:root {
  color-scheme: light;
  --page: #f5f6f9;
  --surface: #ffffff;
  --ink: #17181c;
  --muted: #747780;
  --line: #dfe1e7;
  --link: #173f93;
  --focus: rgba(77, 126, 255, 0.32);
  --added: #2d8a56;
  --added-bg: #eaf6ee;
  --changed: #bd7d18;
  --changed-bg: #fff3d6;
  --removed: #bd4f45;
  --removed-bg: #fcebea;
  --ease-enter: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-standard: cubic-bezier(0.65, 0, 0.35, 1);
  font-family: Arial, Helvetica, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  min-width: 320px;
  margin: 0;
  background:
    radial-gradient(circle at 76% 9%, rgba(77, 126, 255, 0.08), transparent 29rem),
    var(--page);
  color: var(--ink);
}

button,
select {
  font: inherit;
}

.skip-link {
  position: fixed;
  z-index: 10;
  top: 8px;
  left: 8px;
  padding: 8px 12px;
  background: var(--ink);
  color: #ffffff;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.page-shell {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
  padding: 72px 0 88px;
}

.intro {
  max-width: 720px;
  margin-bottom: 38px;
}

.eyebrow,
.control-kicker {
  margin: 0 0 10px;
  color: #4f70c4;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.intro h1 {
  max-width: 680px;
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(38px, 6vw, 68px);
  font-weight: 500;
  letter-spacing: -0.045em;
  line-height: 0.98;
  text-wrap: balance;
}

.intro-copy {
  max-width: 620px;
  margin: 22px 0 0;
  color: #5d6069;
  font-size: 16px;
  line-height: 1.6;
  text-wrap: pretty;
}

.demo-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  align-items: start;
  gap: 34px;
}

.demo-stage {
  min-width: 0;
}

.timeline-card {
  overflow: hidden;
  border: 1px solid transparent;
  border-radius: 10px;
  background:
    linear-gradient(var(--surface), var(--surface)) padding-box,
    linear-gradient(105deg, #ff4f60 0%, #dc5e89 31%, #8967cf 63%, #4d7eff 100%) border-box;
}

.timeline-card-header {
  display: flex;
  align-items: center;
  min-height: 48px;
  gap: 7px;
  padding: 10px 18px 6px;
}

.sparkles {
  width: 24px;
  height: 22px;
  flex: 0 0 24px;
  color: #d95583;
}

.sparkles svg {
  display: block;
  width: 100%;
  height: 100%;
}

.timeline-card-header h2 {
  margin: 0;
  background: linear-gradient(90deg, #e94e67 0%, #9b64c8 50%, #4f77dd 100%);
  background-clip: text;
  color: transparent;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.025em;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.mode-label {
  margin-left: 3px;
  padding: 3px 5px 2px;
  border: 1px solid #cfd3df;
  border-radius: 2px;
  color: #6d7280;
  font-size: 8px;
  font-weight: 800;
  letter-spacing: 0.08em;
  line-height: 1;
  text-transform: uppercase;
}

.mode-label.is-running {
  border-color: #7890d8;
  background: #f3f6ff;
  color: #31509d;
}

.mode-label.is-complete {
  border-color: #4f70c4;
  background: #4f70c4;
  color: #ffffff;
}

.timeline-list {
  position: relative;
  padding: 2px 0 8px;
}

.timeline-list::before {
  position: absolute;
  top: 13px;
  bottom: 15px;
  left: 27px;
  border-left: 1px dashed #a8a8a8;
  content: "";
}

.timeline-group {
  position: relative;
  padding: 8px 20px 8px 46px;
}

.timeline-group-dot {
  position: absolute;
  top: 13px;
  left: 24px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #939393;
  box-shadow: 0 0 0 2px #ffffff;
}

.timeline-group-head {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 3px 6px;
  min-width: 0;
  padding-bottom: 4px;
}

.timeline-date {
  color: #747474;
  font-size: 12px;
  font-variant-numeric: tabular-nums;
}

.timeline-summary {
  min-width: 0;
  color: #202020;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.3;
  text-wrap: pretty;
}

.timeline-summary::before {
  margin-right: 6px;
  color: #858585;
  font-weight: 400;
  content: "|";
}

.timeline-items,
.removed-cluster-items {
  display: grid;
  gap: 0;
  min-width: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.timeline-row {
  display: grid;
  grid-template-columns: 8px minmax(0, 1fr) minmax(68px, 82px);
  align-items: baseline;
  gap: 6px;
  min-width: 0;
  padding: 3px 0;
}

.row-marker {
  align-self: center;
  width: 3px;
  height: 3px;
  margin-left: 2px;
  border-radius: 50%;
  background: #31509d;
}

.row-copy {
  min-width: 0;
}

.row-headline {
  color: var(--link);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 14px;
  line-height: 1.3;
  text-decoration: none;
  text-wrap: pretty;
}

.row-date {
  justify-self: end;
  color: #747474;
  font-size: 10.5px;
  line-height: 1.3;
  text-align: right;
}

.diff-field {
  padding: 0 2px;
  border-radius: 2px;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

.timeline-row[data-diff="added"] .diff-field,
.timeline-group[data-diff="added"] .timeline-group-head {
  background: var(--added-bg);
  box-shadow: inset 0 -2px var(--added);
}

.timeline-row[data-diff="added"] .row-marker,
.timeline-group[data-diff="added"] .timeline-group-dot {
  background: var(--added);
}

.timeline-row[data-diff="changed"] .diff-field {
  background: var(--changed-bg);
  box-shadow: inset 0 -2px var(--changed);
}

.timeline-row[data-diff="removed"] {
  opacity: 0.56;
}

.timeline-row[data-diff="removed"] .diff-field {
  background: var(--removed-bg);
  box-shadow: inset 0 -2px var(--removed);
  text-decoration: line-through;
}

.timeline-row[data-diff="removed"] .row-marker {
  background: var(--removed);
}

.diff-tag {
  display: inline-flex;
  margin-left: 5px;
  padding: 1px 3px;
  border: 1px solid currentColor;
  border-radius: 2px;
  font-family: Arial, sans-serif;
  font-size: 7px;
  font-weight: 800;
  letter-spacing: 0.05em;
  line-height: 1.15;
  text-transform: uppercase;
  vertical-align: 1px;
}

.diff-tag.added {
  color: #247047;
}

.diff-tag.changed {
  color: #8d5b0c;
}

.diff-tag.removed {
  color: #9a3f38;
}

.timeline-row.is-reviewing {
  animation: row-review 180ms var(--ease-standard) both;
}

.timeline-row.is-arriving {
  animation: row-arrive 280ms var(--ease-enter) both;
}

.timeline-row.is-changing {
  animation: row-change 260ms var(--ease-enter) both;
}

.timeline-row.is-removing {
  animation: row-remove 220ms ease-out both;
}

.timeline-row.is-collapsing {
  transform-origin: top left;
  pointer-events: none;
  animation: row-collapse 180ms cubic-bezier(0.55, 0, 1, 0.45) both;
}

.timeline-group.is-arriving {
  animation: group-arrive 300ms var(--ease-enter) both;
}

@keyframes row-review {
  0%, 100% { transform: translateX(0); }
  50% { transform: translateX(2px); }
}

@keyframes row-arrive {
  from { opacity: 0; transform: translateX(5px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes row-change {
  from { opacity: 0.84; transform: translateX(3px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes row-remove {
  from { opacity: 1; }
  to { opacity: 0.56; }
}

@keyframes row-collapse {
  from { opacity: 0.48; transform: translateY(0) scaleY(1); }
  to { opacity: 0; transform: translateY(-2px) scaleY(0.55); }
}

@keyframes group-arrive {
  from { opacity: 0; transform: translateY(5px); }
  to { opacity: 1; transform: translateY(0); }
}

.removed-cluster {
  display: block;
  padding: 0;
}

.removed-cluster-toggle {
  display: grid;
  grid-template-columns: 8px minmax(0, 1fr) auto;
  align-items: center;
  gap: 6px;
  width: 100%;
  min-height: 28px;
  padding: 3px 0;
  border: 0;
  border-radius: 2px;
  background: transparent;
  color: inherit;
  text-align: left;
  cursor: pointer;
  transition: background-color 160ms ease;
}

.removed-cluster-toggle:hover {
  background: rgba(189, 79, 69, 0.055);
}

.removed-cluster-toggle:active {
  background: rgba(189, 79, 69, 0.09);
}

.removed-cluster-toggle:focus-visible,
.primary-button:focus-visible,
.secondary-button:focus-visible,
select:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.removed-cluster-toggle .row-marker {
  background: var(--removed);
}

.removed-cluster-label {
  color: #9a3f38;
  font-size: 11px;
  font-weight: 700;
}

.removed-cluster-action {
  color: #31509d;
  font-size: 10.5px;
  font-weight: 700;
}

.removed-cluster-content {
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  transition:
    grid-template-rows 220ms var(--ease-standard),
    opacity 160ms ease-out;
}

.removed-cluster-content > div {
  min-height: 0;
  overflow: hidden;
}

.removed-cluster[data-expanded="true"] .removed-cluster-content {
  grid-template-rows: 1fr;
  opacity: 1;
}

.removed-cluster.is-arriving {
  transform-origin: top left;
  animation: cluster-arrive 170ms var(--ease-enter) both;
}

@keyframes cluster-arrive {
  from { opacity: 0; transform: translateY(3px) scaleY(0.88); }
  to { opacity: 1; transform: translateY(0) scaleY(1); }
}

.timeline-footer {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 9px 18px 12px;
  border-top: 1px solid #e3e3e3;
  color: #31509d;
  font-size: 12px;
  font-weight: 700;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #aeb2bc;
}

.status-dot.is-running {
  background: #4f70c4;
  animation: status-pulse 900ms ease-in-out infinite alternate;
}

.status-dot.is-complete {
  background: var(--added);
}

@keyframes status-pulse {
  to { box-shadow: 0 0 0 5px rgba(79, 112, 196, 0.13); }
}

.control-panel {
  display: grid;
  gap: 24px;
  padding: 24px;
  border-top: 2px solid #1f2e5f;
  background: rgba(255, 255, 255, 0.72);
}

.control-panel h2 {
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 23px;
  font-weight: 500;
  letter-spacing: -0.025em;
  line-height: 1.1;
}

.control-panel p {
  margin: 10px 0 0;
  color: #666a73;
  font-size: 13px;
  line-height: 1.55;
}

.button-row {
  display: grid;
  gap: 8px;
}

.primary-button,
.secondary-button {
  min-height: 40px;
  padding: 8px 12px;
  border-radius: 3px;
  font-weight: 700;
  cursor: pointer;
  transition: transform 120ms ease, background-color 160ms ease;
}

.primary-button {
  border: 1px solid #31509d;
  background: #31509d;
  color: #ffffff;
}

.secondary-button {
  border: 1px solid #b8bfd4;
  background: transparent;
  color: #31509d;
}

.primary-button:hover {
  background: #263f7e;
}

.secondary-button:hover {
  background: #f0f3fb;
}

.primary-button:active,
.secondary-button:active {
  transform: translateY(1px);
}

.primary-button:disabled,
.secondary-button:disabled {
  cursor: wait;
  opacity: 0.62;
}

.speed-control {
  display: grid;
  gap: 7px;
  color: #494d57;
  font-size: 12px;
  font-weight: 700;
}

.speed-control select {
  min-height: 38px;
  padding: 7px 10px;
  border: 1px solid #cdd0d8;
  border-radius: 3px;
  background: #ffffff;
  color: var(--ink);
}

.legend {
  display: grid;
  gap: 9px;
  padding-top: 18px;
  border-top: 1px solid #d9dce4;
  color: #555963;
  font-size: 12px;
}

.legend span {
  display: flex;
  align-items: center;
  gap: 8px;
}

.legend-swatch {
  width: 22px;
  height: 8px;
  border-radius: 2px;
}

.legend-swatch.is-added {
  background: var(--added-bg);
  box-shadow: inset 0 -2px var(--added);
}

.legend-swatch.is-changed {
  background: var(--changed-bg);
  box-shadow: inset 0 -2px var(--changed);
}

.legend-swatch.is-removed {
  background: var(--removed-bg);
  box-shadow: inset 0 -2px var(--removed);
}

.implementation-note {
  padding-top: 16px;
  border-top: 1px solid #d9dce4;
  font-size: 11px !important;
}

@media (max-width: 820px) {
  .page-shell {
    width: min(100% - 28px, 680px);
    padding-top: 42px;
  }

  .demo-layout {
    grid-template-columns: 1fr;
  }

  .control-panel {
    order: -1;
  }
}

@media (max-width: 560px) {
  .timeline-group {
    padding-right: 13px;
    padding-left: 36px;
  }

  .timeline-list::before {
    left: 20px;
  }

  .timeline-group-dot {
    left: 17px;
  }

  .timeline-row {
    grid-template-columns: 8px minmax(0, 1fr);
  }

  .row-date {
    grid-column: 2;
    justify-self: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}


/* Blog navigation; demo styling and motion are preserved. */
.lab-nav { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; margin-bottom: 32px; color: var(--muted); font-size: 12px; }
.lab-nav a { color: var(--ink); text-decoration: none; }
.lab-nav a:hover { text-decoration: underline; }
.lab-nav a:focus-visible { outline: 2px solid var(--link); outline-offset: 5px; }

/* Quiet standalone presentation: the diff states carry the colour. */
:root { --page: #fff; --ink: #252525; --link: #363636; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; }
body { background: var(--page); }
.page-shell { width: min(820px, calc(100% - 40px)); padding: 48px 0 64px; }
.intro { margin-bottom: 24px; }
.intro h1 { font: 500 24px/1.3 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; letter-spacing: -.025em; }
.intro-copy { margin-top: 8px; font-size: 14px; }
.sample-note { margin: 8px 0 0; font-size: 12px; color: var(--muted); }
.playback-bar { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.primary-button, .secondary-button { min-height: 36px; font-size: 12px; font-weight: 500; border-radius: 5px; }
.primary-button { background: #333; border-color: #333; }
.primary-button:hover { background: #555; }
.secondary-button { color: #444; border-color: #ddd; }
.secondary-button:hover { background: #f6f6f6; }
.speed-control { display: flex; align-items: center; gap: 8px; margin-left: auto; font-weight: 400; }
.speed-control select { min-height: 36px; border-color: #ddd; border-radius: 5px; }
.legend { display: flex; flex-wrap: wrap; gap: 20px; padding: 0; margin: 22px 0 12px; border: 0; font-size: 11px; }
.legend-swatch { width: 14px; }
.timeline-card { border: 1px solid #e7e7e7; border-radius: 6px; background: #fff; }
.timeline-card-header { padding-top: 16px; padding-bottom: 14px; }
.timeline-card-header h2 { color: #333; background: none; -webkit-text-fill-color: currentColor; font-size: 13px; font-weight: 500; }
.mode-label { margin-left: auto; font-weight: 500; }
.mode-label.is-running, .mode-label.is-complete { color: #555; background: #f6f6f6; border-color: #ddd; }
.timeline-group { padding-top: 12px; padding-bottom: 12px; }
.timeline-group-dot { top: 17px; }
.timeline-summary { font-weight: 500; }
.timeline-footer { color: #666; font-weight: 400; }
.status-dot.is-running { background: #777; }
@media (max-width: 560px) { .page-shell { width: calc(100% - 28px); padding-top: 28px; } .timeline-group-head { row-gap: 5px; } }

/* Embedded live preview: same rows and event engine, without page controls. */
html[data-preview] .lab-nav, html[data-preview] .intro, html[data-preview] .playback-bar,
html[data-preview] .legend, html[data-preview] .timeline-footer, html[data-preview] .skip-link { display: none; }
html[data-preview] body { min-width: 0; overflow: hidden; }
html[data-preview] .page-shell { width: 100%; padding: 16px; }
html[data-preview] .timeline-card { border: 0; background: transparent; }
html[data-preview] .timeline-card-header { padding: 8px 12px 16px; }
html[data-preview] .timeline-card-header h2 { font-size: 16px; }
html[data-preview] .timeline-group { padding-bottom: 18px; }
html[data-preview] .timeline-row { grid-template-columns: 8px minmax(0, 1fr); }
html[data-preview] .row-date { display: none; }
html[data-preview] .row-headline { font-size: 15px; }
html[data-preview] .timeline-date, html[data-preview] .timeline-summary { font-size: 14px; }
html[data-preview][data-theme="dark"] { color-scheme: dark; --page: #202220; --surface: #202220; --ink: #e5e7e5; --link: #d1d6d1; --muted: #a1a8a1; --added: #6abf85; --added-bg: #294234; --changed: #d1ab61; --changed-bg: #433a27; --removed: #d18479; --removed-bg: #432c29; }
html[data-preview][data-theme="dark"] .timeline-card-header h2,
html[data-preview][data-theme="dark"] .timeline-summary { color: #e5e7e5; }
html[data-preview][data-theme="dark"] .timeline-date { color: #a1a8a1; }
html[data-preview][data-theme="dark"] .timeline-group-dot { box-shadow: 0 0 0 2px #202220; }
html[data-preview][data-theme="dark"] .mode-label { color: #b5bcb5; background: #292e29; border-color: #485048; }
html[data-preview][data-theme="dark"] .diff-tag.added { color: var(--added); }
html[data-preview][data-theme="dark"] .diff-tag.changed { color: var(--changed); }
html[data-preview][data-theme="dark"] .diff-tag.removed { color: var(--removed); }