/* ---------- Tokens ---------- */
:root {
  /* Okabe–Ito color-blind-safe palette */
  --c-orange:    #E69F00;
  --c-skyblue:   #56B4E9;
  --c-green:     #009E73;
  --c-yellow:    #F0E442;
  --c-blue:      #0072B2;
  --c-vermilion: #D55E00;
  --c-purple:    #CC79A7;
  --c-black:     #000000;

  /* Series assignments (override Plotly defaults) */
  --series-1: var(--c-blue);
  --series-2: var(--c-vermilion);
  --series-3: var(--c-green);
  --series-4: var(--c-orange);
  --series-5: var(--c-purple);
  --series-6: var(--c-skyblue);

  /* UI palette */
  --ink:     #1a1a1a;
  --muted:   #5a5a5a;
  --subtle:  #8a8a8a;
  --border:  #d8d8d8;
  --bg:      #fafafa;
  --surface: #ffffff;
  --accent:  #0072B2;
  --accent-soft: #e8f1f8;
  --good:    #009E73;
  --warn:    #D55E00;

  /* Type & rhythm */
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --measure: 70ch;
  --radius: 10px;
  --radius-sm: 6px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.05), 0 1px 3px rgba(0,0,0,.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,.08), 0 2px 4px rgba(0,0,0,.05);
}

/* ---------- Reset & base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
}
img, svg { display: block; max-width: 100%; }
a { color: var(--accent); text-decoration: underline; text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
  border-radius: 3px;
}

h1, h2, h3 { line-height: 1.2; color: var(--ink); margin: 0 0 .5em; }
h1 { font-size: clamp(1.8rem, 2.4vw + 1rem, 2.6rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.3rem, 1vw + 1rem, 1.7rem); margin-top: 2.2em; }
h3 { font-size: 1.05rem; margin-top: 1.6em; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
p  { max-width: var(--measure); }
small, .small { font-size: .87rem; color: var(--muted); }

/* ---------- Layout ---------- */
.site {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}
.site-header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 1.5rem;
  margin-bottom: 2rem;
}
.site-header .lead {
  color: var(--muted);
  font-size: 1.05rem;
  max-width: var(--measure);
  margin: .5em 0 0;
}
.site-footer {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: .9rem;
}
.site-footer a { color: var(--muted); }

/* ---------- Card grid (landing) ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0;
  padding: 0;
  list-style: none;
}
.card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
  text-decoration: none;
  color: inherit;
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent);
  text-decoration: none;
}
.card-thumb {
  background: var(--accent-soft);
  border-radius: var(--radius-sm);
  padding: 1rem;
  margin-bottom: .9rem;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 110px;
}
.card-thumb svg { width: 100%; height: auto; max-height: 110px; }
.card h2 { font-size: 1.15rem; margin: 0 0 .25rem; }
.card p { color: var(--muted); margin: 0; font-size: .95rem; }
.card-cta {
  margin-top: auto;
  padding-top: .8rem;
  color: var(--accent);
  font-weight: 600;
  font-size: .9rem;
}

/* ---------- Buttons ---------- */
.btn, button.btn {
  font: inherit;
  display: inline-block;
  background: var(--surface);
  color: var(--ink);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: .45rem .85rem;
  cursor: pointer;
  transition: background .12s ease, border-color .12s ease;
  text-decoration: none;
}
.btn:hover { background: var(--accent-soft); border-color: var(--accent); }
.btn-primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}
.btn-primary:hover { background: #005a8c; border-color: #005a8c; }

/* ---------- Form controls ---------- */
.controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem 1.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 1rem 0;
}
.control {
  display: flex;
  flex-direction: column;
  gap: .25rem;
}
.control label {
  font-weight: 600;
  font-size: .9rem;
  color: var(--ink);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: .5rem;
}
.control label output {
  font-family: var(--font-mono);
  color: var(--accent);
  font-weight: 700;
  font-size: .9rem;
}
.control .hint {
  font-size: .78rem;
  color: var(--subtle);
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 22px;
  background: transparent;
  margin: 0;
}
input[type="range"]:focus { outline: none; }
input[type="range"]::-webkit-slider-runnable-track {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid white;
  margin-top: -8px;
  box-shadow: 0 1px 3px rgba(0,0,0,.25);
  cursor: pointer;
}
input[type="range"]:focus-visible::-webkit-slider-thumb {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}
input[type="range"]::-moz-range-track {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
}
input[type="range"]::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid white;
  box-shadow: 0 1px 3px rgba(0,0,0,.25);
  cursor: pointer;
}

.radio-group, .check-group {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem .6rem;
  align-items: center;
}
.radio-group label, .check-group label {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  font-weight: 400;
  font-size: .9rem;
  cursor: pointer;
  padding: .25rem .55rem;
  border-radius: var(--radius-sm);
  background: var(--bg);
  border: 1px solid var(--border);
}
.radio-group input, .check-group input {
  margin: 0;
  accent-color: var(--accent);
}
.radio-group label:has(input:checked),
.check-group label:has(input:checked) {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  align-items: center;
}

/* ---------- Callouts & takeaway ---------- */
.callout {
  background: var(--surface);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: .9rem 1.1rem;
  margin: 1rem 0;
  font-size: .95rem;
  color: var(--ink);
  box-shadow: var(--shadow-sm);
}
.callout strong { color: var(--accent); }
.takeaway {
  background: var(--accent-soft);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 1.25rem 0 2.5rem;
}
.takeaway h3 {
  margin: 0 0 .35rem;
  color: var(--accent);
  font-size: .8rem;
  text-transform: uppercase;
  letter-spacing: .08em;
}
.takeaway p { margin: 0; max-width: none; }

/* ---------- Stat readout tables ---------- */
.stat-table {
  width: 100%;
  border-collapse: collapse;
  margin: .5rem 0;
  font-size: .92rem;
}
.stat-table th, .stat-table td {
  padding: .45rem .65rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.stat-table th {
  font-weight: 600;
  color: var(--muted);
  background: var(--bg);
  font-size: .82rem;
  text-transform: uppercase;
  letter-spacing: .04em;
}
.stat-table td.num {
  font-family: var(--font-mono);
  text-align: right;
  font-variant-numeric: tabular-nums;
}
.stat-table tr.headline td { font-weight: 700; color: var(--accent); }

/* ---------- Visually hidden (a11y) ---------- */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* ---------- Skip link ---------- */
.skip-link {
  position: absolute;
  top: -40px; left: 8px;
  background: var(--accent); color: white;
  padding: .5rem .85rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  z-index: 100;
}
.skip-link:focus { top: 8px; }