/* AI Progress notes: stacked panes in the map's paper and type.
 * Panes sit side by side in a horizontally scrolling stack; each sticks at
 * its own left offset, so as later panes slide over it, it folds to a spine
 * that shows its title. On a phone only the last pane shows.
 */
:root {
  --paper: #f7f5ef;
  --card: #fbfaf6;
  --ink: #1b1a17;
  --ink-2: #4f4c45;
  --ink-3: #8a867c;
  --rule: #dcd8cd;
  --rule-soft: #e9e6dc;
  --accent: #b5601e;
  --accent-wash: rgba(181, 96, 30, 0.1);
  --serif: "Instrument Serif", Georgia, serif;
  --sans: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, sans-serif;
  --cond: "IBM Plex Sans Condensed", "IBM Plex Sans", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;
  --pane-w: 620px;
  --spine: 40px;
  --head-h: 58px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}
a { color: var(--accent); text-underline-offset: 2px; }

/* ---------- header ---------- */

.nb-head {
  height: var(--head-h);
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0 1.2rem;
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
}
.nb-brand { font-family: var(--serif); font-size: 1.7rem; color: var(--ink); text-decoration: none; line-height: 1; }
.nb-brand em { font-style: italic; color: var(--accent); }
.nb-sub { font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink-3); }
.nb-search { position: relative; flex: 0 1 340px; margin-left: auto; }
.nb-search input {
  width: 100%;
  font: inherit;
  font-size: 0.92rem;
  padding: 0.38rem 0.75rem;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: var(--card);
  color: var(--ink);
}
.nb-search input:focus { outline: 2px solid var(--accent-wash); border-color: var(--accent); }
.nb-results {
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  right: 0;
  z-index: 20;
  list-style: none;
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 10px;
  box-shadow: 0 16px 40px rgba(27, 26, 23, 0.14);
  max-height: 60vh;
  overflow-y: auto;
  padding: 0.3rem;
}
.nb-results li { padding: 0.35rem 0.6rem; border-radius: 7px; cursor: pointer; font-size: 0.9rem; display: flex; gap: 0.6rem; align-items: baseline; }
.nb-results li[aria-selected="true"], .nb-results li:hover { background: var(--accent-wash); }
.nb-results .k { font-family: var(--mono); font-size: 0.66rem; color: var(--ink-3); text-transform: uppercase; letter-spacing: 0.06em; flex: 0 0 auto; }
.nb-map { font-size: 0.9rem; white-space: nowrap; }

/* ---------- the stack ---------- */

.stack {
  display: flex;
  height: calc(100vh - var(--appnav-h, 56px) - var(--head-h));
  overflow-x: auto;
  overflow-y: hidden;
  overscroll-behavior-x: contain;
}
.loading { margin: 2rem; color: var(--ink-3); }

.pane {
  position: sticky;
  left: calc(var(--i) * var(--spine));
  flex: 0 0 var(--pane-w);
  height: 100%;
  background: var(--card);
  border-left: 1px solid var(--rule);
  box-shadow: -10px 0 18px -14px rgba(27, 26, 23, 0.45);
}
.pane:first-child { border-left: 0; }
.pane-body {
  height: 100%;
  overflow-y: auto;
  padding: 2rem 2.4rem 4rem;
  transition: opacity 0.15s;
}
.pane.folded .pane-body { opacity: 0; pointer-events: none; }
.pane.active { box-shadow: -10px 0 22px -12px rgba(181, 96, 30, 0.55); }

.spine {
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--spine);
  display: none;
  cursor: pointer;
  background: var(--card);
  border-right: 1px solid var(--rule-soft);
}
.pane.folded .spine { display: block; }
.spine span {
  position: absolute;
  top: 1.1rem;
  left: 50%;
  writing-mode: vertical-rl;
  transform: translateX(-50%);
  font-family: var(--cond);
  font-size: 0.86rem;
  font-weight: 500;
  color: var(--ink-2);
  white-space: nowrap;
}
.spine:hover span { color: var(--accent); }

.close {
  position: absolute;
  top: 0.7rem;
  right: 0.8rem;
  width: 1.9rem;
  height: 1.9rem;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--ink-3);
  font-size: 1.2rem;
  line-height: 1;
  cursor: pointer;
}
.close:hover { background: var(--rule-soft); color: var(--ink); }
.pane:first-child .close { display: none; }
.pane.folded .close { display: none; }
.back { display: none; }

/* ---------- a note ---------- */

.kind { font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-3); }
.pane h1 { font-family: var(--serif); font-weight: 400; font-size: 2.35rem; line-height: 1.05; margin: 0.3rem 0 1rem; }
.pane h2, .pane h3 { font-family: var(--serif); font-weight: 400; font-size: 1.45rem; line-height: 1.2; margin: 1.6rem 0 0.5rem; }
.pane h4 { font-size: 1rem; font-weight: 600; margin: 1.2rem 0 0.35rem; }
.pane p, .pane ul, .pane ol { margin: 0 0 0.85rem; }
.pane ul, .pane ol { padding-left: 1.2rem; }
.pane li { margin: 0.2rem 0; }
.pane .meta { font-family: var(--mono); font-size: 0.74rem; color: var(--ink-3); letter-spacing: 0.02em; }
.pane .meta a { color: var(--ink-2); }
.pane .figure {
  margin: 0 0 1rem;
  padding: 0.35rem 0 0.35rem 0.9rem;
  border-left: 3px solid var(--accent);
  font-family: var(--serif);
  font-size: 1.28rem;
  line-height: 1.3;
}
.pane code { font-family: var(--mono); font-size: 0.88em; background: var(--rule-soft); padding: 0 0.25em; border-radius: 3px; }
.pane a.int { text-decoration: none; border-bottom: 1px solid rgba(181, 96, 30, 0.35); border-radius: 2px; }
.pane a.int:hover, .pane a.int:focus-visible { background: var(--accent-wash); border-bottom-color: var(--accent); }
.pane a.int.open { background: var(--accent-wash); }
.pane a.ext::after { content: " ↗"; font-size: 0.8em; }
.table { overflow-x: auto; margin: 0 0 1rem; }
.pane table { border-collapse: collapse; font-size: 0.82rem; min-width: 100%; }
.pane th, .pane td { text-align: left; padding: 0.3rem 0.55rem; border-bottom: 1px solid var(--rule-soft); vertical-align: top; }
.pane th { font-weight: 600; color: var(--ink-2); }

.backlinks { margin-top: 2.4rem; padding-top: 1rem; border-top: 1px solid var(--rule); }
.backlinks h2 { font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 0.7rem; }
.backlinks ul { list-style: none; padding: 0; display: grid; gap: 0.45rem; }
.backlinks li { background: var(--paper); border: 1px solid var(--rule-soft); border-radius: 8px; padding: 0.55rem 0.75rem; }
.backlinks li a { font-weight: 500; }
.backlinks .ctx { display: block; font-size: 0.84rem; color: var(--ink-3); line-height: 1.45; margin-top: 0.15rem; }

/* ---------- link previews ---------- */

.pop {
  position: fixed;
  z-index: 30;
  width: 340px;
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 10px;
  box-shadow: 0 18px 44px rgba(27, 26, 23, 0.18);
  padding: 0.8rem 0.95rem;
  pointer-events: none;
}
.pop .kind { margin-bottom: 0.15rem; }
.pop strong { display: block; font-family: var(--serif); font-weight: 400; font-size: 1.3rem; line-height: 1.15; margin-bottom: 0.35rem; }
.pop p { font-size: 0.86rem; color: var(--ink-2); line-height: 1.5; }

/* ---------- phones: one pane at a time ---------- */

@media (max-width: 760px) {
  :root { --head-h: 54px; }
  .nb-sub, .nb-map { display: none; }
  .nb-search { flex: 1 1 auto; }
  .stack { overflow-x: hidden; }
  .pane { display: none; position: static; flex: 1 0 100%; border-left: 0; box-shadow: none; }
  .pane:last-child { display: block; }
  .pane-body { padding: 1.2rem 1.1rem 3rem; }
  .pane h1 { font-size: 2rem; }
  .close { display: none; }
  .back {
    display: inline-block;
    font: inherit;
    font-size: 0.85rem;
    border: 0;
    background: none;
    color: var(--accent);
    padding: 0;
    margin-bottom: 0.6rem;
    cursor: pointer;
  }
  .pop { display: none; }
}