:root {
  --bg: #fbfaf7; --fg: #1d1b18; --muted: #6b665e; --line: #d9d4ca; --panel: #ffffff;
  --accent: #3b5bdb;
  --c-cosmology: #6741d9; --c-geology: #a0522d; --c-biology: #2b8a3e; --c-human-evolution: #d9480f;
  --c-history: #c2255c; --c-science: #1971c2; --c-technology: #0c8599; --c-culture: #e67700;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1115; --fg: #ebe9e4; --muted: #9a958c; --line: #2b2f37; --panel: #171a20; --accent: #91a7ff;
    --c-cosmology: #b197fc; --c-geology: #e0a07a; --c-biology: #69db7c; --c-human-evolution: #ffa94d;
    --c-history: #f783ac; --c-science: #74c0fc; --c-technology: #66d9e8; --c-culture: #ffd43b;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0f1115; --fg: #ebe9e4; --muted: #9a958c; --line: #2b2f37; --panel: #171a20; --accent: #91a7ff;
  --c-cosmology: #b197fc; --c-geology: #e0a07a; --c-biology: #69db7c; --c-human-evolution: #ffa94d;
  --c-history: #f783ac; --c-science: #74c0fc; --c-technology: #66d9e8; --c-culture: #ffd43b;
  color-scheme: dark;
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  background: var(--bg); color: var(--fg);
  font: 15px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  display: grid; grid-template-rows: auto 1fr auto; overflow: hidden;
}
header { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 12px 16px; border-bottom: 1px solid var(--line); }
h1 { font-size: 18px; margin: 0; letter-spacing: .01em; }
.controls { display: flex; align-items: center; gap: 8px; }
.range { color: var(--muted); font-size: 13px; white-space: nowrap; }
button {
  font: inherit; color: var(--fg); background: transparent; border: 1px solid var(--line);
  border-radius: 8px; min-width: 36px; height: 36px; padding: 0 10px; cursor: pointer;
}
button:hover { border-color: var(--accent); }
.controls input {
  font: inherit; color: var(--fg); background: transparent; border: 1px solid var(--line);
  border-radius: 8px; min-width: 36px; height: 36px; padding: 0 10px; cursor: text;
}
.controls input::placeholder {
  color: var(--muted);
  opacity: 1; /* Firefox */
}
.controls input:focus {
  outline: none;
  border-color: var(--accent);
}
main { position: relative; min-height: 0; }
svg { width: 100%; height: 100%; display: block; touch-action: none; cursor: grab; user-select: none; }
svg.dragging { cursor: grabbing; }
.axis line { stroke: var(--line); }
.axis text { fill: var(--muted); font-size: 12px; }
.baseline { stroke: var(--fg); stroke-width: 2; opacity: .6; }
.event { cursor: pointer; }
.event text { fill: var(--fg); font-size: 13px; }
.event.l1 text { font-weight: 650; font-size: 14px; }
.event .stem { stroke-width: 1; opacity: .55; }
.event:hover text, .event:focus text { text-decoration: underline; }
.event.cluster text { fill: var(--fg); font-size: 12px; font-weight: 700; }
.event.cluster circle { opacity: .95; }
.event.cluster:hover circle, .event.cluster:focus circle { stroke: var(--fg); stroke-width: 2; }
#cluster-pop {
  position: absolute; z-index: 5; transform: translate(-50%, -100%);
  min-width: 190px; max-width: 320px; max-height: 45vh; overflow: auto; padding: 6px;
  background: var(--panel); border: 1px solid var(--line); border-radius: 12px;
  box-shadow: 0 8px 30px rgba(0,0,0,.18);
}
.cp-item {
  display: flex; align-items: center; gap: 10px; width: 100%;
  min-width: 0; height: auto; margin: 0; padding: 7px 9px;
  background: transparent; border: none; border-radius: 8px;
  color: var(--fg); font: inherit; text-align: left; cursor: pointer;
}
.cp-item:hover { background: rgba(128, 128, 128, .16); }
.cp-item .cp-dot { width: 9px; height: 9px; border-radius: 50%; background: var(--dot); flex: none; }
.cp-item .cp-title { font-weight: 600; }
.cp-item .cp-when { margin-left: auto; color: var(--muted); font-size: 12px; white-space: nowrap; }
.hint { position: absolute; left: 16px; bottom: 8px; margin: 0; color: var(--muted); font-size: 12px; pointer-events: none; }
aside {
  position: fixed; right: 16px; top: 72px; bottom: 56px; width: min(420px, calc(100vw - 32px));
  background: var(--panel); border: 1px solid var(--line); border-radius: 14px; padding: 20px 20px 16px;
  overflow: auto; box-shadow: 0 10px 40px rgba(0,0,0,.18);
}
aside h2 { margin: 0 32px 4px 0; font-size: 20px; line-height: 1.25; }
aside .when { color: var(--muted); margin: 0 0 12px; }
aside .tag { display: inline-block; font-size: 12px; border-radius: 999px; padding: 2px 10px; color: #fff; margin-bottom: 10px; }
aside img { max-width: 100%; border-radius: 8px; margin: 8px 0 2px; }
aside .credit { color: var(--muted); font-size: 12px; margin: 0 0 8px; }
aside ul { padding-left: 18px; }
aside a { color: var(--accent); }
#close { position: absolute; right: 12px; top: 12px; border: none; font-size: 22px; }
footer { padding: 8px 16px; border-top: 1px solid var(--line); color: var(--muted); font-size: 12px; }
footer a { color: inherit; }
@media (max-width: 600px) {
  h1 { font-size: 16px; }
  .range { display: none; }
  aside { left: 12px; right: 12px; top: auto; bottom: 12px; width: auto; max-height: 60vh; }
}