/* -----------------------------------------
   SVG Defaults (protect lines from resets)
------------------------------------------*/
svg line {
  fill: none;
  stroke: #000;          /* fallback */
  stroke-width: 2;       /* fallback */
}

/* -----------------------------------------
   Required CSS variables (define once)
------------------------------------------*/
:root {
  --ink: #1f2937;        /* slate-800 */
  --pop: #94a3b8;        /* for pop curve */
  --pop-mean: #1d4ed8;   /* your brand blue */
  --blue: #2563eb;       /* sample mean */
  --blue-soft: #3b82f6;  /* CI line + caps */
}

/* -----------------------------------------
   Axes + Grid
------------------------------------------*/
.grid line {
  stroke: #e5e7eb;
  stroke-width: 1;
}

.axis {
  stroke: var(--ink);
  stroke-width: 1.4;
}

.tickline {
  stroke: var(--ink);
  stroke-width: 1.2;
}

.tick {
  fill: #475569;
  font-size: 12px;
}

/* -----------------------------------------
   Population curve + mean
------------------------------------------*/
.pop-curve {
  fill: none;
  stroke: var(--pop);
  stroke-width: 2;
}

.pop-mean {
  stroke: #2563EB;
  stroke-width: 2;
  stroke-dasharray: 4 4;
}

/* -----------------------------------------
   Sample dots + sample mean
------------------------------------------*/
.sample-point {
  fill: var(--ink);
  opacity: .9;
}

.sample-mean {
  stroke: var(--blue);
  stroke-width: 2.5;
}

/* -----------------------------------------
   Confidence interval
------------------------------------------*/
.ci-line {
  stroke: var(--blue-soft);
  stroke-width: 4;
}

.ci-cap {
  stroke: var(--blue-soft);
  stroke-width: 3;
}

/* -----------------------------------------
   Text labels
------------------------------------------*/
.label {
  fill: #111827;
  font-size: 12px;
}

.mono {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas,
    "Liberation Mono", monospace;
}

/* -----------------------------------------
   SVG sizing
------------------------------------------*/
svg {
  width: 100%;
  height: auto;
}