/* ========== Reset & Base ========== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg-deep:       #070b14;
  --bg-mid:        #0d1321;
  --text:          #e0e6f0;
  --text-dim:      #8899b0;
  --text-faint:    #55667a;
  --text-muted:    #3a4a5e;
  --accent:        #f0b429;
  --accent-dim:    rgba(240, 180, 41, 0.12);
  --card-bg:       rgba(255, 255, 255, 0.06);
  --card-border:   rgba(255, 255, 255, 0.08);
  --card-hover-border: rgba(240, 180, 41, 0.2);
  --line-color:    rgba(255, 255, 255, 0.08);
  --dot-color:     rgba(240, 180, 41, 0.7);
}

html { scroll-behavior: smooth; }

body {
  width: 100%;
  min-height: 100vh;
  background: var(--bg-deep);
  color: var(--text);
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ========== Starry Background ========== */
.stars-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse at 20% 50%, #141f38 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, #181430 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, #0c1a22 0%, transparent 50%),
    var(--bg-deep);
}
.stars-bg::before,
.stars-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(1px 1px at 10% 20%, rgba(255,255,255,0.5), transparent),
    radial-gradient(1px 1px at 30% 70%, rgba(255,255,255,0.35), transparent),
    radial-gradient(1px 1px at 50% 30%, rgba(255,255,255,0.45), transparent),
    radial-gradient(1px 1px at 70% 80%, rgba(255,255,255,0.25), transparent),
    radial-gradient(1px 1px at 90% 40%, rgba(255,255,255,0.4), transparent),
    radial-gradient(1.5px 1.5px at 15% 85%, rgba(255,255,255,0.6), transparent),
    radial-gradient(1.5px 1.5px at 85% 15%, rgba(255,255,255,0.5), transparent),
    radial-gradient(1px 1px at 45% 55%, rgba(255,255,255,0.25), transparent),
    radial-gradient(1px 1px at 65% 25%, rgba(255,255,255,0.35), transparent),
    radial-gradient(1px 1px at 25% 45%, rgba(255,255,255,0.25), transparent);
  background-size: 100% 100%;
  animation: twinkle 8s ease-in-out infinite alternate;
}
.stars-bg::after {
  background-image:
    radial-gradient(1px 1px at 5% 60%, rgba(255,255,255,0.35), transparent),
    radial-gradient(1px 1px at 35% 15%, rgba(255,255,255,0.45), transparent),
    radial-gradient(1px 1px at 55% 75%, rgba(255,255,255,0.25), transparent),
    radial-gradient(1px 1px at 75% 45%, rgba(255,255,255,0.5), transparent),
    radial-gradient(1px 1px at 95% 85%, rgba(255,255,255,0.35), transparent),
    radial-gradient(2px 2px at 50% 10%, rgba(255,255,255,0.7), transparent),
    radial-gradient(1.5px 1.5px at 20% 90%, rgba(255,255,255,0.4), transparent);
  animation-delay: -4s;
}
@keyframes twinkle {
  0%   { opacity: 0.4; }
  100% { opacity: 0.9; }
}

/* ========== Back Link ========== */
.back-link {
  position: fixed;
  top: 1.5rem;
  left: 1.5rem;
  z-index: 100;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-dim);
  text-decoration: none;
  padding: 0.5rem 1rem;
  background: rgba(255, 255, 255, 0.04);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 8px;
  transition: all 0.25s ease;
}
.back-link:hover {
  color: var(--accent);
  border-color: rgba(240, 180, 41, 0.25);
}

/* ========== Timeline Page ========== */
.timeline-page {
  max-width: 800px;
  margin: 0 auto;
  padding: 5rem 1.5rem 3rem;
}

.timeline-title {
  text-align: center;
  font-size: 1.6rem;
  font-weight: 300;
  letter-spacing: 0.08em;
  color: var(--text);
  margin-bottom: 3.5rem;
}

/* ========== Timeline ========== */
.timeline {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* Vertical line through the center column */
.timeline::before {
  content: '';
  position: absolute;
  left: 7rem;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--line-color);
}

/* ---- Item row: three-column layout ---- */
.tl-item {
  position: relative;
  display: flex;
  align-items: center;
  padding: 1rem 0;
}

/* ---- Year column (left) ---- */
.tl-year {
  width: 5rem;
  flex-shrink: 0;
  text-align: right;
  padding-right: 1.5rem;
  font-size: 0.9rem;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: var(--text-dim);
  letter-spacing: 0.03em;
}

/* ---- Middle column: dot + age ---- */
.tl-mid {
  position: relative;
  width: 2rem;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  z-index: 2;
}

.tl-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--dot-color);
  box-shadow: 0 0 8px rgba(240, 180, 41, 0.3);
  flex-shrink: 0;
}

.tl-age {
  font-size: 0.65rem;
  font-weight: 500;
  color: var(--text-faint);
  letter-spacing: 0.03em;
  font-variant-numeric: tabular-nums;
}

/* ---- Card column (right) ---- */
.tl-card {
  flex: 1;
  padding-left: 1.5rem;
  min-width: 0;
}

.tl-card-content {
  display: inline-block;
  padding: 0.65rem 1.3rem;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  transition: all 0.25s ease;
}

.tl-card-content:hover {
  border-color: var(--card-hover-border);
  transform: translateY(-1px);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}

.tl-event {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--text);
  letter-spacing: 0.02em;
  line-height: 1.5;
}

/* ========== Footer ========== */
.site-footer {
  text-align: center;
  padding: 2rem 1rem 3rem;
  color: var(--text-faint);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}

/* ========== Responsive ========== */
@media (max-width: 640px) {
  .timeline-page {
    padding: 4rem 1rem 2rem;
  }

  .timeline-title {
    font-size: 1.3rem;
    margin-bottom: 2.5rem;
  }

  .timeline::before {
    left: 4.5rem;
  }

  .tl-item {
    padding: 0.8rem 0;
  }

  .tl-year {
    width: 3.2rem;
    font-size: 0.78rem;
    padding-right: 0.8rem;
  }

  .tl-mid {
    width: 1.5rem;
  }

  .tl-dot {
    width: 8px;
    height: 8px;
  }

  .tl-age {
    font-size: 0.55rem;
  }

  .tl-card {
    padding-left: 0.8rem;
  }

  .tl-card-content {
    padding: 0.5rem 0.9rem;
  }

  .tl-event {
    font-size: 0.82rem;
  }

  .back-link {
    top: 0.75rem;
    left: 0.75rem;
    font-size: 0.75rem;
    padding: 0.4rem 0.75rem;
  }
}