:root {
  --max-width: 70rem;
  --color-bg: #f5f5f5;
  --color-text: #161616;
  --color-text-alt: #444;
  --color-accent: #d4d4d4;
  --color-border: #e7e7e8;
  --space-lg: 3.2rem;
  --space-md: 2.4rem;
  --space-sm: 1.6rem;
  --space-xs: 1rem;
  --font-xs: 1rem;
  --font-sm: 1.4rem;
  --font-md: 1.6rem;
  --font-lg: 2.4rem;
}

html {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-size: 62.5%;
}

body {
  font-family:
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    Roboto,
    sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  margin: 0;
  padding: var(--space-md);
  display: flex;
  justify-content: center;
}

.container {
  max-width: var(--max-width);
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

header h1 {
  font-size: var(--font-lg);
  border-bottom: 0.2rem solid var(--color-text);
  padding-bottom: var(--space-xs);
}

header span {
  font-size: var(--font-sm);
  color: var(--color-text-alt);
  line-height: 1.2;
  margin-top: 0;
}

.simulation {
  display: flex;
  justify-content: center;
}

canvas {
  background-color: #fff;
  max-width: 100%;
  height: auto;
  image-rendering: pixelated;
}

.stats {
  display: flex;
  justify-content: space-between;
  font-size: var(--font-md);
  background: var(--color-accent);
  padding: var(--space-xs);
  border-radius: 0.4rem;
  border: 1px solid var(--color-border);
}

.controls {
  display: grid;
  grid-template-columns: 0.5fr 1fr;
  gap: var(--space-sm);
}

.buttons {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

button {
  flex: 1;
  padding: 0.8rem 3.2rem;
  background: var(--color-accent);
  color: var(--color-text);
  border: none;
  border-radius: 0.4rem;
  cursor: pointer;
  font-family: inherit;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

button:hover:not(:disabled) {
  opacity: 0.8;
}

.params {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-sm);
}

.param-item {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.param-item label {
  font-size: var(--font-sm);
  display: flex;
  justify-content: space-between;
}

.param-item small {
  font-size: var(--font-xs);
  color: var(--color-text-alt);
}

input[type="range"] {
  width: 100%;
  cursor: pointer;
  accent-color: var(--color-accent);
}

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