/* General Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: 'Arial', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f7f7f7;
  }
  
  .calculator {
    background-color: #ffffff;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    width: 320px;
  }
  
  .display {
    background-color: #f0f0f0;
    color: #333;
    font-size: 2.2em;
    text-align: right;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    word-wrap: break-word;
    word-break: break-all;
    border: 1px solid #ddd;
  }
  
  .buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
  }
  
  .button {
    background-color: #f9f9f9;
    color: #333;
    font-size: 1.2em;
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .button:hover {
    background-color: #e0e0e0;
  }
  
  .button.operator {
    background-color: #ff9500;
    color: #fff;
    border: none;
  }
  
  .button.operator:hover {
    background-color: #e08900;
  }
  
  .button.scientific {
    background-color: #34c759;
    color: #fff;
    border: none;
  }
  
  .button.scientific:hover {
    background-color: #2da94f;
  }
  
  .button.clear {
    background-color: #ff3b30;
    color: #fff;
    grid-column: span 2;
    border: none;
  }
  
  .button.clear:hover {
    background-color: #e63329;
  }
  
  .button.zero {
    grid-column: span 2;
  }
  
  .button.equal {
    grid-column: span 3;
  }