:root {
  --paper: #f1eee6;
  --ink: #151b1d;
  --muted: #696961;
  --soft: #d9d4c9;
  --red: #ba3d2c;
  --navy: #1c3142;
  --gold: #e4cc72;
  --sans: Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --serif: Georgia, "Songti SC", serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  overflow-x: hidden;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
}
a { color: inherit; }

.timeline-nav {
  position: sticky;
  top: 0;
  z-index: 30;
  height: 58px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 0 25px;
  border-bottom: 1px solid var(--ink);
  background: #f1eee6ed;
  backdrop-filter: blur(12px);
  font-size: 10px;
}
.timeline-nav a { text-decoration: none; }
.timeline-nav .brand { font-weight: 700; letter-spacing: .08em; }
.timeline-nav .current { color: var(--red); }
.timeline-nav > span { justify-self: end; color: var(--muted); }

.timeline-page {
  --progress: 0%;
  position: relative;
  max-width: 1500px;
  margin: 0 auto;
  padding: 125px clamp(30px, 5vw, 80px) 150px;
}
.timeline-track {
  position: absolute;
  z-index: 0;
  left: 50%;
  top: 92px;
  bottom: 95px;
  width: 1px;
  background: #77766e;
}
.timeline-track::before,
.timeline-track::after {
  content: "";
  position: absolute;
  left: -5px;
  width: 11px;
  height: 11px;
  border: 1px solid var(--ink);
  border-radius: 50%;
  background: var(--paper);
}
.timeline-track::before { top: 0; transform: translateY(-50%); }
.timeline-track::after { bottom: 0; transform: translateY(50%); }
.timeline-track > i {
  position: absolute;
  left: -1px;
  top: 0;
  width: 3px;
  height: var(--progress);
  background: var(--red);
  transition: height .12s linear;
}
.continuity-link {
  position: absolute;
  z-index: 2;
  left: calc(50% + 27px);
  top: var(--continuity-top, 0);
  width: 1px;
  height: var(--continuity-height, 0);
  border-left: 1px dashed #c49a3b;
  pointer-events: none;
}
.continuity-link::before,.continuity-link::after {
  content: "";
  position: absolute;
  left: -27px;
  width: 27px;
  border-top: 1px solid #c49a3b;
}
.continuity-link::before { top: 0; }
.continuity-link::after { bottom: 0; }
.continuity-link span {
  position: sticky;
  top: 90px;
  display: inline-block;
  margin: 22px 0 0 7px;
  padding: 7px 4px;
  background: var(--paper);
  color: #a7772c;
  font: 7px ui-monospace, Consolas, monospace;
  letter-spacing: .08em;
  white-space: nowrap;
  writing-mode: vertical-rl;
}
.start-mark {
  position: absolute;
  left: 50%;
  top: 50px;
  display: grid;
  justify-items: center;
  gap: 14px;
  transform: translateX(-50%);
  color: var(--red);
  font: 9px ui-monospace, Consolas, monospace;
  letter-spacing: .12em;
}
.start-mark i { width: 1px; height: 28px; background: var(--ink); }

.moment {
  position: relative;
  min-height: 285px;
  display: flex;
  align-items: center;
  margin-bottom: 48px;
}
.moment::after {
  content: "";
  position: absolute;
  top: calc(50% - 18px);
  width: 83px;
  height: 35px;
  border-top: 1px solid var(--accent);
  opacity: .85;
  pointer-events: none;
}
.side-left::after {
  right: 50%;
  border-right: 1px solid var(--accent);
  border-radius: 0 28px 0 0;
}
.side-right::after {
  left: 50%;
  border-left: 1px solid var(--accent);
  border-radius: 28px 0 0 0;
}
.node {
  position: absolute;
  z-index: 3;
  left: 50%;
  top: 50%;
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  transform: translate(-50%, -50%);
  border: 1px solid var(--accent);
  border-radius: 50%;
  background: var(--paper);
  transition: background .25s ease, color .25s ease, transform .25s ease;
  color: inherit;
  text-decoration: none;
}
.node b { font: 8px ui-monospace, Consolas, monospace; }
.moment:hover .node { transform: translate(-50%, -50%) scale(1.12); background: var(--accent); color: white; }
.node:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }

.event {
  position: relative;
  z-index: 1;
  width: calc(50% - 82px);
  min-height: 205px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 155px;
  gap: clamp(20px, 3vw, 48px);
  align-items: center;
  padding: 20px 0;
  text-decoration: none;
}
.side-left .event { margin-right: auto; }
.side-right .event {
  grid-template-columns: 155px minmax(0, 1fr);
  margin-left: auto;
}
.side-right .event-copy { order: 2; }
.side-right .visual { order: 1; }
.event-copy { position: relative; }
.meta {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--accent);
  font: 8px ui-monospace, Consolas, monospace;
  letter-spacing: .06em;
}
.meta span::before { content: "/"; margin-right: 12px; color: var(--soft); }
.event h2 {
  margin: 17px 0 10px;
  font: 500 clamp(29px, 3vw, 48px)/1.02 var(--serif);
  letter-spacing: -.04em;
  transition: color .25s ease;
}
.event p {
  max-width: 430px;
  margin: 0;
  color: #5c5e59;
  font-size: 12px;
  line-height: 1.75;
}
.event em {
  display: inline-block;
  margin-top: 18px;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--accent);
  color: var(--accent);
  font-size: 9px;
  font-style: normal;
  opacity: 0;
  transform: translateY(4px);
  transition: opacity .25s ease, transform .25s ease;
}
.event:hover h2,
.event:focus-visible h2 { color: var(--accent); }
.event:hover em,
.event:focus-visible em { opacity: 1; transform: none; }
.event:focus-visible { outline: 1px dashed var(--accent); outline-offset: 10px; }

.visual {
  position: relative;
  width: 155px;
  height: 155px;
  transition: transform .35s ease;
}
.event:hover .visual { transform: rotate(-2deg) scale(1.04); }
.side-right .event:hover .visual { transform: rotate(2deg) scale(1.04); }

.visual-foundation {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  padding: 16px;
  border: 1px solid #8c7b4f;
  border-radius: 50%;
  background: #d8c99f;
  transform: rotate(5deg);
}
.visual-foundation span {
  display: grid;
  place-items: center;
  border: 1px solid #8c7b4f;
  background: var(--paper);
  font: 7px ui-monospace, Consolas, monospace;
}
.visual-foundation span:first-child { border-radius: 100% 0 0; }
.visual-foundation span:nth-child(2) { border-radius: 0 100% 0 0; }
.visual-foundation span:nth-child(3) { border-radius: 0 0 0 100%; }
.visual-foundation span:nth-child(4) { border-radius: 0 0 100%; }

.visual-reason {
  display: flex;
  flex-wrap: wrap;
  align-content: center;
  align-items: center;
  justify-content: center;
  gap: 5px;
  transform: rotate(-4deg);
}
.visual-reason::before {
  content: "";
  position: absolute;
  inset: 4px;
  border: 1px solid #8b7c55;
  background: #ded3b0;
  transform: rotate(45deg);
  z-index: -1;
}
.visual-reason span { padding: 6px; border: 1px solid #8a7d58; background: #f7f1df; font: 7px ui-monospace, Consolas, monospace; }
.visual-reason i { color: var(--red); font-style: normal; }
.visual-reason b { width: 100%; text-align: center; color: var(--red); font: 500 23px var(--serif); }

.visual-router { display: grid; place-items: center; }
.router {
  position: absolute;
  left: 20px;
  bottom: 32px;
  width: 115px;
  height: 49px;
  border: 2px solid var(--navy);
  border-radius: 8px 8px 18px 18px;
  background: #dce2df;
  box-shadow: 0 7px 0 #819296;
}
.router::before,.router::after { content: ""; position: absolute; bottom: 39px; width: 3px; height: 55px; background: var(--navy); transform-origin: bottom; }
.router::before { left: 16px; transform: rotate(-14deg); }.router::after { right: 16px; transform: rotate(14deg); }
.router i { display: inline-block; width: 5px; height: 5px; margin: 29px 0 0 11px; border-radius: 50%; background: var(--red); }
.signal { position: absolute; left: 50%; top: 4px; width: 70px; height: 44px; transform: translateX(-50%); }
.signal i { position: absolute; left: 50%; bottom: 0; border: 2px solid var(--navy); border-bottom: 0; border-left-color: transparent; border-right-color: transparent; border-radius: 50% 50% 0 0; transform: translateX(-50%); }
.signal i:nth-child(1) { width: 18px; height: 10px; }.signal i:nth-child(2) { width: 39px; height: 21px; }.signal i:nth-child(3) { width: 64px; height: 34px; }
.visual-router small { position: absolute; bottom: 4px; color: #42575f; font: 7px ui-monospace, Consolas, monospace; }

.main-event .event {
  width: calc(50% - 68px);
  padding: 32px;
  border-radius: 40px 4px 40px 4px;
  background: var(--navy);
  color: white;
  box-shadow: 0 22px 60px #1c31421c;
}
.main-event .event p { color: #bdc9cf; }
.main-event .event em { color: var(--gold); }
.visual-query {
  height: 145px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 9px;
  padding: 14px;
  border: 1px solid #ffffff20;
  border-radius: 50% 50% 8px 50%;
  background: #263f4e;
  font: 6px/1.4 ui-monospace, Consolas, monospace;
}
.visual-query span { width: fit-content; padding: 7px; border: 1px solid #ffffff2c; color: #d9e2e6; background: #172d3d; }
.visual-query .user { align-self: end; background: var(--paper); color: var(--ink); }
.visual-query .tool { color: var(--gold); border-color: #e4cc7250; }
.visual-query .result i { display: inline-block; width: 4px; height: 8px; margin-left: 3px; background: var(--gold); animation: blink .8s steps(1) infinite; }

.visual-delivery {
  display: grid;
  align-content: center;
  gap: 15px;
  padding: 15px;
  border: 1px solid #e4cc7255;
  border-radius: 46% 8px 46% 46%;
  background: #263f4e;
}
.delivery-flow,.delivery-work { display: grid; grid-template-columns: 1fr auto 1.4fr; align-items: center; gap: 6px; }
.delivery-flow span,.delivery-flow strong,.delivery-work span {
  display: grid;
  min-height: 28px;
  place-items: center;
  padding: 5px;
  border: 1px solid #ffffff32;
  color: #d9e2e6;
  text-align: center;
  font: 6px/1.35 ui-monospace, Consolas, monospace;
}
.delivery-flow strong { border-color: var(--gold); color: var(--gold); font-weight: 400; }
.delivery-flow i,.delivery-work b { color: var(--gold); font-size: 9px; font-style: normal; font-weight: 400; }
.delivery-work { grid-template-columns: 1fr auto 1fr; }
.delivery-work span { font-family: var(--sans); font-size: 7px; }

.visual-dapo { display: grid; place-items: center; }
.visual-dapo::before { content: ""; position: absolute; inset: 19px; border: 1px solid #607781; border-radius: 50%; border-right: 3px solid var(--red); animation: spin 12s linear infinite; }
.visual-dapo strong { z-index: 1; color: var(--navy); font: 500 22px var(--serif); }
.visual-dapo span { position: absolute; padding: 4px 5px; background: var(--paper); border: 1px solid #607781; font: 6px ui-monospace, Consolas, monospace; }
.visual-dapo span:nth-of-type(1) { top: 6px; }.visual-dapo span:nth-of-type(2) { right: 0; top: 48%; }.visual-dapo span:nth-of-type(3) { bottom: 6px; }.visual-dapo span:nth-of-type(4) { left: 0; top: 48%; }

.visual-room { width: 170px; height: 145px; padding: 8px; background: #d7ddd9; clip-path: polygon(8% 0,100% 9%,93% 100%,0 89%); }
.visual-room svg { width: 100%; height: 100%; }.visual-room .walls { fill: #e8e7df; stroke: #566865; stroke-width: 2; fill-rule: evenodd; }.visual-room .route { fill: none; stroke: var(--red); stroke-width: 2.5; stroke-dasharray: 5 4; }.visual-room circle { fill: var(--red); stroke: var(--paper); stroke-width: 2; }.visual-room text { fill: white; text-anchor: middle; font: 7px ui-monospace, monospace; }

.visual-trajectory { width: 180px; height: 140px; transform: rotate(3deg); }
.visual-trajectory::before { content: ""; position: absolute; inset: 4px 0; border-radius: 50%; background: var(--navy); }
.visual-trajectory svg { position: relative; z-index: 1; width: 100%; height: 100%; padding: 15px; }.visual-trajectory path { fill: none; stroke-width: 2.5; }.visual-trajectory .before { stroke: #91a7b2; stroke-dasharray: 4 4; }.visual-trajectory .after { stroke: var(--gold); }.visual-trajectory circle { fill: var(--red); }
.visual-trajectory span,.visual-trajectory b { position: absolute; z-index: 2; color: white; font: 6px ui-monospace, Consolas, monospace; letter-spacing: .08em; }.visual-trajectory span { left: 16px; top: 14px; color: #91a7b2; }.visual-trajectory b { right: 14px; bottom: 14px; color: var(--gold); font-weight: 400; }

.end-mark {
  position: relative;
  z-index: 2;
  width: 92px;
  height: 92px;
  display: grid;
  place-items: center;
  margin: 70px auto 0;
  border: 1px solid var(--ink);
  border-radius: 50%;
  background: var(--paper);
  font: 9px ui-monospace, Consolas, monospace;
  letter-spacing: .1em;
}
.end-mark i { position: absolute; inset: 7px; border: 1px solid var(--red); border-radius: 50%; }

.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.on { opacity: 1; transform: none; }

@keyframes blink { 50% { opacity: 0; } }
@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 920px) {
  .timeline-page { padding-left: 24px; padding-right: 24px; }
  .event { grid-template-columns: 1fr 120px; gap: 18px; }
  .side-right .event { grid-template-columns: 120px 1fr; }
  .visual { width: 120px; height: 120px; }
  .visual-room,.visual-trajectory { width: 130px; height: 120px; }
  .main-event .event { padding: 25px; }
}

@media (max-width: 680px) {
  .timeline-nav { grid-template-columns: 1fr auto; padding: 0 16px; }
  .timeline-nav > span { display: none; }
  .timeline-page { padding: 100px 18px 110px 70px; }
  .timeline-track { left: 31px; top: 72px; bottom: 74px; }
  .continuity-link { left: 50px; }
  .continuity-link::before,.continuity-link::after { left: -19px; width: 19px; }
  .continuity-link span { margin-left: 4px; padding: 5px 3px; font-size: 6px; }
  .start-mark { left: 31px; top: 31px; }
  .moment { min-height: 0; margin-bottom: 95px; align-items: start; }
  .moment::after { left: -39px; right: auto; top: 28px; width: 39px; height: 24px; border-left: 0; border-right: 1px solid var(--accent); border-radius: 0 20px 0 0; }
  .node { left: -39px; top: 52px; width: 34px; height: 34px; }
  .moment:hover .node { transform: translate(-50%, -50%); }
  .event,.side-right .event,.main-event .event { width: 100%; display: block; margin: 0; padding: 0; }
  .main-event .event { padding: 24px 20px; border-radius: 28px 3px 28px 3px; }
  .side-right .event-copy,.side-right .visual { order: initial; }
  .event h2 { font-size: 34px; }
  .event p { font-size: 11px; }
  .event em { opacity: 1; transform: none; }
  .visual { width: 145px; height: 145px; margin: 30px auto 0; }
  .visual-room { width: 180px; height: 145px; }
  .visual-trajectory { width: 190px; height: 145px; }
  .main-event .visual { margin-top: 24px; }
  .end-mark { width: 74px; height: 74px; margin: 35px 0 0 -39px; transform: translateX(-50%); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .visual-dapo::before,.visual-query .result i { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .visual,.node { transition: none; }
}