body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.8;
  margin: 24px;
}

h1 {
  font-size: 28px;
  margin-bottom: 8px;
}

.sub {
  color: #444;
}

.card {
  max-width: 720px;
  padding: 20px;
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, .04);
}

.btn {
  display: inline-block;
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid #111;
  background: #111;
  color: #fff;
  cursor: pointer;
  font-weight: 600;
  transition: background 0.2s ease;
}

.btn:hover {
  background: #333;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.hidden {
  display: none;
}

.q {
  margin: 16px 0;
}

.progress {
  font-size: 14px;
  color: #666;
  margin: 8px 0 12px;
}

.nav {
  margin-top: 12px;
  display: flex;
  gap: 8px;
}

#result {
  margin-top: 12px;
}

#landing {
  text-align: center;
  padding: 40px;
}

#landing h1 {
  font-size: 32px;
  margin-bottom: 12px;
}

#landing p {
  font-size: 16px;
  margin-bottom: 24px;
}