.book-cover {
      font-family: 'Helvetica Neue', Arial, sans-serif;
      max-width: 100%;
      padding: 20px;
      box-sizing: border-box;
      background: white;
      text-align: center;
      position: relative;
    }

    .title-main {
      font-size: clamp(3rem, 10vw, 11rem);
      font-weight: 800;
      line-height: 0.9;
      color: #1a1a1a;
      margin: 0;
      
    }

    .title-sub {
      font-size: clamp(1rem, 4vw, 2.5rem);
      font-weight: 700;
      color: #007acc;
     
      padding: 0.2em 0.5em;
      
      display: inline-block;
      margin: 0.5em 0;
    }

    .author {
      font-size: clamp(0.7rem, 2vw, 1rem);
      font-weight: 500;
      color: #555;
      margin-top: 1.5em;
      letter-spacing: 0.05em;
      text-transform: uppercase;
    }

    /* Дополнительно: если нужно добавить изображение руки */
    .cover-image {
      position: absolute;
      left: 0;
      top: 0;
      width: 25%;
      height: auto;
      object-fit: cover;
      opacity: 0.8;
      z-index: -1;
    }

    @media (max-width: 600px) {
      .book-cover {
        padding: 10px;
      }
      .title-main {
        font-size: clamp(2rem, 12vw, 8rem);
      }
      .title-sub {
        font-size: clamp(0.8rem, 5vw, 1.5rem);
      }
      .author {
        font-size: 0.8rem;
      }
    }

* {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

   

    h1 {
      font-size: clamp(1.8rem, 5vw, 2.8rem);
      margin: 20px 0 25px;
      color: #c0392b;
      text-align: center;
    }

    h2 {
      font-size: clamp(1.4rem, 4vw, 1.8rem);
      margin: 30px 0 15px;
      color: #2c3e50;
      
      padding-left: 12px;
    }

    h3 {
      font-size: clamp(1.2rem, 3.5vw, 1.5rem);
      margin: 25px 0 12px;
      color: #2980b9;
    }

    p {
      margin-bottom: 18px;
      font-size: clamp(0.95rem, 2.5vw, 1.1rem);
    }

    .intro {
      font-style: italic;
      background: #fff4e6;
      padding: 18px;
      border-radius: 8px;
      margin: 20px 0;
    }

    .exercise-list {
      background: #f9f9f9;
      padding: 18px;
      border-radius: 8px;
      margin: 20px 0;
    }

    .exercise-list h3 {
      margin-top: 0;
    }

    .exercise-item {
      margin-bottom: 12px;
      font-weight: 600;
      color: #27ae60;
    }

    .note {
      background: #e8f4fc;
      padding: 15px;
      border-radius: 8px;
      margin: 25px 0;
      font-style: italic;
    }

   

    @media (max-width: 600px) {
      
      h1 {
        font-size: 1.6rem;
      }
    }

table {
      width: 100%;
      border-collapse: collapse;
      margin-top: 15px;
    }
    th, td {
      padding: 12px 15px;
      text-align: left;
      border-bottom: 1px solid #ddd;
    }
    th {
      background-color: #2980b9;
      color: white;
    }
    tr:nth-child(even) {
      background-color: #f2f7ff;
    }
    tr:hover {
      background-color: #e8f4fc;
    }