/* Allgemeine Einstellungen */
* {
    box-sizing: border-box;
  }
  
  body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
  }
  
  /* Container, damit der Inhalt zentriert und responsiv ist */
  #main-container {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .screen {
    background-color: #fff;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
    width: 90%;
    max-width: 800px;
    margin: auto;
  }
  
  /* Spielbildschirm */
  #game-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
  }
  
  #game-header {
    display: flex;
    justify-content: space-between;
    width: 100%;
    font-size: 1.5em;
    margin-bottom: 20px;
  }
  
  #question-display {
    font-size: 2em;
    margin-bottom: 20px;
  }
  
  #input-display {
    margin-bottom: 20px;
  }
  
  #answer-input {
    width: 100%;
    font-size: 2em;
    text-align: center;
    padding: 10px;
  }
  
  /* Tastatur */
  #keypad {
    display: flex;
    flex-direction: column;
    gap: 10px;
  }
  
  .keypad-row {
    display: flex;
    justify-content: center;
    gap: 10px;
  }
  
  .key {
    padding: 20px;
    font-size: 1.5em;
    width: 80px;
    height: 80px;
    border: none;
    border-radius: 10px;
    background-color: #000;
    color: #fff;
    transition: background-color 0.1s, color 0.1s;
  }
  
  /* Visuelles Feedback beim Tastendruck */
  .key:active,
  .key.active {
    background-color: #fff;
    color: #000;
  }
  
  /* Matrix-Stil */
  #matrix-container {
    margin-top: 20px;
  }
  
  #matrix {
    display: grid;
    grid-template-columns: repeat(10, 1fr);
    gap: 2px;
  }
  
  .matrix-cell {
    border: 1px solid #ccc;
    padding: 5px;
    font-size: 0.8em;
  }