/* Versió de mòbil */
* {
    margin: 0.3125em; /* 5px / 16 */
    border-radius: 0.3125em; /* 5px / 16 */
}

body {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-start;
    width: 100%;
    justify-content: space-around;
}

header {
    background-color: #ffb700;
    width: 100%;
    text-align: left;
}

h1,
h2,
h3,
h4 {
    width: 100%;
}

nav {
    background-color: #ff8000;
    width: 100%;
}

nav select {
    display: inline;
    background-color: white;
}

nav ul {
    display: none;
    list-style: none;
    margin: 0;
    padding: 0;
    background-color: #333;
    display: flex;  
}

nav ul li {
    position: relative;
}

nav ul li > a {
  display: block;
  padding: 12px 20px;
  color: white;
  text-decoration: none;
  white-space: nowrap;
}
nav ul li > a:hover {
  background-color: red;
}

main {
    width: 200%;
    display: flex;
    flex-direction: column;
    flex-wrap: wrap;
    align-items: flex-start;
}

aside {
    width: 100%;
    background-color: #ffb700;
}

.categories {
    flex-direction: row;
    flex-wrap: wrap;
    align-items: flex-start;
    justify-content: space-around;
}

main article {
    background-color: #4143cc;
    width: 100%;
    color: white;
}

main {
    background-color: #0022ff;
    width: 47%;
    color: white;
}

footer {
    background-color: #ffb700;
    width: 100%;  
    text-align: center; 
}

img {
    width: 56.25em; /* 900px / 16 */
    height: 31.25em; /* 500px / 16 */
    margin-left: 1.25em; /* 20px / 16 */
}

iframe{
    width: 50em; /* 800px / 16 */
    height: 31.25em; /* 500px / 16 */
    margin-left: 4.0625em; /* 65px / 16 */
}

.skip-link {
    position: absolute;
    top: -2.5em; /* -40px / 16 */
    left: 0;
    background: #000;
    color: #fff;
    padding: 0.5em; /* 8px / 16 */
    z-index: 100;
    text-decoration: none;
}

.skip-link:focus {
    top: 0;
}

/* Versió de tablet o desktop */
@media screen and (min-width: 58.5em) { /* 936px / 16 */

    nav {
        width: 100%;
        height: 2.5em; /* 40px / 16 */
    }

    nav select {
        display: none;
    }

    nav ul,
    nav ul li {
        display: inline;
        position: relative;
          list-style: none;
  margin: 0;
  padding: 0;
  background-color: #ffb700;
  display: flex; 

    }

    nav ul li > a:hover {
  background-color: red;
  
}

nav ul li:hover > ul {
  display: block;
}

nav ul li ul li a:hover {
  background-color: #ff0000;
}

nav ul li ul li a {
  color: #000000;
  padding: 12px 16px;
  display: block;
}
nav ul li > a {
  display: block;
  padding: 12px 20px;
  color: rgb(0, 0, 0);
  text-decoration: none;
  white-space: nowrap;
}

    
    nav ul li ul {
        display: none;            /* oculto por defecto */
        position: absolute;       /* se superpone debajo del enlace principal */
        top: 100%;                /* justo debajo del enlace principal */
        left: 0;
        background-color: #0022ff;
        min-width: 180px;
        padding: 0;
        margin: 0;
        list-style: none;
        z-index: 999;
        flex-direction: column;   /* submenú vertical */
}

    main {
        width: 70%;
    }

    aside {
        display: block;
        width: 25%;
        height: 18.75em; /* 300px / 16 */
        background-color: #ffb700;
        margin-top: 2em;
    }

    main {
        flex-direction: row;
        margin-top: 1.3em;
    }

    main article {
        width: 46%;
    }

    .categories article {
        width: 22%;
    }
    #contador {
        width: 5%;
        margin-left: 18.75em; /* 300px / 16 */
    }

    footer{
        text-align: center;
    }
}