/*
 * chart.css: styling for the three-panel deep-time chart.
 *
 * Loaded only by chart.html. Follows the data-viz mark specs: 2px lines, ≥8px
 * markers, 10% area washes, solid hairline grid one step off the surface, and
 * text that never wears the series colour: identity comes from a small coloured
 * swatch beside the label, never from colouring the text itself.
 *
 * KEY LAYOUT DECISION: each panel is an SVG (geometry only, stretched with
 * preserveAspectRatio="none") plus an absolutely positioned HTML label layer on
 * top. Stretching the SVG distorts glyphs, so no text lives inside it: labels
 * are HTML placed by percentage off the same scales. See assets/chart.js.
 *
 * The series hues are slots 1–3 of the reference categorical palette (dark
 * steps), validated against this surface under the all-pairs check before any of
 * this was written.
 *
 * Read alongside: assets/chart.js (emits the markup), assets/site.css (shell).
 */

.viz-root {
  --surface-1: #07080a;
  --series-o2: #3987e5;
  --series-co2: #d95926;
  --series-temp: #199e70;
  --grid: #23272e;
  --rule-ink: #565d68;
  --plot-h: 168px;
}

/* ---- stack ---- */
.c-stack { position: relative; margin-top: 2rem; outline: none; }
.c-stack:focus-visible { outline: 2px solid var(--accent-2); outline-offset: 8px; }

.c-panel + .c-panel { margin-top: 1.6rem; }
/* flex-wrap plus min-width:0 on the title: without both, the title refuses to
   shrink below its content and runs straight through the unit label on narrow
   screens. */
.c-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.2rem 1rem;
  margin-bottom: 0.55rem;
}
.c-title {
  font-family: var(--mono);
  font-size: 0.84rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  min-width: 0;
}
/* The swatch carries identity, so the label text stays in an ink token. */
.c-title i { width: 12px; height: 12px; border-radius: 2px; display: block; flex: none; }
.c-unit { font-family: var(--mono); font-size: 0.78rem; color: var(--ink-dim); flex: none; }

/* The threshold caption. In the plot on wide screens; promoted to the panel head
   on narrow ones, where the plot is too small to hold a line of text without
   covering the curve and the y-ticks. */
.c-rulenote {
  display: none;
  width: 100%;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--rule-ink);
}

/* ---- plot: stretched geometry + undistorted HTML labels ---- */
.c-plot { position: relative; height: var(--plot-h); }
.c-svg { width: 100%; height: 100%; display: block; overflow: visible; }
.c-labels { position: absolute; inset: 0; pointer-events: none; }

.c-line { fill: none; stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; vector-effect: non-scaling-stroke; }
.c-area { opacity: 0.1; stroke: none; }
.c-grid { stroke: var(--grid); stroke-width: 1; vector-effect: non-scaling-stroke; }
.c-rule { stroke: var(--rule-ink); stroke-width: 1; vector-effect: non-scaling-stroke; }
.c-cross { stroke: var(--ink-dim); stroke-width: 1; vector-effect: non-scaling-stroke; }

/* ≥8px marker with a 2px surface ring so it stays legible over the line. */
.c-dot {
  position: absolute;
  width: 9px; height: 9px;
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--bg);
  transform: translate(-50%, -50%);
}

.c-ytick, .c-rulelabel, .c-xtick {
  position: absolute;
  font-family: var(--mono);
  white-space: nowrap;
}
.c-ytick {
  font-size: 0.7rem;
  color: var(--ink-dim);
  transform: translateY(-50%);
  width: 42px;
  text-align: right;
  font-variant-numeric: tabular-nums;
}
.c-rulelabel {
  font-size: 0.64rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--rule-ink);
  transform: translateY(-130%);
}

/* ---- shared axis ---- */
.c-axis { position: relative; margin-top: 0.5rem; }
.c-xticks { position: relative; height: 20px; }
.c-xtick {
  font-size: 0.7rem;
  color: var(--ink-dim);
  transform: translateX(-50%);
  top: 4px;
  font-variant-numeric: tabular-nums;
}
.c-strip { position: relative; height: 20px; margin-top: 2px; }
.c-era {
  position: absolute;
  top: 0;
  height: 20px;
  background: #12151a;
  border-radius: 1px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  text-decoration: none;
  transition: background 160ms;
}
.c-era:hover { background: #212833; }
.c-era span {
  font-family: var(--mono);
  font-size: 0.58rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--ink-dim);
  white-space: nowrap;
}
.c-era:hover span { color: var(--ink); }

/* ---- the scale break ----
   One per plot and one over the axis, each filling only its own box. A single
   overlay across the stack would also sit on top of the panel headings. */
.c-break {
  position: absolute;
  top: 0; bottom: 0;
  background: var(--bg);
  border-left: 1px dashed var(--grid);
  border-right: 1px dashed var(--grid);
  z-index: 3;
  pointer-events: none;
}

/* ---- readout ---- */
.c-readout {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 1.6rem;
  margin-top: 1.6rem;
  padding: 0.9rem 1.1rem;
  border: 1px solid var(--rule);
  background: var(--bg-raise);
  font-family: var(--mono);
  font-size: 0.84rem;
}
.c-readout[hidden] { display: none; }
.c-r-age { color: var(--ink); font-weight: 600; letter-spacing: 0.08em; }
.c-r-era { color: var(--accent-2); text-decoration: none; border-bottom: 1px solid var(--rule); letter-spacing: 0.06em; }
.c-r-vals { display: flex; flex-wrap: wrap; gap: 0.4rem 1.2rem; margin-left: auto; color: var(--ink-dim); }
.c-r-vals span { display: flex; align-items: center; gap: 0.45rem; }
.c-r-vals i { width: 10px; height: 10px; border-radius: 2px; display: block; flex: none; }

.c-hint { font-family: var(--mono); font-size: 0.82rem; line-height: 1.7; color: var(--ink-faint); margin-top: 1.1rem; }

/* ---- caveats, 2×2 on this page ----
   Four roughly equal-length notes read better as a block of four than as a tall
   stack; site.css caps .caveat at 74ch for single-column use, so that cap is
   released here and the grid does the measure control instead. */
.caveat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.1rem;
}
.caveat-grid .caveat { max-width: none; margin-top: 0; }
@media (max-width: 820px) { .caveat-grid { grid-template-columns: 1fr; } }

/* ---- table view ---- */
.c-tablewrap { margin-top: 2.5rem; border-top: 1px solid var(--rule); padding-top: 1.6rem; }
.c-tablewrap summary {
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-dim);
  cursor: pointer;
}
.c-tablewrap summary:hover { color: var(--ink); }
.c-tablescroll { overflow-x: auto; margin-top: 1.2rem; }
table.c-table { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: 0.82rem; }
table.c-table th {
  text-align: left;
  font-weight: 500;
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-dim);
  padding: 0 1rem 0.7rem 0;
  border-bottom: 1px solid var(--rule);
  white-space: nowrap;
}
table.c-table td {
  padding: 0.6rem 1rem 0.6rem 0;
  border-bottom: 1px solid color-mix(in srgb, var(--rule) 55%, transparent);
  color: var(--ink-dim);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}
table.c-table td:first-child { color: var(--ink); }
table.c-table a { color: inherit; text-decoration: none; border-bottom: 1px solid var(--rule); }
table.c-table a:hover { border-color: var(--accent-2); }

@media (max-width: 760px) {
  .viz-root { --plot-h: 132px; }
  .c-r-vals { margin-left: 0; width: 100%; }
  .c-era span { font-size: 0.5rem; }
  /* Swap the threshold caption from inside the plot to the panel head. */
  .c-rulelabel { display: none; }
  .c-rulenote { display: block; }
  /* Drop the in-between ticks; the full set collides either side of the break. */
  .c-xtick[data-opt] { display: none; }
}