#header {
  border-style: none;
  margin-top: -18px;
  width: 870px;
  height: 238px;
  font-weight: normal;
  line-height: 1em;
  display: block;
  background-image: url(blog.JPG);
}
.logo{
border-radius: 50%;
width: 96px;
height: 96px;
 padding-top: 20px;
 padding-left: 20px;
 text-decoration: none;
}
.container {
    display: flex;
    padding: 0px;
    flex-wrap: wrap;
    justify-content: center;
    align-items: column; 
  }
  .card {
   padding: 10px;
    flex: 0 0 200px;
    margin: 10px;
    background: white;
    border: 1px solid #ccc;
    box-shadow: 2px 2px 6px 0px  rgba(0,0,0,0.3);

  } 
  .card img {
   padding: 0px;
    max-width: 100%;
  }
  .card .text {
    padding: 0 20px 20px;
  }
  .card .text > button {
    background: gray;
    border: 0;
    color: white;
    padding: 10px;
    width: 100%;
    }
.button {
    background: gray;
    border: 1px solid gray;
    color: white;
    padding: 10px;
    width: 100%;
    }
.button:hover {
    background: #ebebeb;
    color: black;
border: 1px solid black;
}

.newspaper {
  column-count: 3;
}

.img{
border-radius: 50%;
width: 100px;
height: 68px;
 padding-top: 20px;
 padding-left: 20px;
 text-decoration: none;
}

h1 {
  font-family: Great Victorian; 
  line-height: 1em;
  text-align: center;
  color: #73AD21;
  font-size: 2.5em;
  text-decoration: none;
}
h2 {
  text-decoration: none;
  font-style: normal;
  line-height: 1em;
  font-weight: normal;
  font-family: Gabriola;
  color: #73AD21;
  font-size: 1,875em;
  text-align: center;
  text-transform: uppercase;
 }
h3 {
  line-height: 1em;
  text-decoration: none;
  font-style: normal;
  color: #73AD21;
  font-family: Great Victorian;
  font-weight: bold;
  text-align: center;
  text-decoration: none;
  font-size: 1.5em;
}

a {
 text-decoration: none;
 color: #666699;
}

.grid-container {
    display: flex;
    padding: 0px;
    flex-wrap: wrap;
    justify-content: center;
    text-decoration: none;
    align-items: column; 
    text-decoration: none;
  } 

#rcorners1 {
 border-radius: 25px;
  border: 2px solid #73AD21;
  padding-left: 10px;
  padding-top: 10px;    
  padding-right: 10px;
  padding-bottom: 10px;
  margin-left: 10px;
  text-decoration: none;
  margin-top: 10px;    
  margin-right: 10px;
  margin-bottom: 10px;
  border-spacing: 10px;
  text-align: left;
  color: #696969;
  width: 400px;
  height: 300px; 
}
#rcorners2 {
  border-radius: 25px;
  border: 2px solid #73AD21;
  padding-left: 10px;
  padding-top: 10px;    
  padding-right: 10px;
  padding-bottom: 10px;
  margin-left: 10px;
  text-decoration: none;
  margin-top: 10px;    
  margin-right: 10px;
  margin-bottom: 10px;
  border-spacing: 10px;
  text-align: left; 
  color: #696969;
  width: 200px;
  height: 300px;
}
#rcorners3 {
  border-radius: 25px;
  border: 2px solid #73AD21;
  padding-left: 10px;
  padding-top: 10px;    
  padding-right: 10px;
  padding-bottom: 10px;
  text-align: center;
  text-decoration: none;
  margin-left: 10px;
  margin-top: 10px;    
  margin-right: 10px;
  margin-bottom: 10px;
  border-spacing: 10px;
  color: #696969;
  width: 400px;
  height: 300px; 
}

body {
background-image :url(mappemonde.JPG);
background-color:white;
margin: 0 auto;
border: 2px dotted #73AD21;
font-family: Verdana, Arial;
font-size: 100%;
text-decoration: none;
margin: 0px auto;
min-width: 320px;
max-width: 870px;
margin: 0 auto;
  }
.content {
line-height: 0.9em;
font-style: normal;
text-decoration: none;
font-weight: normal;
font-style: normal;
font-weight: normal;
font-size: 0.875em;
font-family: verdana;
display: block;
text-align: left;
background-color: #FFF;
color: #696969;
}

.footer {
text-align: center;
padding: 3px;
text-decoration: none;
background-color: #73AD21;
color: white;
height: 50px;
}

p {
  margin:30px;
  padding-left: 30px;
  padding-right: 20px;
  text-align: left;
  font-family: Verdana, Arial;
  font-size: 1em;
  line-height: normal;
  color: #696969;
  font-weight: normal;
  font-style: normal;
  text-transform: none;
  text-decoration: none;
}

.menu {
  margin: 0 auto;
  font-style: normal;
  text-decoration: none;
  text-align: center;
  text-decoration: none;
  line-height: 1em;
  font-size: 0.9em;
  font-family: verdana;
  color: #73AD21; 
}
menu a {
margin: 0;
font-weight: bold;
text-align: center;
color: #73AD21;
padding-right: 20px;
text-decoration: none;
}
ul {
list-style-type: none;
margin: 0;
color: #73AD21;
overflow: hidden;
text-decoration: none; 
padding-right: 20px;
}

ul li {
  float: right;
}

li a {
text-align: center;
color: #73AD21;
font-weight: bold;
padding-right: 20px;
text-decoration: none;
}
.pagination-container {
text-align: center;
}

.pagination {
  display: inline-block;
margin: 0;
}

.pagination a {
  color: black;
  float: left;
  padding: 7px 14px;
  text-decoration: none;
  transition: background-color .3s;
  border: 1px solid #ddd;
 }
.pagination li {
display: inline;
}

.pagination a.active {
  background-color: #4CAF50;
  color: white;
  border: 1px solid #4CAF50;
}
.pagination a:hover:not(.active) {background-color: #ddd;
}

@media (max-width: 640px) {
	* {
		box-sizing: border-box;
	}
	
	/* passer body (et tous les éléments de largeur fixe) en largeur automatique */

	body {
		width: auto;
		margin: 0;
		padding: 0;
	}
	
	/* fixer une largeur maximale de 100% aux éléments potentiellement problématiques */

	img,
	table,
	td,
	blockquote,
	code,
	pre,
	textarea,
	input,
	iframe,
	object,
	embed,
	video {
		max-width: 100%;
	}
	
	/* conserver le ratio des images */

	img {
		height: auto;
	}
	
	/* gestion des mots longs */

	textarea,
	table,
	td,
	th,
	code,
	pre,
	samp {
		-webkit-hyphens: auto; /* césure propre */
		-moz-hyphens: auto;
		hyphens: auto;
		word-wrap: break-word; /* passage à la ligne forcé */
	}
	
	code,
	pre,
	samp {
		white-space: pre-wrap; /* passage à la ligne spécifique pour les éléments à châsse fixe */
	}
	
	/* Passer à une seule colonne (à appliquer aux éléments multi-colonnes) */

	.element1,
	.element2 {
		float: none;
		width: auto;
	}
	
	/* masquer les éléments superflus */

	.hide_mobile {
		display: none !important;
	}
	

La touche finale : réduire de façon harmonieuse toutes les tailles de polices en orientation paysage (car bugguée sur les périphériques iPhone et iPad).

@media (max-device-width:768px) and (orientation: landscape) {
  html {
   -webkit-text-size-adjust: 100%;
   -ms-text-size-adjust: 100%;
  }