style.css

/* Reset some default styles and provide a background color */
body {
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
  background-color: #f0f0f0;
}

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

.calculator {
  background-color: #ffffff;
  border-radius: 8px;
  box-shadow: 0px 4px 6px rgba(0, 0, 0, 0.1);
  width: 300px;
}

.output {
  text-align: right;
  padding: 10px;
  border-bottom: 1px solid #ddd;
  font-size: 24px;
  line-height: 1.2;
  white-space: pre-wrap;
}

#upper {
  color: #777;
}

.input {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}

button {
  background-color: #f0f0f0;
  border: none;
  padding: 10px;
  font-size: 20px;
  cursor: pointer;
  transition: background-color 0.2s;
}

button:hover {
  background-color: #ccc;
}

/* Style the clear button with a different color */
button:nth-child(2) {
  background-color: #f3a501;
  color: #fff;
}

/* Style the equal button with a different color */
button:last-child {
  background-color: #009688;
  color: #fff;
}