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

body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
}

header {
    background-color: #fff;
    padding: 0px;
    text-align: center;

}

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


footer {
    font-family: 'Roboto', sans-serif;
    background-color: #f6f6f6;
    color: #818181;
    text-align: left;
    padding-top: 20px;
    font-size: 12px;
}

#progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background-color: #CC0000;
    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;
}