body {
  font-family: system-ui, sans-serif;
  margin: 0 auto;
  max-width: 900px;
  padding: 1rem;
  line-height: 1.5;
}

.page-list {
  list-style: none;
  padding: 0;
}
.page-list li {
  margin: 0.5rem 0;
}

.columns {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
}
.instructions, .reading-form {
  flex: 1 1 300px;
}

.reading-form label {
  display: block;
  margin-top: 1rem;
  font-weight: bold;
}
.reading-form .range {
  font-weight: normal;
  color: #666;
  font-size: 0.85em;
}
.reading-form input[type="number"] {
  display: block;
  width: 100%;
  padding: 0.5rem;
  font-size: 1.1rem;
  box-sizing: border-box;
  margin-top: 0.25rem;
}
.reading-form button {
  margin-top: 1.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  cursor: pointer;
}

.message {
  padding: 0.75rem 1rem;
  border-radius: 4px;
  margin: 1rem 0;
}
.message.success {
  background: #e6f4ea;
  color: #1e4620;
}
.message.error, ul.message.error {
  background: #fce8e6;
  color: #611a15;
  list-style: none;
}