:root {
  --navy: #111d3a;
  --blue: #2351dc;
  --cyan: #28a8b8;
  --orange: #ed6a3a;
  --gold: #d7a420;
  --cream: #f5f0e6;
  --paper: #fcfaf5;
  --ink: #17203a;
  --muted: #687086;
  --rule: #dcd6c8;
  --proof: #2351dc;
  --formal: #28a8b8;
  --discovery: #ed6a3a;
  --benchmark: #d7a420;
  font-family: Inter, "Aptos", "Segoe UI", system-ui, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-size: 1rem;
  line-height: 1.55;
}

a { color: inherit; }

.hero {
  position: relative;
  display: flex;
  min-height: 5.5rem;
  padding: 1.5rem max(1.5rem, calc((100vw - 76rem) / 2));
  align-items: center;
  gap: clamp(1.25rem, 4vw, 3.5rem);
  overflow: hidden;
  color: white;
  background:
    radial-gradient(circle at 82% 30%, rgb(40 168 184 / 36%) 0 1px, transparent 2px),
    linear-gradient(125deg, #111d3a 0 62%, #173469 100%);
}

.hero::after {
  content: "∀";
  position: absolute;
  right: clamp(1rem, 9vw, 8rem);
  bottom: -13rem;
  color: rgb(255 255 255 / 5%);
  font: 700 clamp(20rem, 38vw, 36rem)/1 Georgia, serif;
  transform: rotate(-8deg);
  pointer-events: none;
}

.back {
  position: relative;
  z-index: 1;
  color: #dce7ff;
  font-size: .86rem;
  font-weight: 700;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: .08em;
}

.kicker, .section-number {
  margin: 0;
  color: var(--orange);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .15em;
  text-transform: uppercase;
}

.hero .kicker {
  position: relative;
  z-index: 1;
  padding-left: clamp(1.25rem, 4vw, 3.5rem);
  border-left: 1px solid rgb(255 255 255 / 25%);
  color: var(--orange);
  font-size: clamp(.82rem, 1.5vw, 1rem);
}

.hero h1 {
  position: relative;
  z-index: 1;
  max-width: 54rem;
  margin: 0;
  font: 700 clamp(3.2rem, 8vw, 7rem)/.88 Georgia, "Times New Roman", serif;
  letter-spacing: -.055em;
}

.lede {
  position: relative;
  z-index: 1;
  max-width: 39rem;
  margin: 1.8rem 0 3rem;
  color: #c9d5ee;
  font-size: clamp(1.05rem, 2vw, 1.35rem);
}

main { overflow: hidden; }

.timeline-section, .context, .event-index {
  padding: 5rem max(1.5rem, calc((100vw - 76rem) / 2));
}

.timeline-section { padding-top: 2.5rem; }

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 2rem;
}

.section-number { margin: 0 0 .7rem; }

h2 {
  margin: 0;
  font: 700 clamp(2rem, 5vw, 4rem)/1 Georgia, "Times New Roman", serif;
  letter-spacing: -.035em;
}

.controls {
  display: flex;
  align-items: center;
  gap: .35rem;
  padding-bottom: .3rem;
}

.timeline-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  margin-bottom: .8rem;
}

.controls button {
  min-width: 2.7rem;
  min-height: 2.7rem;
  border: 1px solid var(--rule);
  border-radius: 50%;
  color: var(--ink);
  background: transparent;
  font: 700 1.3rem/1 inherit;
  cursor: pointer;
}

.controls button:hover, .controls button:focus-visible {
  border-color: var(--blue);
  color: white;
  background: var(--blue);
}

.controls output {
  width: 4.2rem;
  color: var(--muted);
  font-size: .8rem;
  text-align: center;
}

.controls .reset {
  width: auto;
  margin-left: .35rem;
  padding: 0 1rem;
  border-radius: 999px;
  font-size: .78rem;
  text-transform: uppercase;
  letter-spacing: .06em;
}

.instructions {
  margin: 0;
  color: var(--muted);
  font-size: .82rem;
  text-transform: uppercase;
  letter-spacing: .07em;
}

.timeline-frame {
  position: relative;
  height: 35rem;
  border: 1px solid var(--rule);
  border-radius: .35rem;
  overflow: hidden;
  background:
    linear-gradient(rgb(17 29 58 / 3%) 1px, transparent 1px),
    var(--cream);
  background-size: 100% 4.5rem;
  cursor: grab;
  touch-action: none;
}

.timeline-frame:focus-visible { outline: 3px solid rgb(35 81 220 / 35%); }
.timeline-frame.dragging { cursor: grabbing; }
#timeline { display: block; width: 100%; height: 100%; user-select: none; }
.loading { position: absolute; inset: 50% auto auto 50%; transform: translate(-50%, -50%); color: var(--muted); }

.axis-line { stroke: #98a0b2; stroke-width: 1; }
.tick-line { stroke: #aeb3bf; stroke-width: 1; }
.tick-label { fill: var(--muted); font-size: 12px; font-weight: 650; }
.era-label { fill: #a3a7af; font-size: 11px; font-weight: 800; letter-spacing: .12em; }
.event-stem { stroke-width: 1.5; stroke-dasharray: 2 3; opacity: .65; }
.event-node { stroke: var(--cream); stroke-width: 4; transition: r 120ms ease; }
.event-hit { fill: transparent; cursor: pointer; }
.event-group:hover .event-node, .event-group:focus .event-node { r: 10; }
.event-group:focus { outline: none; }
.event-year { fill: var(--ink); font-size: 12px; font-weight: 800; }
.event-title { fill: var(--ink); font: 700 15px/1.15 Georgia, serif; }
.event-category { fill: var(--muted); font-size: 10px; font-weight: 750; letter-spacing: .08em; text-transform: uppercase; }

.legend { display: flex; flex-wrap: wrap; gap: 1.2rem 2rem; margin-top: 1.2rem; color: var(--muted); font-size: .82rem; }
.legend span { display: flex; align-items: center; gap: .45rem; }
.dot { width: .65rem; height: .65rem; border-radius: 50%; }
.proof { background: var(--proof); }
.formal { background: var(--formal); }
.discovery { background: var(--discovery); }
.benchmark { background: var(--benchmark); }

.tooltip {
  position: fixed;
  z-index: 20;
  width: min(22rem, calc(100vw - 2rem));
  padding: 1.1rem 1.2rem 1.2rem;
  border-top: .3rem solid var(--event-color, var(--blue));
  border-radius: .25rem;
  color: white;
  background: var(--navy);
  box-shadow: 0 1.2rem 3rem rgb(0 0 0 / 25%);
  pointer-events: auto;
}

.tooltip-meta { margin: 0 0 .35rem; color: #aebddd; font-size: .7rem; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.tooltip h3 { margin: 0; font: 700 1.25rem/1.15 Georgia, serif; }
.tooltip-description { margin: .7rem 0; color: #d6def0; font-size: .88rem; line-height: 1.45; }
.tooltip-source { color: white; font-size: .78rem; font-weight: 750; text-decoration-color: var(--event-color, var(--orange)); text-underline-offset: .2rem; }

.context { color: white; background: var(--navy); }
.context .section-number { color: #77d5de; }
.context-grid { display: grid; grid-template-columns: minmax(15rem, .9fr) minmax(18rem, 1fr); gap: clamp(2rem, 8vw, 8rem); align-items: start; }
.context-grid p { margin: 0 0 1rem; color: #c9d5ee; font-size: 1.08rem; }

.event-index { background: #fff; }
.event-list { margin-top: 0; border-top: 1px solid var(--rule); }
.index-event { display: grid; grid-template-columns: 8rem 1fr auto; gap: 1.5rem; align-items: baseline; padding: 1rem 0; border-bottom: 1px solid var(--rule); text-decoration: none; }
.index-event time { color: var(--muted); font-size: .82rem; font-variant-numeric: tabular-nums; }
.index-event strong { font: 700 1.08rem Georgia, serif; }
.index-event span { color: var(--muted); font-size: .8rem; text-transform: uppercase; letter-spacing: .06em; }
.index-event:hover strong { color: var(--blue); }

footer { display: flex; justify-content: space-between; gap: 2rem; padding: 2rem max(1.5rem, calc((100vw - 76rem) / 2)); border-top: 1px solid var(--rule); color: var(--muted); font-size: .78rem; }
footer p { max-width: 38rem; margin: 0; }

@media (max-width: 700px) {
  .hero { min-height: 4.75rem; padding-block: 1.1rem; gap: 1rem; }
  .hero .kicker { padding-left: 1rem; font-size: .72rem; }
  .back { font-size: .72rem; }
  .section-heading { align-items: start; flex-direction: column; }
  .timeline-toolbar { align-items: flex-start; flex-direction: column-reverse; }
  .controls { align-self: flex-end; }
  .timeline-frame { height: 31rem; }
  .context-grid { grid-template-columns: 1fr; }
  .index-event { grid-template-columns: 6rem 1fr; gap: .75rem; }
  .index-event span { display: none; }
  footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  .event-node { transition: none; }
}