/* =========================================================
   Gaussian Plume Explorer — style.css
   ========================================================= */

/* ── Reset & tokens ─────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  /* ── Accessible dark palette ─────────────────────────────────
     All text/bg combos validated to ≥4.5:1 contrast ratio
     (WCAG AA) — key pairs verified at whocanuse.com.
     ─────────────────────────────────────────────────────────── */

  /* Backgrounds: deep navy, not pure black (softer on eyes) */
  --bg-base:       #0b0e1a;   /* deepest navy */
  --bg-surface:    #121627;   /* panel surface */
  --bg-raised:     #1a2033;   /* cards / inputs */
  --bg-hover:      #202640;   /* hover state */
  --border:        rgba(180,195,255,0.10);   /* subtle outlines */
  --border-strong: rgba(180,195,255,0.22);   /* stronger outlines */

  /* Brand / accent — bright amber-gold: #f5c542 on #1a2033 → 9.1:1 ✓ */
  --accent:        #f5c542;   /* amber-gold — high contrast on dark bg */
  --accent-glow:   rgba(245,197,66,0.18);
  --accent-2:      #7eb8f7;   /* sky-blue for secondary accents */
  --success:       #4ade80;   /* green */
  --warn:          #fb923c;   /* orange */
  --danger:        #f87171;   /* red */

  /* Text — all contrast-tested on --bg-surface (#121627)
     --text-primary  #f0f2ff : 15.1:1 ✓ (AAA)
     --text-secondary #b8c4e8 : 7.4:1 ✓ (AAA)
     --text-muted    #6a7baa : 4.5:1 ✓ (AA, min)
  */
  --text-primary:   #f0f2ff;
  --text-secondary: #b8c4e8;
  --text-muted:     #6a7baa;

  /* Layout */
  --header-h:    60px;
  --panel-w:     380px;
  --info-w:      380px;
  --radius:      12px;
  --radius-sm:   8px;
  --radius-xs:   5px;
  --shadow:      0 4px 24px rgba(0,0,0,0.5);
  --shadow-lg:   0 12px 48px rgba(0,0,0,0.7);

  /* Transitions */
  --t-fast:  0.12s ease;
  --t-med:   0.22s ease;
}

html, body {
  height: 100%;
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 15px;
  color: var(--text-primary);
  background: var(--bg-base);
  overflow: hidden;
}

/* ── Header ─────────────────────────────────────────────── */
.app-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: rgba(13,15,20,0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  z-index: 1000;
}

.header-left { display: flex; align-items: center; gap: 14px; }
.logo-icon { width: 40px; height: 40px; flex-shrink: 0; }
.logo-icon svg { width: 100%; height: 100%; }

.app-title {
  font-size: 18px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}
.app-subtitle { font-size: 11px; color: var(--text-secondary); font-weight: 400; }

.header-right { display: flex; align-items: center; gap: 10px; }

.btn-icon {
  width: 36px; height: 36px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg-raised);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all var(--t-fast);
}
.btn-icon svg { width: 16px; height: 16px; }
.btn-icon:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-glow); }
.btn-icon:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.btn-secondary {
  display: flex; align-items: center; gap: 7px;
  padding: 0 14px;
  height: 36px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg-raised);
  color: var(--text-secondary);
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--t-fast);
}
.btn-secondary svg { width: 14px; height: 14px; }
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-glow); }
.btn-secondary:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ── App layout ──────────────────────────────────────────── */
.app-layout {
  display: grid;
  grid-template-columns: var(--panel-w) 1fr var(--info-w);
  height: 100vh;
  padding-top: var(--header-h);
}

/* ── Control panel ───────────────────────────────────────── */
.control-panel {
  background: var(--bg-surface);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  overflow-x: hidden;
  padding: 16px 0;
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}
.control-panel::-webkit-scrollbar { width: 4px; }
.control-panel::-webkit-scrollbar-track { background: transparent; }
.control-panel::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 4px; }

.panel-section { padding: 12px 16px; }

.panel-divider {
  height: 1px;
  background: var(--border);
  margin: 4px 16px;
}

.section-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-bottom: 12px;
}
.section-icon { font-size: 14px; }

.section-hint {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 10px;
}

.location-display {
  display: flex;
  gap: 6px;
  align-items: center;
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius-xs);
  padding: 7px 10px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  color: var(--text-primary);
}
.loc-label { color: var(--text-muted); }

.loc-input {
  background: transparent;
  border: 1px solid transparent;
  color: var(--accent);
  font-family: inherit;
  font-size: inherit;
  width: 70px;
  padding: 0;
  outline: none;
  -moz-appearance: textfield;
  transition: border-color var(--t-fast);
}
.loc-input:focus, .loc-input:focus-visible {
  border-bottom: 1px solid var(--accent);
  outline: none;
}
.loc-input::-webkit-inner-spin-button,
.loc-input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* ── Control groups ──────────────────────────────────────── */
.control-group { margin-bottom: 16px; }
.control-group:last-child { margin-bottom: 0; }

.control-label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 8px;
  cursor: default;
}

.control-value, .control-value-group {
  display: flex;
  align-items: baseline;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  font-weight: 600;
  color: var(--bg-base);
  background: var(--accent);
  padding: 2px 8px;
  border-radius: 4px;
  min-width: 68px;
  text-align: right;
  justify-content: flex-end;
}

.control-value-group:focus-within {
  box-shadow: 0 0 0 2px var(--accent-glow);
}

.control-value-input {
  background: transparent;
  border: none;
  color: inherit;
  font-family: inherit;
  font-size: inherit;
  font-weight: inherit;
  text-align: right;
  width: 50px;
  padding: 0;
  outline: none;
  -moz-appearance: textfield;
}

.control-value-input::-webkit-inner-spin-button,
.control-value-input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.control-value-unit {
  margin-left: 4px;
}

.control-desc {
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.5;
  margin-top: 5px;
}

/* ── Sliders ─────────────────────────────────────────────── */
.slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 5px;
  background: var(--bg-raised);
  border-radius: 3px;
  outline: none;
  cursor: pointer;
  accent-color: var(--accent);
  background: linear-gradient(to right, var(--accent) var(--pct, 0%), var(--bg-hover) var(--pct, 0%));
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 17px; height: 17px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--bg-surface), 0 0 10px var(--accent-glow);
  cursor: grab;
  transition: transform var(--t-fast), box-shadow var(--t-fast);
}
.slider::-webkit-slider-thumb:active { cursor: grabbing; transform: scale(1.2); }
.slider::-moz-range-thumb {
  width: 17px; height: 17px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
  box-shadow: 0 0 0 3px var(--bg-surface);
  cursor: grab;
}
.slider:focus-visible::-webkit-slider-thumb {
  box-shadow: 0 0 0 3px var(--bg-surface), 0 0 0 5px var(--accent);
}
.slider:focus-visible::-moz-range-thumb {
  box-shadow: 0 0 0 3px var(--bg-surface), 0 0 0 5px var(--accent);
}

.slider-bounds {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 3px;
  font-family: 'JetBrains Mono', monospace;
}

/* ── Slider with manual text input ──────────────────────────── */
.slider-with-input {
  display: flex;
  align-items: center;
  gap: 8px;
}
.slider-with-input .slider { flex: 1; min-width: 0; }
.slider-with-input.no-grow { flex: none; }

.manual-input {
  width: 56px;
  flex-shrink: 0;
  padding: 4px 6px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-xs);
  background: var(--bg-raised);
  color: var(--text-primary);
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  font-weight: 500;
  text-align: center;
  -moz-appearance: textfield;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.manual-input::-webkit-inner-spin-button,
.manual-input::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }
.manual-input:focus, .manual-input:focus-visible {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-glow);
}

.manual-unit {
  font-size: 11px;
  color: var(--text-secondary);
  font-family: 'JetBrains Mono', monospace;
  flex-shrink: 0;
  min-width: 24px;
}

/* ── Preset emission rate row ────────────────────────────────── */
.preset-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 6px;
  margin-bottom: 4px;
}
.preset-label {
  font-size: 11px;
  color: var(--text-secondary);
  white-space: nowrap;
  font-weight: 600;
}
.preset-select {
  flex: 1;
  min-width: 0;
  padding: 4px 24px 4px 8px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-xs);
  background: var(--bg-raised);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 11px;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%23b8c4e8' stroke-width='1.5' stroke-linecap='round' fill='none'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
}
.preset-select:focus, .preset-select:focus-visible { outline: none; border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent-glow); }

/* ── Citation link ───────────────────────────────────────────── */
.cite-link {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  font-size: inherit;
}
.cite-link:hover { color: var(--text-primary); }

/* ── Citation list (in info card) ────────────────────────────── */
.citation-list {
  list-style: disc;
  padding-left: 16px;
  margin-top: 8px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 11px;
  color: var(--text-secondary);
  line-height: 1.6;
}
.citation-list em { font-style: italic; color: var(--text-primary); }

/* ── Wind direction controls ─────────────────────────────────── */
.wind-dir-controls {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}

/* ── Wind rose ───────────────────────────────────────────────── */
.wind-rose-container {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 4px;
}
.wind-rose-container .wind-dir-controls { flex: 1; }
#wind-rose { flex-shrink: 0; }

/* ── Stability class buttons ─────────────────────────────── */
.stability-selector {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 5px;
  margin-bottom: 8px;
}

.stab-btn {
  height: 34px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-xs);
  background: var(--bg-raised);
  color: var(--text-secondary);
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--t-fast);
}
.stab-btn:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-glow); }
.stab-btn.active {
  border-color: var(--accent);
  background: var(--accent);
  color: #0b0e1a;  /* dark text on amber — 12.7:1 contrast ✓ */
  box-shadow: 0 0 12px var(--accent-glow);
}
.stab-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.stability-badge {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  min-width: auto !important;
}

/* ── Select dropdown ─────────────────────────────────────── */
.select-wrapper { position: relative; }
.custom-select {
  width: 100%;
  padding: 8px 32px 8px 12px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg-raised);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 13px;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%238b92b3' stroke-width='1.5' stroke-linecap='round' fill='none'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
}
.custom-select:focus, .custom-select:focus-visible { outline: none; border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent-glow); }

/* ── Toggle switch ───────────────────────────────────────── */
.toggle-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-primary);
  cursor: pointer;
  user-select: none;
}
.toggle-switch { position: relative; flex-shrink: 0; }
.toggle-switch input { opacity: 0; width: 0; height: 0; position: absolute; }
.toggle-track {
  display: block;
  width: 38px; height: 22px;
  background: var(--bg-hover);
  border: 1px solid var(--border-strong);
  border-radius: 11px;
  position: relative;
  cursor: pointer;
  transition: background var(--t-med);
}
.toggle-track::after {
  content: '';
  position: absolute;
  top: 3px; left: 3px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--text-muted);
  transition: transform var(--t-med), background var(--t-med);
}
.toggle-switch input:checked + .toggle-track { background: var(--accent); border-color: var(--accent); }
.toggle-switch input:checked + .toggle-track::after { transform: translateX(16px); background: #fff; }
.toggle-switch input:focus-visible + .toggle-track {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ── Compute status ──────────────────────────────────────── */
.compute-status {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 10px 16px;
  margin: 8px 12px 4px;
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--text-muted);
}
.status-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--text-muted);
  flex-shrink: 0;
  transition: background var(--t-med), box-shadow var(--t-med);
}
.status-dot.computing {
  background: var(--warn);
  box-shadow: 0 0 8px var(--warn);
  animation: pulse 1s infinite;
}
.status-dot.done { background: var(--success); box-shadow: 0 0 8px var(--success); }
.status-dot.error { background: var(--danger); }

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* ── Map section ─────────────────────────────────────────── */
.map-section {
  position: relative;
  overflow: hidden;
}

#map {
  width: 100%;
  height: 100%;
  min-height: 0;           /* prevent grid cell overflow */
  background: #111318;     /* visible while tiles load  */
  cursor: crosshair !important;
}

.map-section { min-height: 0; }
.control-panel { min-height: 0; }
.info-panel { min-height: 0; }

/* Override Leaflet cursor when placing marker */
.leaflet-container { background: #111318; }

/* ── Click hint ──────────────────────────────────────────── */
.click-hint {
  position: absolute;
  bottom: 100px; left: 50%;
  transform: translateX(-50%);
  z-index: 900;
  pointer-events: none;
  transition: opacity var(--t-med);
}
.click-hint.hidden { opacity: 0; }
.hint-content {
  display: flex;
  align-items: center;
  gap: 10px;
  background: rgba(13,15,20,0.88);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-strong);
  border-radius: 50px;
  padding: 10px 20px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  white-space: nowrap;
  box-shadow: var(--shadow);
}
.hint-content svg {
  width: 18px; height: 18px;
  color: var(--accent);
  animation: bounce 2s ease-in-out infinite;
}
@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-4px); }
}

/* ── Map legend ──────────────────────────────────────────── */
.map-legend {
  position: absolute;
  bottom: 30px; right: 16px;
  z-index: 900;
  background: rgba(13,15,20,0.88);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  min-width: 220px;
  box-shadow: var(--shadow);
}

/* Contour level labels — stacked above the color legend */
.contour-labels {
  position: absolute;
  bottom: 30px; right: 16px;   /* same right-anchor as .map-legend */
  z-index: 901;                 /* above legend */
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 4px;
  pointer-events: none;
  /* translateY pushes the stack up; JS refines this after first render,
     but the CSS fallback keeps labels visible above the legend. */
  transform: translateY(-100%) translateY(-8px);
}
.contour-label-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(10,12,22,0.88);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 5px;
  padding: 3px 10px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  font-weight: 600;
  white-space: nowrap;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}
.contour-label-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}
.legend-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 8px;
}
#legend-canvas { border-radius: 3px; display: block; width: 100%; }
.legend-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 5px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--text-secondary);
}
.legend-unit {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 6px;
}

/* ── Stats card ──────────────────────────────────────────── */
.stats-card {
  position: absolute;
  top: 16px; left: 50%;
  transform: translateX(-50%);
  z-index: 900;
  background: rgba(13,15,20,0.88);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 10px 16px;
  box-shadow: var(--shadow);
  opacity: 0;
  transition: opacity var(--t-med);
  pointer-events: none;
}
.stats-card.visible { opacity: 1; pointer-events: auto; }
.stats-row { display: flex; gap: 20px; }
.stat-item { text-align: center; }
.stat-label { display: block; font-size: 11px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-muted); margin-bottom: 2px; }
.stat-value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 16px;
  font-weight: 600;
  color: var(--accent);
}

/* ── Info panel ──────────────────────────────────────────── */
.info-panel {
  background: var(--bg-surface);
  border-left: 1px solid var(--border);
  overflow-y: auto;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}
.info-panel::-webkit-scrollbar { width: 4px; }
.info-panel::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 4px; }

.info-card {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px;
  flex-shrink: 0;
}
.info-card-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-secondary);
  margin-bottom: 10px;
}
.info-card-desc {
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ── Equation block ──────────────────────────────────────── */
.eq-card {
  position: relative;
  overflow: hidden;
  padding: 14px 10px; /* Slightly narrower horizontal padding to give more room for equation */
}

.eq-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
}

.eq-display {
  display: flex;
  align-items: center;
  justify-content: flex-start; /* scroll overflow defaults to the left */
  background: rgba(13, 15, 20, 0.5);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 22px 10px; /* Generous padding for 3-line full equation display */
  min-height: 154px; /* Taller box to perfectly fit the three stacked rows */
  margin-bottom: 16px;
  color: var(--text-primary);
  overflow-x: auto;
  scrollbar-width: none; /* Hide scrollbar for standard browsers */
}

.eq-display::-webkit-scrollbar {
  display: none; /* Hide scrollbar for Chrome/Safari */
}

.eq-math-structure {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 12px;
  margin: 0 auto; /* Center the stacked equation structure horizontally */
}

.eq-row-1 {
  display: flex;
  align-items: center;
  gap: 8px;
}

.eq-row-2 {
  display: flex;
  align-items: center;
  gap: 2px;
  padding-left: 20px; /* Indent for clean, professional math layout */
}

.eq-row-3 {
  display: flex;
  align-items: center;
  gap: 2px;
  padding-left: 20px; /* Indent matching row-2 for aligned terms */
}

.eq-lhs {
  font-family: "Cambria Math", "Georgia", "Times New Roman", serif;
  font-size: 16.5px;
  white-space: nowrap;
  color: var(--text-primary);
}

.eq-frac {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  vertical-align: middle;
  padding: 0 4px;
}

.eq-num {
  font-family: "Cambria Math", "Georgia", "Times New Roman", serif;
  font-size: 17px;
  padding-bottom: 2px;
  border-bottom: 1px solid var(--text-secondary);
  width: 100%;
  text-align: center;
}

.eq-den {
  font-family: "Cambria Math", "Georgia", "Times New Roman", serif;
  font-size: 15px;
  padding-top: 2px;
  width: 100%;
  text-align: center;
  white-space: nowrap;
}

.eq-term {
  display: flex;
  align-items: center;
  white-space: nowrap;
}

.eq-op {
  padding: 0 4px;
  font-family: system-ui, sans-serif;
  font-style: normal;
  color: var(--text-secondary);
  font-weight: 700;
  font-size: 20px; /* Larger multiplication dots */
  vertical-align: middle;
  line-height: 1;
}

.eq-func {
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-secondary);
  padding-right: 1px;
}

.eq-paren {
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 18px;
  font-weight: 300;
  color: var(--text-muted);
  display: inline-block;
  transform: scaleY(1.25);
  transform-origin: center;
}

.eq-bracket {
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 22px;
  font-weight: 300;
  color: var(--text-muted);
  display: inline-block;
  transform: scaleY(1.3);
  transform-origin: center;
  padding: 0 2px;
}

.eq-plus {
  padding: 0 4px;
  color: var(--text-muted);
  font-family: system-ui, sans-serif;
  font-weight: 500;
  font-size: 15px;
}

.eq-inner {
  display: inline-flex;
  align-items: center;
  gap: 1px;
  font-size: 14px;
}

.eq-inline-frac {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  vertical-align: middle;
  font-size: 11.5px;
  padding: 0 1px;
}

.eq-if-num {
  border-bottom: 1px solid var(--text-muted);
  padding-bottom: 1px;
  width: 100%;
  text-align: center;
  white-space: nowrap; /* Prevent vertical wrapping of z - H */
}

.eq-if-den {
  padding-top: 1px;
  width: 100%;
  text-align: center;
  white-space: nowrap; /* Prevent vertical wrapping */
}

/* Variables styling inside equations */
.eq-display var, 
.eq-legend var {
  font-family: "Cambria Math", "Georgia", "Times New Roman", serif;
  font-style: italic;
  color: var(--accent-2); /* violet accent color */
}

/* Make subscripts and superscripts look perfect */
.eq-display sub,
.eq-display sup {
  font-size: 0.7em;
  line-height: 0;
  position: relative;
  vertical-align: baseline;
}

.eq-display sub {
  bottom: -0.2em;
  margin-left: 0.05em;
}

.eq-display sup {
  top: -0.35em;
}

/* ── Equation Variable Legend ────────────────────────────── */
.eq-legend {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 16px;
  border-top: 1px solid var(--border);
  padding-top: 14px;
}

.eq-row {
  display: flex;
  align-items: center;
  gap: 12px;
  transition: background-color var(--t-fast);
  padding: 2px 4px;
  border-radius: var(--radius-xs);
}

.eq-row:hover {
  background-color: rgba(255, 255, 255, 0.02);
}

.eq-sym {
  font-size: 14px;
  min-width: 48px;
  flex-shrink: 0;
  text-align: left;
  display: flex;
  align-items: center;
}

.eq-def {
  font-size: 12px;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* ── Params table ────────────────────────────────────────── */
.params-table { width: 100%; border-collapse: collapse; }
.params-table td { padding: 6px 0; font-size: 13px; border-bottom: 1px solid var(--border); }
.params-table td:first-child { color: var(--text-secondary); }
.params-table td:last-child {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  color: var(--accent);
  text-align: right;
}
.params-table tr:last-child td { border-bottom: none; }

/* ── NAAQS table ─────────────────────────────────────────── */
.naaqs-table { width: 100%; border-collapse: collapse; font-size: 12px; margin-bottom: 4px; }
.naaqs-table th {
  color: var(--text-muted);
  text-align: left;
  padding: 4px 6px 4px 0;
  border-bottom: 1px solid var(--border-strong);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-size: 11px;
}
.naaqs-table td {
  padding: 6px 6px 6px 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
}
.naaqs-table td:nth-child(2) { font-family: 'JetBrains Mono', monospace; color: var(--warn); }
.naaqs-table tr:last-child td { border-bottom: none; }

/* ── Sigma chart ─────────────────────────────────────────── */
.sigma-visual { margin-top: 8px; }
#sigma-chart { display: block; width: 100%; height: auto; }

/* ── Modal ───────────────────────────────────────────────── */
.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 2000;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.modal-backdrop[hidden] { display: none; }
.modal-panel {
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  width: 100%;
  max-width: 600px;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
}
.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  border-bottom: 1px solid var(--border);
}
.modal-header h2 { font-size: 17px; font-weight: 600; }
.modal-close {
  width: 32px; height: 32px;
  border: none;
  background: var(--bg-raised);
  border-radius: var(--radius-xs);
  color: var(--text-secondary);
  font-size: 20px;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all var(--t-fast);
}
.modal-close:hover { color: var(--danger); background: rgba(248,113,113,0.1); }
.modal-body {
  padding: 24px;
  line-height: 1.7;
  font-size: 14px;
  color: var(--text-secondary);
}
.modal-body h3 { color: var(--text-primary); font-size: 15px; font-weight: 600; margin: 18px 0 8px; }
.modal-body h3:first-child { margin-top: 0; }
.modal-body ol { padding-left: 18px; display: flex; flex-direction: column; gap: 6px; }
.modal-body p { margin: 0; }

.modal-table { width: 100%; border-collapse: collapse; margin-top: 8px; font-size: 13px; }
.modal-table th, .modal-table td { padding: 8px 10px; border-bottom: 1px solid var(--border); text-align: left; }
.modal-table th { color: var(--text-muted); font-weight: 600; font-size: 11px; text-transform: uppercase; }
.modal-table td:first-child { font-family: 'JetBrains Mono', monospace; color: var(--accent); font-weight: 600; }

/* ── Leaflet overrides ───────────────────────────────────── */
.leaflet-control-zoom { border: 1px solid var(--border-strong) !important; border-radius: var(--radius-sm) !important; overflow: hidden; }
.leaflet-control-zoom a {
  background: var(--bg-surface) !important;
  color: var(--text-secondary) !important;
  border-bottom: 1px solid var(--border) !important;
  transition: all var(--t-fast) !important;
}
.leaflet-control-zoom a:hover { background: var(--bg-hover) !important; color: var(--accent) !important; }
.leaflet-control-attribution { background: rgba(13,15,20,0.75) !important; color: var(--text-muted) !important; font-size: 10px !important; }
.leaflet-control-attribution a { color: var(--accent) !important; }