:root {
  --bg: #0f1720;
  --bg-raised: #182a3a;
  --bg-editor: #131f2b;
  --border: #2a3f52;
  --text: #d7e2ec;
  --text-dim: #8aa0b4;
  --accent: #7ec8e3;
  --error: #ff7b72;
  --com: #6a7f92;
  --str: #a8d08d;
  --chr: #e5c07b;
  --num: #d19a66;
  --kw: #c678dd;
  --type: #e5c07b;
  --key: #7ec8e3;
  --attr: #56b6c2;
  --punc: #9aa8b5;
  --mono: "SF Mono", "Cascadia Code", "Fira Code", Consolas, Menlo, monospace;

  /* The structural view: one pastel per shape, two for names. On the dark
     page they are tints over the editor background. */
  --sh-struct: 205 60% 68%;
  --sh-tuple: 265 50% 72%;
  --sh-list: 150 45% 62%;
  --sh-map: 28 70% 68%;
  --sh-type: 42 80% 70%;
  --sh-variant: 335 65% 72%;
  --sh-tint: 14%;
  --sh-line: 40%;
}

/* The same page in light, for those who asked their system for it. */
@media (prefers-color-scheme: light) {
  :root {
    --bg: #f7f9fb;
    --bg-raised: #eef2f6;
    --bg-editor: #ffffff;
    --border: #d3dbe3;
    --text: #1f2933;
    --text-dim: #5b6b7b;
    --accent: #0b6e99;
    --error: #c2362f;
    --com: #7a8794;
    --str: #2f7d32;
    --chr: #9a5b00;
    --num: #b35c00;
    --kw: #7a3fb8;
    --type: #9a5b00;
    --key: #0b5fa5;
    --attr: #137a7f;
    --punc: #6b7a89;

    --sh-struct: 205 70% 45%;
    --sh-tuple: 265 55% 55%;
    --sh-list: 150 50% 38%;
    --sh-map: 28 80% 48%;
    --sh-type: 40 85% 42%;
    --sh-variant: 335 65% 52%;
    --sh-tint: 12%;
    --sh-line: 45%;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
}

header {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  padding: 0.9rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg-raised);
}

h1 {
  margin: 0;
  font-size: 1.35rem;
  font-family: var(--mono);
}

h1 a {
  color: var(--accent);
  text-decoration: none;
}

.tagline {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.95rem;
}

nav {
  margin-left: auto;
  display: flex;
  gap: 1rem;
}

nav a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 0.9rem;
}

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

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 1.25rem;
  padding: 0.6rem 1.25rem;
  border-bottom: 1px solid var(--border);
}

.toolbar label {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.85rem;
  color: var(--text-dim);
}

.toolbar select,
.toolbar input {
  background: var(--bg-editor);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.25rem 0.4rem;
  font: inherit;
  font-size: 0.85rem;
}

.toolbar input {
  width: 4.5rem;
}

.toolbar button {
  background: var(--bg-raised);
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.3rem 0.8rem;
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
}

.toolbar button:hover {
  border-color: var(--accent);
}

.toolbar .spacer {
  flex: 1;
}

main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
  min-height: 0;
}

@media (max-width: 55rem) {
  main {
    grid-template-columns: 1fr;
  }
}

.pane {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 18rem;
  background: var(--bg);
}

.pane-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding-right: 1.25rem;
}

.hint {
  margin: 0;
  font-size: 0.75rem;
  color: var(--text-dim);
}

.pane h2 {
  margin: 0;
  padding: 0.45rem 1.25rem;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dim);
}

.editor {
  position: relative;
  flex: 1;
  margin: 0 1.25rem 1rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg-editor);
  overflow: hidden;
}

.editor pre,
.editor textarea {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 0.75rem;
  overflow: auto;
  font: 0.85rem/1.5 var(--mono);
  font-variant-ligatures: none;
  white-space: pre;
  tab-size: var(--tab, 4);
}

/* The band behind the line a parse error points at; main.js places it. */
.error-mark {
  position: absolute;
  left: 0;
  right: 0;
  background: color-mix(in srgb, var(--error) 18%, transparent);
  border-left: 3px solid var(--error);
  pointer-events: none;
}

.error-mark[hidden] {
  display: none;
}

.error.clickable {
  cursor: pointer;
}

/*
 * The textarea is the only scroller; the pre follows it via syncScroll().
 * Both layers must keep identical text metrics, so neither may ever reserve
 * a scrollbar gutter — the pre is overflow: hidden, and the textarea's bars
 * are invisible (it still scrolls by wheel and keyboard).
 */
.editor pre {
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.editor textarea {
  z-index: 1;
  width: 100%;
  height: 100%;
  border: 0;
  outline: none;
  resize: none;
  background: transparent;
  color: transparent;
  caret-color: var(--text);
  scrollbar-width: none;
}

.editor textarea::-webkit-scrollbar {
  display: none;
}

/*
 * Plain mode, for input too large to highlight on every keystroke (main.js
 * decides), and for forced-colors mode, which paints the textarea's text in
 * its own color and would show it twice: the textarea shows its own text and
 * the overlay is dropped.
 */
.editor.plain textarea {
  color: var(--text);
}

.editor.plain pre {
  display: none;
}

@media (forced-colors: active) {
  .editor textarea {
    color: CanvasText;
  }

  .editor pre {
    display: none;
  }
}

.editor.output {
  overflow: auto;
  padding: 0.75rem;
  font: 0.85rem/1.5 var(--mono);
  font-variant-ligatures: none;
  white-space: pre;
  tab-size: var(--tab, 4);
}

.editor textarea::selection {
  background: rgba(126, 200, 227, 0.25);
}

.editor.output code {
  font: inherit;
}

.error {
  margin: 0 1.25rem 1rem;
  padding: 0.75rem;
  border: 1px solid color-mix(in srgb, var(--error) 45%, var(--border));
  border-radius: 6px;
  background: color-mix(in srgb, var(--error) 10%, var(--bg-editor));
  color: var(--error);
  font: 0.8rem/1.5 var(--mono);
  white-space: pre;
  overflow-x: auto;
}

/* Neutral variant for notes: while the wasm module loads, or a caveat. */
.error.note {
  border-color: var(--border);
  background: var(--bg-editor);
  color: var(--text-dim);
}

/* Syntax highlighting token classes. */
.tok-com { color: var(--com); font-style: italic; }
.tok-str { color: var(--str); }
.tok-chr { color: var(--chr); }
.tok-num { color: var(--num); }
.tok-kw  { color: var(--kw); }
.tok-type { color: var(--type); }
.tok-key { color: var(--key); }
.tok-attr { color: var(--attr); }
.tok-id  { color: var(--text); }
.tok-punc { color: var(--punc); }

footer {
  padding: 0.7rem 1.25rem;
  border-top: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 0.8rem;
}

footer p {
  margin: 0;
}

footer code {
  font-family: var(--mono);
}

/* --- Output view switch ------------------------------------------------ */

.views {
  display: inline-flex;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.views button {
  background: transparent;
  color: var(--text-dim);
  border: 0;
  padding: 0.2rem 0.7rem;
  font: inherit;
  font-size: 0.75rem;
  cursor: pointer;
}

.views button + button {
  border-left: 1px solid var(--border);
}

.views button[aria-selected="true"] {
  background: var(--bg-raised);
  color: var(--accent);
}

/* --- Structural view ----------------------------------------------------- */

.editor.structure {
  overflow: auto;
  padding: 0.75rem;
  font-size: 0.82rem;
  line-height: 1.45;
}

.structure-root > .node,
.structure-root > .wrapper {
  display: block;
}

.attributes {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  margin-bottom: 0.6rem;
}

/* Every shape box takes its hue from --sh and its tint from the theme. */
.node {
  --sh: var(--sh-struct);
  border: 1px solid hsl(var(--sh) / var(--sh-line));
  border-radius: 8px;
  background: hsl(var(--sh) / var(--sh-tint));
  padding: 0.35rem 0.5rem 0.5rem;
  min-width: 0;
}

.node.tuple { --sh: var(--sh-tuple); }
.node.list { --sh: var(--sh-list); }
.node.map { --sh: var(--sh-map); }

details.node > summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.05rem 0.1rem 0.3rem;
  color: var(--text-dim);
}

details.node > summary::-webkit-details-marker {
  display: none;
}

details.node > summary::before {
  content: "▾";
  font-size: 0.7rem;
  color: hsl(var(--sh) / 90%);
  transition: transform 120ms;
}

details.node:not([open]) > summary::before {
  transform: rotate(-90deg);
}

details.node:not([open]) > summary {
  padding-bottom: 0;
}

.kind {
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: hsl(var(--sh) / 95%);
}

.count {
  font-size: 0.72rem;
}

/* Struct fields and map entries: key column, value column. */
.fields,
.entries {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 0.3rem 0.8rem;
  align-items: start;
}

.fields > .row,
.entries > .row {
  display: contents;
}

.key {
  font-family: var(--mono);
  color: var(--key);
  padding-top: 0.15rem;
  white-space: nowrap;
}

.mapkey {
  padding-top: 0.05rem;
}

.val,
.mapkey {
  min-width: 0;
}

.val.nested {
  /* A nested box fills the value column; it reads as a sub-card. */
  display: block;
}

/* Tuples and word lists flow horizontally; card lists form a grid. */
.node.tuple {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem;
  vertical-align: top;
}

.items {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  align-items: flex-start;
}

.node.list.cards > .items {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(16rem, 100%), 1fr));
  gap: 0.45rem;
}

.wrapper {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  vertical-align: top;
}

/* Chips: scalars, bare identifiers and names. */
.chip {
  display: inline-block;
  font-family: var(--mono);
  padding: 0.05rem 0.45rem;
  border-radius: 999px;
  border: 1px solid transparent;
  line-height: 1.5;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  color: var(--text);
  background: hsl(0 0% 50% / 12%);
}

.chip.num { color: var(--num); }
.chip.str { color: var(--str); }
.chip.chr { color: var(--chr); }
.chip.bool { color: var(--kw); }
.chip.empty { color: var(--text-dim); }
.chip.attr { color: var(--attr); font-size: 0.78rem; }
.chip.more { color: var(--text-dim); font-style: italic; }

.chip.name,
.chip.type,
.chip.variant {
  font-weight: 600;
}

.chip.type,
.chip.name.type {
  --sh: var(--sh-type);
  color: hsl(var(--sh) / 95%);
  background: hsl(var(--sh) / 18%);
  border-color: hsl(var(--sh) / 45%);
}

.chip.variant,
.chip.name.variant {
  --sh: var(--sh-variant);
  color: hsl(var(--sh) / 95%);
  background: hsl(var(--sh) / 18%);
  border-color: hsl(var(--sh) / 45%);
}

.legend {
  margin: 1rem 0 0;
  font-size: 0.75rem;
  color: var(--text-dim);
  line-height: 1.9;
}

.swatch {
  display: inline-block;
  padding: 0 0.4rem;
  border-radius: 4px;
  border: 1px solid hsl(var(--sh) / var(--sh-line));
  background: hsl(var(--sh) / var(--sh-tint));
  --sh: var(--sh-struct);
}

.swatch.tuple { --sh: var(--sh-tuple); }
.swatch.list { --sh: var(--sh-list); }
.swatch.map { --sh: var(--sh-map); }