body {
  background-color: black;
  color: white;
  font-family: Arial, Helvetica, sans-serif;
}
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

h1 {
  text-align: center;
  margin: 1rem 0;
}

.main {
  background-color: green;
  display: flex;
  justify-content: center;
  margin: 2rem auto;
  padding: 1rem;
}

.result {
  color: white;
  background-color: black;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: end;
  padding-right: 10px;
  border-radius: 10px;
  margin-bottom: 1rem;
  font-size: 2rem;
  font-weight: bold;
}

.buttons {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

button {
  padding: 1.5rem 3rem;
  border-radius: 10px;
  border: none;
  font-weight: bold;
  font-size: 2rem;
  margin: 0 0.3rem;
  background-color: black;
  color: white;
}

button:focus {
  background-color: yellow;
  color: black;
}