:root {
  --bg-lightness: 0%;
  --bg-chroma: 0;
  --bg-hue: 0;
  --bg-color: oklch(var(--bg-lightness) var(--bg-chroma) var(--bg-hue));

  --dot-lightness: 100%;
  --dot-chroma: 0;
  --dot-hue: 0;
  --dot-color: oklch(var(--dot-lightness) var(--dot-chroma) var(--dot-hue));

  --control-bg: oklch(20% 0 0 / 0.8);
  --control-bg-hover: oklch(30% 0 0 / 0.9);
  --control-border: oklch(40% 0 0);
  --text-color: oklch(90% 0 0);
  --text-muted: oklch(60% 0 0);

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;

  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-full: 9999px;

  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 500ms ease;

  --font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
}

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

html,
body {
  overflow: hidden;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}

html {
  color-scheme: dark;
}

body {
  background-color: var(--bg-color);
  font-family: var(--font-family);
  color: var(--text-color);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  position: fixed;
  inset: 0;
  touch-action: none;
}

#particle-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.text-overlay {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  font-size: clamp(2.5rem, 10vw, 7.5rem);
  font-weight: 700;
  color: var(--dot-color);
  white-space: nowrap;
  pointer-events: none;
  transition: opacity var(--transition-slow);
  z-index: 10;
}

.text-overlay.hidden {
  opacity: 0;
}

.flush-link {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  z-index: 20;
  opacity: 0;
  transition: opacity var(--transition-slow);
  pointer-events: none;
}

.flush-link.visible {
  opacity: 1;
  pointer-events: auto;
}

.flush-link a {
  color: var(--dot-color);
  font-size: var(--font-size-lg);
  text-decoration: none;
  padding: var(--spacing-md) var(--spacing-xl);
  border: 2px solid var(--dot-color);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.flush-link a:hover {
  background: var(--dot-color);
  color: var(--bg-color);
}

.flush-link a:focus-visible {
  outline: 2px solid var(--dot-color);
  outline-offset: 4px;
}

.icon-btn {
  --size: 2.75rem;
  position: fixed;
  width: var(--size);
  height: var(--size);
  border: 1px solid oklch(50% 0 0 / 0.3);
  border-radius: var(--radius-full);
  background: oklch(10% 0 0 / 0.5);
  color: var(--dot-color);
  cursor: pointer;
  transition: background var(--transition-fast), transform var(--transition-fast), border-color var(--transition-fast);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 100;
  padding: 0.6rem;
}

.icon-btn svg {
  width: 100%;
  height: 100%;
  display: block;
}

.icon-btn:hover {
  background: oklch(20% 0 0 / 0.6);
  border-color: oklch(60% 0 0 / 0.4);
  transform: scale(1.08);
}

.icon-btn:active {
  transform: scale(0.95);
}

.icon-btn:focus-visible {
  outline: 2px solid var(--dot-color);
  outline-offset: 2px;
}

.settings-btn {
  top: var(--spacing-lg);
  right: var(--spacing-lg);
}

.flush-btn {
  bottom: var(--spacing-lg);
  left: 50%;
  transform: translateX(-50%);
}

.flush-btn:hover {
  transform: translateX(-50%) scale(1.08);
}

.flush-btn:active {
  transform: translateX(-50%) scale(0.95);
}

.flush-btn.reloading {
  animation: spin-centered 1s linear infinite;
}

.flush-btn .icon-wrapper {
  display: grid;
  width: 100%;
  height: 100%;
}

.flush-btn .icon-wrapper svg {
  grid-area: 1 / 1;
  width: 100%;
  height: 100%;
  transition: opacity var(--transition-normal) ease, transform var(--transition-normal) ease;
}

.flush-btn .icon-flush {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.flush-btn .icon-reload {
  opacity: 0;
  transform: rotate(-90deg) scale(0.8);
}

.flush-btn.show-reload .icon-flush {
  opacity: 0;
  transform: rotate(90deg) scale(0.8);
}

.flush-btn.show-reload .icon-reload {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

@keyframes spin-centered {
  from { transform: translateX(-50%) rotate(0deg); }
  to { transform: translateX(-50%) rotate(360deg); }
}

.settings-popover {
  position: fixed;
  top: calc(var(--spacing-lg) + 3.5rem);
  right: var(--spacing-lg);
  background: var(--control-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--control-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  min-width: 320px;
  max-width: 90vw;
  z-index: 100;
  transition: transform var(--transition-normal), opacity var(--transition-normal), display var(--transition-normal) allow-discrete;
}

.settings-popover[popover] {
  margin: 0;
  inset: unset;
  top: calc(var(--spacing-lg) + 3.5rem);
  right: var(--spacing-lg);
  opacity: 0;
  transform: translateY(10px);
}

.settings-popover:popover-open {
  opacity: 1;
  transform: translateY(0);
}

@starting-style {
  .settings-popover:popover-open {
    opacity: 0;
    transform: translateY(10px);
  }
}

.settings-popover::backdrop {
  background: transparent;
}

.settings-popover h2 {
  color: var(--text-color);
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-base);
  font-weight: 500;
}

.setting-group {
  border: none;
  margin-bottom: var(--spacing-lg);
}

.setting-group:last-of-type {
  margin-bottom: var(--spacing-md);
}

.setting-group legend {
  color: var(--text-muted);
  font-size: var(--font-size-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-sm);
  padding: 0;
  float: left;
  width: 100%;
}

.setting-row {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
  clear: both;
}

.setting-row:last-child {
  margin-bottom: 0;
}

.setting-row label {
  color: var(--text-muted);
  font-size: var(--font-size-sm);
}

.slider-container {
  display: grid;
  grid-template-columns: 1fr 2.5rem;
  align-items: center;
  gap: var(--spacing-sm);
}

input[type="range"] {
  --track-height: 4px;
  --thumb-size: 16px;
  width: 100%;
  height: var(--thumb-size);
  appearance: none;
  -webkit-appearance: none;
  background: transparent;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-runnable-track {
  height: var(--track-height);
  background: var(--control-border);
  border-radius: var(--radius-full);
}

input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  -webkit-appearance: none;
  width: var(--thumb-size);
  height: var(--thumb-size);
  background: var(--text-color);
  border-radius: var(--radius-full);
  margin-top: calc((var(--track-height) - var(--thumb-size)) / 2);
  transition: transform var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

input[type="range"]::-moz-range-track {
  height: var(--track-height);
  background: var(--control-border);
  border-radius: var(--radius-full);
}

input[type="range"]::-moz-range-thumb {
  width: var(--thumb-size);
  height: var(--thumb-size);
  background: var(--text-color);
  border-radius: var(--radius-full);
  border: none;
  transition: transform var(--transition-fast);
}

input[type="range"]::-moz-range-thumb:hover {
  transform: scale(1.1);
}

input[type="range"]:focus-visible {
  outline: none;
}

input[type="range"]:focus-visible::-webkit-slider-thumb {
  outline: 2px solid var(--dot-color);
  outline-offset: 2px;
}

input[type="range"]:focus-visible::-moz-range-thumb {
  outline: 2px solid var(--dot-color);
  outline-offset: 2px;
}

.value-display {
  color: var(--text-color);
  font-size: var(--font-size-sm);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.color-buttons {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-sm);
  clear: both;
}

.btn-secondary {
  padding: var(--spacing-sm) var(--spacing-md);
  background: transparent;
  border: 1px solid var(--control-border);
  border-radius: var(--radius-md);
  color: var(--text-muted);
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.btn-secondary:hover {
  background: var(--control-bg-hover);
  color: var(--text-color);
  border-color: var(--text-muted);
}

.btn-secondary:focus-visible {
  outline: 2px solid var(--dot-color);
  outline-offset: 2px;
}

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

.btn-secondary:disabled:hover {
  background: transparent;
  color: var(--text-muted);
  border-color: var(--control-border);
}

.color-back-btn {
  padding: var(--spacing-sm);
}

.color-back-btn svg {
  width: 1rem;
  height: 1rem;
  display: block;
}

.randomize-btn {
  flex: 1;
}

.reset-btn {
  width: 100%;
  margin-top: var(--spacing-sm);
}

@media (max-width: 480px) {
  .settings-popover[popover] {
    right: var(--spacing-sm);
    left: var(--spacing-sm);
    min-width: auto;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}