@import url("https://fonts.googleapis.com/css2?family=Kode+Mono:wght@400..700&display=swap");
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Kode Mono", monospace;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #f0f0f0;
}

.calculator {
  position: relative;
  width: 300px;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  padding: 20px;
}

.calculator .button {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 10px;
}

.calculator .button #value {
  grid-column: span 4;
  height: 80px;
  line-height: 80px;
  padding: 0 20px;
  border-radius: 8px;
  background: #f5f5f5;
  text-align: right;
  font-size: 1.5rem;
  color: #333;
}

.calculator .button span {
  padding: 15px;
  font-size: 1.2em;
  display: flex;
  justify-content: center;
  align-items: center;
  color: #333;
  border: 2px solid #ccc;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s ease;
  user-select: none;
}

.calculator .button span:hover {
  background-color: #f0f0f0;
}

.calculator .button span#clear {
  grid-column: span 2;
  background: #e74c3c;
  color: #fff;
}

.calculator .button span#plus {
  grid-row: span 2;
  background: #2ecc71;
  color: #fff;
}

.calculator .button span#equal {
  background: #3498db;
  color: #fff;
}