/* Extra styles for the explainer page. The colour tokens and the board and tile
   styles come from style.css. */

:root {
  --gd-bg: #fbf9f4;
  --gd-grid: #e0dacb;
  --gd-wall: #3b372f;
  --gd-frontier: #bfd9f2;
  --gd-expanded: #e9d6a8;
  --gd-route: #b5532b;
  --gd-start: #3f7d4e;
  --gd-goal: #b5532b;
  --link: #9a4423;
}

@media (prefers-color-scheme: dark) {
  :root {
    --gd-bg: #22201c;
    --gd-grid: #36322b;
    --gd-wall: #8d8574;
    --gd-frontier: #2f5273;
    --gd-expanded: #5b4a25;
    --gd-route: #e0805a;
    --gd-start: #5aa56c;
    --gd-goal: #e0805a;
    --link: #f0a07c;
  }
}

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

main.article { max-width: 46rem; }

.article h2 { margin: 2.5rem 0 0.75rem; font-size: 1.4rem; }
.article h3 { margin: 1.75rem 0 0.5rem; font-size: 1.05rem; }
.article p, .article li { max-width: 40rem; }

.nav { margin: 0 0 1rem; font-size: 0.9rem; }

.lede { font-size: 1.1rem; }

.summary {
  margin: 1.5rem 0;
  padding: 0.5rem 1.25rem 0.75rem;
  background: var(--surface);
  border-left: 4px solid var(--accent);
  border-radius: 0 8px 8px 0;
}
.summary h2 { margin: 0.5rem 0 0.25rem; font-size: 1rem; }
.summary ul { margin: 0; padding-left: 1.1rem; }

.toc { margin: 1.5rem 0 2rem; font-size: 0.95rem; }
.toc ol { margin: 0; padding-left: 1.4rem; columns: 2 16rem; column-gap: 2rem; }

.formula {
  margin: 1rem 0;
  font-size: 1.25rem;
  font-family: Georgia, "Times New Roman", serif;
  text-align: center;
}

var { font-family: Georgia, "Times New Roman", serif; }
code { font-size: 0.9em; }
sup a { text-decoration: none; }

.note { padding: 0.5rem 1rem; background: var(--surface); border-radius: 6px; }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* ---------- widgets ---------- */

.widget {
  margin: 1.25rem 0;
  padding: 1rem;
  background: var(--surface);
  border-radius: 10px;
}

.widget button:not(.tile):not(.succ) { min-height: 2.25rem; padding: 0 0.9rem; }
.widget label { font-size: 0.9rem; }
.widget input[type="range"] { vertical-align: middle; accent-color: var(--accent); }

table.data { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
table.data th, table.data td {
  padding: 0.35rem 0.5rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}
table.data th { font-weight: 600; color: var(--muted); }
table.data td.num, table.data th.num { text-align: right; font-variant-numeric: tabular-nums; }
table.data tr.current th, table.data tr.current td { background: color-mix(in srgb, var(--accent) 14%, transparent); }

/* ---------- puzzle playground ---------- */

.playground {
  display: grid;
  grid-template-columns: minmax(0, 17rem) minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
}

.playground .board { width: 100%; font-size: 1rem; }
.playground .tile { font-size: 1.6rem; }
.playground .pg-controls { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 0.75rem; align-items: center; }
.playground .pg-side p { margin: 0 0 0.6rem; }
.playground .pg-side ul { margin: 0 0 0.6rem; padding-left: 1.1rem; }
.playground .pg-status { font-size: 0.95rem; }
.playground .ok { color: var(--gd-start); font-weight: 600; }
.playground .bad { color: var(--gd-goal); font-weight: 600; }

/* A tile's Manhattan distance, shown in its corner. */
.board.show-d .tile[data-d]::after {
  content: attr(data-d);
  position: absolute;
  right: calc(var(--gap) / 2 + 7px);
  bottom: calc(var(--gap) / 2 + 3px);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--accent);
}
.board .tile.conflict::before { outline: 2px dashed var(--accent); outline-offset: -3px; }

.mini {
  display: inline-grid;
  grid-template-columns: repeat(3, 1.35rem);
  gap: 2px;
  padding: 4px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
}
.mini span {
  display: grid;
  place-items: center;
  height: 1.35rem;
  font-size: 0.78rem;
  background: var(--tile);
  border-radius: 3px;
}
.mini span.blank { background: transparent; }
.mini span.moved { outline: 2px solid var(--accent); outline-offset: -2px; }

.successors { display: flex; flex-wrap: wrap; gap: 0.6rem; margin: 0.5rem 0; }

button.succ {
  display: grid;
  justify-items: center;
  gap: 0.3rem;
  padding: 0.5rem 0.6rem;
  border: 2px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font: inherit;
  font-size: 0.8rem;
  cursor: pointer;
}
button.succ:hover { border-color: var(--accent); }
button.succ.best { border-color: var(--accent); }
button.succ .tag { color: var(--accent); font-weight: 700; min-height: 1.1em; }
button.succ:not(.best) .tag { color: var(--muted); font-weight: 400; }

/* ---------- grid demo ---------- */

.gd-controls, .gd-buttons, .cmp-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 0.9rem;
  align-items: center;
  margin-bottom: 0.75rem;
}

.weight-label { font-size: 0.85rem; color: var(--muted); }

#gd-canvas {
  display: block;
  width: 100%;
  background: var(--gd-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  touch-action: none;
  cursor: crosshair;
}

.status { margin: 0.6rem 0 0.2rem; min-height: 1.5em; font-weight: 600; }
.readout { margin: 0; min-height: 1.5em; font-size: 0.85rem; color: var(--muted); font-variant-numeric: tabular-nums; }

.legend { display: flex; flex-wrap: wrap; gap: 0.25rem 1rem; margin: 0.5rem 0 0; padding: 0; list-style: none; font-size: 0.85rem; }
.swatch { display: inline-block; width: 0.9rem; height: 0.9rem; vertical-align: -0.1rem; border: 1px solid var(--border); border-radius: 2px; }
.swatch.frontier { background: var(--gd-frontier); }
.swatch.expanded { background: var(--gd-expanded); }
.swatch.route { background: var(--gd-route); }
.swatch.wall { background: var(--gd-wall); }

.gd-compare { margin-top: 1rem; }
.gd-compare button { margin-bottom: 0.6rem; }

/* ---------- strategy comparison ---------- */

.cmp-top { display: flex; flex-wrap: wrap; gap: 1rem; align-items: center; margin-bottom: 0.9rem; }
.cmp-board .mini { grid-template-columns: repeat(3, 1.8rem); }
.cmp-board .mini span { height: 1.8rem; font-size: 0.95rem; }

.bar-col { width: 25%; }
.bar { display: block; height: 0.7rem; min-width: 2px; background: var(--accent); border-radius: 2px; }
.cmp-ida { margin-top: 1rem; font-size: 0.9rem; }
.cmp-ida table { max-width: 24rem; }
.cmp-ida p { margin: 0 0 0.5rem; }

.refs { font-size: 0.9rem; padding-left: 1.4rem; }
.refs li { margin-bottom: 0.4rem; }

@media (max-width: 34rem) {
  .playground { grid-template-columns: minmax(0, 1fr); }
  .bar-col { display: none; }
  table.data td.bar-cell { display: none; }
}

/* ---------- the "solving it by hand" page ---------- */

.maps { display: flex; flex-wrap: wrap; gap: 1.5rem; justify-content: center; }
.maps figure, .frames figure { margin: 0; text-align: center; }
.maps figure { flex: 1 1 12rem; max-width: 15rem; }
figcaption { margin-top: 0.4rem; font-size: 0.85rem; color: var(--muted); }

.omap { display: grid; gap: 2px; }
.omap span {
  display: grid;
  place-items: center;
  aspect-ratio: 1;
  font-size: 0.8rem;
  font-weight: 600;
  background: hsl(calc(25 + 300 * var(--k) / var(--of)) 55% 78%);
  color: #26231d;
  border-radius: 3px;
}
@media (prefers-color-scheme: dark) {
  .omap span { background: hsl(calc(25 + 300 * var(--k) / var(--of)) 40% 34%); color: #ece7db; }
}

.frames { display: flex; flex-wrap: wrap; gap: 1rem 1.25rem; justify-content: center; }
.frames figure { flex: 0 1 8.5rem; }
.frames .mini { margin: 0 auto; }

.tr-options { display: flex; flex-wrap: wrap; gap: 0.5rem 1rem; margin-bottom: 0.75rem; }
.tr-main { display: grid; grid-template-columns: minmax(0, 21rem) minmax(0, 1fr); gap: 1.25rem; align-items: start; }
.tr-buttons { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 0.75rem; }
.tr-count { margin: 0 0 0.25rem; font-size: 0.85rem; color: var(--muted); }
.tr-right h3 { margin: 0 0 0.4rem; font-size: 1.05rem; }
.tr-right p { margin: 0 0 0.6rem; }
.tr-sub { font-weight: 600; min-height: 1.5em; }

.layers { display: flex; flex-wrap: wrap; gap: 0.35rem; margin: 0.75rem 0 0; padding: 0; list-style: none; }
.layers li {
  padding: 0.1rem 0.55rem;
  font-size: 0.8rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--muted);
}
.layers li.finished { background: var(--tile-home); color: var(--text); }
.layers li.active { border-color: var(--accent); color: var(--text); font-weight: 700; }

/* A tile that is finished and locked. */
.board .tile.locked::before { background: var(--tile-home); border-color: color-mix(in srgb, var(--gd-start) 55%, var(--border)); }

.hc-controls { display: flex; flex-wrap: wrap; gap: 0.5rem 1rem; align-items: center; margin-bottom: 0.75rem; }

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