body {
  background-color: yellow;
  font-family: Arial, Helvetica, sans-serif;
}

.container {
  width: 100%;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

.counter-box {
  width: 30rem;
  height: 15rem;
  background-color: aliceblue;
  border: 2px solid gainsboro;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

.counter-box h3 {
  font-size: 2rem;
  margin: 0;
}

#counter {
  font-size: 5rem;
  margin: 10px 0;
  font-weight: 400;
}

.btn {
  background-color: transparent;
  width: 5rem;
  height: 2.5rem;
  cursor: pointer;
  border-radius: 5px;
  border: 1px solid black;
}

.btn:active {
  border: 2px solid black;
}

#decrease {
  margin-right: 5px;
}