/* body {
      font-family: sans-serif;
      background-color: #f4f4f9;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 2rem;
    } */
    h1 {
      margin-bottom: 1rem;
      /* font-size: 2.5vw; */
      text-align: center;
    }
    .flashcard {
      width: 90vw;
      max-width: 600px;
      min-width: 400px;
      height: 60vw;
      max-height: 600px;
      perspective: 1000px;
      cursor: pointer;
      border-radius: 12px;
      font-family: sans-serif;
      background-color: #f4f4f9;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 2rem;
    }
    .card-inner {
      width: 100%;
      height: 100%;
      transition: transform 0.6s;
      transform-style: preserve-3d;
      position: relative;
    }
    .flashcard.flipped .card-inner {
      transform: rotateY(180deg);
    }
    .card-front, .card-back {
      position: absolute;
      width: 100%;
      height: 100%;
      backface-visibility: hidden;
      border: 1px solid #ccc;
      border-radius: 12px;
      padding: 1rem;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      font-size: 6vw;
      max-font-size: 1.5rem;
      box-sizing: border-box;
    }
    .card-front {
      background-color: white;
    }
    .card-back {
      transform: rotateY(180deg);
      background-color: #e6f7ff;
    }
    .nav-buttons {
      margin-top: 1rem;
      display: flex;
      gap: 1rem;
    }
    .nav-buttons button {
      padding: 0.5rem 1.5rem;
      font-size: 1rem;
      border: none;
      background-color: #007bff;
      color: white;
      border-radius: 5px;
      cursor: pointer;
    }
    .nav-buttons button:disabled {
      background-color: #ccc;
      cursor: not-allowed;
    }
    @media (min-width: 600px) {
      .card-front, .card-back {
        font-size: 1.2rem;
      }
    }