.float_left {
	float:left;
	}
.float_right {
	float:right;
	}
@media screen and (min-width:1000px) {
	#cont_accueil {
		float:left;
		width:950px;
	}
}
#left_1, #revisions, #meiigle, #left_3, #centre_1, #expertsmei, #challenge_revisions, #centre_3, #liste_tp, #reseaux_soc, #yt_video, #linux_3d, #mac_3d, #windows_3d {
	-webkit-border-radius:6px;
	-moz-border-radius:6px;
	-o-border-radius:6px;
	border-radius:6px;
	border:1px solid #ccc;
	background-color: #f5f5f5;
	text-align: justify;
	margin-bottom: 10px;
	padding: 8px;
	}

#reseaux_soc, #yt_video {
	width: 930px;
	}
@media screen and (min-width:1000px) {
	#liste_tp {
		float: right;
	}
}
#left_1 {
	width:250px;
}

@media screen and (min-width:750px) {
	#left_1 {
		float:left;
	}
}
@media screen and (min-width:1000px) {
	#left_1 {
		height: 260px;
	}
}
@media screen and (max-width:750px) {
	#left_1 {
		width: 100%;
	}
}
#left_2 {
	height: 260px;
	text-align: center;
	margin:0;
	padding:0;
}
@media screen and (min-width:750px) {
	#left_2 {
	width:250px;
	float:left;
	}
}
#left_2 img {
	padding-top: 5px;
	margin: auto;
	height:100px;
	}
#left_3 {
	height: 290px;
	width:365px;
	text-align: center;
	float:left;
	}
#left_3 img {
	padding-top: 20px;
	}
@media screen and (min-width:1000px) {
	#centre_1{
		width:630px;
		height: 460px;
		float:right;
	}
}
@media screen and (min-width:750px) and (max-width:999px) {
	#centre_1{
		width:630px;
		float:right;
	}
}
@media screen and (max-width:749px) {
	#centre_1 {
	width:100%;
	}
}
#challenge_revisions {
	text-align: center;
	height: 265px;
	}
@media screen and (min-width:750px) {
	#challenge_revisions {
		width:630px;
		float: right;
	}
}
#centre_3 {
	height: 290px;
	width:365px;
	float:right;
	text-align: center;
	}
#centre_3 p{
	padding-top: 5px;
	text-align: center;
	}
#revisions, #expertsmei {
	text-align: center;
	}
@media screen and (min-width:750px) {
	#revisions, #expertsmei {
	width:250px;
	}
}
#meiigle {
	width: 755px;
	float: left;
	height:150px;
	}
#liste_tp {
	width:300px;
}
@media screen and (max-width:999px) {
	#liste_tp {
	min-width:320px;
	width: 100%;
}

}