/* Prewarm Styles */

:root {
  --color-bg: #1a1410;
  --color-surface: #2d2118;
  --color-primary: #c4956a;
  --color-secondary: #4a3728;
  --color-text: #ebe3d7;
  --color-text-muted: #a89080;
  --color-cold: #6a9fd4;
  --color-hot: #d4826a;
  --color-drinkable: #8bc47a;

  --font-main:
    system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --radius: 8px;
  --spacing: 1rem;
}

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

html {
  font-size: 16px;
}

body {
  font-family: var(--font-main);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  position: relative;
}

/* Global link styling */
a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Navigation bar */
.site-nav {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-secondary);
}

.site-nav-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0.75rem var(--spacing);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
}

.nav-brand:hover {
  text-decoration: none;
  opacity: 0.85;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.nav-link:hover {
  color: var(--color-text);
  text-decoration: none;
}

.nav-link.active {
  color: var(--color-primary);
  font-weight: 600;
}

@media (max-width: 600px) {
  .site-nav-inner {
    flex-direction: column;
    gap: 0.5rem;
  }

  .nav-links {
    gap: 1rem;
  }
}

/* Subtle coffee bean texture overlay */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  opacity: 0.8;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.5' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 250px 250px;
  mix-blend-mode: overlay;
  z-index: -1;
}

/* Vignette effect - darker on left/right edges */
body::after {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  /* More color stops to reduce banding */
  background: linear-gradient(
    to right,
    rgba(0, 0, 0, 0.3) 0%,
    rgba(0, 0, 0, 0.22) 3%,
    rgba(0, 0, 0, 0.15) 6%,
    rgba(0, 0, 0, 0.08) 10%,
    rgba(0, 0, 0, 0.03) 13%,
    transparent 18%,
    transparent 82%,
    rgba(0, 0, 0, 0.03) 87%,
    rgba(0, 0, 0, 0.08) 90%,
    rgba(0, 0, 0, 0.15) 94%,
    rgba(0, 0, 0, 0.22) 97%,
    rgba(0, 0, 0, 0.3) 100%
  );
  z-index: -1;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--spacing);
}

/* Header */
header {
  text-align: center;
  padding: 2rem 0;
  border-bottom: 1px solid var(--color-secondary);
  margin-bottom: 2rem;
}

header h1 {
  font-size: 2.5rem;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}

.tagline {
  color: var(--color-text-muted);
  font-size: 1.1rem;
}


/* Sections */
section {
  margin-bottom: 2.5rem;
}

section h2 {
  color: var(--color-primary);
  margin-bottom: 1rem;
  font-size: 1.5rem;
}

/* Intro */
.intro p {
  margin-bottom: 1rem;
}

.intro strong {
  color: var(--color-hot);
}

/* Interactive Model */
.model-container {
  display: grid;
  grid-template-columns: minmax(200px, 280px) 1fr;
  gap: 1.5rem;
  align-items: stretch;
}

@media (max-width: 700px) {
  .model-container {
    grid-template-columns: 1fr;
  }
}

/* Controls */
.controls {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
}

.controls h3 {
  color: var(--color-text);
  font-size: 1rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-secondary);
}

.control-group {
  margin-bottom: 1rem;
}

.control-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.control-group select,
.control-group input[type="range"] {
  width: 100%;
}

.control-group select {
  background: var(--color-bg);
  color: var(--color-text);
  border: 1px solid var(--color-secondary);
  padding: 0.5rem;
  border-radius: var(--radius);
  font-size: 1rem;
}

.control-group input[type="range"] {
  -webkit-appearance: none;
  height: 8px;
  background: var(--color-secondary);
  border-radius: 4px;
  outline: none;
}

.control-group input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  background: var(--color-primary);
  border-radius: 50%;
  cursor: pointer;
}


.control-group-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-secondary);
}

.control-group-header h3 {
  margin: 0;
  padding: 0;
  border: none;
}

.unit-toggle {
  padding: 0.25rem 0.5rem;
  background: transparent;
  color: var(--color-text-muted);
  border: 1px solid var(--color-secondary);
  border-radius: var(--radius);
  font-size: 0.7rem;
  cursor: pointer;
  transition: all 0.2s;
}

.unit-toggle:hover {
  color: var(--color-text);
  border-color: var(--color-text-muted);
}

.reset-button {
  margin-top: 1rem;
  padding: 0.4rem 0.8rem;
  background: transparent;
  color: var(--color-text-muted);
  border: 1px solid var(--color-secondary);
  border-radius: var(--radius);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all 0.2s;
}

.reset-button:hover {
  color: var(--color-text);
  border-color: var(--color-text-muted);
}

/* Work-in-progress note */
.wip-note {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
  line-height: 1.5;
}


/* Solver Toggle */
.solver-toggle {
  display: flex;
  align-items: center;
  gap: 0;
  margin-bottom: 1rem;
}

.solver-toggle button {
  padding: 0.35rem 0.75rem;
  background: transparent;
  color: var(--color-text-muted);
  border: 1px solid var(--color-secondary);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all 0.2s;
}

.solver-toggle button:first-child {
  border-radius: var(--radius) 0 0 var(--radius);
  border-right: none;
}

.solver-toggle button:nth-child(2) {
  border-radius: 0 var(--radius) var(--radius) 0;
}

/* 3-button solver toggle (home page tab selector) */
.solver-toggle--3 button:first-child {
  border-radius: var(--radius) 0 0 var(--radius);
  border-right: none;
}

.solver-toggle--3 button:nth-child(2) {
  border-radius: 0;
  border-right: none;
}

.solver-toggle--3 button:nth-child(3) {
  border-radius: 0 var(--radius) var(--radius) 0;
}

.solver-toggle button.active {
  background: var(--color-primary);
  color: var(--color-bg);
  border-color: var(--color-primary);
}

.solver-toggle .compute-time {
  margin-left: 0.75rem;
  font-size: 0.7rem;
  color: var(--color-text-muted);
}

/* Temperature Display */
.temperature-display {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
}

.metrics {
  display: flex;
  justify-content: space-around;
  margin-bottom: 1.5rem;
}

.metric {
  text-align: center;
}

.metric-value {
  display: block;
  font-size: 1.8rem;
  font-weight: bold;
}

.metric-value.cold {
  color: var(--color-cold);
}

.metric-value.hot {
  color: var(--color-hot);
}

.metric.highlight .metric-value {
  color: var(--color-drinkable);
}

.metric-label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.metrics-note {
  text-align: center;
  font-size: 0.7rem;
  color: var(--color-text-muted);
  margin-top: -0.5rem;
  margin-bottom: 1rem;
}

/* Drinkable Time */
.drinkable-time {
  margin-bottom: 1.5rem;
}

.drinkable-time h4 {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}

.time-comparison {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.time-bar {
  height: 30px;
  background: var(--color-bg);
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
}

.time-bar .time-fill {
  height: 100%;
  transition: width 0.3s ease;
}

.time-bar.cold .time-fill {
  background: var(--color-cold);
}

.time-bar.hot .time-fill {
  background: var(--color-hot);
}

.time-bar span {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.9rem;
  font-weight: bold;
}

.time-labels {
  display: flex;
  justify-content: flex-start;
  gap: 1rem;
  margin-top: 0.5rem;
  font-size: 0.8rem;
}

.time-labels .time-diff {
  margin-left: auto;
  margin-right: 10px;
  color: var(--color-drinkable);
  font-weight: bold;
  font-size: 0.9rem;
}

.cold-label {
  color: var(--color-cold);
}

.hot-label {
  color: var(--color-hot);
}

/* Chart */
.chart-placeholder {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 200px;
}

.chart-placeholder h4 {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.temp-chart {
  width: 100%;
  flex: 1;
  background: var(--color-bg);
  border-radius: var(--radius);
}

.temp-chart .axis-label {
  fill: var(--color-text-muted);
  font-size: 10px;
}

.temp-chart .grid-line {
  stroke: var(--color-secondary);
  stroke-width: 1;
  stroke-dasharray: 4;
}

.temp-chart .grid-line.drinkable {
  stroke: var(--color-drinkable);
  stroke-opacity: 0.5;
}

.temp-chart .grid-line.room-temp {
  stroke: var(--color-text-muted);
  stroke-opacity: 0.4;
  stroke-dasharray: 2 4;
}

.temp-chart .temp-line {
  fill: none;
  stroke-width: 2;
}

.temp-chart .temp-line.cold {
  stroke: var(--color-cold);
}

.temp-chart .temp-line.hot {
  stroke: var(--color-hot);
}

.temp-chart .temp-line.mug-temp {
  stroke-dasharray: 4 3;
  opacity: 0.4;
  stroke-width: 1.5;
}

.temp-chart .crossing-marker {
  stroke-width: 2;
}

.temp-chart .crossing-marker.cold {
  fill: var(--color-bg);
  stroke: var(--color-cold);
}

.temp-chart .crossing-marker.hot {
  fill: var(--color-bg);
  stroke: var(--color-hot);
}

.temp-chart .crossing-label {
  font-size: 9px;
  text-anchor: middle;
  font-weight: bold;
}

.temp-chart .crossing-label.cold {
  fill: var(--color-cold);
}

.temp-chart .crossing-label.hot {
  fill: var(--color-hot);
}

.chart-legend {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  margin-top: 0.5rem;
}

.legend-row {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.legend-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  width: 70px;
  text-align: right;
}

.legend-item {
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.legend-item::before {
  content: "";
  width: 20px;
  height: 3px;
  display: inline-block;
}

.legend-item.cold::before {
  background: var(--color-cold);
}

.legend-item.hot::before {
  background: var(--color-hot);
}

.legend-item.dotted::before {
  height: 2px;
  opacity: 0.6;
  background: repeating-linear-gradient(
    to right,
    currentColor 0px,
    currentColor 4px,
    transparent 4px,
    transparent 7px
  );
}

.legend-item.cold.dotted::before {
  color: var(--color-cold);
  background: repeating-linear-gradient(
    to right,
    var(--color-cold) 0px,
    var(--color-cold) 4px,
    transparent 4px,
    transparent 7px
  );
}

.legend-item.hot.dotted::before {
  color: var(--color-hot);
  background: repeating-linear-gradient(
    to right,
    var(--color-hot) 0px,
    var(--color-hot) 4px,
    transparent 4px,
    transparent 7px
  );
}

.chart-duration {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.chart-duration input[type="range"] {
  width: 150px;
  -webkit-appearance: none;
  height: 6px;
  background: var(--color-secondary);
  border-radius: 3px;
  outline: none;
}

.chart-duration input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  background: var(--color-primary);
  border-radius: 50%;
  cursor: pointer;
}

/* Physics Cards */
.physics-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.card {
  background: var(--color-surface);
  padding: 1.25rem;
  border-radius: var(--radius);
  border-left: 3px solid var(--color-primary);
}

.card h3 {
  color: var(--color-primary);
  font-size: 1rem;
  margin-bottom: 0.5rem;
}

.card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

/* Footer */
footer {
  text-align: center;
  padding: 2rem 0;
  border-top: 1px solid var(--color-secondary);
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

footer .disclaimer {
  font-size: 0.8rem;
  max-width: 500px;
  margin: 0 auto 1rem;
  line-height: 1.5;
}

footer .analytics-note {
  font-size: 0.75rem;
  margin-bottom: 0.5rem;
}


/* Mobile sticky summary bar */
.mobile-summary {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--color-surface);
  border-top: 2px solid var(--color-primary);
  padding: 0.75rem 1rem;
  z-index: 100;
  box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.3);
}

.mobile-summary .summary-content {
  display: flex;
  justify-content: space-around;
  align-items: center;
  max-width: 500px;
  margin: 0 auto;
}

.mobile-summary .summary-item {
  text-align: center;
}

.mobile-summary .summary-value {
  font-size: 1.2rem;
  font-weight: bold;
  display: block;
}

.mobile-summary .summary-value.cold {
  color: var(--color-cold);
}

.mobile-summary .summary-value.hot {
  color: var(--color-hot);
}

.mobile-summary .summary-value.diff {
  color: var(--color-drinkable);
}

.mobile-summary .summary-label {
  font-size: 0.65rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Accordion groups (mobile simulator overlay) */
.accordion-group {
  border-bottom: 1px solid var(--color-border);
}

.accordion-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--color-surface);
  border: none;
  color: var(--color-text);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  text-align: left;
}

.accordion-header:active {
  background: var(--color-bg);
}

.accordion-arrow {
  font-size: 0.7rem;
  color: var(--color-text-muted);
}

.accordion-body {
  padding: 0 1rem 0.75rem;
}

.accordion-body.collapsed {
  display: none;
}

/* Simulator overlay — hidden by default, shown on mobile only */
.simulator-overlay {
  display: none;
}

/* Mobile entry card — hidden by default, shown on mobile only */
.mobile-sim-entry {
  display: none;
}

/* Desktop simulator wrapper */
.desktop-sim {
  display: block;
}

@media (max-width: 700px) {
  .mobile-summary {
    display: block;
  }

  /* Add padding to body so footer isn't hidden behind sticky bar */
  body {
    padding-bottom: 70px;
  }

  /* Larger touch targets for sliders on mobile */
  .control-group input[type="range"] {
    height: 12px;
  }

  .control-group input[type="range"]::-webkit-slider-thumb {
    width: 28px;
    height: 28px;
  }

  .control-group input[type="range"]::-moz-range-thumb {
    width: 28px;
    height: 28px;
    background: var(--color-primary);
    border-radius: 50%;
    border: none;
    cursor: pointer;
  }

  .chart-duration input[type="range"]::-webkit-slider-thumb {
    width: 24px;
    height: 24px;
  }

  .chart-duration input[type="range"]::-moz-range-thumb {
    width: 24px;
    height: 24px;
    background: var(--color-primary);
    border-radius: 50%;
    border: none;
    cursor: pointer;
  }

  /* Mobile simulator entry card */
  .mobile-sim-entry {
    display: block;
    text-align: center;
    padding: 1.5rem 1rem;
    background: var(--color-surface);
    border-radius: 8px;
    border: 1px solid var(--color-border);
  }

  .mobile-sim-entry p {
    margin: 0.5rem 0 1rem;
    color: var(--color-text-muted);
    font-size: 0.9rem;
  }

  .mobile-sim-entry .open-sim-btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    background: var(--color-primary);
    color: var(--color-bg);
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
  }

  .mobile-sim-entry .open-sim-btn:active {
    opacity: 0.8;
  }

  /* Hide inline desktop simulator on mobile */
  .desktop-sim {
    display: none;
  }

  /* Fullscreen simulator overlay */
  .simulator-overlay {
    display: flex;
    flex-direction: column;
    position: fixed;
    inset: 0;
    z-index: 200;
    background: var(--color-bg);
    overflow: hidden;
  }

  .simulator-overlay .overlay-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.5rem 0.75rem;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    flex-shrink: 0;
  }

  .simulator-overlay .overlay-tabs {
    display: flex;
    gap: 0.25rem;
  }

  .simulator-overlay .overlay-tabs button {
    padding: 0.4rem 0.6rem;
    font-size: 0.75rem;
    background: transparent;
    color: var(--color-text-muted);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    cursor: pointer;
  }

  .simulator-overlay .overlay-tabs button.active {
    background: var(--color-primary);
    color: var(--color-bg);
    border-color: var(--color-primary);
  }

  .simulator-overlay .close-btn {
    padding: 0.4rem 0.75rem;
    background: transparent;
    color: var(--color-text-muted);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: 0.85rem;
    cursor: pointer;
  }

  .simulator-overlay .close-btn:active {
    background: var(--color-bg);
  }

  .simulator-overlay .overlay-chart {
    flex-shrink: 0;
    height: 45vh;
    padding: 0.5rem;
    overflow-y: auto;
    overflow-x: hidden;
    -webkit-overflow-scrolling: touch;
  }

  .simulator-overlay .overlay-chart svg {
    width: 100%;
    height: 100%;
  }

  .simulator-overlay .overlay-controls {
    flex: 1;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding-bottom: 1rem;
  }

  /* Inside overlay: hide panel controls (accordion replaces them) */
  .simulator-overlay .overlay-chart .controls {
    display: none;
  }

  /* Inside overlay: override model-container grid to block layout */
  .simulator-overlay .overlay-chart .model-container {
    display: block;
  }

  /* Hide metrics/toggles in overlay chart area to save space */
  .simulator-overlay .overlay-chart .metrics,
  .simulator-overlay .overlay-chart .metrics-note,
  .simulator-overlay .overlay-chart .drinkable-time,
  .simulator-overlay .overlay-chart .solver-toggle,
  .simulator-overlay .overlay-chart .compute-time {
    display: none;
  }

  /* Hide mobile summary bar inside overlay */
  .simulator-overlay .overlay-chart .mobile-summary {
    display: none;
  }

  /* Hide mobile summary bar when overlay is open */
  body.sim-overlay-open .mobile-summary {
    display: none;
  }

  /* Lock body scroll when overlay is open */
  body.sim-overlay-open {
    overflow: hidden;
    padding-bottom: 0;
  }
}

/* Details link on main page */
.details-link {
  text-align: center;
  margin-top: 1.5rem;
}

.details-link a {
  font-size: 0.95rem;
}

/* Details Page Styles */
.details-page .back-nav {
  margin-bottom: 2rem;
}

.details-page .back-nav.bottom {
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.details-page .back-nav a {
  font-size: 0.9rem;
}

.physics-detail {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.physics-detail h2 {
  color: var(--color-primary);
  margin-bottom: 1rem;
  font-size: 1.3rem;
}

.physics-detail h3 {
  color: var(--color-text);
  margin: 1.25rem 0 0.5rem;
  font-size: 1rem;
}

.physics-detail p {
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
  line-height: 1.7;
}

.physics-detail ul {
  color: var(--color-text-muted);
  margin-left: 1.5rem;
  margin-bottom: 0.75rem;
}

.physics-detail li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
}


.formula {
  background: var(--color-bg);
  padding: 1rem 1.5rem;
  border-radius: var(--radius);
  margin: 1rem 0;
  text-align: center;
  border-left: 3px solid var(--color-primary);
  overflow-x: auto;
}

.formula code {
  font-size: 1.1rem;
  color: var(--color-text);
  font-family: "SF Mono", Monaco, "Cascadia Code", monospace;
}

.formula .katex-display {
  margin: 0;
}

.formula .katex {
  color: var(--color-text);
}

.formula-explanation {
  font-size: 0.9rem;
}

.formula-explanation code {
  background: var(--color-bg);
  padding: 0.15rem 0.4rem;
  border-radius: 3px;
  font-size: 0.85rem;
  color: var(--color-primary);
}

.formula-explanation .katex,
.physics-detail p .katex,
.heat-flow p .katex {
  color: var(--color-primary);
}

.heat-flow {
  margin: 1.5rem 0;
  padding-left: 1rem;
  border-left: 2px solid var(--color-secondary);
}

.heat-flow h3 {
  margin-top: 0;
}

/* Materials table */
.materials-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
}

.materials-table th,
.materials-table td {
  padding: 0.75rem;
  text-align: center;
  border-bottom: 1px solid var(--color-secondary);
}

.materials-table th {
  background: var(--color-bg);
  color: var(--color-text);
  font-weight: 600;
}

.materials-table th .unit {
  display: block;
  font-weight: normal;
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.materials-table td {
  color: var(--color-text-muted);
}

.materials-table td:first-child {
  text-align: left;
  color: var(--color-text);
}

.materials-table tbody tr:hover {
  background: var(--color-bg);
}

.physics-detail .note {
  font-size: 0.85rem;
  font-style: italic;
  margin-top: 1rem;
}

/* DES Page (Heat Equation) Styles */
.des-page .des-intro,
.des-page .des-equation,
.des-page .des-boundary,
.des-page .des-simulation,
.des-page .des-numerical,
.des-page .des-observations {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.des-page h2 {
  color: var(--color-primary);
  margin-bottom: 1rem;
  font-size: 1.3rem;
}

.des-page p {
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
  line-height: 1.7;
}

.des-page strong {
  color: var(--color-text);
}

.des-page .formula.large code {
  font-size: 1.3rem;
}

.des-page .formula.small {
  padding: 0.5rem 1rem;
  margin: 0.5rem 0;
}

.des-page .formula.small code {
  font-size: 0.95rem;
}

/* Material properties grid */
.material-props {
  margin-top: 1.5rem;
}

.material-props h3 {
  color: var(--color-text);
  margin-bottom: 1rem;
  font-size: 1rem;
}

.props-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}

.prop-card {
  background: var(--color-bg);
  padding: 1rem;
  border-radius: var(--radius);
  border-left: 3px solid var(--color-primary);
}

.prop-card h4 {
  color: var(--color-text);
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
}

.prop-card ul {
  list-style: none;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.prop-card li {
  margin-bottom: 0.25rem;
}

.prop-card strong {
  color: var(--color-primary);
}

/* Simulation layout - sticky sidebar */
.sim-layout {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
}

.sim-content {
  flex: 1;
  min-width: 0;
}

/* Simulation controls */
.sim-controls {
  position: sticky;
  top: 1rem;
  width: 240px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 1rem;
  background: var(--color-bg);
  border-radius: var(--radius);
  max-height: calc(100vh - 2rem);
  overflow-y: auto;
}

.sim-controls h3 {
  color: var(--color-text);
  font-size: 0.9rem;
  margin: 0.25rem 0 0 0;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--color-secondary);
}

@media (max-width: 900px) {
  .sim-layout {
    flex-direction: column;
  }

  .sim-controls {
    position: static;
    width: 100%;
    max-height: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  }
}

/* PDE controls — horizontal grid above charts */
.pde-controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.75rem;
  padding: 1rem;
  background: var(--color-bg);
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.pde-controls .control-group {
  margin-bottom: 0;
}

.pde-controls label {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.pde-controls input[type="range"] {
  width: 100%;
  -webkit-appearance: none;
  height: 6px;
  background: var(--color-secondary);
  border-radius: 3px;
}

.pde-controls input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  background: var(--color-primary);
  border-radius: 50%;
  cursor: pointer;
}

.des-page .sim-controls .control-group,
.details-page .sim-controls .control-group {
  margin-bottom: 0;
}

.des-page .sim-controls label,
.details-page .sim-controls label {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.des-page .sim-controls input[type="range"],
.details-page .sim-controls input[type="range"] {
  width: 100%;
  -webkit-appearance: none;
  height: 6px;
  background: var(--color-secondary);
  border-radius: 3px;
}

.des-page .sim-controls input[type="range"]::-webkit-slider-thumb,
.details-page .sim-controls input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  background: var(--color-primary);
  border-radius: 50%;
  cursor: pointer;
}

.reset-group {
  margin-top: 0.5rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--color-secondary);
}

.reset-button {
  width: 100%;
  padding: 0.5rem 1rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  background: var(--color-surface);
  border: 1px solid var(--color-secondary);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s ease;
}

.reset-button:hover {
  color: var(--color-text);
  background: var(--color-bg);
  border-color: var(--color-primary);
}

/* Simulation visualizations */
.sim-viz {
  margin-bottom: 1.5rem;
}

.sim-viz h3 {
  color: var(--color-text);
  font-size: 1rem;
  margin-bottom: 0.75rem;
}

.time-slider {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.75rem;
  padding: 0.5rem 1rem;
  background: var(--color-bg);
  border-radius: var(--radius);
}

.time-slider label {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  min-width: 80px;
}

.time-slider input[type="range"] {
  flex: 1;
  -webkit-appearance: none;
  height: 6px;
  background: var(--color-secondary);
  border-radius: 3px;
}

.time-slider input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  background: var(--color-drinkable);
  border-radius: 50%;
  cursor: pointer;
}

/* Profile chart */
.profile-chart,
.time-chart {
  width: 100%;
  background: var(--color-surface);
  border-radius: var(--radius);
}

.profile-chart .axis-label,
.time-chart .axis-label {
  fill: var(--color-text-muted);
  font-size: 10px;
}

.temp-profile-line {
  fill: none;
  stroke: var(--color-hot);
  stroke-width: 2.5;
}

.temp-profile-line.initial {
  stroke: var(--color-text-muted);
  stroke-width: 1;
  stroke-dasharray: 4 4;
  opacity: 0.4;
}

/* Hover elements */
.hover-line {
  stroke: var(--color-text);
  stroke-width: 1;
  stroke-dasharray: 2 2;
  opacity: 0.5;
}

.hover-dot {
  fill: var(--color-primary);
  stroke: var(--color-text);
  stroke-width: 2;
}

.hover-text {
  fill: var(--color-text);
  font-size: 11px;
  font-weight: 500;
  pointer-events: none;
}

.legend-label {
  fill: var(--color-text);
  font-size: 9px;
}

.chart-legend {
  pointer-events: none;
}

.time-chart .temp-line {
  fill: none;
  stroke-width: 2;
}

.time-chart .temp-line.center {
  stroke: var(--color-hot);
}

.time-chart .temp-line.average {
  stroke: var(--color-cold);
  stroke-dasharray: 6 3;
}

/* Legends */
.profile-legend,
.time-legend {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 0.5rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.time-legend .legend-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.time-legend .legend-item::before {
  content: "";
  width: 20px;
  height: 3px;
  display: inline-block;
}

.time-legend .legend-item.center::before {
  background: var(--color-hot);
}

.time-legend .legend-item.average::before {
  background: var(--color-cold);
  background: repeating-linear-gradient(
    to right,
    var(--color-cold) 0px,
    var(--color-cold) 6px,
    transparent 6px,
    transparent 9px
  );
}

.time-legend .legend-item.marker::before {
  background: var(--color-drinkable);
  height: 12px;
  width: 3px;
}

/* Stats */
.sim-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 1rem;
}

.sim-stats .stat {
  text-align: center;
  padding: 1rem;
  background: var(--color-bg);
  border-radius: var(--radius);
}

.sim-stats .stat-value {
  display: block;
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--color-hot);
  margin-bottom: 0.25rem;
}

.sim-stats .stat-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* Observations list */
.des-observations ul {
  list-style: none;
  color: var(--color-text-muted);
}

.des-observations li {
  margin-bottom: 1rem;
  padding-left: 1rem;
  border-left: 2px solid var(--color-secondary);
}

.des-observations li strong {
  color: var(--color-primary);
}

/* Numerical section */
.des-numerical p {
  margin-bottom: 0.5rem;
}

/* Region colors */
.region-list {
  list-style: none;
  margin: 1rem 0;
}

.region-list li {
  margin-bottom: 0.5rem;
  padding-left: 0;
}

.region {
  display: inline-block;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-weight: 600;
  margin-right: 0.5rem;
}

.region.liquid {
  background: var(--color-cold);
  color: var(--color-bg);
}

.region.shell {
  background: var(--color-primary);
  color: var(--color-bg);
}

.region.air {
  background: var(--color-text-muted);
  color: var(--color-bg);
}

/* Property cards with region colors */
.prop-card.liquid {
  border-left-color: var(--color-cold);
}

.prop-card.shell {
  border-left-color: var(--color-primary);
}

.prop-card.air {
  border-left-color: var(--color-text-muted);
}

/* Control labels with colors */
.liquid-label {
  color: var(--color-cold) !important;
}

.shell-label {
  color: var(--color-primary) !important;
}

.air-label {
  color: var(--color-text-muted) !important;
}

.exposure-label {
  color: var(--color-drinkable) !important;
}

.evaporation-label {
  color: var(--color-hot) !important;
}

.convection-label {
  color: var(--color-text-muted) !important;
}

/* Disabled control groups (solver-specific sliders) */
.control-group.disabled {
  opacity: 0.35;
  pointer-events: none;
}

.control-group.disabled input[type="range"]::-webkit-slider-thumb {
  background: var(--color-text-muted);
  cursor: default;
}

.control-group.disabled input[type="range"]::-moz-range-thumb {
  background: var(--color-text-muted);
  cursor: default;
}

.control-hint {
  display: block;
  font-size: 0.7rem;
  color: var(--color-text-muted);
  margin-top: 0.25rem;
  opacity: 0.7;
}

.control-hint.model-note {
  font-style: italic;
  opacity: 0.6;
  margin-top: 0.5rem;
  padding-left: 0.5rem;
  border-left: 2px solid var(--color-text-muted);
}

/* Profile legend */
.profile-legend .legend-item.liquid::before {
  content: "";
  display: inline-block;
  width: 12px;
  height: 12px;
  background: var(--color-cold);
  opacity: 0.3;
  margin-right: 0.25rem;
}

.profile-legend .legend-item.shell::before {
  content: "";
  display: inline-block;
  width: 12px;
  height: 12px;
  background: var(--color-secondary);
  opacity: 0.5;
  margin-right: 0.25rem;
}

.profile-legend .legend-item.air::before {
  content: "";
  display: inline-block;
  width: 12px;
  height: 12px;
  background: var(--color-bg);
  border: 1px solid var(--color-secondary);
  margin-right: 0.25rem;
}

.profile-legend .legend-item.initial::before {
  content: "";
  display: inline-block;
  width: 20px;
  height: 2px;
  background: repeating-linear-gradient(
    to right,
    var(--color-text-muted) 0px,
    var(--color-text-muted) 4px,
    transparent 4px,
    transparent 8px
  );
  opacity: 0.5;
  margin-right: 0.25rem;
}

/* Time chart lines */
.time-chart .temp-line.liquid-center {
  stroke: var(--color-cold);
  stroke-width: 2.5;
}

.time-chart .temp-line.liquid-avg {
  stroke: var(--color-cold);
  stroke-width: 2;
  stroke-dasharray: 6 3;
  opacity: 0.7;
}

.time-chart .temp-line.shell-avg {
  stroke: var(--color-primary);
  stroke-width: 2;
}

/* Time legend updates */
.time-legend .legend-item.liquid-center::before {
  background: var(--color-cold);
}

.time-legend .legend-item.liquid-avg::before {
  background: repeating-linear-gradient(
    to right,
    var(--color-cold) 0px,
    var(--color-cold) 6px,
    transparent 6px,
    transparent 9px
  );
}

.time-legend .legend-item.shell-avg::before {
  background: var(--color-primary);
}

/* Stats with region colors */
.sim-stats--4col {
  grid-template-columns: repeat(4, 1fr);
}

.sim-stats .stat.liquid .stat-value {
  color: var(--color-cold);
}

.sim-stats .stat.shell .stat-value {
  color: var(--color-primary);
}

.sim-stats .stat.ambient .stat-value {
  color: var(--color-text-muted);
}

@media (max-width: 600px) {
  .sim-stats {
    grid-template-columns: repeat(2, 1fr);
  }

}


/* Two equation boxes side by side */
.two-equations {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 1.5rem 0;
}

.equation-box {
  background: var(--color-surface);
  padding: 1rem;
  border-radius: var(--radius);
  text-align: center;
}

.equation-box h4 {
  margin-bottom: 0.75rem;
  color: var(--color-primary);
}

.equation-box .solution {
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--color-secondary);
  color: var(--color-drinkable);
  font-weight: 500;
}

.equation-box .formula {
  margin: 0.5rem 0;
}

/* Region diagram */
.region-diagram {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin: 1.5rem 0;
}

.region-box {
  padding: 1rem;
  border-radius: var(--radius);
  text-align: center;
  font-size: 0.9rem;
  line-height: 1.6;
}

.region-box.liquid {
  background: rgba(106, 159, 212, 0.2);
  border: 1px solid var(--color-cold);
}

.region-box.shell {
  background: rgba(196, 149, 106, 0.2);
  border: 1px solid var(--color-primary);
}

.region-box.air {
  background: rgba(168, 144, 128, 0.2);
  border: 1px solid var(--color-text-muted);
}

.region-box code {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Interface conditions */
.interface-conditions {
  background: var(--color-surface);
  padding: 1rem 1.5rem;
  border-radius: var(--radius);
  margin: 1rem 0;
}

.interface-conditions .condition {
  margin-bottom: 0.75rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-secondary);
}

.interface-conditions .condition:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.interface-conditions strong {
  color: var(--color-primary);
  display: block;
  margin-bottom: 0.25rem;
}

.interface-conditions code {
  color: var(--color-text);
  background: var(--color-bg);
  padding: 0.2rem 0.4rem;
  border-radius: 3px;
  font-size: 0.9rem;
}

/* Key insight box */
.key-insight {
  background: rgba(139, 196, 122, 0.1);
  border: 2px solid var(--color-drinkable);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 1.5rem 0;
}

.key-insight h4 {
  color: var(--color-drinkable);
  margin-bottom: 0.75rem;
  font-size: 1rem;
}

.key-insight p {
  margin-bottom: 0.75rem;
}

.key-insight p:last-child {
  margin-bottom: 0;
}

/* Interpretation list */
.interpretation-list {
  list-style: none;
  margin-left: 0;
}

.interpretation-list li {
  padding: 0.75rem 1rem;
  margin-bottom: 0.5rem;
  background: var(--color-surface);
  border-radius: var(--radius);
}

.interpretation-list strong {
  color: var(--color-primary);
}

/* Summary box */
.summary-box {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
}

.summary-box h4 {
  color: var(--color-primary);
  margin-bottom: 0.75rem;
  margin-top: 1rem;
}

.summary-box h4:first-child {
  margin-top: 0;
}

.summary-box ul {
  margin-left: 1.25rem;
}

.summary-box li {
  margin-bottom: 0.5rem;
  color: var(--color-text-muted);
}

.summary-box code {
  color: var(--color-text);
  font-size: 0.9em;
}

/* References section */
.references ul {
  list-style: none;
  margin-left: 0;
}

.references li {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--color-secondary);
}

.references li:last-child {
  border-bottom: none;
}

.references em {
  color: var(--color-primary);
  font-style: normal;
}

/* Responsive adjustments */
@media (max-width: 600px) {
  .two-equations {
    grid-template-columns: 1fr;
  }

  .region-diagram {
    grid-template-columns: 1fr;
  }

}

/* Shared info card / chart section styles */

.info-card {
  background: var(--color-bg);
  padding: 1rem;
  border-radius: var(--radius);
  text-align: center;
}

.info-card h4 {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.info-card .big-number {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--color-primary);
  margin-bottom: 0.25rem;
}

.info-card .info-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  font-family: monospace;
}

.mode-label {
  color: var(--color-text-muted);
}

.chart-section {
  background: var(--color-surface);
  padding: 1rem;
  border-radius: var(--radius);
}

.chart-section h4 {
  font-size: 0.9rem;
  color: var(--color-text);
  margin-bottom: 0.75rem;
  text-align: center;
}

.chart-section .time-slider {
  margin-bottom: 0.75rem;
}

.chart-section .time-slider input {
  width: 100%;
}

/* ========================================
   Three-Region Simulator Styles
   ======================================== */

.three-region-sim {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 2px solid var(--color-drinkable);
}

.three-region-controls {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.three-region-controls .control-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 1rem;
}

.three-region-controls .control-row:last-child {
  margin-bottom: 0;
}

.three-region-controls .control-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.three-region-controls label {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.three-region-controls input[type="range"] {
  width: 100%;
  -webkit-appearance: none;
  height: 6px;
  background: var(--color-secondary);
  border-radius: 3px;
}

.three-region-controls input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  background: var(--color-drinkable);
  border-radius: 50%;
  cursor: pointer;
}

.three-region-info {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.three-region-info .info-card {
  background: var(--color-bg);
  padding: 1rem;
  border-radius: var(--radius);
  text-align: center;
}

.three-region-info .info-card h4 {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.three-region-info .big-number {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--color-drinkable);
  margin-bottom: 0.25rem;
}

.three-region-info .info-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  font-family: monospace;
}

.eigenvalue-list {
  list-style: none;
  margin: 0;
  padding: 0;
  text-align: left;
  font-size: 0.8rem;
}

.eigenvalue-list li {
  display: flex;
  justify-content: space-between;
  padding: 0.2rem 0;
  border-bottom: 1px solid var(--color-secondary);
}

.eigenvalue-list li:last-child {
  border-bottom: none;
}

.mode-value {
  color: var(--color-drinkable);
  font-family: monospace;
}

.three-region-charts {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.three-region-charts .chart-section {
  background: var(--color-surface);
  padding: 1rem;
  border-radius: var(--radius);
}

.three-region-charts .chart-section h4 {
  font-size: 0.9rem;
  color: var(--color-text);
  margin-bottom: 0.75rem;
  text-align: center;
}

.three-region-chart {
  width: 100%;
  height: auto;
}

.three-region-chart .axis-label {
  font-size: 10px;
  fill: var(--color-text-muted);
}

.three-region-chart .region-label {
  font-size: 10px;
  font-weight: 600;
}

.three-region-notes {
  background: var(--color-surface);
  padding: 1rem 1.5rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.three-region-notes h4 {
  color: var(--color-drinkable);
  margin-bottom: 0.5rem;
}

.three-region-notes ul {
  margin-left: 1.25rem;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.three-region-notes li {
  margin-bottom: 0.5rem;
  line-height: 1.5;
}

/* Three-region responsive */
@media (max-width: 700px) {
  .three-region-controls .control-row {
    grid-template-columns: 1fr;
  }

  .three-region-info {
    grid-template-columns: 1fr;
  }

  .three-region-charts {
    grid-template-columns: 1fr;
  }
}

/* ========================================
   Learn More Section (Home Page)
   ======================================== */

.learn-more-links {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.learn-more-card {
  display: block;
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  border-left: 3px solid var(--color-primary);
  transition: border-color 0.2s, background 0.2s;
}

.learn-more-card:hover {
  border-left-color: var(--color-text);
  background: var(--color-secondary);
  text-decoration: none;
}

.learn-more-card h3 {
  color: var(--color-primary);
  font-size: 1rem;
  margin-bottom: 0.5rem;
}

.learn-more-card p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin: 0;
}

@media (max-width: 600px) {
  .learn-more-links {
    grid-template-columns: 1fr;
  }
}

/* ========================================
   About Page Styles
   ======================================== */

.about-page .back-nav {
  margin-bottom: 2rem;
}

.about-page .back-nav.bottom {
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.about-page .back-nav a {
  font-size: 0.9rem;
}

.about-section {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.about-section h2 {
  color: var(--color-primary);
  margin-bottom: 1rem;
  font-size: 1.3rem;
}

.about-section p {
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
  line-height: 1.7;
}

.about-section p:last-child {
  margin-bottom: 0;
}


.version-history dt {
  font-weight: 600;
  color: var(--color-primary);
  margin-top: 1rem;
}

.version-date {
  font-size: 0.8em;
  font-style: italic;
  font-weight: 400;
  color: var(--color-text-muted);
}

.version-history dt:first-child {
  margin-top: 0;
}

.version-history dd {
  margin-left: 0;
}

.version-history ul {
  margin: 0.25rem 0 0 1.25rem;
  padding: 0;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* ========================================
   Theory Page Styles
   ======================================== */

.theory-page .back-nav {
  margin-bottom: 2rem;
}

.theory-page .back-nav.bottom {
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.theory-page .back-nav a {
  font-size: 0.9rem;
}

.theory-intro {
  margin-bottom: 2rem;
  padding: 1.5rem;
  background: var(--color-surface);
  border-radius: var(--radius);
  border-left: 4px solid var(--color-primary);
}

.theory-intro p {
  color: var(--color-text-muted);
  line-height: 1.7;
  margin: 0;
}

.theory-section {
  background: var(--color-surface);
  padding: 1.5rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}

.theory-section h2 {
  color: var(--color-primary);
  margin-bottom: 1rem;
  font-size: 1.3rem;
}

.theory-section p {
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
  line-height: 1.7;
}

.theory-section p:last-child {
  margin-bottom: 0;
}


.theory-link {
  margin-top: 1rem;
}

.theory-link a {
  font-weight: 500;
}

/* ========================================
   Compare Panel Styles
   ======================================== */

/* Compare chart line styles */
.temp-chart .temp-line.lumped-analytical {
  stroke: var(--color-cold);
  stroke-width: 2;
}

.temp-chart .temp-line.lumped-numerical {
  stroke: var(--color-cold);
  stroke-width: 2;
  stroke-dasharray: 4 3;
}

.temp-chart .temp-line.heateq-analytical {
  stroke: var(--color-hot);
  stroke-width: 2;
}

.temp-chart .temp-line.heateq-numerical {
  stroke: var(--color-hot);
  stroke-width: 2;
  stroke-dasharray: 4 3;
}

/* Compare panel — don't let chart stretch to fill all vertical space */
.compare-panel .chart-placeholder {
  flex: none;
}

.compare-panel .temp-chart {
  max-height: 250px;
}

/* Compare legend */
.compare-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem 1.25rem;
  margin-top: 0.5rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.compare-legend-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.compare-swatch {
  display: inline-block;
  width: 20px;
  height: 3px;
}

.compare-swatch.lumped-analytical {
  background: var(--color-cold);
}

.compare-swatch.lumped-numerical {
  background: repeating-linear-gradient(
    to right,
    var(--color-cold) 0px,
    var(--color-cold) 4px,
    transparent 4px,
    transparent 7px
  );
}

.compare-swatch.heateq-analytical {
  background: var(--color-hot);
}

.compare-swatch.heateq-numerical {
  background: repeating-linear-gradient(
    to right,
    var(--color-hot) 0px,
    var(--color-hot) 4px,
    transparent 4px,
    transparent 7px
  );
}

/* Compare stats table */
.compare-stats {
  margin-top: 1rem;
}

.compare-stats table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.compare-stats th,
.compare-stats td {
  padding: 0.5rem 0.75rem;
  text-align: left;
  border-bottom: 1px solid var(--color-secondary);
}

.compare-stats th {
  color: var(--color-text-muted);
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.compare-stats td {
  color: var(--color-text);
}

.compare-stats .lumped-a-row td:first-child,
.compare-stats .lumped-n-row td:first-child {
  color: var(--color-cold);
}

.compare-stats .heateq-a-row td:first-child,
.compare-stats .heateq-n-row td:first-child {
  color: var(--color-hot);
}

.compare-stats td:last-child {
  color: var(--color-text-muted);
  font-size: 0.8rem;
}

/* ========================================
   Accessibility
   ======================================== */

/* Focus-visible styles for keyboard navigation */
button:focus-visible,
select:focus-visible,
input[type="range"]:focus-visible,
a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}