/* ============================================================
   KASIAN SULTAN — design system
   Palette: ink, paper, champagne gold. Nothing else, ever.
   ============================================================ */

:root {
  --ink: #0B0B0C;
  --paper: #F6F4EF;
  --gold: #C6A15B;
  --gold-hi: #E9CD8F;
  --line-dark: rgba(246, 244, 239, .14);
  --line-light: rgba(11, 11, 12, .12);
  --muted-dark: rgba(246, 244, 239, .55);
  --muted-light: rgba(11, 11, 12, .55);

  --font-display: "Fraunces", Georgia, "Times New Roman", serif;
  --font-ui: "Inter", system-ui, -apple-system, sans-serif;

  --step-hero: clamp(3rem, 10vw, 9rem);
  --step-h2: clamp(2rem, 6vw, 4.5rem);
  --dur: 700ms;
  --ease: cubic-bezier(.22, .8, .24, 1);
}

:lang(th) {
  --font-display: "IBM Plex Sans Thai Looped", "Thonburi", sans-serif;
  --font-ui: "IBM Plex Sans Thai Looped", "Thonburi", system-ui, sans-serif;
  --step-hero: clamp(2.5rem, 8vw, 7rem);
}

* { box-sizing: border-box; margin: 0; }

html {
  scroll-behavior: smooth;
  scroll-snap-type: y proximity;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-ui);
  background: var(--ink);
  color: var(--paper);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

::selection { background: var(--gold); color: var(--ink); }

:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
}

/* ---------- scenes ---------- */

.chapter {
  min-height: 100svh;
  display: grid;
  place-items: center;
  padding: clamp(4.5rem, 10vh, 7rem) clamp(1.25rem, 6vw, 5rem) clamp(3.5rem, 8vh, 5rem);
  position: relative;
  scroll-snap-align: start;
  overflow: hidden;
}

.scene-ink {
  background: var(--ink); color: var(--paper);
  --line: var(--line-dark); --muted: var(--muted-dark);
}
.scene-paper {
  background: var(--paper); color: var(--ink);
  --line: var(--line-light); --muted: var(--muted-light);
}

.chapter__inner {
  width: min(100%, 68rem);
  position: relative;
  z-index: 2;
}

/* chapter number, set large and faint behind the content */
.chapter__num {
  position: absolute;
  top: clamp(3.5rem, 9vh, 6rem);
  right: clamp(1.25rem, 6vw, 5rem);
  font-family: var(--font-display);
  font-size: clamp(4rem, 14vw, 12rem);
  font-weight: 300;
  line-height: 1;
  color: var(--gold);
  opacity: .10;
  pointer-events: none;
  user-select: none;
  z-index: 1;
}

/* ---------- type ---------- */

.display {
  font-family: var(--font-display);
  font-weight: 340;
  line-height: .98;
  font-size: var(--step-h2);
  letter-spacing: -0.015em;
  text-wrap: balance;
}
.hero-title { font-size: var(--step-hero); font-weight: 300; }

.microlabel {
  font-size: .72rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 500;
}
:lang(th) .microlabel { letter-spacing: .06em; text-transform: none; font-size: .8rem; }

.lede {
  font-size: clamp(1rem, 1.6vw, 1.25rem);
  line-height: 1.6;
  color: var(--muted);
  max-width: 44ch;
}

.gold { color: var(--gold); }
.stat { font-variant-numeric: tabular-nums; font-weight: 600; }

.hairline { border: 0; border-top: 1px solid var(--line); margin-block: clamp(1.5rem, 4vh, 2.5rem); }

.note {
  font-size: .82rem;
  line-height: 1.55;
  color: var(--muted);
  max-width: 58ch;
  margin-top: 1rem;
}

/* ---------- choreography ---------- */

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.reveal:nth-child(2) { transition-delay: 90ms; }
.reveal:nth-child(3) { transition-delay: 180ms; }
.reveal:nth-child(4) { transition-delay: 260ms; }
.reveal:nth-child(5) { transition-delay: 330ms; }
.is-active .reveal { opacity: 1; transform: none; }

.drawline {
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 900ms var(--ease) 120ms;
}
.is-active .drawline { transform: scaleX(1); }

/* gold sweep on chapter entry */
.chapter::before {
  content: "";
  position: absolute;
  inset: 0 100% 0 0;
  background: var(--gold);
  opacity: .06;
  transition: inset 800ms var(--ease);
  pointer-events: none;
  z-index: 0;
}
.is-active::before { inset: 0; }

/* ---------- chrome ---------- */

#chrome {
  position: fixed;
  inset: 0 0 auto 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 1.1rem clamp(1.25rem, 4vw, 3rem);
  z-index: 30;
  mix-blend-mode: difference;
  color: #fff;
}
#chrome .wordmark {
  font-size: .78rem;
  letter-spacing: .26em;
  font-weight: 600;
}
#chrome button {
  all: unset;
  cursor: pointer;
  font-size: .72rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  padding: .4rem .7rem;
  border: 1px solid rgba(255, 255, 255, .35);
  border-radius: 2px;
  transition: border-color .3s, background .3s;
}
#chrome button:hover { border-color: #fff; }
#chrome .chrome-right { display: flex; gap: .5rem; align-items: center; }

/* chapter index panel */
#index-panel {
  position: fixed;
  inset: 0;
  background: var(--ink);
  color: var(--paper);
  z-index: 40;
  display: none;
  place-items: center;
}
#index-panel[data-open="true"] { display: grid; }
#index-panel ol { list-style: none; padding: 0; margin: 0; }
#index-panel li { margin-block: .4rem; }
#index-panel a {
  color: var(--paper);
  text-decoration: none;
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 3vw, 2rem);
  display: flex;
  gap: 1.2rem;
  align-items: baseline;
  transition: color .3s;
}
#index-panel a:hover { color: var(--gold); }
#index-panel a span:first-child {
  font-family: var(--font-ui);
  font-size: .7rem;
  letter-spacing: .18em;
  color: var(--gold);
  min-width: 2.5rem;
}
#index-close {
  position: absolute; top: 1.1rem; right: clamp(1.25rem, 4vw, 3rem);
  all: unset; cursor: pointer; font-size: .72rem; letter-spacing: .18em;
  text-transform: uppercase; color: var(--paper);
  border: 1px solid var(--line-dark); padding: .4rem .7rem; border-radius: 2px;
}

/* ---------- progress rail ---------- */

#rail {
  position: fixed;
  right: clamp(.6rem, 2vw, 1.6rem);
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: .9rem;
  z-index: 30;
  mix-blend-mode: difference;
}
#rail a {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: rgba(255, 255, 255, .3);
  transition: background .3s, transform .3s;
  display: block;
}
#rail a[aria-current="true"] { background: var(--gold); transform: scale(1.5); }
@media (max-width: 640px) { #rail { display: none; } }

/* ---------- controls ---------- */

.control-row {
  display: flex;
  justify-content: space-between;
  gap: .6rem;
  align-items: baseline;
  margin-block: .9rem .35rem;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--gold);
  height: 1.6rem;
  cursor: pointer;
}

output { font-variant-numeric: tabular-nums; font-weight: 600; font-size: 1.05rem; }

.panel { max-width: 46rem; }

.readout {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(1.5rem, 5vw, 3.5rem);
  margin-top: 1.5rem;
}
.readout > div { min-width: 7rem; }
.readout .big {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4.5vw, 3rem);
  line-height: 1;
  font-variant-numeric: tabular-nums;
  display: block;
}

/* bracket staircase */
.stair {
  position: relative;
  height: 2.2rem;
  border: 1px solid var(--line);
  margin-block: .35rem;
  display: flex;
  align-items: center;
  padding-inline: .6rem;
  overflow: hidden;
}
.stair__fill {
  position: absolute;
  inset: 0;
  transform-origin: left;
  background: var(--gold);
  opacity: .85;
  transition: transform 500ms var(--ease);
}
.stair__label {
  position: relative;
  z-index: 1;
  font-size: .72rem;
  letter-spacing: .06em;
  mix-blend-mode: difference;
  color: #fff;
  white-space: nowrap;
}

/* ceiling meters */
.meter {
  position: relative;
  height: .55rem;
  border: 1px solid var(--line);
  overflow: hidden;
  margin-block: .4rem .2rem;
}
.meter__fill {
  position: absolute; inset: 0;
  transform-origin: left;
  background: var(--gold);
  transition: transform 400ms var(--ease);
}
.chip {
  font-size: .62rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  border: 1px solid var(--gold);
  color: var(--gold);
  padding: .1rem .4rem;
  border-radius: 2px;
  margin-left: .5rem;
}

/* cards */
.cards { display: grid; gap: .5rem; grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr)); }
.card { border: 1px solid var(--line); padding: .9rem 1.1rem; }
.card > summary {
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 1.15rem;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
}
.card > summary::-webkit-details-marker { display: none; }
.card > summary::after { content: "+"; color: var(--gold); font-size: 1.2rem; }
.card[open] > summary::after { content: "−"; }
.card[open] { border-left: 2px solid var(--gold); }
.card dl { margin: .8rem 0 0; display: grid; gap: .5rem; }
.card dt { font-size: .64rem; letter-spacing: .16em; text-transform: uppercase; color: var(--muted); }
.card dd { margin: .1rem 0 0; font-size: .85rem; line-height: 1.5; }
.dots { display: inline-flex; gap: 3px; }
.dots i { width: 6px; height: 6px; border-radius: 50%; background: var(--line); display: block; }
.dots i.on { background: var(--gold); }

/* timeline */
.timeline {
  display: flex;
  gap: 1rem;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding-bottom: 1rem;
  margin-top: 1.5rem;
  scrollbar-width: thin;
}
.tl-card {
  scroll-snap-align: center;
  flex: 0 0 min(19rem, 78vw);
  border: 1px solid var(--line);
  border-top: 2px solid var(--gold);
  padding: 1rem;
}
.tl-card.is-milestone { border-top-color: var(--line); border-left: 2px solid var(--gold); }
.tl-date { font-size: .68rem; letter-spacing: .16em; text-transform: uppercase; color: var(--gold); }
.tl-title { font-family: var(--font-display); font-size: 1.1rem; margin-block: .4rem .3rem; }
.tl-note { font-size: .78rem; line-height: 1.5; color: var(--muted); }

.btn {
  display: inline-block;
  margin-top: 1.2rem;
  padding: .7rem 1.3rem;
  border: 1px solid var(--gold);
  color: var(--gold);
  text-decoration: none;
  font-size: .72rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  transition: background .3s, color .3s;
}
.btn:hover { background: var(--gold); color: var(--ink); }

.seg { display: inline-flex; border: 1px solid var(--line); margin-top: .5rem; }
.seg button {
  all: unset;
  cursor: pointer;
  padding: .45rem .9rem;
  font-size: .68rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  transition: background .3s, color .3s;
}
.seg button[aria-pressed="true"] { background: var(--gold); color: var(--ink); }

/* chart */
.chart-wrap { margin-top: 1.5rem; overflow-x: auto; }
svg.chart { width: 100%; height: auto; display: block; min-width: 20rem; }

/* colophon — credits and terms */
.colophon__who {
  display: grid;
  grid-template-columns: minmax(6rem, auto) 1fr;
  gap: .45rem 1.5rem;
  align-items: baseline;
  margin: 1rem 0 0;
  max-width: 46rem;
}
.colophon__who dt { padding-top: .15rem; }
.colophon__who dd { margin: 0; font-size: .9rem; line-height: 1.5; }
.colophon__name { font-family: var(--font-display); font-size: 1.35rem; line-height: 1.2; }

.colophon__terms {
  list-style: none;
  padding: 1rem 0 0 1rem;
  margin: 1.5rem 0 0;
  border-left: 2px solid var(--gold);
  display: grid;
  gap: .7rem;
  max-width: 58ch;
}
.colophon__terms li {
  font-size: .74rem;
  line-height: 1.6;
  letter-spacing: .06em;
  color: var(--muted);
}
.colophon__terms li:first-child { color: var(--gold); }
:lang(th) .colophon__terms li { letter-spacing: 0; font-size: .8rem; }

/* sources */
.sources { font-size: .76rem; line-height: 1.7; color: var(--muted); word-break: break-word; }
.sources h3 { font-size: .68rem; letter-spacing: .16em; text-transform: uppercase; color: var(--gold); margin-top: 1.2rem; font-weight: 600; }
.sources a { color: inherit; }

/* footer disclaimer inside each chapter */
.chapter__foot {
  position: absolute;
  bottom: clamp(1.1rem, 3vh, 2rem);
  left: clamp(1.25rem, 6vw, 5rem);
  right: clamp(1.25rem, 6vw, 5rem);
  z-index: 2;
  font-size: .62rem;
}

/* banners */
#stale-banner {
  position: fixed; inset: auto 0 0 0;
  background: var(--gold); color: var(--ink);
  padding: .5rem 1rem; font-size: .78rem; text-align: center;
  z-index: 50; display: none;
}

/* hero atmosphere: drifting gold particles */
.particles { position: absolute; inset: 0; z-index: 0; pointer-events: none; }
.particles i {
  position: absolute;
  width: 2px; height: 2px;
  background: var(--gold);
  border-radius: 50%;
  opacity: .35;
  animation: drift linear infinite;
}
@keyframes drift {
  from { transform: translate3d(0, 0, 0); opacity: 0; }
  15% { opacity: .45; }
  85% { opacity: .35; }
  to { transform: translate3d(14px, -90px, 0); opacity: 0; }
}

.scroll-cue { display: inline-flex; align-items: center; gap: .5rem; margin-top: 2.5rem; }
.scroll-cue::after {
  content: ""; width: 1px; height: 2rem; background: var(--gold);
  animation: cue 2.2s var(--ease) infinite;
  transform-origin: top;
}
@keyframes cue { 0%, 100% { transform: scaleY(.3); opacity: .4; } 50% { transform: scaleY(1); opacity: 1; } }

noscript .note { color: var(--gold); }

/* ---------- reduced motion ---------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; scroll-snap-type: none; }
  .reveal, .drawline, .chapter::before, #rail a, .stair__fill, .meter__fill { transition: none !important; }
  .reveal { opacity: 1; transform: none; }
  .drawline { transform: scaleX(1); }
  .particles i, .scroll-cue::after { animation: none; }
  .particles { display: none; }
}