:root {
  font-family: system-ui, -apple-system, "Hiragino Kaku Gothic ProN", sans-serif;
  color: #222;
  background: #fafafa;
}

body {
  max-width: 720px;
  margin: 2rem auto;
  padding: 0 1rem;
  line-height: 1.5;
}

h1 {
  font-size: 1.3rem;
  border-bottom: 2px solid #d0d0d0;
  padding-bottom: 0.4rem;
}

.note {
  color: #555;
  font-size: 0.9rem;
}

code {
  background: #eef;
  padding: 0 0.3em;
  border-radius: 3px;
}

.controls {
  display: flex;
  gap: 0.5rem;
  margin: 1rem 0;
}

button {
  font-size: 1rem;
  padding: 0.5rem 1rem;
  border: 1px solid #888;
  background: #fff;
  border-radius: 4px;
  cursor: pointer;
}

button:hover:not(:disabled) {
  background: #eef;
}

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

fieldset {
  border: 1px solid #ccc;
  border-radius: 6px;
  margin: 0.8rem 0;
  padding: 0.7rem 1rem;
  background: #fff;
}

legend {
  font-weight: bold;
  font-size: 0.9rem;
  color: #444;
  padding: 0 0.4rem;
}

label {
  display: grid;
  grid-template-columns: 220px 1fr;
  align-items: center;
  gap: 0.6rem;
  margin: 0.3rem 0;
  font-size: 0.9rem;
}

input[type="range"] {
  width: 100%;
}

.status {
  color: #b00;
  font-size: 0.9rem;
  min-height: 1.2em;
}