#h2 {
  margin: 0 auto 16px;
  padding: 10px;
  text-align: center;
  background-color: green;
  color: #f8fafc;
  border-radius: 8px;
  font-size: 24px;
}

#h1 {
  margin: 0 auto 16px;
  padding: 10px;
  text-align: center;
  background-color: red;
  color: #f8fafc;
  border-radius: 8px;
  font-size: 24px;
}

#start {
  margin: 100px auto;
  padding: 20px 40px;
  border: black;
  border-radius: 40px;
  background-color: red;
  color: #e5e7eb;
  font-size: 0.95rem;
  cursor: pointer;
  display: block;
}

#stop {
  margin: 100px auto;
  padding: 20px 40px;
  border: black;
  border-radius: 40px;
  background-color: blue;
  color: #fef3c7;
  font-size: 0.95rem;
  cursor: pointer;
  display: block;
}

button:hover {
  opacity: 0.9;
  transform: translateY(-4px);
}

h2:hover {
  opacity: 0.9;
  transform: translateY(-4px);
}