* {
    margin: 0;
    padding: 0;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

body {
    font-family: 'Open Sans', sans-serif;
    background: #000 url('imagenes/fondo.jpg');
    background-size: cover;
    background-attachment: fixed;
}

.contenedor {
    margin: auto;
    width: 90%;
    max-width: 1000px;
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
}

header {
    width: 100%;
    padding: 20px 20px;
    background: rgba(255, 255, 255, .3);
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
}

header .menu {
    background: rgba(255, 255, 255, .2);
    text-align: center;
    padding: 20px;

}

header .menu a {
    color: #fff;
    text-decoration: none;
    margin-right: 40px;
    font-size: 18px;
}

header .menu a:hover {
    text-decoration: underline;
}

.main {
    background: #fff;
    padding: 20px;
    width: 70%;
}

.main article .thumb {
    margin-bottom: 20px;
}

.main article .thumb img {
    width: 100%;
    vertical-align: top;
}

.main article h2 {
    margin-bottom: 20px;
    font-weight: normal;
    font-size: 32px;
}

.main article p {
    margin-bottom: 20px;
    font-size: 14px;
    line-height: 27px;
}

aside {
    width: 30%;
    background: #537dca;
    padding: 20px;
    display: flex;
    flex-direction: column;
    flex-wrap: wrap;

    justify-content: flex-start;
}

aside .ad {
    font-size: 14px;
    text-align: left;
    color: #fff;
    padding: 20px 20px;
    background: #4264a2;
    margin: 10px 0;
}

footer {
    margin: 20px 0;
    background: rgba(255, 255, 255, .2);
    padding: 20px;
    width: 100%;
    color: #fff;
    display: flex;
    flex-direction: column;
    flex-wrap: nowrap;  /* estaba en no-wrap que no es una opción válida */
    justify-content: space-between;
    text-align: center;
}


footer .contacto .formulario {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    margin-top: 10px;
}

footer .contacto .formulario input[type="text"],
footer .contacto .formulario input[type="email"],
footer .contacto .formulario textarea {
    border: 2px solid #cecece;
    border-radius: 5px;
    padding: 15px 20px;
    font-size: 20px;
    color: #a4a4a4;
}

footer .contacto .formulario input[type="text"]:focus,
footer .contacto .formulario input[type="email"]:focus,
footer .contacto .formulario textarea:focus {
    border: 2px solid #3895ea;
}

footer .contacto .formulario input[type="text"],
footer .contacto .formulario input[type="email"] {
    width: 49%;
    margin-bottom: 15px;
}

footer .contacto .formulario textarea {
    width: 100%;
    height: 100px;
    min-width: 100%;
    max-width: 100%;
    min-height: 100px;
    max-height: 300px;
    margin-bottom: 15px;
}

footer .contacto .formulario .boton {
    margin: auto;
    background: #3895ea;
    color: #fff;
    border: none;
    border-radius: 3px;
    padding: 15px 40px;
    cursor: pointer;
}

footer .contacto .formulario .boton:hover {
    background: #387bea;
}

footer .ubicacion .contenedor {

    padding: 20px 0 0 0;
}

footer .ubicacion .direccion {
    float: left;
    width: 100%;
    text-align: left;
    padding: 20px 0;
}

footer .ubicacion .direcion .calle {
    margin-bottom: 15px;
}

footer .mapa {
    width: 100%;
    overflow: hidden;
}

footer .mapa iframe {
    width: 100%;
    max-height: 600px;
}

footer .autor {
    order: 2;
}

footer .redes-sociales {
    order: 1;
    margin-bottom: 20px;
}

#spam {
    display: none;
}

footer .redes-sociales a {
    color: #fff;
    text-decoration: underline;
    margin-left: 20px;
}

footer .redes-sociales a:hover {
    text-decoration: none;
}

@media screen and (max-width: 900px) {

    header {
        flex-direction: column;
        padding-bottom: 20px;
    }

    header .menu {
        width: 100%;
        background: rgba(255, 255, 255, .2);
        text-align: center;
        padding: 20px;

    }

    header .menu a {
        margin: 0 20px;
    }

    header .logo {
        margin-bottom: 20px;

    }

    .main {
        width: 100%;
    }

    aside {
        width: 100%;
        flex-direction: row;
    }

    aside .ad {
        width: 100%;

    }
}

@media screen and (max-width: 600px) {
    header {
        flex-direction: column;
        padding-bottom: 20px;
    }

    header .menu {
        width: 100%;
        background: rgba(255, 255, 255, .2);
        text-align: center;
        padding: 20px;

    }

    header .menu a {
        margin: 0 20px;
    }

    header .logo {
        margin-bottom: 20px;

    }

    footer {
        flex-direction: column;
        text-align: center;
    }

    footer .autor {
        order: 2;
    }

    footer .redes-sociales {
        order: 1;
        margin-bottom: 20px;
    }
}