* {
  box-sizing: border-box;
}

body {
  font-family: Arial;
  padding: 10px;
  background: #f1f1f1;
  font-family: "Times New Roman", Times, serif;
}

.centre {
  text-align: center;
 }

ul.liste {
  list-style-type: circle;
}

ul.liste li {
  padding: 5px;
}

/* Header/Blog Title */
.header {
  padding: 15px;
  text-align: center;
  background-image: url('Images/Fond.jpg');
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-size: cover ;
}

.header h1 {
  font-size: 30px;
  color: black;
  font-weight: bold;
}

img {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

/* Style the top navigation bar */
ul.topnav {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333;
  position: -webkit-sticky; /* Safari */
  position: sticky;
  top: 0;
  z-index: 100;
}

/* Style the topnav links */
li.topnav {
  float: left;
}

li.topnav a {
  font-size: 18px;
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-family: "Times New Roman", Times, serif;
}

/* Change color on hover */
.topnav a:hover {
  background-color:#ff4d94;
  color: white;
}

/* Create two unequal columns that floats next to each other */
/* Left column */
.leftcolumn {   
  float: left;
  width: 75%;
}

/* Right column */
.rightcolumn {
  float: left;
  width: 25%;
  background-color: #f1f1f1;
  padding-left: 20px;
}


/* Add a card effect for articles */
.card {
  background-color: white;
  padding: 20px;
  margin-top: 20px;
}

/* Clear floats after the columns */
.row:after {
  content: "";
  display: table;
  clear: both;
}

/* Footer */
.footer {
  padding: 15px;
  text-align: center;
  background-image: url('https://4.bp.blogspot.com/-eH7xVexAlgk/UHTLbYZ1IKI/AAAAAAAACWg/g1mtu58Ov74/s1600/218439.jpg');
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-size: cover ;
  margin-top: 20px;
}

/* Responsive layout - when the screen is less than 800px wide, make the two columns stack on top of each other instead of next to each other */
@media screen and (max-width: 800px) {
  .leftcolumn, .rightcolumn {   
    width: 100%;
    padding: 0;
  }
}

/* Responsive layout - when the screen is less than 400px wide, make the navigation links stack on top of each other instead of next to each other */
@media screen and (max-width: 400px) {
  .topnav a {
    float: none;
    width: 100%;
  }
}