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

body {
    font-family: Arial, sans-serif;
}

header {
    background-color: #000;
    padding: 0px;
    text-align: center;
    height:240px;
}

.fondo_menu {
    background-color: #333;
    height: 40px;
    padding-top: 5px;
}

.contenido {
    display: flex;
    justify-content: center;
    background-color: #000;
}

.header_contenido {
    display: flex;
	justify-content: center;
	background-image: url('../img/encabezadoaetm.png');
	background-size:cover;

}

footer {
    font-family: 'Roboto', sans-serif;
    background-color: #000;
    color: white;
    text-align: left;
    padding-top: 20px;
    font-size: 12px;
}

#progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background-color: #4CAF50;
    width: 0%;
    z-index: 1001;
}

#scroll-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: #333;
    color: white;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 20px;
    cursor: pointer;
    display: none;
    transition: opacity 0.3s, visibility 0.3s;
}

#scroll-to-top:hover {
    background-color: #555;
}

#articulo {
  
    background-color: #fff;
  
}