:root {
  color-scheme: dark;
  --ink: #effbf5;
  --muted: #9db3aa;
  --dim: #6f837b;
  --surface: #0c1715;
  --surface-2: #101f1c;
  --line: rgba(205, 239, 224, 0.14);
  --line-strong: rgba(205, 239, 224, 0.25);
  --mint: #58efb0;
  --mint-soft: #a6ffd7;
  --amber: #ffd36a;
  --activity: #ff8d73;
  --page: #07100f;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 50% -15%, rgba(46, 179, 125, 0.18), transparent 36rem),
    var(--page);
  min-width: 320px;
}
a { color: inherit; text-underline-offset: 0.2em; }
button, input, select { font: inherit; }
button { color: inherit; }

.site-header,
main,
footer {
  width: min(1180px, calc(100% - 40px));
  margin-inline: auto;
}

.site-header {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}
.wordmark {
  color: var(--ink);
  font-size: 1.35rem;
  font-weight: 760;
  letter-spacing: -0.05em;
  text-decoration: none;
}
.wordmark span { color: var(--mint); }
.site-header nav, footer nav { display: flex; gap: clamp(14px, 2vw, 30px); align-items: center; }
.site-header nav a, footer nav a, .raw-link {
  color: var(--muted);
  font-size: 0.83rem;
  font-weight: 620;
  text-decoration: none;
}
.site-header nav a:hover, footer nav a:hover, .raw-link:hover { color: var(--mint-soft); }

.hero {
  padding: clamp(70px, 10vw, 132px) 0 clamp(56px, 8vw, 96px);
  max-width: 940px;
}
.eyebrow, .section-kicker {
  margin: 0 0 16px;
  color: var(--mint);
  font: 700 0.73rem/1.2 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}
h1, h2, h3, p { margin-top: 0; }
h1 {
  margin-bottom: 30px;
  font-size: clamp(3rem, 8vw, 6.8rem);
  line-height: 0.93;
  letter-spacing: -0.07em;
  font-weight: 760;
}
h1 span { color: var(--mint); }
.lede {
  max-width: 680px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: clamp(1.05rem, 2vw, 1.34rem);
  line-height: 1.55;
}

.demo-shell {
  padding: clamp(24px, 4vw, 44px);
  border: 1px solid var(--line-strong);
  border-radius: 28px;
  background: linear-gradient(145deg, rgba(19, 38, 33, 0.92), rgba(8, 17, 15, 0.98));
  box-shadow: 0 38px 90px rgba(0, 0, 0, 0.32);
}
.demo-heading {
  display: flex;
  gap: 28px;
  justify-content: space-between;
  align-items: end;
}
.demo-heading h2, .reading-guide > h2, .limits h2 {
  margin-bottom: 0;
  font-size: clamp(1.65rem, 3vw, 2.8rem);
  line-height: 1.04;
  letter-spacing: -0.045em;
}
.mode-control { flex: 0 0 auto; }
.mode-control > span {
  display: block;
  margin: 0 0 8px 4px;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 680;
}
.segment {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: rgba(0, 0, 0, 0.24);
}
.mode-button {
  min-height: 44px;
  padding: 0 16px;
  border: 0;
  border-radius: 9px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 700;
}
.mode-button.is-active { background: var(--mint); color: #062016; }
.recording-picker {
  display: grid;
  grid-template-columns: auto minmax(220px, 370px) 1fr;
  gap: 10px 14px;
  align-items: center;
  margin-top: 24px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: rgba(0, 0, 0, 0.18);
}
.recording-picker label {
  color: var(--mint-soft);
  font-size: .75rem;
  font-weight: 720;
}
.recording-picker select {
  width: 100%;
  min-height: 44px;
  padding: 0 38px 0 12px;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: var(--surface-2);
  color: var(--ink);
  cursor: pointer;
  font-size: .82rem;
  font-weight: 650;
}
.recording-picker select:disabled { color: var(--dim); cursor: wait; }
.recording-picker p {
  margin: 0;
  color: var(--muted);
  font-size: .78rem;
  line-height: 1.45;
}
.mode-explanation {
  min-height: 23px;
  margin: 22px 0 18px;
  color: var(--muted);
  font-size: 0.88rem;
}

.comparison {
  display: grid;
  grid-template-columns: minmax(330px, 0.82fr) minmax(440px, 1.32fr);
  gap: 14px;
}
.screen-column, .state-column {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 19px;
  background: rgba(3, 9, 8, 0.65);
  overflow: hidden;
}
.screen-column { display: flex; flex-direction: column; padding: 18px; }
.state-column { display: flex; flex-direction: column; }
.pane-title {
  min-height: 46px;
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 14px;
}
.pane-title > div { display: flex; align-items: baseline; gap: 10px; min-width: 0; }
.pane-title h3 { margin: 0; font-size: 0.94rem; letter-spacing: -0.015em; }
.pane-number { color: var(--dim); font: 600 0.68rem ui-monospace, SFMono-Regular, Menlo, monospace; }
.pane-tag, .raw-link {
  flex: 0 0 auto;
  padding: 5px 8px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--mint-soft);
  font-size: 0.66rem;
  font-weight: 720;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.raw-link { color: var(--muted); text-transform: none; letter-spacing: 0; }
.state-title-row { padding: 18px 18px 0; }
.raw-links { display: flex; flex: 0 0 auto; gap: 6px; }
.raw-link[aria-disabled="true"] { color: var(--dim); pointer-events: none; }

.overlay-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 7px 13px;
  min-height: 25px;
  margin: -2px 0 9px;
  color: var(--dim);
  font: 600 .63rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace;
}
.overlay-legend span { display: inline-flex; align-items: center; gap: 5px; }
.overlay-legend i { width: 13px; height: 9px; border-radius: 2px; }
.legend-retained { border: 1px solid rgba(88, 239, 176, .78); background: rgba(88, 239, 176, .04); }
.legend-change { border: 2px solid var(--amber); background: rgba(255, 211, 106, .13); }
.legend-activity { border: 2px dashed var(--activity); background: rgba(255, 141, 115, .1); }

.phone-stage {
  position: relative;
  width: min(100%, var(--stage-width, 304px));
  aspect-ratio: var(--frame-ratio, 304 / 640);
  margin: auto;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.17);
  border-radius: 20px;
  background: #111;
  box-shadow: 0 18px 42px rgba(0, 0, 0, 0.42);
}
.phone-stage video, .overlay { position: absolute; inset: 0; width: 100%; height: 100%; }
.phone-stage video { display: block; object-fit: fill; }
.overlay { pointer-events: none; overflow: visible; }
.overlay .element-box {
  fill: rgba(88, 239, 176, 0.025);
  stroke: rgba(88, 239, 176, 0.68);
  stroke-width: 1;
  vector-effect: non-scaling-stroke;
}
.overlay .change-box {
  fill: rgba(255, 211, 106, .12);
  stroke: var(--amber);
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}
.overlay .change-box.is-disappeared,
.overlay .move-origin { fill: rgba(255, 211, 106, .035); stroke-dasharray: 3 3; }
.overlay .move-origin {
  stroke: rgba(255, 211, 106, .9);
  stroke-width: 1.5;
  vector-effect: non-scaling-stroke;
}
.overlay .activity-box {
  fill: rgba(255, 141, 115, .1);
  stroke: var(--activity);
  stroke-width: 2;
  stroke-dasharray: 4 3;
  vector-effect: non-scaling-stroke;
}
.overlay .change-path,
.overlay .activity-path {
  fill: none;
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}
.overlay .change-path { stroke: var(--amber); }
.overlay .activity-path { stroke: var(--activity); stroke-dasharray: 4 2; }
.overlay .change-arrow-head { fill: var(--amber); }
.overlay .activity-arrow-head { fill: var(--activity); }
.screen-caption {
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 10px;
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 7px 9px;
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: 9px;
  background: rgba(3, 10, 8, 0.84);
  backdrop-filter: blur(8px);
  color: #eafff4;
  font: 600 0.65rem/1.25 ui-monospace, SFMono-Regular, Menlo, monospace;
}
.status-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--mint); box-shadow: 0 0 0 3px rgba(88,239,176,.14); }

.playback-controls {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 12px;
  margin-top: 16px;
}
.play-button, #follow-button {
  min-height: 44px;
  border: 1px solid var(--line-strong);
  border-radius: 11px;
  background: rgba(255,255,255,.055);
  cursor: pointer;
  font-size: 0.78rem;
  font-weight: 700;
}
.play-button { display: inline-flex; align-items: center; gap: 7px; padding: 0 12px; }
.play-button svg { width: 14px; height: 14px; fill: currentColor; }
.play-button .pause-icon { display: none; }
.play-button.is-playing .play-icon { display: none; }
.play-button.is-playing .pause-icon { display: block; }
.timeline-wrap { position: relative; display: flex; align-items: center; min-width: 0; }
#timeline { width: 100%; accent-color: var(--mint); cursor: pointer; }
.marker-rail { position: absolute; inset: auto 2px -3px; height: 4px; pointer-events: none; }
.marker-rail i { position: absolute; width: 1px; height: 4px; background: rgba(166,255,215,.52); }
#time-output { color: var(--muted); font: 600 0.68rem ui-monospace, SFMono-Regular, Menlo, monospace; white-space: nowrap; }
.asset-error, .noscript { margin: 14px 0 0; padding: 12px; border-radius: 10px; background: rgba(255, 141, 115, .1); color: #ffd7cf; font-size: .8rem; line-height: 1.5; }

.grammar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  padding: 10px 18px;
  border-bottom: 1px solid var(--line);
  color: var(--dim);
  font: 600 0.65rem/1.3 ui-monospace, SFMono-Regular, Menlo, monospace;
}
.grammar b { color: var(--mint-soft); }
.state-viewport-wrap { position: relative; flex: 1; min-height: 0; }
.state-viewport {
  height: 578px;
  overflow: auto;
  padding: 12px 12px 50vh;
  scrollbar-color: rgba(88,239,176,.34) transparent;
  scrollbar-width: thin;
  overscroll-behavior: contain;
}
.state-block {
  position: relative;
  margin: 0 0 5px;
  padding: 10px 12px 10px 25px;
  border: 1px solid transparent;
  border-radius: 9px;
  color: #8ba097;
  background: transparent;
  font: 500 0.73rem/1.48 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  white-space: pre-wrap;
  word-break: break-word;
  transition: color 150ms ease, background 150ms ease, border-color 150ms ease;
}
.state-block::before { content: ""; position: absolute; left: 10px; top: 16px; width: 5px; height: 5px; border-radius: 50%; background: #3d514a; }
.state-block.is-past { color: #b8c9c1; }
.state-block.is-current { color: #effff7; border-color: rgba(88,239,176,.35); background: rgba(88,239,176,.085); }
.state-block.is-current::before { background: var(--mint); box-shadow: 0 0 0 4px rgba(88,239,176,.12); }
.state-footer {
  min-height: 54px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 7px 18px;
  border-top: 1px solid var(--line);
  color: var(--dim);
  font-size: 0.7rem;
}
#follow-button { min-height: 36px; padding: 0 12px; color: var(--mint-soft); }
.not-sent {
  position: absolute;
  inset: 0;
  z-index: 2;
  display: grid;
  place-content: center;
  gap: 6px;
  padding: 28px;
  text-align: center;
  background: rgba(6, 14, 12, 0.91);
  opacity: 0;
  pointer-events: none;
  transition: opacity 160ms ease;
}
.not-sent strong { font-size: 1.05rem; }
.not-sent span { max-width: 280px; color: var(--muted); font-size: 0.82rem; line-height: 1.5; }
.comparison[data-mode="pixels"] .overlay { opacity: 0; }
.comparison[data-mode="pixels"] .overlay-legend { visibility: hidden; }
.comparison[data-mode="pixels"] .not-sent { opacity: 1; }
.comparison[data-mode="pixels"] .pane-tag { color: var(--muted); }

.reading-guide, .limits { padding: clamp(88px, 12vw, 150px) 0; }
.reading-guide > h2 { max-width: 620px; }
.fact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  margin-top: 50px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 20px;
  overflow: hidden;
}
.fact-grid article { padding: clamp(24px, 3.5vw, 40px); background: var(--page); }
.fact-grid article > span { color: var(--mint); font: 650 .7rem ui-monospace, SFMono-Regular, Menlo, monospace; text-transform: uppercase; letter-spacing: .08em; }
.fact-grid h3 { margin: 28px 0 12px; font-size: 1.25rem; }
.fact-grid p, .limits-copy p, .attribution p { margin-bottom: 0; color: var(--muted); font-size: .92rem; line-height: 1.65; }
.limits { display: grid; grid-template-columns: minmax(260px, .8fr) minmax(400px, 1.2fr); gap: clamp(50px, 10vw, 130px); border-top: 1px solid var(--line); }
.limits-copy { display: grid; gap: 24px; }
.limits-copy strong { color: var(--ink); }
.limits-copy a { color: var(--mint-soft); }
.attribution { padding: 30px 0 60px; border-top: 1px solid var(--line); }
.attribution h2 { font-size: .8rem; text-transform: uppercase; letter-spacing: .09em; }
.attribution p { max-width: 900px; font-size: .78rem; }
.attribution code { color: #cde6db; }

footer {
  min-height: 112px;
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 24px;
  align-items: center;
  border-top: 1px solid var(--line);
}
footer p { margin: 0; color: var(--dim); font-size: .78rem; }

button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible, .state-viewport:focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 3px;
}

@media (max-width: 900px) {
  .site-header nav a:nth-child(3) { display: none; }
  .demo-heading { align-items: stretch; flex-direction: column; }
  .mode-control { align-self: start; }
  .recording-picker { grid-template-columns: auto minmax(220px, 1fr); }
  .recording-picker p { grid-column: 1 / -1; }
  .comparison { grid-template-columns: 1fr; }
  .phone-stage { max-height: 68vh; }
  .state-viewport { height: min(60vh, 510px); }
  .fact-grid { grid-template-columns: 1fr; }
  .limits { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .site-header, main, footer { width: min(100% - 24px, 1180px); }
  .site-header { min-height: 66px; }
  .site-header nav { gap: 14px; }
  .site-header nav a { font-size: .75rem; }
  .site-header nav a:first-child { display: none; }
  .hero { padding-top: 58px; }
  h1 { font-size: clamp(2.65rem, 14vw, 4.2rem); }
  .demo-shell { padding: 14px; border-radius: 20px; }
  .demo-heading { padding: 9px 6px 0; }
  .mode-control { width: 100%; }
  .segment { width: 100%; }
  .mode-button { padding-inline: 8px; }
  .mode-explanation { margin-inline: 6px; }
  .recording-picker { grid-template-columns: 1fr; margin-inline: 6px; padding: 12px; }
  .recording-picker p { grid-column: auto; }
  .screen-column { padding: 12px; }
  .phone-stage { max-height: 62vh; max-width: 100%; }
  .playback-controls { grid-template-columns: auto 1fr; }
  #time-output { grid-column: 1 / -1; justify-self: end; margin-top: -6px; }
  .grammar { padding-inline: 12px; }
  .state-title-row { padding-inline: 12px; }
  .state-viewport { height: 430px; padding-inline: 7px; }
  .state-block { font-size: .69rem; }
  .reading-guide, .limits { padding-block: 90px; }
  footer { grid-template-columns: auto 1fr; }
  footer nav { grid-column: 1 / -1; padding-bottom: 24px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
}