matrizheader, footer, aside, nav, article, section {  
    display: block;  
}

body {  
    background-color: #dddddd;
    font-family: Arial, Helvetica, sans-serif;
}

body > header {
    background-color: #6C8D7C;
    background-image: linear-gradient(top, #6C8D7C, #eeeeee);
    background-image: -moz-linear-gradient(top, #6C8D7C, #eeeeee);
    background-image: -webkit-linear-gradient(top, #6C8D7C, #eeeeee);
    background-image: -o-linear-gradient(top, #6C8D7C, #eeeeee);
    border: 5px solid black;
    border-style: solid none solid none;
    padding: 0px 0px 0px 5px;
}

body > section {
    background-color: #8DC6A9;
    background-image: linear-gradient(top, #8DC6A9, #CCFFCC);
    background-image: -moz-linear-gradient(top, #8DC6A9, #CCFFCC);
    background-image: -webkit-linear-gradient(top, #8DC6A9, #CCFFCC);
    background-image: -o-linear-gradient(top, #8DC6A9, #CCFFCC);
    margin-top: 25px;
    padding:  15px;
    border:    5px solid DarkGray;
    border-radius: 15px;
    box-shadow: 10px 10px 5px gray;
}

.opcional {
    border-radius: 15px;
//    background-color: LightGreen;
    background-color: LightGray;
}

h1 {
    letter-spacing:2px;
    font-size: 2em;
}

h2 , h3, h4, h5 {
    border-radius: 10px;
    border: 2px solid black;
    border-style: solid;
    padding: 5px;
    background-color: white;
}

section, section > p, .item {
    margin-left: 1em;
    margin-right: 1em;
}

section > p, .item {
//    background-color: white;
}
.item {
//    border: 2px solid red;
}
section p {
//    border: 2px solid green;
    padding: 5px;
}


table {
//    border-collapse: collapse;
    border-top: 1px solid;
    border-bottom: 1px solid;
    margin-left: 10px;
//    margin-left: auto; /* Centrado horizontal si meto la tabla en un div */
    margin-right: auto;
    background-color: white;
    text-align: center;
}
table th {
    text-align: left;
}
//table tr:nth-child(2n) {
//    background-color: #E7E7FF;
//}
//table tr:nth-child(2n+1) {
//    background-color: #F5F5FF;
//}
table td, table th {
    padding: 10px 20px 10px 20px;
    text-align: right;
}

.matriz, .matriz td {
    border-top: 1px solid;
    border-bottom: 1px solid;
    border-left: 1px solid;
    border-right: 1px solid;
}

.vector {
    border: 1px solid;
    margin-left: 10px;
    text-align: center;
}

.vector td {
    text-align: center;
}

.desplegable > :not(header) {
    display: none;
}
.desplegable:target > :not(header) {
    display: block;
}

.problema {
    background-color: #CCCCFF;
    font-weight: bold;
}

.solucion {
    background-color: yellow;
}

.destacado {
    background-color: orange;
    font-weight: bold;
}

.error {
//    background-color: red;
    background-color: orange;
//    color: white;
}

.inactivo {
    color: gray;
}

.fecha {
    color: yellow;
    background-color: black;
    font-size: 80%;
}

.fuente {
    color: green;
    background-color: lightgray;
//    font-size: 80%;
}

.fechaevaluacion{
    background-color: #cc66ff;
    font-weight: bold;
}

.recuadro {
//    background-color: lightgray;
    border-radius: 8px;
    border: 1px solid black;
    background-color: white;
    font-size: 120%;
}

#menu {
//    text-align: center;
    margin-top: 1em;
}

#menu > ul {
    display: inline-block;
}

#menu ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

#menu > ul > li {
    display: table-cell;
    vertical-align: top;
}

#menu p {
    border-radius: 10px;
    border: 2px solid black;
    border-style: solid;
    padding: 5px;
    margin: 0 10px 0 0;
    background-color: white;
}

.ejercicio {
    margin-top: 25px;
    padding:  0px 15px 0px 15px;
    border:    5px solid DarkGray;
    border-radius: 15px;
    box-shadow: 10px 10px 5px gray;
}

img {
    border : 0;
}

.img {
    float: left;
    margin-right : 10px;
}

.tab {
    margin-left: 40px;
}

.sombreado {
    background-color: LightSlateGray;
}

.practicas {
    background-color: cyan;
}

.cpp {
    margin-top: 25px;
    padding:  0px 15px 0px 15px;
    border:    5px solid DarkGray;
    border-radius: 15px;
    box-shadow: 10px 10px 5px gray;
    background-color: #66aaff;
}