body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  text-align: center;
}

.container {
  background: #222;
  display: inline-block;
  padding: 15px;
  border-radius: 10px;
  color: white;
}

.calc-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.calc-solar {
  width: 60px;
  height: 20px;
  background: linear-gradient(90deg, #555, #111);
}

.calc-screen {
  background: black;
  color: lime;
  text-align: right;
  font-size: 2rem;
  padding: 10px;
  margin: 10px 0;
  border-radius: 5px;
  overflow-x: auto;
}

.calc-keys {
  display: grid;
  grid-template-columns: repeat(4, 60px);
  gap: 10px;
}

button {
  background: #444;
  border: none;
  color: white;
  font-size: 1.2rem;
  padding: 15px;
  border-radius: 5px;
  cursor: pointer;
}

button:hover {
  background: #666;
}

.text-sm {
  font-size: 1.5rem;
}
.text-xs {
  font-size: 1.2rem;
}
.text-xxs {
  font-size: 1rem;
}