/* Body layout */
body {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
  background: #f5f5f5;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding-top: 20px;
  min-height: 100vh;
}

/* Calculator Box */
.calc-body {
  background: #ffffff;
  border-radius: 8px;
  padding: 8px;
  box-shadow: 0 0 8px rgba(0, 0, 0, 0.15);
  width: 100%;
  max-width: 300px;
}

/* Display screen */
.screen {
  margin-bottom: 8px;
}

#display {
  width: 100%;
  height: 38px;
  font-size: 1.1rem;
  padding: 6px;
  border: 1px solid #aaa;
  border-radius: 4px;
  text-align: right;
  background: #eef;
  box-sizing: border-box;
}

/* Button Grid */
.button-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 5px;
}

.button-grid button {
  padding: 8px;
  font-size: 0.9rem;
  border: none;
  border-radius: 4px;
  background-color: #e0e0e0;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
  transition: background 0.2s;
}

.button-grid button:hover {
  background-color: #cfcfcf;
}

/* Color accents */
.button-grid .red {
  background-color: #f44336;
  color: white;
}

.button-grid .green {
  background-color: #4caf50;
  color: white;
}

/* Even smaller on narrow screens */
@media (max-width: 400px) {
  .calc-body {
    max-width: 270px;
    padding: 6px;
  }

  #display {
    height: 36px;
    font-size: 1rem;
    padding: 5px;
  }

  .button-grid {
    gap: 4px;
  }

  .button-grid button {
    padding: 7px;
    font-size: 0.85rem;
  }
}