.main-nav {
    max-width: 932px;
    margin: 0 auto;
    background-image: url("../imag/panp55d.jpg"); /* default background */
    background-repeat: no-repeat;
    font-size: 16px;
    font-weight: bold;
    text-align: center;
  }

  .main-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex; /* horizontal menu */
  }

  .main-nav li {
    flex: 1; /* each item same width */
  }

  .main-nav a {
    display: block;
    height: 54px;
    line-height: 54px;
    color: white;
    text-decoration: none;
    transition: color 0.2s ease;
  }

  .main-nav a:hover {
    color: #e30000;
    background-image: url("../imag/panp55.jpg");
    background-repeat: no-repeat;
  }

  /* Sprite slicing: shift the hover background for each item */
  .main-nav li:nth-child(1) a:hover { background-position:   0    0; }
  .main-nav li:nth-child(2) a:hover { background-position: -157px 0; }
  .main-nav li:nth-child(3) a:hover { background-position: -356px 0; }
  .main-nav li:nth-child(4) a:hover { background-position: -545px 0; }
  .main-nav li:nth-child(5) a:hover { background-position: -782px 0; }

  /* black bar under menu */
  .main-nav::after {
    content: "";
    display: block;
    height: 5px;
    background: black;
  }