:root {
  --bg: #f6f1e8;
  --paper: #f8f4ec;
  --text: #4f463d;
  --muted: #8a7f72;
  --line: #d8cfc3;
  --accent: #a79b8c;
  --max-width: 1180px;
  --content-width: 1040px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Georgia, "Times New Roman", serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
}

.site-header {
  border-bottom: 1px solid rgba(79, 70, 61, 0.12);
}

.site-header__inner {
  max-width: none;
  margin: 0;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.site-brand,
.site-nav a,
.back-link,
.entry-dates,
.timeline-kicker {
  font-family: Georgia, "Times New Roman", serif;
  letter-spacing: 0.08em;
  text-transform: none;
}

.site-brand {
  font-size: 0.95rem;
  font-weight: 700;
  color: #1b3a2f;
}

.site-nav {
  display: flex;
  gap: 1.35rem;
}

.site-nav a {
  font-size: 0.95rem;
  opacity: 1;
  color: #1b3a2f;
}

.site-nav a[aria-current="page"] {
  opacity: 1;
}

.timeline-hero {
  padding: 3.35rem 1.75rem 3.05rem;
}

.timeline-hero__inner {
  max-width: 780px;
  margin: 0 auto;
  text-align: center;
}

.back-link {
  display: inline-block;
  margin-bottom: 1.65rem;
  padding: 0.48rem 0.9rem;
  border: 1px solid rgba(79, 70, 61, 0.14);
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.72rem;
}

.timeline-kicker {
  margin: 0 0 0.7rem;
  color: var(--muted);
  font-size: 0.7rem;
}

.timeline-title {
  margin: 0;
  font-size: clamp(2.8rem, 5.3vw, 4.55rem);
  font-weight: 400;
  line-height: 1.02;
  letter-spacing: -0.02em;
}

.timeline-intro {
  max-width: 690px;
  margin: 1.15rem auto 0;
  color: #6d6258;
  font-size: 1.05rem;
  line-height: 1.76;
}

.timeline-list {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0.25rem 1.75rem 3.5rem;
}

.timeline-entry {
  display: grid;
  grid-template-columns: 232px 54px 1fr;
  gap: 0;
  align-items: start;
  padding: 2.45rem 0;
  border-top: 1px solid var(--line);
}

.timeline-entry:first-child {
  border-top: none;
  padding-top: 0.7rem;
}

.entry-label {
  padding-right: 1.65rem;
}

.entry-dates {
  margin: 0 0 0.72rem;
  color: var(--muted);
  font-size: 0.7rem;
}

.entry-title {
  margin: 0;
  font-size: 2.12rem;
  font-weight: 400;
  line-height: 1.06;
  letter-spacing: -0.01em;
}

.entry-tagline {
  margin: 0.45rem 0 0;
  color: var(--muted);
  font-size: 1rem;
}

.entry-marker {
  position: relative;
  min-height: 100%;
  display: flex;
  justify-content: center;
}

.entry-dot {
  position: relative;
  z-index: 2;
  width: 0.82rem;
  height: 0.82rem;
  margin-top: 0.48rem;
  border-radius: 50%;
  background: #9d9183;
}

.entry-line {
  position: absolute;
  top: 1.3rem;
  bottom: -2.45rem;
  width: 1px;
  background: var(--line);
}

.timeline-entry:last-child .entry-line {
  bottom: 1rem;
}

.entry-content {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 2.75rem;
  align-items: start;
  padding-left: 0.4rem;
}

.entry-copy {
  display: flex;
  flex-direction: column;
  gap: 0.95rem;
  max-width: 39rem;
}

.entry-copy p {
  margin: 0;
  font-size: 1.03rem;
  line-height: 1.76;
}

.entry-notes {
  margin: 0.1rem 0 0;
  padding-left: 1.15rem;
  color: #6f665c;
  font-size: 0.97rem;
  line-height: 1.68;
}

.entry-notes li + li {
  margin-top: 0.34rem;
}

.entry-illustration {
  width: 100%;
  aspect-ratio: 4 / 3;
  border-radius: 14px;
  overflow: hidden;
  background: linear-gradient(180deg, rgba(167, 155, 140, 0.08), rgba(167, 155, 140, 0.04));
  box-shadow: 0 1px 0 rgba(79, 70, 61, 0.06);
}

.entry-illustration img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  filter: saturate(0.95) contrast(0.98);
}


.species-inset {
  margin-top: 0.2rem;
  padding: 1rem 1.05rem 1.05rem;
  border: 1px solid rgba(79, 70, 61, 0.1);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.34);
  box-shadow: 0 1px 0 rgba(79, 70, 61, 0.04);
}

.species-inset__eyebrow {
  margin: 0 0 0.34rem;
  font-family: "Helvetica Neue", Arial, sans-serif;
  font-size: 0.66rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.species-inset__title {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 400;
  line-height: 1.3;
}

.species-inset__title span {
  color: #74695f;
  font-size: 0.92em;
  font-style: italic;
}

.species-inset__text {
  margin: 0.42rem 0 0;
  color: #6d6258;
  font-size: 0.94rem;
  line-height: 1.68;
}

.bird-signal {
  display: inline-flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.35rem;
}

.bird-signal__name {
  font-size: 0.95rem;
  color: #6f665c;
  font-style: italic;
}

.bird-audio-button {
  appearance: none;
  border: 1px solid rgba(74, 67, 60, 0.16);
  background: rgba(255, 255, 255, 0.45);
  color: #4a433c;
  border-radius: 999px;
  padding: 0.48rem 0.82rem;
  font: inherit;
  font-size: 0.9rem;
  line-height: 1;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.2s ease, border-color 0.2s ease;
}

.bird-audio-button:hover {
  background: rgba(255, 255, 255, 0.72);
  border-color: rgba(74, 67, 60, 0.28);
}

.bird-audio-button:active {
  transform: scale(0.98);
}

.bird-audio-button.is-playing {
  background: rgba(167, 155, 140, 0.18);
  border-color: rgba(74, 67, 60, 0.26);
}

.timeline-footer {
  padding: 0.75rem 1.75rem 4.4rem;
  text-align: center;
}

.timeline-footer__line {
  margin: 0;
  font-style: italic;
  color: #766a5f;
  font-size: 1.02rem;
}

.timeline-footer__subline {
  margin: 0.42rem 0 0;
  font-size: 0.92rem;
  color: var(--muted);
  letter-spacing: 0.03em;
}

@media (max-width: 900px) {
  .site-header__inner {
    flex-wrap: wrap;
    justify-content: center;
  }

  .timeline-hero {
    padding-top: 2.8rem;
    padding-bottom: 2.5rem;
  }

  .timeline-entry {
    grid-template-columns: 1fr;
    gap: 1rem;
    padding: 2rem 0;
  }

  .entry-label {
    padding-right: 0;
  }

  .entry-marker {
    display: none;
  }

  .entry-content {
    grid-template-columns: 1fr;
    gap: 1.15rem;
    padding-left: 0;
  }

  .entry-copy {
    max-width: none;
  }

  .entry-illustration {
    max-width: 360px;
  }
}

@media (max-width: 640px) {
  .site-nav {
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.75rem 1rem;
  }

  .timeline-title {
    font-size: 2.5rem;
  }

  .timeline-intro,
  .entry-copy p {
    font-size: 1rem;
  }

  .entry-title {
    font-size: 1.72rem;
  }

  .timeline-hero,
  .timeline-list,
  .timeline-footer {
    padding-left: 1rem;
    padding-right: 1rem;
  }
}