/* ========== CSS Variables for Theming ========== */
:root {
  /* Light theme (default) */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-panel: #ffffff;
  --bg-histogram: #ffffff;
  --text-primary: #1e293b;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --border-strong: #cbd5e1;
  --accent-color: #3b82f6;
  --accent-hover: #2563eb;
  --accent-light: #eff6ff;
  --success-color: #10b981;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 10px;
  --canvas-bg: #ffffff;
  --canvas-border: #1e293b;
  --font-size-base: 15px;
  --font-size-sm: 14px;
  --font-size-xs: 13px;
  --font-size-info: 15px;
}

[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --bg-panel: #1e293b;
  --bg-histogram: #ffffff;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --border-color: #334155;
  --border-strong: #475569;
  --accent-color: #60a5fa;
  --accent-hover: #3b82f6;
  --accent-light: #1e3a5f;
  --success-color: #34d399;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4), 0 2px 4px -1px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.5), 0 4px 6px -2px rgba(0,0,0,0.4);
  --canvas-bg: #000000;
  --canvas-border: #3b82f6;
  --font-size-base: 14px;
  --font-size-sm: 13px;
  --font-size-xs: 12px;
  --font-size-info: 14px;
  --slit-open-color: #22c55e;
  --slit-closed-color: #ef4444;
  --tab-inactive-bg: #475569;
}

/* Dark mode specific overrides */
[data-theme="dark"] #rationale,
[data-theme="dark"] #rationale p,
[data-theme="dark"] #rationale h1,
[data-theme="dark"] #rationale article {
  color: #f1f5f9;
}

[data-theme="dark"] #psiTabs .ui-tabs-nav li:not(.ui-state-active) {
  background: #475569;
}

[data-theme="dark"] #superContainer > .ui-tabs-nav li:not(.ui-state-active) a {
  color: #cbd5e1;
}

[data-theme="dark"] .ui-slider {
  background: #475569;
  border-color: #475569;
}

[data-theme="dark"] .ui-slider-range {
  background: var(--accent-color);
}

[data-theme="dark"] .ui-slider-handle {
  background: #f1f5f9;
  border-color: var(--accent-color);
}

[data-theme="dark"] #waveRangeLabel {
  color: #f1f5f9;
}

[data-theme="dark"] #graphics-parameter-container label,
[data-theme="dark"] #graphics-parameter-container td {
  color: #f1f5f9;
}

[data-theme="dark"] #toggleSlits,
[data-theme="dark"] #toggleWhichPath,
[data-theme="dark"] #toggleView,
[data-theme="dark"] .math-slit-btn {
  color: #ffffff;
  border: 1px solid rgba(255,255,255,0.2);
}

[data-theme="dark"] #math-container .katex,
[data-theme="dark"] #math-container .katex .mord,
[data-theme="dark"] #math-container .katex .mbin,
[data-theme="dark"] #math-container .katex .mrel,
[data-theme="dark"] #math-container .katex .mopen,
[data-theme="dark"] #math-container .katex .mclose,
[data-theme="dark"] #math-container .katex .mpunct,
[data-theme="dark"] #math-container .katex .minner {
  color: #f1f5f9;
}

/* ========== Base Styles ========== */
* {
  box-sizing: border-box;
}

body {
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  margin: 0;
  padding: 12px;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-size: var(--font-size-base);
  line-height: 1.4;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* ========== View-Link Styles (Rationale tab) ========== */
.view-link {
  color: var(--accent-color);
  text-decoration: underline;
  text-decoration-style: dotted;
  text-underline-offset: 2px;
  cursor: pointer;
  transition: color 0.15s, text-decoration-color 0.15s;
}
.view-link:hover {
  color: var(--accent-hover);
  text-decoration-style: solid;
}
[data-theme="dark"] .view-link {
  color: #93c5fd;
}
[data-theme="dark"] .view-link:hover {
  color: #ffffff;
}

/* ========== Main Layout ========== */
.main-container {
  position: relative;
  display: flex;
  gap: 16px;
}

#leftPanel {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 12px;
  width: 380px;
  min-width: 250px;
  max-width: none;
}

/* ========== Resizable Panel Handles ========== */
.ui-resizable-e {
  width: 8px;
  right: -4px;
  background: linear-gradient(90deg, transparent 2px, var(--border-strong) 2px, var(--border-strong) 4px, transparent 4px);
  cursor: ew-resize;
  opacity: 0.6;
  transition: opacity 0.2s;
}
.ui-resizable-e:hover { opacity: 1; }

.ui-resizable-s {
  height: 8px;
  bottom: -4px;
  background: linear-gradient(0deg, transparent 2px, var(--border-strong) 2px, var(--border-strong) 4px, transparent 4px);
  cursor: ns-resize;
  opacity: 0.6;
  transition: opacity 0.2s;
}
.ui-resizable-s:hover { opacity: 1; }

#canvas-container.ui-resizable {
  overflow: hidden;
}

#controls {
  margin-top: 20px;
}

.container {
  display: flex;
  flex-direction: column;
}

/* ========== Input Groups ========== */
.input-group {
  display: flex;
  align-items: center;
  margin-bottom: 6px;
  max-width: 100%;
}
.input-group label {
  width: 95px;
  margin-right: 4px;
  flex-shrink: 0;
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--text-secondary);
}
.input-group input[type=range] {
  flex: 1 1 auto;
  margin-right: 4px;
  max-width: 100px;
  accent-color: var(--accent-color);
  height: 5px;
}
.input-group input[type=number] {
  width: 5em;
  margin-right: 2px;
  flex-shrink: 0;
  padding: 3px 4px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: var(--font-size-base);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.input-group input[type=number]:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 2px var(--accent-light);
}
.input-group select {
  min-width: 45px;
  flex-shrink: 0;
  padding: 4px 6px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: var(--font-size-base);
  cursor: pointer;
}

/* ========== Wave Controls Box ========== */
.wave-range-box {
  border: 1px solid var(--border-color);
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 8px 10px 4px;
  margin-bottom: 8px;
}

/* ========== Opacity Controls Box ========== */
.opacity-box {
  border: 1px solid var(--border-color);
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 6px 10px 4px;
  margin-bottom: 8px;
}
.opacity-box-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 4px;
}
.opacity-box .input-group label {
  width: 65px;
}
.opacity-box .input-group select {
  display: none;
}

#waveFunctionOption,
#sourceOption {
  min-width: 110px;
}

#particle-parameter-container .amplitude-label {
  width: auto;
  margin-left: 8px;
  margin-right: 4px;
}

/* Make the Sim. Speed "x" look like plain text, not a dropdown */
#animationStep-units {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  border: none;
  background: transparent;
  padding: 0;
  pointer-events: none;
  color: var(--text-secondary);
}

/* ========== Info Panel ========== */
#Info {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-panel);
  box-shadow: var(--shadow-sm);
  font-size: var(--font-size-info);
}

/* ========== Tooltips (data-tip, not title, to avoid native double-tooltip) ========== */
label[data-tip], div[data-tip], tr[data-tip] td.label, td[data-tip]:first-child {
  border-bottom: 1px dotted var(--text-muted);
  cursor: help;
}
tr[data-tip] td.label {
  border-bottom: 1px dotted var(--text-muted);
}

[data-tip] {
  position: relative;
}
label[data-tip]:hover::after,
div[data-tip]:hover::after,
tr[data-tip]:hover::after,
td[data-tip]:hover::after,
canvas[data-tip]:hover::after {
  content: attr(data-tip);
  position: absolute;
  left: 0;
  top: 100%;
  margin-top: 6px;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  padding: 10px 14px;
  border-radius: var(--radius-md);
  font-size: 13px;
  white-space: normal;
  max-width: 300px;
  z-index: 1000;
  pointer-events: none;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border-color);
  line-height: 1.5;
  opacity: 0;
  animation: tooltipFadeIn 0s 1s forwards;
}
@keyframes tooltipFadeIn {
  to { opacity: 1; }
}
#Info tr[data-tip]:hover::after {
  left: 100%;
  top: 50%;
  transform: translateY(-50%);
  margin-left: 10px;
  margin-top: 0;
  white-space: nowrap;
  max-width: none;
}

/* ========== Math tab compactness ========== */
#math-container .katex-display {
  margin: 0.2em 0;
}
#math-container .katex {
  font-size: 1.1em;
}

/* ========== Button status lines ========== */
.btn-status-line {
  font-size: 0.8em;
  color: var(--text-muted);
  min-height: 1.4em;
  margin-top: 4px;
  margin-bottom: 4px;
  line-height: 1.4;
  transition: opacity 0.15s;
}

/* ========== Info Panel Layout ========== */
.info-layout {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
}

.info-metrics table {
  border-collapse: collapse;
  width: 100%;
}

.info-metrics td.label {
  padding-right: 18px;
  font-size: 13px;
  color: var(--text-secondary);
}

.info-metrics td.value {
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--text-primary);
}

.info-controls {
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: stretch;
}

.info-metrics {
  flex: 2;
}

.info-controls {
  flex: 1;
}

#histo-info {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 200px;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-panel);
}

.histogram {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  width: 200px;
  height: 70px;
  border: 1px solid var(--border-color);
  margin: 16px auto;
  background: var(--bg-histogram);
}
.bar {
  width: 30px;
  background-color: var(--accent-color);
  text-align: center;
  margin: 1px;
  position: relative;
}
.bar-label {
  font-size: 12px;
  color: #fff;
  position: absolute;
  bottom: 0;
  width: 100%;
}

/* ========== Tab Navigation ========== */
#psiTabs {
  display: flex;
  flex-direction: column;
  flex: 1 1 auto;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-panel);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

#psiTabs .ui-tabs-nav {
  display: flex;
  flex-direction: row;
  margin: 0;
  padding: 0;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-tertiary);
}

#psiTabs .ui-tabs-nav li {
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px 12px;
  cursor: pointer;
  border-right: 1px solid var(--border-color);
  transition: background-color 0.2s;
}

#psiTabs .ui-tabs-nav li:hover {
  background: var(--bg-secondary);
}

#psiTabs .ui-tabs-nav li:last-child {
  border-right: none;
}

#psiTabs .ui-tabs-nav li a {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  color: var(--text-secondary);
  padding: 2px 0;
  width: 100%;
  height: 100%;
  gap: 1px;
}

#psiTabs .tab-label {
  font-size: 9px;
  letter-spacing: 0.3px;
  text-transform: uppercase;
  line-height: 1;
  opacity: 0.75;
}

#psiTabs .tab-icon.material-icons {
  font-size: 20px;
  line-height: 1;
}

#psiTabs .tab-icon-svg {
  width: 22px;
  height: 22px;
  display: block;
  color: var(--accent-color);
}

/* Per-tab icon colors */
#psiTabs .tab-physics a { color: var(--accent-color); }
#psiTabs .tab-physics  .tab-icon { color: var(--accent-color); }
#psiTabs .tab-setup    .tab-icon { color: #8b5cf6; }
#psiTabs .tab-setup    a { color: #8b5cf6; }
#psiTabs .tab-math     .tab-icon { color: #f59e0b; }
#psiTabs .tab-math     a { color: #f59e0b; }
#psiTabs .tab-graphics .tab-icon { color: #10b981; }
#psiTabs .tab-graphics a { color: #10b981; }
#psiTabs .tab-views    .tab-icon { color: #ef4444; }
#psiTabs .tab-views    a { color: #ef4444; }

#psiTabs .ui-tabs-nav li.ui-state-active {
  background: var(--bg-panel);
  border-bottom: 2px solid var(--accent-color);
  margin-bottom: -1px;
}

#psiTabs .ui-tabs-panel {
  flex: 1 1 auto;
  padding: 12px;
  overflow: auto;
  background: var(--bg-panel);
}

/* ========== Color Picker Modal ========== */
#colorPickerModal {
  display: none;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: var(--bg-panel);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  padding: 20px 24px;
  max-height: 80%;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  z-index: 1001;
  min-width: 320px;
}

#colorPickerModal h3 {
  margin: 0 0 12px;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
}

.palette {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(28px, 1fr));
  gap: 8px;
}

.colorOption {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-md);
  border: 2px solid transparent;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
}

.colorOption:hover {
  transform: scale(1.1);
  border-color: var(--accent-color);
  box-shadow: var(--shadow-md);
}

#overlay {
  display: none;
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.5);
  backdrop-filter: blur(2px);
  z-index: 1000;
}

.pick-color {
  width: 32px;
  height: 22px;
  border: 2px solid var(--border-color);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: border-color 0.2s;
}
.pick-color:hover {
  border-color: var(--accent-color);
}

#canvas {
  margin-top: 20px;
}

/* ========== Canvas Container ========== */
#canvas-wrapper {
  display: flex;
  flex-direction: column;
}

#canvas-container {
  position: relative;
  width: 800px;
  height: 600px;
  border: 2px solid var(--canvas-border);
  border-radius: var(--radius-md);
  margin: 20px 0;
  min-width: 400px;
  min-height: 300px;
  max-width: 1200px;
  max-height: 900px;
  background: var(--canvas-bg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
canvas {
  position: absolute;
}
#waveCanvas  { z-index: 0; }
#setupCanvas { z-index: 1; }
#partCanvas  { z-index: 2; }

#view-label {
  text-align: center;
  font-size: 16.5px;
  color: var(--text-muted);
  margin-bottom: 4px;
  letter-spacing: 0.03em;
  opacity: 0.7;
}

#shortcut-hint {
  text-align: center;
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
  letter-spacing: 0.02em;
  opacity: 0.7;
}

/* ========== Buttons ========== */
button {
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  padding: 8px 16px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s ease;
}

button:hover {
  background: var(--bg-tertiary);
  border-color: var(--accent-color);
}

button:active {
  transform: translateY(1px);
}

#startButton, #resetButton {
  min-width: 90px;
  padding: 10px 16px;
  font-weight: 600;
}

#startButton {
  background: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
}

#startButton:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

#resetButton {
  background: #b91c1c;
  color: white;
  border-color: #b91c1c;
}

#resetButton:hover {
  background: #991b1b;
  border-color: #991b1b;
}

#toggleSlits, #toggleWhichPath, #toggleView, .math-slit-btn {
  background: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
  min-width: 80px;
  padding: 6px 10px;
  font-weight: 500;
}

#toggleSlits:hover, #toggleWhichPath:hover, #toggleView:hover, .math-slit-btn:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

.button-group {
  display: flex;
  gap: 10px;
  margin-top: 10px;
}

.interp-btn {
  padding: 10px 18px;
  border: 1px solid var(--border-color);
  background: var(--bg-secondary);
  cursor: pointer;
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: all 0.2s;
}

.interp-btn.active {
  background: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
  cursor: default;
}

.views-buttons {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.particle-second-line {
  display: block;
  margin-top: 2px;
}

/* ========== Branch Counter ========== */
#worldCountDisplay {
  font-size: 1.3em;
  font-weight: 600;
  color: var(--accent-color);
  background: var(--accent-light);
  padding: 10px 14px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  text-align: center;
  border: 1px solid var(--border-color);
}

#worldCountDisplay {
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%   { transform: scale(1); }
  50%  { transform: scale(1.02); }
  100% { transform: scale(1); }
}

.branch-button {
  background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  padding: 10px 18px;
  font-size: 1rem;
  font-weight: 500;
  box-shadow: var(--shadow-md);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  cursor: pointer;
}

.branch-button:hover {
  transform: scale(1.03);
  box-shadow: var(--shadow-lg);
}

#worldFactor {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-tertiary);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

/* ========== Checkboxes ========== */
input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--accent-color);
  cursor: pointer;
}

/* ========== Super Container Tabs ========== */
#superContainer.ui-tabs {
  background: transparent;
  border: none;
  padding: 0;
}

#superContainer > .ui-tabs-nav {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  padding: 0;
  margin-bottom: 0;
}

#superContainer > .ui-tabs-nav li {
  margin: 0;
  border: none;
  background: transparent;
}

#superContainer > .ui-tabs-nav li a {
  padding: 12px 20px;
  color: var(--text-secondary);
  font-weight: 500;
}

#superContainer > .ui-tabs-nav li.ui-state-active {
  background: var(--bg-panel);
  border-bottom: 2px solid var(--accent-color);
}

#superContainer > .ui-tabs-nav li.ui-state-active a {
  color: var(--text-primary);
}

#superContainer > .ui-tabs-panel {
  border: 1px solid var(--border-color);
  border-top: none;
  border-radius: 0 0 var(--radius-md) var(--radius-md);
  background: var(--bg-primary);
  padding: 20px;
}

/* ========== Timing Fieldset ========== */
fieldset {
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  background: var(--bg-tertiary);
}

fieldset legend {
  font-size: 12px;
  font-weight: 500;
  color: var(--text-muted);
  padding: 0 6px;
}

fieldset table {
  font-size: 12px;
  color: var(--text-secondary);
}

/* ========== Responsive Layout ========== */

/* Tablet / narrow window: stack sidebar above canvas */
@media (max-width: 900px) {
  body {
    padding: 8px;
  }

  .main-container {
    flex-direction: column;
    align-items: stretch;
  }

  #leftPanel {
    width: 100% !important;
    height: auto !important;
    min-width: 0;
    max-width: none;
  }

  #canvas-container {
    width: 100% !important;
    height: auto !important;
    aspect-ratio: 4 / 3;
    min-width: 0 !important;
    min-height: 0 !important;
    max-width: none;
    margin: 8px 0;
  }

  /* Hide drag-resize handles on narrow screens */
  .ui-resizable-e,
  .ui-resizable-s,
  .ui-resizable-se {
    display: none !important;
  }
}

/* Small phones */
@media (max-width: 520px) {
  body {
    padding: 4px;
  }

  #psiTabs .ui-tabs-nav li {
    padding: 4px 6px;
  }

  #psiTabs .tab-label {
    font-size: 7px;
  }

  #psiTabs .tab-icon-svg {
    width: 18px;
    height: 18px;
  }

  #psiTabs .tab-icon.material-icons {
    font-size: 16px;
  }

  .info-layout {
    flex-direction: column;
    gap: 8px;
  }

  .info-controls {
    flex-direction: row;
    justify-content: center;
  }

  .input-group label {
    font-size: 12px;
  }

  #toggleSlits, #toggleWhichPath, #toggleView,
  #mathToggleSlits, #mathToggleWhichPath, #mathToggleView {
    min-width: 60px;
    padding: 4px 6px;
    font-size: 12px;
  }

  #rationale {
    padding: 12px;
  }

  #rationale h1 {
    font-size: 1.3em;
  }
}