/* ==========================================================
   FOUNDATIONS
   ========================================================== */

:root {
  /* palette */
  --bg:          #F7F3EB;
  --text:        #1A1612;
  --text-muted:  #6B6258;
  --text-light:  #9B9488;
  --accent:      #C75B39;
  --rule:        #D4CFC4;

  /* type */
  --font-display: 'Playfair Display', Georgia, serif;
  --font-body:    'DM Sans', system-ui, sans-serif;

  /* spacing */
  --sp-xs: 0.5rem;
  --sp-sm: 1rem;
  --sp-md: 2rem;
  --sp-lg: 4rem;
  --sp-xl: 6rem;
}

*,*::before,*::after { margin:0; padding:0; box-sizing:border-box; }

html { font-size:16px; scroll-behavior:smooth; }

body {
  font-family: var(--font-body);
  color: var(--text);
  background-color: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.skip-link {
  position: absolute;
  left: 0.75rem;
  top: -40px;
  background: var(--text);
  color: var(--bg);
  padding: 0.5rem 0.75rem;
  border-radius: 4px;
  font-size: 0.85rem;
  text-decoration: none;
  z-index: 1001;
}
.skip-link:focus {
  top: 0.75rem;
}

.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;
}

/* ==========================================================
   LAYOUT
   ========================================================== */

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 var(--sp-md);
}

/* ---------- HEADER ---------- */

header {
  text-align: center;
  padding: var(--sp-xl) var(--sp-md) var(--sp-lg);
  position: relative;
}
.header-divider {
  width: 56px;
  height: 3px;
  background: var(--accent);
  margin: var(--sp-md) auto 0;
  border-radius: 2px;
}

header h1 {
  font-family: var(--font-display);
  font-size: clamp(2.6rem, 5vw, 3.6rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.08;
  margin-bottom: var(--sp-sm);
}

header .subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto;
  font-weight: 400;
}

header .problem-question {
  max-width: 760px;
  margin: var(--sp-md) auto 0;
  font-family: var(--font-display);
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  line-height: 1.35;
  font-style: italic;
  color: var(--text);
}

header .meta {
  font-size: 0.72rem;
  color: var(--text-light);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  margin-bottom: var(--sp-sm);
  font-weight: 500;
}

/* ---------- SECTIONS ---------- */

section {
  padding: var(--sp-lg) 0;
  position: relative;
}
section + section {
  border-top: 1px solid var(--rule);
}

.section-header { margin-bottom: 1.4rem; }

.section-header h2 {
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}
.section-header p {
  color: var(--text-muted);
  /* max-width: 680px; */
  font-size: 0.92rem;
  margin-bottom: 1rem;
}

/* ==========================================================
   TABS & BUTTONS
   ========================================================== */

.age-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 0.85rem;
  flex-wrap: wrap;
  justify-content: center;
}

.age-tabs button {
  font-family: var(--font-body);
  font-size: 0.82rem;
  font-weight: 600;
  padding: 7px 22px;
  border: 1.5px solid var(--rule);
  border-radius: 100px;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.22s ease;
}
.age-tabs button:hover {
  border-color: var(--text);
  color: var(--text);
}
.age-tabs button.active {
  background: var(--text);
  border-color: var(--text);
  color: var(--bg);
}
.age-tabs button:focus-visible,
.cat-buttons button:focus-visible {
  outline: 2px solid var(--text);
  outline-offset: 2px;
}

.cat-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: var(--sp-md);
}

.cat-buttons-side {
  flex: 0 0 216px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  margin: 0;
  align-content: start;
}

.cat-buttons button {
  font-family: var(--font-body);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 7px 18px;
  border: 1.5px solid var(--rule);
  border-radius: 100px;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.22s ease;
  display: flex;
  align-items: center;
  gap: 6px;
}

.cat-buttons-side button {
  width: 100%;
  justify-content: flex-start;
  padding: 9px 14px;
  font-size: 0.8rem;
  box-shadow: 0 1px 0 rgba(26, 22, 18, 0.04);
}

.cat-buttons button:hover {
  border-color: var(--text);
  color: var(--text);
}
.cat-buttons button.active {
  color: #fff;
}
.cat-buttons button .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ==========================================================
   CHART CONTAINERS
   ========================================================== */

.chart-wrap {
  padding: 0.35rem 0 1rem;
  overflow: hidden;
}

.line-chart-layout {
  display: flex;
  align-items: flex-start;
  flex-direction: row-reverse;
  gap: clamp(0.75rem, 1.6vw, 1.5rem);
}

.chart-wrap-line {
  flex: 1 1 auto;
  min-width: 0;
  margin-bottom: 0;
  overflow: visible;
}

.chart-wrap svg,
.chart-wrap-line svg {
  display: block;
  width: 100%;
  height: auto;
  overflow: visible;
}

/* ==========================================================
   LEGEND
   ========================================================== */

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-xs) var(--sp-md);
  margin-top: var(--sp-sm);
  padding: var(--sp-xs) 0;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  color: var(--text-muted);
  transition: opacity 0.2s;
}

.legend-item-button {
  border: 0;
  background: transparent;
  padding: 0;
  text-align: left;
  cursor: pointer;
  font: inherit;
  color: inherit;
}
.legend-item-button:hover { opacity: 1 !important; }
.legend-item-button:focus-visible {
  outline: 2px solid var(--text);
  outline-offset: 2px;
  border-radius: 4px;
}

.legend-swatch {
  width: 12px;
  height: 12px;
  border-radius: 3px;
  flex-shrink: 0;
}

/* ==========================================================
   TOOLTIP
   ========================================================== */

#tooltip {
  position: fixed;
  pointer-events: none;
  background: rgba(26,22,18,0.92);
  color: #F7F3EB;
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 0.78rem;
  line-height: 1.55;
  z-index: 1000;
  opacity: 0;
  transform: translateY(5px);
  transition: opacity 0.15s, transform 0.15s;
  max-width: 280px;
  backdrop-filter: blur(8px);
  box-shadow: 0 4px 20px rgba(0,0,0,0.22);
  font-variant-numeric: tabular-nums;
}
#tooltip.visible {
  opacity: 1;
  transform: translateY(0);
}
#tooltip .tt-title {
  font-weight: 700;
  margin-bottom: 3px;
}

/* ==========================================================
   CHART-NOTE
   ========================================================== */

.chart-note {
  font-size: 0.84rem;
  color: var(--text-muted);
  margin-top: 0.85rem;
  margin-left: auto;
  margin-right: auto;
  font-style: italic;
  max-width: 750px;
  line-height: 1.55;
  text-align: center;
}
.chart-note strong {
  color: var(--text);
  font-style: normal;
}

/* ==========================================================
   WAFFLE
   ========================================================== */

.waffle-row {
  display: flex;
  gap: var(--sp-md);
  justify-content: center;
  flex-wrap: nowrap;
  padding: 0.4rem 0;
}

.waffle-year { text-align: center; }
.waffle-year:focus-visible {
  outline: 2px solid var(--text);
  outline-offset: 4px;
  border-radius: 8px;
}

.waffle-year-label {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.waffle-pcts {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin-top: 8px;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
}
.waffle-pcts span {
  display: flex;
  align-items: center;
  gap: 4px;
}

.waffle-grid {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 3px;
}

.waffle-cell {
  width: 22px;
  height: 22px;
  border-radius: 4px;
  transition: transform 0.15s ease, opacity 0.15s ease;
  cursor: default;
}
.waffle-cell:hover {
  transform: scale(1.25);
  z-index: 2;
  position: relative;
}
.waffle-cell.dimmed { opacity: 0.3; }

.waffle-legend {
  display: flex;
  gap: var(--sp-md);
  justify-content: center;
  margin-top: var(--sp-sm);
}
.waffle-legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 500;
}
.waffle-legend-swatch {
  width: 16px;
  height: 16px;
  border-radius: 4px;
}

/* ==========================================================
   SVG CHART ELEMENTS
   ========================================================== */

svg text { user-select: none; }

.bump-area {
  transition: opacity 0.22s ease;
  cursor: pointer;
}
.bump-area.dimmed  { opacity: 0.15 !important; }
.bump-area.bright  { opacity: 1 !important; }
.bump-area:focus-visible {
  stroke-width: 2.4px;
  opacity: 1 !important;
}

.line-path {
  fill: none;
  stroke-width: 2.5px;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 6 8;
  transition: opacity 0.22s ease;
}
.line-path.dimmed { opacity: 0.12; }

.line-dot {
  transition: r 0.18s ease, opacity 0.18s ease;
}
.line-dot:focus-visible {
  stroke: var(--text);
  stroke-width: 3px;
}

.axis text {
  font-family: var(--font-body);
  font-size: 11px;
  fill: var(--text-muted);
}
.axis line, .axis .domain {
  stroke: var(--rule);
}

/* ==========================================================
   SCROLL REVEAL
   ========================================================== */

.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.75s cubic-bezier(0.22,1,0.36,1),
              transform 0.75s cubic-bezier(0.22,1,0.36,1);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal-delay-1 { transition-delay: 0.08s; }
.reveal-delay-2 { transition-delay: 0.18s; }
.reveal-delay-3 { transition-delay: 0.30s; }

@media (max-width: 768px) {
  .chart-wrap-line {
    flex-direction: column;
    gap: var(--sp-sm);
  }

  .cat-buttons-side {
    width: 100%;
    flex: 0 0 auto;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    margin-top: 0;
    margin-right: 0 !important;
  }

  .waffle-row {
    flex-direction: column;
    align-items: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal,
  .reveal.visible,
  .waffle-cell,
  .line-path,
  .line-dot,
  .bump-area {
    transition: none !important;
    animation: none !important;
    transform: none !important;
  }
}

/* ==========================================================
   FOOTER
   ========================================================== */

footer {
  text-align: center;
  padding: var(--sp-lg) var(--sp-md);
  color: var(--text-light);
  font-size: 0.78rem;
  border-top: 1px solid var(--rule);
  line-height: 1.5;
}