body {
  font-family: Helvetica;
  margin: 0;
  background-color: rgb(230, 230, 230);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header, main, footer {
  width: 100%;
  box-sizing: border-box;
}
header {
  background-color: rgb(12, 12, 12);
  padding: 12px 20px;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
}

ul.header {
  list-style-type: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
}

ul.header li {
  display: inline-block;
  padding-right: 20px;
}
ul.header li a{
  display: block;
  color: white;
  text-decoration: none;
  padding: 14px 16px;

}
ul.header li a:hover{
  background-color: lightskyblue;
  color: black;
  border-radius: 10px;
}


ul.header li:last-child {
  margin-left: auto; 
}

ul.header li button {
  display: block;
  color: white;
  text-decoration: none;
  padding: 14px 16px;
  background: none;
  border: none;
  cursor: pointer;
}
ul.header li button:hover{
  background-color: rgb(250, 162, 135);
  color: black;
  border-radius: 10px;
}

div{
  top: 96px;
  flex: 1;
  position: relative;
  margin-bottom: 15vh;
}
.description{
  font-style: italic;
}
h1, h2, h3, p, img.alt, img {
  text-align: center;
}


#page1 {
    background-color: rgb(230, 230, 230);
    padding: 20px;
    margin-top: 80px;
    margin-bottom: 100px;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    box-sizing: border-box;
    overflow-y: auto; 
}
.video-container {
  position: relative;
  padding-bottom: 56.25%; /* Rapport hauteur/largeur (9/16) pour conserver le ratio 16:9 */
  overflow: hidden;
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 50%;
  height: 50%;
}

footer {
  background-color: rgb(12, 12, 12);
  color: white;
  padding: 12px 20px;
  position: relative;
  bottom: 0;
  left: 0;
  margin-top: auto;
  width: 100%;
}
.dark-mode {
  background-color: #111;
  color: #fff;
}
.dark-mode #page1 {
  background-color: #111;
  color: #fff;
}