:root {
  color-scheme: light dark;
  --color-bg: #ffffff;
  --color-fg: #1a1a1a;
  --color-muted: #55606b;
  --color-accent: #2563eb;
  --color-accent-fg: #ffffff;
  --color-border: #d7dce1;
  --focus-ring: #2563eb;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #14171a;
    --color-fg: #edeff1;
    --color-muted: #a3adb8;
    --color-accent: #5b8def;
    --color-accent-fg: #0b1220;
    --color-border: #303840;
    --focus-ring: #7fa8f5;
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--color-bg);
  color: var(--color-fg);
  line-height: 1.5;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

main {
  width: 100%;
  max-width: 32rem;
  text-align: center;
}

h1 {
  font-size: clamp(1.5rem, 4vw, 2.25rem);
  margin-bottom: 0.5rem;
  word-break: break-word;
}

p {
  color: var(--color-muted);
}

button {
  font: inherit;
  font-weight: 600;
  padding: 0.75rem 1.5rem;
  margin-top: 1rem;
  border: 1px solid transparent;
  border-radius: 0.5rem;
  background: var(--color-accent);
  color: var(--color-accent-fg);
  cursor: pointer;
  transition: opacity 0.15s ease;
}

button:hover:not(:disabled) {
  opacity: 0.9;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

button:focus-visible,
a:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

#result {
  min-height: 1.5rem;
  margin-top: 1.25rem;
  font-weight: 500;
  color: var(--color-fg);
  word-break: break-word;
}

@media (max-width: 20rem) {
  button {
    width: 100%;
  }
}