:root {
  color-scheme:light;
  --bg:#f7f8f5;
  --paper:#fff;
  --ink:#202a2a;
  --muted:#737b77;
  --line:#e0e5de;
  --green:#20684f;
  --mint:#e8f1e8;
  --sans:Inter,"Helvetica Neue",Arial,"PingFang SC","Microsoft YaHei",sans-serif;
}

* {
  box-sizing:border-box;
}

body {
  margin:0;
  background:var(--bg);
  color:var(--ink);
  font-family:var(--sans);
  -webkit-font-smoothing:antialiased;
}

button,a {
  -webkit-tap-highlight-color:transparent;
}

button {
  font:inherit;
  cursor:pointer;
}

a {
  color:inherit;
  text-decoration:none;
}

button:focus-visible,a:focus-visible,video:focus-visible {
  outline:3px solid #238f68;
  outline-offset:4px;
}

button {
  touch-action:manipulation;
}

button:disabled {
  cursor:wait;
  opacity:.55;
}

[hidden] {
  display:none!important;
}

.site-header {
  max-width:1320px;
  margin:auto;
  padding:25px 48px;
  display:flex;
  align-items:center;
  justify-content:space-between;
}

.wordmark {
  display:flex;
  gap:11px;
  align-items:center;
  font-size:11px;
  font-weight:700;
  letter-spacing:1.7px;
}

.brand-symbol {
  display:grid;
  place-items:center;
  width:33px;
  height:33px;
  background:var(--ink);
  color:white;
  border-radius:9px;
  font-size:15px;
  font-weight:800;
  letter-spacing:-1px;
}

main {
  max-width:1120px;
  margin:auto;
  padding:0 36px;
}

.intro {
  text-align:center;
  padding:38px 0 35px;
}

.eyebrow {
  font-size:10px;
  font-weight:700;
  letter-spacing:2.1px;
  color:var(--green);
  margin:0 0 19px;
  display:flex;
  gap:10px;
  align-items:center;
}

.intro .eyebrow {
  justify-content:center;
}

.status-dot {
  display:inline-block;
  flex-shrink:0;
  width:6px;
  height:6px;
  background:#4a8764;
  border-radius:50%;
}

.divider {
  color:#b6c0b6;
  margin:0 4px;
}

h1 {
  font-size:clamp(32px,4.4vw,53px);
  line-height:1.13;
  letter-spacing:-2px;
  font-weight:650;
  margin:0;
}

h1>span {
  display:block;
  font-size:.61em;
  letter-spacing:-1px;
  font-weight:400;
  color:#778079;
  margin-top:11px;
}

h1 strong {
  font-weight:600;
  color:var(--green);
}

.intro-copy {
  font-size:16px;
  line-height:1.8;
  color:#6b746e;
  max-width:860px;
  margin:22px auto 19px;
}

.tags {
  display:flex;
  flex-wrap:wrap;
  justify-content:center;
  align-items:center;
  gap:13px;
  font-size:13px;
  color:#67736a;
}

.tags span {
  padding:5px 10px;
  border:1px solid #e0e6dc;
  border-radius:5px;
}

.tags i {
  font-style:normal;
  color:#9ba698;
}

.showcase {
  border:1px solid #dce2d9;
  border-radius:14px;
  overflow:hidden;
  background:var(--paper);
  box-shadow:0 12px 42px #263b2510;
}

.toolbar {
  padding:15px 20px;
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:14px;
}

.control-group {
  display:flex;
  align-items:center;
  gap:13px;
}

.control-label {
  font-size:14px;
  color:var(--muted);
}

.segmented {
  display:flex;
  gap:3px;
  background:#f1f3ef;
  border:1px solid #e9ece5;
  padding:3px;
  border-radius:7px;
}

.segmented button {
  border:0;
  background:transparent;
  color:#6a756d;
  border-radius:4px;
  padding:8px 14px;
  font-size:14px;
  line-height:1.1;
  min-height:38px;
  white-space:nowrap;
}

.segmented button[aria-pressed=true] {
  background:var(--ink);
  color:white;
  box-shadow:0 1px 3px #0002;
}

.segmented button:hover:not([aria-pressed=true]) {
  background:#e3e9df;
  color:var(--ink);
}

.speeds button {
  min-width:44px;
  padding:8px 10px;
}

.video-wrap {
  position:relative;
  background:#b7d2e5;
}

video {
  display:block;
  width:100%;
  aspect-ratio:848/480;
  object-fit:contain;
  background:#b7d2e5;
}

.start-button {
  position:absolute;
  inset:0;
  margin:auto;
  width:64px;
  height:64px;
  padding:0;
  border:1px solid rgba(255,255,255,.35);
  border-radius:50%;
  display:flex;
  align-items:center;
  justify-content:center;
  background:rgba(75,75,75,.55);
  color:#fff;
  box-shadow:0 3px 14px rgba(0,0,0,.15);
  backdrop-filter:blur(4px);
  -webkit-backdrop-filter:blur(4px);
}

.start-button:hover {
  background:rgba(75,75,75,.72);
}
.start-button svg {
  width:28px;
  height:28px;
  transform:translateX(2px);
}

.playback-info {
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  align-items:center;
  gap:10px;
  padding:17px 22px;
  font-size:14px;
}

.current-action {
  display:flex;
  align-items:center;
  gap:10px;
  min-width:0;
}

.current-action #playback-state {
  color:var(--muted);
  white-space:nowrap;
}

.current-action strong {
  font-weight:500;
}

.info-divider {
  color:#c1c8bd;
}

.time-display {
  white-space:nowrap;
  font:13px ui-monospace,SFMono-Regular,Consolas,monospace;
  font-variant-numeric:tabular-nums;
}

.time-total {
  color:#90998f;
}

.chapter-progress {
  display:flex;
  gap:3px;
  padding:0 22px 17px;
}

.chapter-progress button {
  position:relative;
  height:5px;
  padding:0;
  border:0;
  border-radius:2px;
  background:#e9ede5;
  overflow:visible;
}

.chapter-progress button:before {
  content:"";
  position:absolute;
  inset:-6px 0;
}

.chapter-progress button span {
  display:block;
  background:#5c8b65;
  height:100%;
  width:0;
  border-radius:2px;
}

.player-caption {
  display:flex;
  align-items:center;
  flex-wrap:wrap;
  justify-content:space-between;
  gap:15px;
  padding:12px 2px;
  color:#7f877e;
  font-size:13px;
  line-height:1.7;
}

.player-caption p {
  margin:0;
}

.player-caption>span {
  white-space:nowrap;
}

.sequence {
  padding:37px 0 58px;
}

.section-heading {
  display:flex;
  justify-content:space-between;
  align-items:end;
  gap:20px;
  margin-bottom:24px;
}

.section-heading .eyebrow {
  font-size:9px;
  margin-bottom:10px;
  letter-spacing:1.7px;
}

h2 {
  font-size:25px;
  letter-spacing:-.7px;
  margin:0;
  font-weight:550;
}

.section-heading>p {
  display:flex;
  align-items:center;
  gap:6px;
  margin:0 0 3px;
  font-size:13px;
  color:#80897e;
}

.legend-dot {
  display:inline-block;
  width:6px;
  height:6px;
  border-radius:50%;
  background:var(--green);
}

.hint-separator {
  margin:0 3px;
}

.phase-grid {
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  gap:12px;
  align-items:start;
}

.phase {
  border:1px solid var(--line);
  border-radius:10px;
  background:#fdfefb;
  overflow:hidden;
  transition:border-color .15s;
}

.phase.active {
  border-color:#719d79;
}

.phase-heading {
  padding:17px 15px 15px;
  border-bottom:1px solid #e8ece3;
}

.phase-topline {
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  justify-content:space-between;
  align-items:center;
  margin-bottom:17px;
}

.phase-number {
  font:14px ui-monospace,monospace;
  color:#8a9787;
}

.phase.active .phase-number {
  color:var(--green);
}

.phase-range {
  font:11px ui-monospace,monospace;
  color:#909a8c;
}

.phase h3 {
  font-size:17px;
  font-weight:600;
  margin:0 0 7px;
}

.phase-subtitle {
  font-size:11px;
  letter-spacing:1.3px;
  color:#8c9687;
  margin:0;
}

.action-list {
  list-style:none;
  padding:8px;
  margin:0;
  display:grid;
  gap:4px;
}

.action-button {
  width:100%;
  min-height:44px;
  text-align:left;
  border:1px solid transparent;
  background:transparent;
  border-radius:5px;
  display:flex;
  align-items:center;
  gap:7px;
  padding:9px 8px;
  font-size:14px;
  color:#6c7868;
  line-height:1.5;
}

.action-button:before {
  content:"";
  width:4px;
  height:4px;
  flex-shrink:0;
  border-radius:50%;
  background:#c2ccbb;
}

.action-button:hover {
  background:#f0f4e9;
  color:#325c36;
}

.action-button[aria-current=step] {
  border-color:#d7e6ce;
  background:#eaf2e4;
  color:#2c6038;
  font-weight:600;
}

.action-button[aria-current=step]:before {
  background:#367d4b;
  box-shadow:0 0 0 3px #d8e8ce;
}

.action-button time {
  margin-left:auto;
  color:#939f8b;
  font:11px ui-monospace,monospace;
  white-space:nowrap;
}

.error {
  margin:14px 20px;
  padding:12px;
  background:#fff1ec;
  border:1px solid #eac2b4;
  border-radius:5px;
  color:#903f24;
  font-size:13px;
  line-height:1.7;
}

footer {
  border-top:1px solid var(--line);
  max-width:1048px;
  margin:auto;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:15px;
  padding:24px 0 32px;
  color:#899180;
  font-size:10px;
}

footer>div {
  display:flex;
  align-items:center;
  gap:8px;
}

.footer-mark {
  font-weight:800;
  color:#57684f;
  font-size:15px;
}

.footer-separator {
  color:#b6bfac;
  margin:0 3px;
}

footer a {
  color:#5f7552;
}

footer a:hover {
  text-decoration:underline;
}

@media(min-width:1500px) {
  .intro {
    padding-top:48px;
  }
}

@media(max-width:850px) {
  .site-header {
    padding:22px 28px;
  }
  main {
    padding:0 24px;
  }
  .intro {
    padding-top:27px;
  }
  .phase-grid {
    grid-template-columns:repeat(2,minmax(0,1fr));
  }
  .section-heading {
    align-items:start;
  }
  .section-heading>p {
    padding-top:20px;
  }
  footer {
    margin:0 24px;
  }
}

@media(max-width:540px) {
  .site-header {
    padding:18px 20px;
  }
  .wordmark {
    font-size:9px;
  }
  .brand-symbol {
    width:29px;
    height:29px;
  }
  main {
    padding:0 16px;
  }
  .intro {
    padding:26px 0;
  }
  .intro .eyebrow {
    font-size:8px;
    letter-spacing:1.6px;
    gap:7px;
    margin-bottom:18px;
  }
  h1 {
    font-size:32px;
    letter-spacing:-1.5px;
  }
  h1>span {
    font-size:21px;
    letter-spacing:-.5px;
    margin-top:10px;
  }
  .intro-copy {
    font-size:15px;
    margin:18px auto;
  }
  .tags {
    gap:5px;
    font-size:11px;
  }
  .tags span {
    padding:5px 6px;
  }
  .toolbar {
    padding:11px;
    gap:10px;
    flex-wrap:wrap;
  }
  .control-group {
    gap:8px;
  }
  .control-label {
    font-size:13px;
  }
  .segmented button {
    font-size:14px;
    padding:8px 10px;
  }
  .speeds button {
    min-width:35px;
    padding:8px;
  }
  .showcase {
    border-radius:10px;
  }
  .playback-info {
    padding:13px 12px;
    font-size:13px;
  }
  .current-action {
    gap:6px;
  }
  .time-display {
    font-size:12px;
  }
  .chapter-progress {
    padding:0 12px 13px;
  }
  .start-button {
    width:56px;
    height:56px;
  }
  .player-caption {
    font-size:13px;
  }
  .player-caption>span {
    display:none;
  }
  .sequence {
    padding:26px 0 34px;
  }
  .section-heading {
    display:block;
    margin-bottom:18px;
  }
  .section-heading>p {
    padding-top:13px;
    font-size:12px;
  }
  h2 {
    font-size:22px;
  }
  .phase-grid {
    gap:10px;
  }
  .phase-heading {
    padding:14px 10px;
  }
  .phase-topline {
    margin-bottom:12px;
  }
  .phase h3 {
    font-size:16px;
  }
  .phase-subtitle {
    font-size:10px;
    letter-spacing:.7px;
  }
  .phase-range {
    font-size:10px;
  }
  .action-list {
    padding:5px;
    gap:3px;
  }
  .action-button {
    font-size:14px;
    padding:8px 5px;
    gap:6px;
  }
  .action-button time {
    font-size:11px;
  }
  footer {
    margin:0 16px;
    font-size:9px;
    flex-wrap:wrap;
    padding:19px 0 25px;
  }
  footer>span {
    display:none;
  }
}

@media(prefers-reduced-motion:reduce) {
  *,*:before,*:after {
    transition:none!important;
    scroll-behavior:auto!important;
  }
}

.download-button {
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  flex-shrink:0;
  min-height:44px;
  padding:10px 18px;
  border:1px solid var(--green);
  border-radius:7px;
  background:var(--green);
  color:#fff;
  font-size:14px;
  font-weight:600;
}
.download-button:hover {
  background:#184f3d;
}
.action-button > span {
  min-width:0;
  overflow-wrap:anywhere;
}
@media(max-width:540px) {
  .player-caption {
    align-items:flex-start;
    flex-direction:column;
  }
  .current-action {
    flex-wrap:wrap;
  }
  .start-button {
    width:56px;
    height:56px;
  }
}

.method-entry {display:flex;justify-content:center;margin:0 0 28px;padding:0}
@media(max-width:540px) {
  .method-entry {margin:0 0 22px}
}

/* Version navigation and paired views share the original visual palette. */
.version-switch {display:flex;justify-content:center;gap:14px;flex-wrap:wrap;margin:0 0 28px}
.version-button {display:inline-flex;align-items:center;justify-content:center;min-height:46px;padding:11px 22px;border:1px solid #20684f;border-radius:7px;background:#20684f;color:#fff;font-size:14px;font-weight:600}
.version-button:hover {background:#184f3d}
.version-button[aria-current="page"] {background:#154b38;box-shadow:0 0 0 3px #cbded1}
.dual-video {display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1px;background:var(--line)}
.video-pane {min-width:0;background:var(--paper)}
.video-heading {font-size:14px;font-weight:500;letter-spacing:0;padding:11px 20px;border-top:1px solid var(--line);color:var(--green)}
@media(max-width:650px) {.dual-video{grid-template-columns:1fr}.version-switch{gap:10px;margin-bottom:22px}.version-button{padding:10px 14px}}

/* Keep the two perspective downloads together at the caption's right edge. */
.download-actions {display:flex;justify-content:flex-end;align-items:center;gap:10px;margin-left:auto;max-width:100%}
@media(max-width:540px) {
  .download-actions {align-self:flex-end;gap:8px}
  .download-actions .download-button {padding:10px 9px;font-size:12px;gap:5px;flex-shrink:1}
}