table, td, th {
    border: 1px solid black;
    margin: 2em ;
  }

  th {
    background-color: #4CAF50;
    color: white;
  }
  tr:nth-child(even) {
    background-color: lightblue;
  }
table {
    border-collapse: collapse;
    border-spacing: 0;
    width: fit-content;
    box-shadow: 0 0 15px rgb(0 0 0 / 25%);
  
    box-sizing: border-box;
    
}

/** formularios */
form {
   
    width: fit-content;
    padding: 1em;
    background-color: #ccc;
    border: 1px solid black;
}

.html-atri {
    color: red
}
.html-atri-valor{
    color: blue;
}

/** barra navegacion */

.topnav {
  width: fit-content;
  overflow: hidden;
  background-color: #333;
}

.topnav a {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}

.topnav a:hover {
  background-color: #ddd;
  color: black;
}

.topnav a.active {
  background-color: #04AA6D;
  color: white;
}

.topnav .icon {
  display: none;
}

/* drag and drop*/
#drop_area {
  width: 150px;
  height: 120px;
  padding: 10px;
  border: 1px solid #aaaaaa;
}
#drag {
  width: 100px;
 
  
}

/* numeracion cabeceras */
body{
  counter-reset: Seccion;
}
h1{
  counter-reset: SubSeccion;
}
h1:before{
  counter-increment: Seccion;
  content: "Capítulo " counter(Seccion)". ";
}
h2{
  counter-reset: SubSubSeccion;
}
h2:before{
  counter-increment: SubSeccion;
  content: counter(Seccion) "." counter(SubSeccion)". ";
}
h3:before{
  counter-increment: SubSubSeccion;
  content: counter(Seccion) "." counter(SubSeccion)"." counter(SubSubSeccion)". ";
}

strong {
  color: red;
}