* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: "Poppins", sans-serif;
    transition: background-color 0.3s, color 0.3s;
    animation: fadeIn 1s ease-in;
    background-color: #fff;
    color: #000;
  }
  
  @keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
  }
  
  .dark-mode {
    background-color: #1f1f1f;
    color: #f1f1f1;
  }
  
  .navbar {
    background-color: #FD6569;
    padding: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
  }
  
  .navbar h1 {
    font-size: 28px;
  }
  
  .actions {
    display: flex;
    gap: 10px;
    align-items: center;
  }
  
  .actions input {
    padding: 6px 10px;
    border-radius: 5px;
    border: none;
  }
  
  .actions button {
    padding: 6px 10px;
    border: none;
    border-radius: 5px;
    background-color: #000;
    color: #fff;
    cursor: pointer;
  }
  
  .container {
    padding: 10px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .book-container {
    padding: 15px;
    width: 250px;
    background-color: black;
    border-radius: 10px;
    color: aliceblue;
    margin: 15px;
    transition: transform 0.3s;
  }
  
  .book-container:hover {
    transform: scale(1.05);
  }
  
  .book-container h2 {
    color: #FD6569;
  }
  
  .book-container button {
    background-color: #FD6569;
    color: black;
    border-radius: 10px;
    padding: 5px 10px;
    margin-top: 10px;
    border: none;
    cursor: pointer;
  }
  
  .add-button {
    background-color: #FD6569;
    color: black;
    border-radius: 50%;
    padding: 20px 30px;
    font-size: 40px;
    border: none;
    position: fixed;
    bottom: 30px;
    right: 30px;
    cursor: pointer;
  }
  
  .popup-overlay {
    background-color: black;
    opacity: 0.8;
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: 1;
    display: none;
  }
  
  .popup-box {
    background-color: #FD6569;
    width: 90%;
    max-width: 500px;
    padding: 30px;
    border-radius: 10px;
    position: fixed;
    top: 20%;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2;
    display: none;
  }
  
  .popup-box input,
  .popup-box textarea {
    background: transparent;
    border: none;
    width: 100%;
    margin: 10px 0;
    padding: 8px;
    font-size: 16px;
    border-bottom: 2px solid black;
    color: black;
  }
  
  .popup-box textarea {
    border: 2px solid black;
    resize: none;
    height: 80px;
  }
  
  .popup-box input::placeholder,
  .popup-box textarea::placeholder {
    color: black;
  }
  
  .popup-box button {
    background-color: black;
    color: aliceblue;
    padding: 10px 20px;
    margin: 5px;
    border: none;
    cursor: pointer;
  }
  
  .popup-box input:focus,
  .popup-box textarea:focus {
    outline: none;
  }
  
  .dark-mode .book-container {
    background-color: #333;
    color: white;
  }
  
  .dark-mode .popup-box {
    background-color: #333;
  }
  
  .dark-mode .popup-box input,
  .dark-mode .popup-box textarea {
    border-color: #fff;
    color: white;
  }
  
  .dark-mode .popup-box input::placeholder,
  .dark-mode .popup-box textarea::placeholder {
    color: white;
  }