body {
  font-family: system-ui;
  text-align: center;
  padding: 24px;
  transition: 0.3s;
}

h1 {
  font-size: 26px;
}

button {
  padding: 12px 20px;
  margin: 6px;
  font-size: 16px;
  border-radius: 14px;
  border: none;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
}

button:active {
  transform: scale(0.95);
}

input {
  padding: 8px;
  width: 70px;
  border-radius: 10px;
  border: none;
  margin: 4px;
}

#result {
  font-size: 28px;
  margin: 16px 0;
}

ul {
  list-style: none;
  padding: 0;
}

li {
  margin: 4px 0;
}