grid-template-columns: minmax(0, 1fr); }
}

.tile {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 1rem;
}

.tile h2 {
  margin: 0;
  font-size: 1rem;
  font-weight: 500;
  overflow-wrap: anywhere;
}

.tile h2 a:not(.badge) { color: var(--text); text-decoration: none; }
.tile h2 a:not(.badge):hover { color: var(--accent); text-decoration: underline; }

.tile h2 .count {
  margin-left: 0.4rem;
  vertical-align: 0.1em;
}

.tile .qid {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.3rem;
  margin: auto 0 0;
  font-size: 0.8rem;
}

/* The photos (P18) of a polymer, at most four: on the front page they just
   fit next to each other; in narrower tiles they wrap. */
.photos {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.3rem;
}

/* A photo is a 75 by 75 pixel cutout from the middle, so it is cropped
   rather than squeezed. */
.photo {
  flex: none;
  width: 75px;
  height: 75px;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.photo img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

/* Small buttons: the Wikipedia buttons after the QID, one per language,
   and the number of members after the name of a class of polymers. */
.badge {
  padding: 0 0.3rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--muted);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.5;
  text-decoration: none;
}

.wiki:first-of-type { margin-left: 0.3rem; }

.badge:hover,
.badge:focus-visible {
  color: var(--accent);
  border-color: var(--accent);
}

/* CDK Depict draws black on white, so the depiction keeps a white
   background in the dark theme too. */
.depiction {
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 4 / 3;
  padding: 0.5rem;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 6px;
  text-decoration: none;
  overflow: hidden;
}

.depiction img {
  max-width: 100%;
  max-height: 100%;
}

.depiction .muted { color: #6b7785; font-size: 0.9rem; }

.depiction.large {
  aspect-ratio: auto;
  min-height: 12rem;
  max-height: 24rem;
  margin-bottom: 0.75rem;
}

.depiction.large img { max-height: 22rem; }

.smiles {
  display: block;
  padding: 0.4rem 0.6rem;
  background: var(--code-bg);
  border-radius: 4px;
  font: 0.8rem/1.4 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  overflow-wrap: anywhere;
}

.card .smiles + .depiction { margin-top: 1rem; }

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 0.6rem 0.75rem;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--border);
  overflow-wrap: anywhere;
}

thead th {
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

tbody th {
  width: 9rem;
  font-weight: 500;
}

tbody tr:last-child th,
tbody tr:last-child td { border-bottom: 0; }

th.num, td.num {
  text-align: right;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.properties td { font-size: 0.9rem; }

/* Property names break between words only. */
.properties td:first-child {
  min-width: 9rem;
  overflow-wrap: normal;
}

.properties td.num {
  width: 10rem;
  white-space: normal;
}

.unit { color: var(--muted); }

.doi { display: block; font-size: 0.85rem; }

@media (max-width: 40rem) {
  .card { padding: 1rem; }
  th, td { padding: 0.5rem 0.4rem; }

  /* On small screens every property is a block with labelled lines. */
  .properties thead { display: none; }
  .properties tr {
    display: block;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border);
  }
  .properties tbody tr:last-child { border-bottom: 0; }
  .properties td,
  .properties td.num {
    display: grid;
    grid-template-columns: 6.5rem minmax(0, 1fr);
    gap: 0.5rem;
    width: auto;
    padding: 0.2rem 0;
    text-align: left;
    border: 0;
  }
  .properties td::before {
    content: attr(data-label);
    color: var(--muted);
    font-size: 0.8rem;
  }
}

/* The polymers in a class, below the card of a polymer page. */
.members { margin-top: 2rem; }
.members .intro { margin-bottom: 1rem; }