:root {
  /* Interaction Pattern:* Pattern:** Interactive elements have visible state changes: hover lifts the shadow. IntersectionObserver` to detect which century section is currently in view and update the active marker accordingly. JetBrains Mono" (Google Fonts Space Grotesk" (Google Fonts */
  --primary-black: #0a0a0a;
  --background-white: #fafafa;
  --card-surface: #f0f0f0;
  --concrete-gray: #d4d4d4;
  --mid-gray: #888888;
  --deep-charcoal: #2a2a2a;
  --light-accent: #e8e8e8;
  --stark-white: #ffffff;
  --metadata-gray: #555555;
  --pure-black: #000000;
  --spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --standard: cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--primary-black);
  background: var(--background-white);
  font-family: "DM Sans", "Inter", sans-serif;
  overflow-x: hidden;
}

.concrete-noise {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    repeating-conic-gradient(from 0deg, var(--pure-black) 0deg 8deg, transparent 8deg 18deg),
    var(--background-white);
  opacity: 0.03;
}

.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 20;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 0 32px;
  background: var(--background-white);
  border-bottom: 4px solid var(--primary-black);
}

.brand {
  flex: 0 0 auto;
  font-family: "Space Grotesk", space, sans-serif;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  text-transform: lowercase;
}

.era-filters {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
  min-width: 0;
}

.filter-button {
  appearance: none;
  border: 3px solid var(--primary-black);
  border-radius: 0;
  background: var(--card-surface);
  color: var(--primary-black);
  box-shadow: 4px 4px 0 var(--primary-black);
  padding: 8px 12px;
  font-family: "JetBrains Mono", monospace;
  font-size: clamp(0.68rem, 1vw, 0.82rem);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform 250ms var(--standard), box-shadow 250ms var(--standard), background-color 250ms var(--standard), color 250ms var(--standard);
}

.filter-button:hover,
.filter-button.active {
  background: var(--primary-black);
  color: var(--stark-white);
}

.filter-button:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 var(--primary-black);
}

.timeline-spine {
  position: fixed;
  left: 32px;
  top: 104px;
  bottom: 40px;
  z-index: 10;
  width: 70px;
  pointer-events: none;
}

.spine-line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 5px;
  width: 2px;
  background: var(--concrete-gray);
}

.spine-marker {
  position: absolute;
  left: 0;
  width: 12px;
  height: 12px;
  border: 3px solid var(--primary-black);
  background: var(--background-white);
  transform: translateY(-50%);
  transition: background-color 200ms var(--standard), transform 200ms var(--standard);
}

.spine-marker:nth-of-type(1) { top: 5%; }
.spine-marker:nth-of-type(2) { top: 36%; }
.spine-marker:nth-of-type(3) { top: 67%; }
.spine-marker:nth-of-type(4) { top: 95%; }

.spine-marker.active {
  background: var(--primary-black);
  transform: translateY(-50%) scale(1.35);
}

.spine-marker span {
  position: absolute;
  left: 22px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--mid-gray);
  font-family: "JetBrains Mono", monospace;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  white-space: nowrap;
}

.exhibition-shell {
  padding: 104px 40px 64px 124px;
}

.archive-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
  min-height: calc(100vh - 168px);
  padding: 24px;
  background: var(--concrete-gray);
  border: 4px solid var(--primary-black);
}

.event-card {
  position: relative;
  display: flex;
  flex-direction: column;
  min-width: 0;
  aspect-ratio: 4 / 3;
  padding: 24px;
  border: 4px solid var(--primary-black);
  border-radius: 0;
  background: var(--card-surface);
  box-shadow: 8px 8px 0 var(--primary-black);
  cursor: pointer;
  transform: perspective(1000px) rotateX(2deg) rotateY(-1deg);
  transform-origin: center center;
  transition: transform 400ms var(--standard), box-shadow 400ms var(--standard), opacity 500ms var(--standard), background-color 400ms var(--standard), min-height 650ms var(--spring);
  overflow: hidden;
}

.event-card:hover {
  box-shadow: 12px 12px 0 var(--primary-black);
  transform: perspective(1000px) rotateX(0) rotateY(0) translate(-3px, -3px);
}

.card-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 18px;
  font-family: "JetBrains Mono", monospace;
  font-size: clamp(0.75rem, 1.2vw, 0.9rem);
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.event-date {
  color: var(--metadata-gray);
  background: var(--stark-white);
  border: 3px solid var(--primary-black);
  padding: 4px 7px;
}

.era-label {
  color: var(--mid-gray);
}

.event-title {
  margin: 0;
  max-width: 13ch;
  font-family: "Space Grotesk", space, sans-serif;
  font-size: clamp(2rem, 5vw, 4.5rem);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.02em;
}

.event-excerpt {
  max-height: 0;
  overflow: hidden;
  margin: auto 0 0;
  color: var(--deep-charcoal);
  font-size: clamp(0.95rem, 1.8vw, 1.1rem);
  line-height: 1.45;
  letter-spacing: 0.01em;
  transition: max-height 350ms var(--standard), margin-top 350ms var(--standard), opacity 250ms var(--standard);
  opacity: 0;
}

.event-card:hover .event-excerpt,
.event-card.expanded .event-excerpt {
  max-height: 80px;
  margin-top: 22px;
  opacity: 1;
}

.event-detail {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  color: var(--primary-black);
  font-size: clamp(0.95rem, 1.8vw, 1.1rem);
  line-height: 1.65;
  letter-spacing: 0.01em;
  transition: max-height 650ms var(--spring), opacity 400ms var(--standard), padding-top 500ms var(--spring);
}

.event-detail p {
  max-width: 78ch;
  margin: 0 0 1rem;
}

.related-block {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-top: 24px;
  padding-top: 18px;
  border-top: 4px solid var(--primary-black);
  font-family: "JetBrains Mono", monospace;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.related-block span {
  color: var(--metadata-gray);
  font-size: 0.76rem;
}

.related-block b {
  display: inline-block;
  border: 3px solid var(--primary-black);
  background: var(--light-accent);
  padding: 6px 8px;
  font-size: 0.75rem;
}

.archive-grid.has-expanded .event-card:not(.expanded) {
  opacity: 0.6;
  transform: perspective(1000px) rotateX(2deg) rotateY(-1deg) scale(0.95);
}

.archive-grid.has-expanded .event-card:not(.expanded):hover {
  opacity: 0.86;
  transform: perspective(1000px) rotateX(0) rotateY(0) scale(0.98);
}

.event-card.filtered-out {
  display: none;
}

.event-card.expanded {
  grid-column: 1 / -1;
  aspect-ratio: auto;
  min-height: 62vh;
  background: var(--background-white);
  box-shadow: 4px 4px 0 var(--primary-black);
  transform: perspective(1000px) rotateX(0) rotateY(0);
  cursor: zoom-out;
  z-index: 3;
}

.event-card.expanded .event-title {
  max-width: 16ch;
  font-size: clamp(3rem, 7vw, 7rem);
}

.event-card.expanded .event-detail {
  max-height: 620px;
  opacity: 1;
  padding-top: 26px;
}

.connection-layer {
  position: fixed;
  inset: 0;
  z-index: 15;
  pointer-events: none;
  overflow: visible;
}

.connection-line {
  fill: none;
  stroke: var(--mid-gray);
  stroke-width: 1;
  stroke-dasharray: 8 8;
  stroke-dashoffset: var(--line-length, 500);
  animation: growLine 600ms var(--standard) forwards;
}

@keyframes growLine {
  to { stroke-dashoffset: 0; }
}

@media (max-width: 1024px) {
  .timeline-spine {
    display: none;
  }

  .exhibition-shell {
    padding: 96px 24px 48px;
  }

  .archive-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
    padding: 20px;
  }

  .event-card {
    box-shadow: 6px 6px 0 var(--primary-black);
  }

  .event-card:hover {
    box-shadow: 8px 8px 0 var(--primary-black);
  }
}

@media (max-width: 767px) {
  .topbar {
    height: auto;
    min-height: 64px;
    align-items: flex-start;
    flex-direction: column;
    padding: 12px 16px;
    gap: 12px;
  }

  .era-filters {
    justify-content: flex-start;
    flex-wrap: wrap;
    gap: 8px;
  }

  .filter-button {
    padding: 7px 9px;
    box-shadow: 3px 3px 0 var(--primary-black);
  }

  .exhibition-shell {
    padding: 150px 12px 32px;
  }

  .archive-grid {
    grid-template-columns: 1fr;
    gap: 16px;
    padding: 16px;
    border-width: 3px;
  }

  .event-card {
    padding: 18px;
    border-width: 3px;
    box-shadow: 4px 4px 0 var(--primary-black);
    transform: none;
  }

  .event-card:hover {
    box-shadow: 6px 6px 0 var(--primary-black);
    transform: translate(-1px, -1px);
  }

  .event-card.expanded {
    grid-column: auto;
    min-height: 78vh;
    box-shadow: 3px 3px 0 var(--primary-black);
  }

  .event-card.expanded .event-title {
    font-size: clamp(2.4rem, 13vw, 4.2rem);
  }

  .connection-layer {
    display: none;
  }
}