/* --- Variables --- */
:root {
  --color-england-wales: #006bb6;
  --color-scotland: #033D69;
  --color-northern-ireland: #23C4FF;
  --color-text: #1a202c;
  --color-text-muted: #718096;
  --color-border: #e2e8f0;
  --color-bg: #f7fafc;
  --color-card: #ffffff;
  --node-size: 42px;
  --card-width: 180px;
  --connector-stroke: #4a5568;
}

/* --- Reset & base --- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
}

/* --- Page layout --- */
.timeline-page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* --- Header & legend --- */
.header {
  padding: 1rem 1.5rem;
  flex-shrink: 0;
}

.legend-wrap {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.legend-wrap.hidden .legend {
  display: none;
}

.legend-toggle {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  cursor: pointer;
  text-decoration: underline;
}

.legend-toggle:hover {
  color: var(--color-text);
}

.legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: none;
  border: none;
  padding: 0.25rem 0;
  font-size: 0.875rem;
  color: var(--color-text);
  cursor: pointer;
}

.legend-item:hover {
  opacity: 0.85;
}

.legend-item.active {
  font-weight: 600;
  color: var(--color-text);
}

.legend-item[aria-pressed="false"]:not([data-region="all"]) {
  color: var(--color-text-muted);
}

.legend-item[aria-pressed="false"]:not([data-region="all"]) .legend-swatch {
  opacity: 0.4;
}

.legend-swatch {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  flex-shrink: 0;
}

.legend-england-wales { background: var(--color-england-wales); }
.legend-scotland { background: var(--color-scotland); }
.legend-northern-ireland { background: var(--color-northern-ireland); }

/* --- Main timeline --- */
.timeline-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 0 1rem 1rem;
  position: relative;
  min-height: 420px;
}

.timeline-viewport {
  flex: 1;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  position: relative;
  padding: 4rem 0 4rem;
}

.fade-edge {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 60px;
  pointer-events: none;
  z-index: 3;
}

.fade-edge.fade-left {
  left: 1rem;
  background: linear-gradient(to right, var(--color-bg), transparent);
}

.fade-edge.fade-right {
  right: 1rem;
  background: linear-gradient(to left, var(--color-bg), transparent);
}

.timeline-track {
  display: flex;
  align-items: stretch;
  position: relative;
  min-width: min-content;
  padding: 0 40px;
  gap: 16px;
  min-height: 380px;
}

/* --- Axis --- */
.timeline-axis {
  position: absolute;
  left: 40px;
  right: 40px;
  top: 50%;
  transform: translateY(-50%);
  height: 3px;
  background: var(--color-text);
  z-index: 0;
}

/* --- Event --- */
.timeline-event {
  flex-shrink: 0;
  width: var(--card-width);
  min-height: 380px;
  position: relative;
  z-index: 1;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

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

.timeline-event .event-connector {
  position: absolute;
  left: 50%;
  width: 3px;
  background: var(--connector-stroke);
  transform: translateX(-50%);
}

.event-connector-top {
  bottom: 50%;
  top: 25%;
}

.event-connector-bottom {
  top: 50%;
  bottom: 25%;
}

.timeline-event .event-node {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: var(--node-size);
  height: var(--node-size);
  border-radius: 50%;
  z-index: 2;
}

.timeline-event[data-region="england-wales"] .event-node { background: var(--color-england-wales); }
.timeline-event[data-region="scotland"] .event-node { background: var(--color-scotland); }
.timeline-event[data-region="northern-ireland"] .event-node { background: var(--color-northern-ireland); }

.timeline-event .event-card {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: var(--card-width);
  padding: 1rem 1.25rem;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

.event-card-top {
  bottom: calc(50% + var(--node-size) / 2 + 12px);
}

.event-card-bottom {
  top: calc(50% + var(--node-size) / 2 + 12px);
}

.event-title {
  margin: 0 0 0.35rem;
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.3;
}

.timeline-event[data-region="england-wales"] .event-title,
.timeline-event[data-region="england-wales"] .event-date { color: var(--color-england-wales); }
.timeline-event[data-region="scotland"] .event-title,
.timeline-event[data-region="scotland"] .event-date { color: var(--color-scotland); }
.timeline-event[data-region="northern-ireland"] .event-title,
.timeline-event[data-region="northern-ireland"] .event-date { color: var(--color-northern-ireland); }

.event-date {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.event-desc {
  margin: 0;
  font-size: 0.8125rem;
  line-height: 1.45;
  color: var(--color-text-muted);
}

/* --- Nav arrows --- */
.timeline-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1.5rem 0;
  flex-shrink: 0;
  position: relative;
  z-index: 100;
}

.timeline-nav {
  display: flex;
  gap: 0.5rem;
  flex-shrink: 0;
}

.nav-arrow {
  width: 40px;
  height: 40px;
  border: none;
  border-radius: 50%;
  background: #4a5568;
  color: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s ease;
}

.nav-arrow:hover {
  background: #2d3748;
}

.nav-arrow:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.brand-logo {
  display: block;
  height: 32px;
  width: auto;
  max-width: 180px;
  object-fit: contain;
  position: relative;
  z-index: 101;
}