.dropbtn {
    background-color: #df0b0b;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
  }
  .dropbtn1 {
    background-color: #df0b0b;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
  }
  .dropbtn2 {
    background-color: #df0b0b;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
  }
  .dropbtn3 {
    background-color: #df0b0b;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
  }
  .dropbtn4 {
    background-color: #df0b0b;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
  }
    .dropbtn:hover, .dropbtn:focus {
    background-color: #2980B9;
  }
  .dropbtn1:hover, .dropbtn1:focus {
    background-color: #2980B9;
  }
    .dropbtn2:hover, .dropbtn2:focus {
    background-color: #2980B9;
  }
  .dropbtn3:hover, .dropbtn3:focus {
    background-color: #2980B9;
  }
  .dropbtn4:hover, .dropbtn4:focus {
    background-color: #2980B9;
  }
    .dropdown {
    display: inline-block;
    position: relative;
  }
  .dropdown1 {
    display: inline-block;
    position: relative;
  }
    .dropdown2 {
    display: inline-block;
    position: relative;
  }
  .dropdown3 {
    display: inline-block;
    position: relative;
  }
  .dropdown4 {
    display: inline-block;
    position: relative;
  }
  .dropdown-content {
    display: none;
    position: absolute;
    min-width: 100px;
    overflow: auto;
    box-shadow: 0px 10px 10px 0px rgba(0,0,0,0.4);
  }
  .dropdown1-content1 {
    display: none;
    position: absolute;
    min-width: 100px;
    overflow: auto;
    box-shadow: 0px 10px 10px 0px rgba(0,0,0,0.4);
  }
  .dropdown2-content2 {
    display: none;
    position: absolute;
    min-width: 100px;
    overflow: auto;
    box-shadow: 0px 10px 10px 0px rgba(0,0,0,0.4);
  }
  .dropdown3-content3 {
    display: none;
    position: absolute;
    min-width: 100px;
    overflow: auto;
    box-shadow: 0px 10px 10px 0px rgba(0,0,0,0.4);
  }
  .dropdown4-content4 {
    display: none;
    position: absolute;
    min-width: 100px;
    overflow: auto;
    box-shadow: 0px 10px 10px 0px rgba(0,0,0,0.4);
  }
  .dropdown:hover .dropdown-content {
    display: block;
    background-color: #2980B9;
  }
  .dropdown1:hover .dropdown1-content1 {
    display: block;
    background-color: #2980B9;
  }
  .dropdown2:hover .dropdown2-content2 {
    display: block;
    background-color: #2980B9;
  }
  .dropdown3:hover .dropdown3-content3 {
    display: block;
    background-color: #2980B9;
  }
  .dropdown4:hover .dropdown4-content4 {
    display: block;
    background-color: #2980B9;
  }
  .dropdown-content a {
    display: block;
    color: #000000;
    min-width: 100px;
    padding: 12px 16px;
    overflow: auto;
    text-decoration: none;
  }
  .dropdown1-content1 a {
    display: block;
    color: #000000;
    min-width: 100px;
    padding: 12px 16px;
    overflow: auto;
    text-decoration: none;
  }
  .dropdown2-content2 a {
    display: block;
    color: #000000;
    min-width: 100px;
    padding: 12px 16px;
    overflow: auto;
    text-decoration: none;
  }
  .dropdown3-content3 a {
    display: block;
    color: #000000;
    min-width: 100px;
    padding: 12px 16px;
    overflow: auto;
    text-decoration: none;
  }
  .dropdown4-content4 a {
    display: block;
    color: #000000;
    min-width: 100px;
    padding: 12px 16px;
    overflow: auto;
    text-decoration: none;
  }
  .dropdown-content a:hover {
    color: #FFFFFF;
    background-color: #00A4BD;
  }
  .dropdown1-content1 a:hover {
    color: #FFFFFF;
    background-color: #00A4BD;
  }
  .dropdown2-content2 a:hover {
    color: #FFFFFF;
    background-color: #00A4BD;
  }
  .dropdown3-content3 a:hover {
    color: #FFFFFF;
    background-color: #00A4BD;
  }
  .dropdown4-content4 a:hover {
    color: #FFFFFF;
    background-color: #00A4BD;
  }

  body{
    background: url(../IMAGENES/Bibloteca2.png);
    background-size:cover;
    background-attachment: fixed;
}
nav{
    display: flex;
    justify-content: center;
    background-color: #df0b0b;
    color: #FFFFFF;
    padding: 10px;
}
nav a{
    margin: 0 30px;
    text-decoration:  none;
    color: #333;
}

span{
  color:#ffffff; 
  font-size: 16px; 
  padding: 16px; 
  cursor: pointer
}
footer{
text-align: center;
background-color: #34495e;
color: #fff;
padding: 10px;
position: fixed;
bottom: 0;
width: 100%;
}