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

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

header {
    background-color: #000;
    padding: 0px;
    text-align: center;
    height: 250px;
}

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

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

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

}

footer {
    font-family: 'Roboto', sans-serif;
    background-color: #f0f0f0;
    color: #000;
    text-align: left;
    font-size: 12px;
    margin: 0px;
}

#progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background-color: #ff0000;
    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;

}


.nav-contenido {
    width: 100%;
    background-color: black;
}

nav {
    background-color: black;
    width: 1200px;
    margin: 0 auto;
}

nav ul {
    list-style-type: none;
}

nav ul li {
    display: inline;
    margin: 0 10px;
}

.sticky-nav {
    position: fixed;
    top: -60px;
    left: 0;
    width: 100%;
    background-color: black;
    color: white;
    padding: 10px;
    transition: top 0.3s;
    z-index: 1000;
}

.sticky-nav ul {
    list-style-type: none;
    text-align: center;
}

.sticky-nav ul li {
    display: inline;
    margin: 0 10px;
}

.sticky-nav a {
    color: white;
    text-decoration: none;
}

.menu {
    background-color: black;
    overflow: hidden;
    font-size: 12px;
}

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

.menu ul li {
    float: left;
    position: relative;
}

.menu ul li a {
    display: block;
    color: white;
    text-align: center;
    padding: 10px 5px;
    text-decoration: none;
}

.menu ul li a:hover {
    background-color: #111;
}

.submenu {
    display: none;
    position: absolute;
    background-color: #333;
    min-width: 160px;
    z-index: 1;
}

.submenu li {
    float: none;
}

.submenu li a {
    padding: 12px 16px;
}

.menu ul li:hover .submenu {
    display: block;
    animation: slide-down 0.5s ease-in-out;
}

@keyframes slide-down {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}


/* --- MENÚ LATERAL OFFCANVAS --- */
/* Limpiamos estilos conflictivos para que Bootstrap lo controle fluido */
.side-menu {
    background-color: #111 !important;
}

.side-menu a {
    padding: 15px 32px;
    text-decoration: none;
    font-size: 18px;
    color: #818181;
    display: block;
    transition: 0.3s;
    border-bottom: 1px solid #222;
    /* Separador sutil */
}

.side-menu a:hover {
    color: #f1f1f1;
    background-color: #222;
}

@media screen and (max-width: 1100px) {
    .sticky-nav nav {
        display: none;
    }

    .hamburger {
        display: block;
    }
}