/* Game of 3D Life - Styles */

:root {
  --bg-primary: #0a0a0f;
  --bg-tertiary: #1a1a25;
  --text-primary: #e8e8ec;
  --text-secondary: #8888a0;
  --accent-primary: #4a9eff;
  --accent-secondary: #7b5cff;
  --border-color: rgba(255, 255, 255, 0.08);
  --shadow-color: rgba(0, 0, 0, 0.4);
  --font-display: "Segoe UI", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: "SF Mono", "Consolas", "Monaco", monospace;
  --radius-sm: 6px;
  --radius-lg: 16px;
  --transition-fast: 150ms ease;
  --screenshow-fade-ms: 900ms;
  /* Controls sizing: keep expanded panels the same width as the top button row */
  --controls-pad-y: 16px;
  --controls-edge-pad: 16px;
  --icon-btn-size: 42px;
  /* Range input sizing (track + thumb). */
  --range-track-height: 4px;
  --range-thumb-size: 16px;
  --icon-btn-gap: 6px;
  --controls-button-count: 6;
  --controls-button-gap-count: 5;
  --controls-content-width: calc(
    (var(--icon-btn-size) * var(--controls-button-count)) +
    (var(--icon-btn-gap) * var(--controls-button-gap-count)) +
    (var(--controls-edge-pad) * 2)
  );
  /* Typography scale for UI elements */
  --panel-font-size: 0.95rem;
  --panel-line-height: 1.4;
  /* Safe-area + comfort insets for HUD elements (iOS notch / Dynamic Island / home indicator). */
  --safe-inset-top: env(safe-area-inset-top, 0px);
  --safe-inset-left: env(safe-area-inset-left, 0px);
  --safe-inset-right: env(safe-area-inset-right, 0px);
  --safe-inset-bottom: env(safe-area-inset-bottom, 0px);

  /* Spacing for HUD elements (panels / buttons / corner chrome). */
  --hud-pad: 12px;
  --hud-inset-top: max(var(--hud-pad), var(--safe-inset-top));
  --hud-inset-left: max(var(--hud-pad), var(--safe-inset-left));
  --hud-inset-right: max(var(--hud-pad), var(--safe-inset-right));
  --hud-inset-bottom: max(var(--hud-pad), var(--safe-inset-bottom));

  /*
   * Viewport height used for scrollable UI chrome (Settings/Help).
   *
   * On iOS Safari, `100vh` is based on the *layout* viewport and can ignore
   * dynamic toolbars in landscape, which may make the bottom of scrollable
   * panels unreachable.
   *
   * CSS-only fix: prefer the *small* viewport height (`svh`) when supported.
   * This guarantees scrollable UI fits when toolbars are present. When the
   * toolbars are hidden, the UI may not fully fill the available height,
   * which is acceptable and avoids content being obscured.
   *
   * If `svh` is not available, we fall back to `vh`.
   */
  --app-vh: 100vh;
}


@supports (height: 100svh) {
  :root {
    --app-vh: 100svh;
  }
}
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
}

html {
  /* Base font size - 16px on desktop, scales on mobile */
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

html,
body {
  height: 100%;
  overflow: hidden;
  font-family: var(--font-display);
  background: var(--bg-primary);
  color: var(--text-primary);
  user-select: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
}

#app {
  width: 100%;
  height: 100%;
  position: relative;
}

#glCanvas {
  width: 100%;
  height: 100%;
  display: block;
  cursor: grab;
  touch-action: none;
  -webkit-user-select: none;
  user-select: none;
  transition: opacity var(--screenshow-fade-ms) ease;
  will-change: opacity;
}

#glCanvas.screen-show-dimmed {
  opacity: 0;
}

#glCanvas:active {
  cursor: grabbing;
}

#glCanvas.nav-disabled,
#glCanvas.nav-disabled:active {
  cursor: default;
}

/* UI Overlay */
#ui-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  pointer-events: none;
}

#ui-overlay > * {
  pointer-events: auto;
}

/* Shared translucent "glass" chrome used by HUD surfaces */
.glass-chrome {
  /*
   * To keep the visual design consistent across desktop + mobile while staying
   * cheap to composite, we emulate the “frosted glass” look using layered
   * translucent fills + highlights (no backdrop blur).
   */
  position: relative;
  overflow: hidden;
  /* Keep pseudo-element effects from leaking into the rest of the page. */
  isolation: isolate;
  background:
    /* Subtle top highlight */
    linear-gradient(
      180deg,
      rgba(255, 255, 255, 0.08) 0%,
      rgba(255, 255, 255, 0.02) 38%,
      rgba(255, 255, 255, 0.0) 100%
    ),
    /* Base tint */
    rgba(18, 18, 26, 0.78);
  border: 1px solid var(--border-color);
  /* Isolate painting/compositing to the panel bounds. */
  contain: layout paint;
}

/* Inner sheen + a hint of texture to mimic glass without blur. */
.glass-chrome::before,
.glass-chrome::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  pointer-events: none;
  z-index: 0;
}

/* Ensure actual UI content sits above the decorative layers. */
.glass-chrome > * {
  position: relative;
  z-index: 1;
}

/* Corner glow */
.glass-chrome::before {
  background:
    radial-gradient(
      120% 140% at 0% 0%,
      rgba(74, 158, 255, 0.14) 0%,
      rgba(74, 158, 255, 0.06) 30%,
      rgba(74, 158, 255, 0.0) 60%
    ),
    radial-gradient(
      140% 160% at 100% 0%,
      rgba(123, 92, 255, 0.12) 0%,
      rgba(123, 92, 255, 0.05) 28%,
      rgba(123, 92, 255, 0.0) 60%
    );
  opacity: 0.9;
}

/* Fine-grain noise (very light). Keeping it subtle avoids banding on OLED. */
.glass-chrome::after {
  background:
    repeating-linear-gradient(
      45deg,
      rgba(255, 255, 255, 0.018) 0px,
      rgba(255, 255, 255, 0.018) 1px,
      rgba(0, 0, 0, 0.0) 1px,
      rgba(0, 0, 0, 0.0) 6px
    );
  /*
   * Avoid `mix-blend-mode`: it forces blending with the animated WebGPU canvas
   * behind the panel, which can trigger extra offscreen composition work on mobile.
   * A slightly lower opacity keeps the visual texture subtle without needing blending.
   */
  opacity: 0.18;
}

/* Loading overlay (shown until WebGPU + UI initialization completes) */
.loading-overlay {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--hud-inset-top) var(--hud-inset-right) var(--hud-inset-bottom)
    var(--hud-inset-left);
  background: rgba(10, 10, 15, 0.82);
  z-index: 1000;

  /* Reduce “flash of loader” on fast loads:
     keep the overlay present (so it can cover slow networks / slow JS),
     but delay its fade-in slightly so it does not appear at all on the fast path. */
  opacity: 0;
  visibility: visible;
  will-change: opacity;
  animation: g3dl-loading-overlay-in 160ms ease-out 500ms both;

  transition: opacity var(--transition-fast), visibility var(--transition-fast);
}

@keyframes g3dl-loading-overlay-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

.loading-overlay.is-hidden {
  /* Cancel delayed fade-in if we hide quickly (fast path) */
  animation: none;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.loading-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 18px;
  border-radius: var(--radius-lg);
  box-shadow: 0 18px 48px var(--shadow-color);
  max-width: min(520px, calc(100vw - 2 * var(--hud-inset-left)));
}

.loading-spinner {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.16);
  border-top-color: var(--accent-primary);
  animation: g3dl-spin 0.9s linear infinite;
  flex: 0 0 auto;
}

.loading-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.loading-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
}

.loading-subtitle {
  margin-top: 2px;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

@keyframes g3dl-spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

@media (prefers-reduced-motion: reduce) {
  .loading-spinner {
    animation: none;
  }
  .loading-overlay {
    transition: none;
    /* Still delay showing the overlay to avoid “flash of loader”, but avoid animation. */
    animation: g3dl-loading-overlay-in 1ms linear 500ms both;
  }
}

/* Header */
#header {
  position: absolute;
  top: var(--hud-inset-top);
  left: var(--hud-inset-left);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  border-radius: var(--radius-lg);
  padding: 12px 20px;
}

#header h1 {
  font-weight: 600;
  background: linear-gradient(
    135deg,
    var(--accent-primary),
    var(--accent-secondary)
  );
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.1;
  white-space: nowrap;
  /* Scale to match credit line width - credit is ~185px at 11px font */
  font-size: clamp(18px, 5vw, 26px);
  letter-spacing: 0.5px;
  text-align: center;
}

#header .credit {
  white-space: nowrap;
  letter-spacing: 0.3px;
  text-align: center;
}

/* Controls Container (chrome + positioning) */
#controls {
  position: absolute;
  top: var(--hud-inset-top);
  right: var(--hud-inset-right);
  border-radius: var(--radius-lg);
  box-sizing: content-box;
  padding: var(--controls-pad-y) 0;
  display: flex;
  flex-direction: column;
  gap: 16px;
  width: var(--controls-content-width);
  max-width: calc(100vw - var(--hud-inset-left) - var(--hud-inset-right));
  max-height: calc(var(--app-vh) - var(--hud-inset-top) - var(--hud-inset-bottom) - (var(--controls-pad-y) * 2));
  box-shadow: 0 8px 32px var(--shadow-color);
  z-index: 100;
}

@supports (width: 100dvw) {
  #controls {
    max-width: calc(100dvw - var(--hud-inset-left) - var(--hud-inset-right));
  }
}


/* Panel body (Settings/Help) */
.panel-body {
  display: flex;
  flex-direction: column;
  gap: 6px;
  overflow-y: auto;
  flex: 1 1 auto;
  min-height: 0;
  padding-left: var(--controls-edge-pad);
  padding-right: var(--controls-edge-pad);
  /* Bottom padding keeps the last items comfortably reachable at the end of the scroll. */
  padding-bottom: var(--controls-edge-pad);
  -webkit-overflow-scrolling: touch;

  --panel-scrollbar-width: 10px;
  --panel-scrollbar-track-bg: rgba(255, 255, 255, 0.06);
  --panel-scrollbar-track-radius: 10px;
  --panel-scrollbar-thumb-bg: rgba(74, 158, 255, 0.55);
  --panel-scrollbar-thumb-radius: 10px;
  --panel-scrollbar-thumb-border: 2px solid rgba(18, 18, 26, 0.7);
  --panel-scrollbar-thumb-hover-bg: rgba(74, 158, 255, 0.75);

  scrollbar-width: thin;
  scrollbar-color: rgba(74, 158, 255, 0.65) rgba(255, 255, 255, 0.06);

  /* Use rem so mobile/root scaling affects readability without needing many overrides */
  font-size: var(--panel-font-size);
  line-height: var(--panel-line-height);
}

#settings-panel {
  align-items: stretch;

  --panel-scrollbar-track-radius: 8px;
  --panel-scrollbar-thumb-bg: rgba(74, 158, 255, 0.65);
  --panel-scrollbar-thumb-radius: 8px;
  --panel-scrollbar-thumb-border: none;
}

.hidden {
  display: none !important;
}

/* Panel scrollbars (WebKit) */
.panel-body::-webkit-scrollbar {
  width: var(--panel-scrollbar-width);
}

.panel-body::-webkit-scrollbar-track {
  background: var(--panel-scrollbar-track-bg);
  border-radius: var(--panel-scrollbar-track-radius);
}

.panel-body::-webkit-scrollbar-thumb {
  background: var(--panel-scrollbar-thumb-bg);
  border-radius: var(--panel-scrollbar-thumb-radius);
  border: var(--panel-scrollbar-thumb-border);
}

.panel-body::-webkit-scrollbar-thumb:hover {
  background: var(--panel-scrollbar-thumb-hover-bg);
}

#settings-panel .control-group {
  align-items: stretch;
}

/* Help button and panel */
#helpBtn {
  font-size: 18px;
  font-weight: 800;
  line-height: 1;
}

#help-panel h2 {
  font-size: 1.15em;
  margin: 0;
  padding: 0;
}

#help-panel h3 {
  font-size: 1.05em;
  font-weight: 600;
  margin: 10px 0 0 0;
  padding: 0;
  color: var(--text-primary);
}

#help-panel p,
#help-panel ul {
  margin: 0;
  color: var(--text-secondary);
  line-height: 1.35;
}

#help-panel ul {
  padding-left: 18px;
}

#help-panel li {
  margin: 4px 0;
}

#help-panel .help-accent {
  color: var(--text-primary);
  font-weight: 700;
}

/* Help links: keep text color consistent on dark background, use underline for affordance */
#help-panel a,
#help-panel a:visited {
  color: inherit;
}

#help-panel a {
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 2px;
  text-decoration-color: currentColor;
}

#help-panel a:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.65);
  outline-offset: 2px;
  border-radius: 4px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.button-row {
  display: flex;
  width: 100%;
  box-sizing: border-box;
  align-items: center;
  justify-content: flex-start;

  /* Use gap + padding rather than per-button margins. This keeps each wrapped row
     aligned and avoids layout drift on narrow viewports. */
  gap: var(--icon-btn-gap);
  padding-left: var(--controls-edge-pad);
  padding-right: var(--controls-edge-pad);

  /* Allow wrapping when max-width clamps the controls panel on narrow screens. */
  flex-wrap: wrap;
}

/* Icon-only buttons */
.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: var(--icon-btn-size);
  height: var(--icon-btn-size);
  margin: 0;
  padding: 0;
  background-color: var(--bg-tertiary);
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    transform var(--transition-fast),
    opacity var(--transition-fast),
    color var(--transition-fast);
  flex-shrink: 0;
}

.icon-btn svg {
  width: 22px;
  height: 22px;
  opacity: 0.85;
}

.icon-btn:hover {
  background-color: var(--bg-primary);
}

.icon-btn:hover svg,
.icon-btn:active {
  transform: scale(0.97);
}

.icon-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.icon-btn:disabled:hover {
  background-color: var(--bg-tertiary);
}

.icon-btn:disabled:active {
  transform: none;
}

.playing #playBtn,
#settingsBtn.active {
  background: var(--accent-primary);
}

/* Settings button active state */
#settingsBtn.active svg {
  opacity: 1;
}

/* Help button active state */
#helpBtn.active {
  background: var(--accent-primary);
  color: var(--text-primary);
}

/* Speed slider - standalone horizontal layout */
.slider-label.speed-slider {
  justify-content: flex-start;
  width: 100%;
}

.speed-slider > span:first-child {
  flex-shrink: 0;
}

.speed-slider input[type="range"] {
  /* In a horizontal flex row, avoid width: 100% forcing the container wider when panels open. */
  flex: 1 1 auto;
  width: auto;
  min-width: 0;
}
/* Common label typography for Settings labels. */
.control-label,
.select-label,
.color-label {
  font-size: inherit;
  color: var(--text-primary);
}
/* Sliders */
.slider-label {
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
}

/* Horizontal row labels shared by speed slider, density slider, and color labels. */
.slider-label.speed-slider,
.density-slider-label,
.color-label {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 6px;
}

/* Density slider with tip */
.density-slider-wrapper {
  position: relative;
  flex: 1;
}

.slider-tip {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  padding: 4px 8px;
  background: var(--accent-primary);
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: inherit;
  color: #000000;
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast);
  pointer-events: none;
}

.slider-tip::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: var(--accent-primary);
  border-bottom: none;
}

.density-slider-label:hover .slider-tip,
.density-slider-wrapper:hover .slider-tip,
.slider-tip.visible {
  opacity: 1;
  visibility: visible;
}

input[type="range"] {
  width: 100%;
  height: var(--range-thumb-size);
  -webkit-appearance: none;
  appearance: none;
  background: transparent;
  padding: 0;
  margin: 0;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: var(--range-track-height);
  background: rgba(74, 158, 255, 0.3);
  border-radius: calc(var(--range-track-height) / 2);
}
input[type="range"]::-moz-range-track {
  height: var(--range-track-height);
  background: rgba(74, 158, 255, 0.3);
  border-radius: calc(var(--range-track-height) / 2);
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: var(--range-thumb-size);
  height: var(--range-thumb-size);
  background: var(--accent-primary);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  transition: transform var(--transition-fast);
  margin-top: calc((var(--range-track-height) - var(--range-thumb-size)) / 2);
}
input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

input[type="range"]::-moz-range-thumb {
  width: var(--range-thumb-size);
  height: var(--range-thumb-size);
  background: var(--accent-primary);
  border: none;
  border-radius: 50%;
  cursor: pointer;
}
/* Rules Group */
.rules-group,
.color-pickers {
  gap: 6px;
}

/* Size Inputs */
.size-inputs {
  flex-direction: row;
  gap: 12px;
}

/* Stacked labels used for inputs and selects. */
.rules-inputs label,
.size-inputs .input-label,
.select-label {
  gap: 6px;
  margin-bottom: 0;
}

.size-inputs .input-label {
  flex: 1;
  gap: 4px;
}

.input-wrapper {
  display: flex;
  align-items: center;
  background: var(--bg-tertiary);
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.input-wrapper input[type="number"],
.input-wrapper input[type="text"] {
  flex: 1;
  width: 100%;
  padding: 8px 10px;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: inherit;
}

.input-wrapper input[type="number"] {
  -moz-appearance: textfield;
}
.input-wrapper input[type="number"]::-webkit-outer-spin-button,
.input-wrapper input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.input-wrapper input:focus {
  outline: none;
}
.input-wrapper.invalid,
.input-wrapper:has(input:invalid) {
  border-color: #ff4a6a;
}

/* Also reflect native HTML validity (e.g., min/max) where supported */
/* Color Labels - match slider-label style */
.color-label > span:first-child {
  flex: 1;
}

.color-gradient-pickers {
  display: flex;
  align-items: center;
  gap: 4px;
}

.gradient-arrow {
  color: var(--text-primary);
  opacity: 0.6;
}

.color-picker {
  -webkit-appearance: none;
  appearance: none;
  width: 32px;
  height: 22px;
  border: 2px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-sm);
  background: transparent;
  cursor: pointer;
  padding: 2px;
  flex-shrink: 0;
  margin: 0;
  outline: none;
}

.color-picker::-webkit-color-swatch-wrapper {
  padding: 0;
}

.color-picker::-webkit-color-swatch {
  border: none;
  border-radius: 3px;
}
.color-picker::-moz-color-swatch {
  border: none;
  border-radius: 3px;
}

.color-picker:focus-visible {
  outline: 2px solid rgba(74, 158, 255, 0.75);
  outline-offset: 2px;
}

.rules-inputs {
  display: flex;
  gap: 8px;
}

.rules-inputs label {
  flex: 1;
  min-width: 0;
  gap: 4px;
}

/* Select dropdown for presets */
.select-label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 0;
}

/* Checkbox label layout: center text vertically next to the box */
.checkbox-label {
  display: flex;
  align-items: center;
  gap: 6px;
}

.select-label select {
  width: 100%;
  padding: 9px 34px 9px 10px;
  background: var(--bg-tertiary);
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: inherit;
  cursor: pointer;
  transition:
    border-color var(--transition-fast),
    background-color var(--transition-fast);
  -webkit-appearance: none;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%238888a0' d='M6 8L2 4h8z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  background-size: 12px;
}

.select-label select:hover {
  border-color: rgba(74, 158, 255, 0.55);
}

.select-label select:focus {
  outline: none;
  border-color: rgba(74, 158, 255, 0.85);
}

.select-label select option {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.checkbox-label input[type="checkbox"] {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  background-color: var(--bg-tertiary);
  border: 2px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    opacity var(--transition-fast);
  position: relative;
  flex-shrink: 0;
}

.checkbox-label input[type="checkbox"]:checked {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
}

.checkbox-label input[type="checkbox"]:checked::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 6px;
  height: 12px;
  border: solid var(--bg-primary);
  border-width: 0 3px 3px 0;
  transform: translate(-50%, -60%) rotate(45deg);
}

.input-wrapper:focus-within,
.checkbox-label input[type="checkbox"]:hover {
  border-color: var(--accent-primary);
}

/* Toast (lightweight user-visible notifications)

   This is intentionally minimal: it is used for non-fatal feedback that would
   otherwise only be visible in the console (which is often inaccessible on mobile).
*/
#toast {
  position: fixed;
  left: 50%;
  bottom: var(--hud-inset-bottom);
  transform: translateX(-50%);
  z-index: 110;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: var(--radius-lg);
  min-width: 240px;
  max-width: min(
    560px,
    calc(100vw - var(--hud-inset-left) - var(--hud-inset-right))
  );
  box-shadow: 0 8px 32px var(--shadow-color);
  pointer-events: auto;
  touch-action: manipulation;
}

#toast[data-kind="error"] {
  border-color: rgba(255, 90, 90, 0.8);
}

#toast[data-kind="success"] {
  border-color: rgba(90, 220, 140, 0.78);
}

#toast[data-kind="warn"] {
  border-color: rgba(255, 196, 90, 0.75);
}

#toast[data-kind="info"] {
  border-color: rgba(74, 158, 255, 0.75);
}

.toast-message {
  flex: 1 1 auto;
  font-size: 0.95rem;
  line-height: 1.3;
  display: flex;
  /* Center-align with the icon and close button for single-line toasts. */
  align-items: center;
  gap: 10px;
}

.toast-message::before {
  content: "";
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  width: 1.4em;
  height: 1.4em;
  font-size: 1.35em;
  line-height: 1;
  margin-top: 0;
  font-weight: 800;
}

#toast[data-kind="info"] .toast-message::before {
  content: "ℹ";
  color: rgba(74, 158, 255, 0.95);
}

#toast[data-kind="success"] .toast-message::before {
  /*
    Force text-style presentation (VS15) so iOS does not render this as an emoji
    glyph (which can ignore CSS `color` and appear grey).
  */
  /* Use a CSS unicode escape (\FE0E), not a JS-style "\uFE0E" escape. */
  content: "✔\FE0E";
  color: rgba(90, 220, 140, 0.95);
}

#toast[data-kind="warn"] .toast-message::before {
  /* Force text-style presentation (VS15) for consistent coloring on iOS. */
  content: "⚠\FE0E";
  color: rgba(255, 196, 90, 0.95);
}

#toast[data-kind="error"] .toast-message::before {
  /* Force text-style presentation (VS15) for consistent coloring on iOS. */
  content: "✖\FE0E";
  color: rgba(255, 90, 90, 0.98);
}

.toast-close {
  flex: 0 0 auto;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 22px;
  line-height: 1;
  transition: transform var(--transition-fast),
    background var(--transition-fast),
    border-color var(--transition-fast);
}

.toast-close:hover {
  background: rgba(255, 255, 255, 0.14);
  border-color: rgba(255, 255, 255, 0.35);
}

.toast-close:active {
  transform: scale(0.98);
}

.toast-close:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

/* Stats */
#stats {
  position: fixed;
  bottom: var(--hud-inset-bottom);
  left: var(--hud-inset-left);
  pointer-events: auto;
  touch-action: auto;
  z-index: 90;
  display: flex;
  flex-direction: column;
  gap: 12px;
  border-radius: var(--radius-lg);
  padding: 16px 20px;
}

.stats-row {
  display: flex;
  gap: 24px;
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.stat-label {
  font-size: 11px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.stat-value {
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 600;
  color: var(--text-primary);
}

.credit {
  font-size: 11px;
  color: var(--text-secondary);
  font-style: italic;
}

/* Bottom-right info panel: GitHub link (desktop) + About/GitHub (mobile). */
#infoPanel {
  position: fixed;
  right: var(--hud-inset-right);
  bottom: var(--hud-inset-bottom);
  width: var(--icon-btn-size);
  height: var(--icon-btn-size);
  padding: 0;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.28);
  z-index: 95;
}

/* About button is mobile-only; GitHub is visible on all platforms. */
#infoBtn {
  display: none;
}

.corner-icon-btn,
.corner-icon-link {
  width: var(--icon-btn-size);
  height: var(--icon-btn-size);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  border: 0;
  background: transparent;
  color: rgba(255, 255, 255, 0.95);
  cursor: pointer;
  border-radius: 12px;
  transition:
    transform var(--transition-fast),
    background var(--transition-fast);
}

.corner-icon-link {
  text-decoration: none;
}

.corner-icon-btn:hover,
.corner-icon-link:hover {
  background: rgba(255, 255, 255, 0.07);
}

/* Keep the About ("i") button background stable on touch devices.
   iOS Safari can leave :hover styles "stuck" after a tap.
*/
#infoBtn.corner-icon-btn:hover,
#infoBtn.corner-icon-btn:active {
  background: transparent;
}

.corner-icon-btn:active,
.corner-icon-link:active {
  transform: scale(0.96);
}

.corner-icon-btn:focus-visible,
.corner-icon-link:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.35);
  outline-offset: 2px;
}

#githubLink svg {
  width: 22px;
  height: 22px;
  display: block;
  fill: currentColor;
}


/* Touch ergonomics (coarse-pointer devices) */
button,
input,
select,
textarea {
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

/* Settings: Copy URL button (flat, rounded, centered) */
#settings-panel .copy-url-group {
  display: flex;
  justify-content: center;
  padding-top: 0.5rem;
  padding-bottom: 0.25rem;
}

#settings-panel .copy-url-btn {
  appearance: none;
  border: 1px solid rgba(74, 158, 255, 0.35);
  background: rgba(255, 255, 255, 0.06);
  color: rgba(232, 241, 255, 0.95);
  padding: 0.6rem 1.1rem;
  border-radius: 999px;
  font: inherit;
  line-height: 1.1;
  cursor: pointer;
}

#settings-panel .copy-url-btn:hover {
  background: rgba(255, 255, 255, 0.09);
  border-color: rgba(74, 158, 255, 0.55);
}

#settings-panel .copy-url-btn:active {
  transform: translateY(1px);
}

#settings-panel .copy-url-btn:focus-visible {
  outline: 2px solid rgba(74, 158, 255, 0.65);
  outline-offset: 2px;
}

/* Mobile styles */
@media (hover: none) and (pointer: coarse) {
  /* iOS: slightly larger base size and stable text rendering */
  html {
    font-size: 18px;
  }

  body {
    -webkit-text-size-adjust: 100%;
  }

  /* Touch-first sizing: improve legibility and meet iOS tap/typing ergonomics */
  :root {
    /* Increase panel text size and leading on mobile (Settings/Help). */
    --panel-font-size: 20px;
    --panel-line-height: 1.5;

    /* Ensure primary controls meet comfortable tap target size. */
    --icon-btn-size: 48px;
    --icon-btn-gap: 4px;

    /* Slightly tighten edge padding to offset the wider buttons. */
    --controls-edge-pad: 14px;
  }

  /* iOS Safari: prevent focus auto-zoom by keeping form controls at >= 16px.
     We intentionally match the panel font size for readability. */
  .panel-body input[type="text"],
  .panel-body input[type="number"],
  .panel-body select,
  .panel-body textarea {
    font-size: var(--panel-font-size);
  }
  /* Mobile: show About and GitHub as a combined bottom-right info panel. */
  #infoPanel {
    width: calc((var(--icon-btn-size) * 2) + 8px);
    justify-content: space-between;
  }

  /* About/Info button: use typography instead of an SVG icon. */
  #infoBtn {
    display: flex;
    font-size: 22px;
    font-weight: 700;
    font-style: italic;
    font-family: Georgia, serif;
  }

  #infoBtn.active {
    background: transparent;
  }

  /* Keep the header hidden unless explicitly toggled via the "i" button. */
  #header {
    display: none;
  }

  #header.visible {
    display: flex;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 16px 22px;
    z-index: 120;
  }

  #header.visible h1 {
    font-size: 1.9rem;
    white-space: nowrap;
  }

  /* Very small phones: slightly reduce title size to prevent overflow. */
  @media (max-width: 360px) {
    #header.visible h1 {
      font-size: 1.75rem;
    }
  }

  #header.visible .credit {
    font-size: 0.95rem;
    white-space: nowrap;
    line-height: 1.25;
  }

  /* Touch devices: avoid sticky :hover states and reduce extra compositing work. */
  .icon-btn:hover {
    background-color: var(--bg-tertiary);
  }

  .icon-btn:hover svg {
    transform: none;
  }

  /* Touch targets: keep control buttons comfortable on touch */
  .icon-btn {
    min-width: var(--icon-btn-size);
    min-height: var(--icon-btn-size);
  }

  /* Help button: keep readable "?" */
  #helpBtn {
    font-size: 22px;
    font-weight: 800;
    line-height: 1;
  }


  /* iOS Safari: avoid focus auto-zoom by keeping form controls at >= 16px. */
  #settings-panel .input-wrapper input[type="text"],
  #settings-panel .input-wrapper input[type="number"] {
    font-size: var(--panel-font-size); /* >=16px and matches panel text */
    padding: 10px 12px;
  }

  #settings-panel .input-wrapper {
    min-height: 44px; /* comfortable tap target */
  }

  /* Slightly larger icons inside the control buttons for touch */
  .icon-btn svg {
    width: 24px;
    height: 24px;
  }

  /* Color pickers: meet touch target guidance */
  .color-picker {
    width: 44px;
    height: 44px;
    padding: 2px;
  }

  /* Larger slider thumb/track for touch: override the CSS variables used by the base range styles. */
  #settings-panel {
    --range-track-height: 6px;
    --range-thumb-size: 28px;
  }

  /* Larger checkbox box (label hit area is handled by padding/min-height below). */
  #settings-panel .checkbox-label input[type="checkbox"] {
    width: 28px;
    height: 28px;
  }

  #settings-panel .checkbox-label {
    min-height: 28px;
    padding: 0.25rem 0.2rem;
  }
}