body {margin-left: 20px; margin-right: 20px; margin-top:40px; width:auto; height:auto; background-image:url('fond.gif');}

p { font-family:  Calibri, Arial; font-size:13pt; text-align:justify; line-height:22px; }
h1 { font-family: Calibri, Arial; font-size:20pt; text-align:center; }
h2 { font-family: Calibri, Arial; font-size:18pt; text-align:justify; }
h3 { font-family: Calibri, Arial; font-size:15pt; text-align:justify; }

img {
max-width : 100%;
height : auto;
}

#slider {
    position: relative;
    width : 1000px;
    max-width : 100%;
    height : auto;
    margin: auto;
    display: flex;
    align-items: center;
}

#precedent,
#suivant {
    cursor: pointer;
    transition: opacity 0.3s ease;
    opacity: 0;
    position: absolute;
    font-size: 30px;
    font-weight: bold;
    color: rgba(220, 220, 220, 0.6);
    background-color: rgba(0, 0, 0, 0.6);
    padding: 5px;
}

#precedent {
    left: 0;
}

#suivant {
    right: 0;
}

#slider:hover #precedent,
#slider:hover #suivant {opacity: 1;
}