body {
    padding:0 20px;
    line-height: 1.5em;
    width: 700px;
    margin: 0 auto;
    font-family: sans-serif;
    background-color: white;
}
h1, h2, h3, p, footer, a, ol, ul, li {
    color:#4e2f26;
}
h1 {
    font-family: 'Roboto', sans-serif;
}

#button {
    margin-bottom:20px;
    padding:20px;
    position: absolute;
    top: 10px;
    right: 10px;
}
  
.background  {
    background-image: url('https://cdui03.afpa-balma.fr/evaluation-CP7-2/img/pexels-micah-boerma-aube.jpg');
    height: 300px;
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center;
}
footer {
    font-size:12px;
    text-align: left;
    padding-top:20px;
    font-style: italic;
}
#content {
    display: flex;
    justify-content: space-between;
    align-items: stretch;
    width: 100%;
}

#content-left {
    flex-basis: 50%;
    background-color: #fe9075;
    padding: 20px;
}

#content-right {
    flex-basis: 50%;
    background-color: #fcc8a1;
    padding: 20px;
}

<link rel="stylesheet" type="text/css" href="https://cdui03.afpa-balma.fr/evaluation-CP7-2/styles-1.css" id="mycss" />
#style-1-button[href*="https://cdui03.afpa-balma.fr/evaluation-CP7-2/styles-1.css"] {
    display: none;
}

<link rel="stylesheet" type="text/css" href="https://cdui03.afpa-balma.fr/evaluation-CP7-2/styles-2.css" id="mycss" />
#style-2-button[href*="https://cdui03.afpa-balma.fr/evaluation-CP7-2/styles-2.css"] {
    display: none;
}

.consignes-button {
    display: inline-block;
    padding: 10px 20px;
    background-color: #fe9075;
    color: #fff;
    text-decoration: none;
    border: 2px solid #fff;
    border-radius: 5px;
    cursor: pointer;
    margin-top: 10px;
}

img[src$="picto-consignes.png"],
img[src$="picto-sources.png"] {
    width: 80px;
    height: 80px;
    filter: brightness(200%);
}

@media screen and (max-width: 380px) {
    h1 {
        display: none;
    }
}

footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    text-align: center;
    background-color: #333;
    color: #fff;
    padding: 10px;
}