/* ================= Variant 3: 3D building story (scroll steps) ================= */
.okb { position: relative; background: var(--white); }
.okb-scroller { position: relative; overflow-y: auto; overflow-x: hidden; overscroll-behavior: contain; scrollbar-width: none; outline: none; }
.okb-scroller::-webkit-scrollbar { display: none; }
.okb-track { position: relative; }
.okb-stage { position: sticky; top: 0; z-index: 1; overflow: hidden; }
.okb-gl { position: absolute; inset: 0; }
.okb-gl canvas { display: block; width: 100% !important; height: 100% !important; }
.okb-fail { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 16px; padding: 24px; background: var(--green); color: var(--white); text-align: center; }
.okb-fail-key { width: 200px; height: auto; color: var(--lime); }

/* labels that follow the 3D scene */
.okb-labels { position: absolute; inset: 0; overflow: hidden; pointer-events: none; }
.okb-node, .okb-chip { position: absolute; left: 0; top: 0; will-change: transform; }
.okb-node { opacity: 0; }
.okb-node-in { position: absolute; display: inline-flex; align-items: center; gap: 8px; height: 34px; padding-inline: 5px 14px; border-radius: var(--radius-pill); background: var(--white); color: var(--black); box-shadow: inset 0 0 0 1px var(--line); font-size: 13px; white-space: nowrap; transform: translate(-50%, calc(-100% - 22px)); }
.okb-node-ico { display: inline-flex; align-items: center; justify-content: center; flex: none; width: 24px; height: 24px; border-radius: 50%; background: var(--black); color: var(--lime); }
.okb-node-ico .ok-icon { width: 14px; height: 14px; }
.okb-chip-in { position: absolute; display: inline-flex; align-items: center; gap: 8px; height: 36px; padding-inline: 12px 14px; border-radius: var(--radius-pill); background: var(--black); color: var(--white); font-size: 13px; white-space: nowrap; opacity: 0; transform: translate(-50%, calc(-100% - 10px)) scale(.86); transition: opacity .8s var(--okx-ease), transform 1s var(--okx-ease); }
.okb-chip-in .ok-icon { color: var(--lime); }
.okb-chip.is-on .okb-chip-in { opacity: 1; transform: translate(-50%, calc(-100% - 16px)); }
.okb-chip.is-final .okb-chip-in { height: 46px; padding-inline: 16px 20px; background: var(--lime); color: var(--black); font-size: 16px; }
.okb-chip.is-final .ok-icon { color: var(--black); }

/* HUD inside the stage */
.okb-hud { position: absolute; inset: auto 0 0 0; display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: 14px 24px; padding-bottom: 26px; pointer-events: none; }
.okb-steps { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 6px 22px; }
.okb-steps button { display: inline-flex; align-items: baseline; gap: 6px; padding: 4px 0; border: 0; background: none; color: var(--ink-muted); font: inherit; font-size: 13px; cursor: pointer; pointer-events: auto; transition: color .8s var(--okx-ease); }
.okb-steps button span { font-size: 11px; }
.okb-steps li.is-done button, .okb-steps li.is-on button, .okb-steps button:hover { color: var(--black); }
.okb-steps li.is-on button::after { content: ""; align-self: center; width: 16px; height: 8px; border-radius: 8px; background: var(--lime); }
.okb-bar { grid-column: 1 / -1; position: relative; height: 1px; overflow: hidden; background: var(--line); }
.okb-bar i { position: absolute; inset: 0; background: var(--black); transform-origin: right center; transform: scaleX(0); }
.okb-hint { display: inline-flex; align-items: center; gap: 10px; font-size: 13px; transition: opacity 1s var(--okx-ease); }
.okb-hint.is-off { opacity: 0; }
.okb-mouse { position: relative; width: 18px; height: 28px; border-radius: 10px; box-shadow: inset 0 0 0 1.5px var(--black); }
.okb-mouse i { position: absolute; left: 50%; top: 6px; width: 2px; height: 6px; margin-left: -1px; border-radius: 2px; background: var(--black); animation: okb-mouse 2.4s ease-in-out infinite; }
@keyframes okb-mouse { 0% { transform: translateY(0); opacity: 1; } 70% { transform: translateY(8px); opacity: 0; } 100% { opacity: 0; } }

/* chapter blocks that scroll over the scene */
.okb-ch { position: relative; z-index: 2; display: flex; align-items: center; box-sizing: border-box; padding-block: 88px 92px; pointer-events: none; scroll-snap-align: start; }
.okb.is-inner .okb-ch { padding-block: 28px 92px; }
.okb-scroller { scroll-snap-type: y mandatory; }
html.okb-snap { scroll-snap-type: y proximity; }
.okb-ch-in { display: flex; width: 100%; }
.okb-ch.side-end .okb-ch-in { justify-content: flex-end; }
.okb-card { position: relative; width: min(540px, 100%); padding: 22px 28px 26px; background: var(--white); pointer-events: auto; transition: opacity 1.8s var(--okx-ease), transform 2.2s var(--okx-ease), background-color 1.2s var(--okx-ease); }
.okb-ch:not(.is-on) .okb-card { opacity: .14; transform: translateY(36px); }
.okb-ch.is-past:not(.is-on) .okb-card { transform: translateY(-36px); }
.okb-card::before, .okb-card::after { content: ""; position: absolute; inset-inline-start: 0; top: 0; bottom: 0; width: 1px; }
.okb-card::before { background: var(--line); }
.okb-card::after { width: 3px; margin-inline-start: -1px; background: var(--lime); transform: scaleY(0); transform-origin: top; transition: transform 2.8s var(--okx-ease) .3s; }
.okb-ch.is-on .okb-card::after { transform: none; }
.okb-card-n { display: block; margin-bottom: 6px; font-family: var(--font-display); font-size: clamp(60px, 6vw, 100px); line-height: .9; color: transparent; -webkit-text-stroke: 1px var(--black); text-align: start; opacity: 0; transform: translateY(40px); transition: opacity 1.8s var(--okx-ease), transform 2.2s var(--okx-ease); }
.okb-ch.is-on .okb-card-n { opacity: 1; transform: none; }
.okb-card-label { display: flex; align-items: center; gap: 10px; margin: 0 0 16px; font-size: 13px; letter-spacing: .04em; color: var(--ink-muted); }
.okb-card-title { margin: 0 0 14px; font-family: var(--font-display); font-weight: 400; font-size: clamp(30px, 3vw, 46px); line-height: 1.08; letter-spacing: -.01em; }
.okb-card-title.is-h1 { font-size: clamp(34px, 3.5vw, 56px); }
.okb-w { display: inline-block; white-space: pre; opacity: 0; transform: translateY(.6em); filter: blur(10px); transition: opacity 1.6s var(--okx-ease), transform 2s var(--okx-ease), filter 1.8s var(--okx-ease); transition-delay: calc(.35s + var(--j) * 120ms); }
.okb-ch.is-on .okb-w { opacity: 1; transform: none; filter: none; }
.okb-card-text { margin: 0; max-width: 34em; font-size: 17px; line-height: 1.65; color: var(--ink-muted); opacity: 0; transition: opacity 1.8s var(--okx-ease) 1s; }
.okb-ch.is-on .okb-card-text { opacity: 1; }
.okb-card-items, .okb-card-ch { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; margin: 22px 0 0; padding: 0; }
.okb-card-items li, .okb-card-ch li { display: inline-flex; align-items: center; gap: 8px; height: 38px; padding-inline: 14px 16px; border-radius: var(--radius-pill); box-shadow: inset 0 0 0 1px var(--black); font-size: 14px; opacity: 0; transform: translateY(14px); transition: opacity 1.4s var(--okx-ease), transform 1.8s var(--okx-ease), background-color .8s; transition-delay: calc(1.2s + var(--j) * 200ms); }
.okb-card-items li::before { content: ""; width: 14px; height: 8px; border-radius: 8px; background: var(--lime); }
.okb-card-ch li { padding-inline: 5px 14px; }
.okb-ch.is-on .okb-card-items li, .okb-ch.is-on .okb-card-ch li { opacity: 1; transform: none; }
.okb-counter { display: flex; align-items: baseline; gap: 14px; margin: 22px 0 0; font-size: 13px; color: var(--ink-muted); opacity: 0; transition: opacity 1.2s var(--okx-ease) .9s; }
.okb-ch.is-on .okb-counter { opacity: 1; }
.okb-counter-v { font-family: var(--font-display); font-size: 34px; line-height: 1; color: var(--black); font-variant-numeric: tabular-nums; }
.okb-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 26px; opacity: 0; transform: translateY(14px); transition: opacity 1.2s var(--okx-ease) 1.1s, transform 1.4s var(--okx-ease) 1.1s; }
.okb-ch.is-on .okb-actions { opacity: 1; transform: none; }

/* text that darkens while reading */
.okb-reveal-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 3fr); gap: 40px; }
.okb-reveal-text { margin: 0; font-family: var(--font-display); font-size: clamp(30px, 3.6vw, 56px); line-height: 1.3; }
.okb-rw { color: var(--green-200); transition: color .8s var(--okx-ease), background-color .8s var(--okx-ease); }
.okb-rw.is-on { color: var(--black); }

/* three numbers */
.okb-stats { padding-bottom: clamp(64px, 8vw, 120px); }
.okb-stats-row { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); box-shadow: inset 0 1px 0 var(--line); }
.okb-stat { display: flex; flex-direction: column; align-items: center; gap: 14px; padding: 52px 16px 8px; text-align: center; color: #6f8a87; transition: color 1.2s var(--okx-ease); }
/* the dimmed numbers keep 3:1 contrast (large text); labels stay readable at 4.5:1 */
.okb-stat:not(.is-on) .okb-stat-l { color: var(--gray-600); }
.okb-stat.is-on { color: var(--black); }
.okb-stat-v { font-family: var(--font-display); font-size: clamp(40px, 4.4vw, 72px); line-height: 1; }
.okb-stat-l { font-size: 13px; letter-spacing: .06em; }

/* the launch chapter: dark card, lime chips over the scene */
.okb-ch.is-accent .okb-card { background: var(--black); color: var(--white); }
.okb-ch.is-accent .okb-card::before { background: rgba(255,255,255,.18); }
.okb-ch.is-accent .okb-card-n { -webkit-text-stroke-color: var(--lime); }
.okb-ch.is-accent .okb-card-label, .okb-ch.is-accent .okb-card-text { color: rgba(255,255,255,.68); }
.okb-ch.is-accent .okx-mark b { background: var(--white); }
.okb-card-ch.is-launch li { box-shadow: inset 0 0 0 1px rgba(255,255,255,.34); }
.okb-card-ch.is-launch .okb-node-ico { background: var(--lime); color: var(--black); }
.okb-chip.is-launch .okb-chip-in { gap: 10px; height: 40px; padding-inline: 5px 16px; background: var(--lime); color: var(--black); font-size: 14px; box-shadow: 0 10px 30px -12px rgba(11,48,44,.45); transition-duration: 1.2s, 1.4s; }
.okb-chip-ico { display: inline-flex; align-items: center; justify-content: center; flex: none; width: 30px; height: 30px; border-radius: 50%; background: var(--black); }
.okb-chip.is-launch .okb-chip-ico .ok-icon { color: var(--lime); }
.okb-chip.is-launch .okb-chip-in::after { content: ""; position: absolute; inset: -6px; border-radius: inherit; box-shadow: 0 0 0 1px var(--lime); opacity: 0; }
.okb-chip.is-launch.is-on .okb-chip-in::after { animation: okb-ring 3.2s var(--okx-ease) 1s infinite; }
@keyframes okb-ring { 0% { opacity: .9; transform: scale(.96); } 70%, 100% { opacity: 0; transform: scale(1.12); } }

/* our pattern as a vertical line that lights up with the scroll */
.okb-code { position: absolute; z-index: 1; top: 120px; inset-inline-end: max(12px, calc(var(--okx-pad) / 2 - 7px)); width: 14px; height: calc(100% - 250px); overflow: visible; pointer-events: none; }
.okb-code path { fill: transparent; stroke: var(--black); stroke-opacity: .2; stroke-width: 1; vector-effect: non-scaling-stroke; transition: fill 1.4s var(--okx-ease), stroke 1.4s var(--okx-ease), stroke-opacity 1.4s var(--okx-ease); }
.okb-code path.is-on { fill: var(--lime); stroke: var(--lime); stroke-opacity: 1; }
.okb-code path.is-head { fill: var(--black); stroke: var(--black); }

@media (max-height: 760px) and (min-width: 761px) {
  .okb-ch { padding-block: 76px 84px; }
  .okb-card { padding: 16px 22px 20px; }
  .okb-card-n { font-size: 52px; margin-bottom: 0; }
  .okb-card-label { margin-bottom: 10px; }
  .okb-card-title, .okb-card-title.is-h1 { font-size: 30px; margin-bottom: 10px; }
  .okb-card-text { font-size: 15px; line-height: 1.55; }
  .okb-card-items, .okb-card-ch { margin-top: 14px; gap: 6px; }
  .okb-card-items li, .okb-card-ch li { height: 32px; font-size: 13px; }
  .okb-counter { margin-top: 12px; }
  .okb-actions { margin-top: 16px; }
  .ok-site .okb-actions a.okx-btn { height: 44px; padding-inline: 18px; font-size: 15px; }
}
@media (max-width: 760px) {
  .okb-ch, .okb.is-inner .okb-ch { align-items: flex-end; padding-top: 0; padding-bottom: 64px; }
  .okb-ch.side-end .okb-ch-in { justify-content: flex-start; }
  .okb-card { width: 100%; padding: 14px 18px 16px; padding-inline-start: 22px; }
  .okb-card-n { font-size: 40px; margin-bottom: 2px; }
  .okb-actions { gap: 8px; margin-top: 18px; }
  .ok-site .okb-actions a.okx-btn { height: 44px; padding-inline: 16px; font-size: 14px; }
  .okb-counter { margin-top: 14px; }
  .okb-counter-v { font-size: 32px; }
  .okb-card-title { font-size: 24px; }
  .okb-card-title.is-h1 { font-size: 27px; }
  .okb-card-text { font-size: 15px; }
  .okb-card-items, .okb-card-ch { margin-top: 14px; }
  .okb-card-items li, .okb-card-ch li { height: 32px; font-size: 12px; }
  .okb-steps, .okb-hint { display: none; }
  .okb-hud { padding-bottom: 14px; }
  .okb-node-t { display: none; }
  .okb-node-in { padding: 5px; height: auto; }
  .okb-chip-in { height: 32px; font-size: 12px; }
  .okb-chip.is-final { display: none; }
  .okb-chip.is-launch .okb-chip-t { display: none; }
  .okb-chip.is-launch .okb-chip-in { padding: 5px; height: auto; }
  .okb-reveal-grid { grid-template-columns: 1fr; gap: 0; }
  .okb-stats-row { grid-template-columns: 1fr; }
  .okb-stat { padding: 32px 16px 0; }
}
@media (prefers-reduced-motion: reduce) {
  .okb-w, .okb-card-text, .okb-actions, .okb-card-items li, .okb-card-ch li, .okb-card-n, .okb-counter, .okb-card, .okb-code path { transition: none; }
  .okb-chip.is-launch.is-on .okb-chip-in::after { animation: none; }
}
.okb-scr.is-wait > span[aria-hidden] { visibility: hidden; }
.ok-vh { position: absolute !important; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap; border: 0; }