*{
	margin:0;
	padding:0;
}

.banner{
	width: 950px;
	height: 300px;
	border: 1px solid black;
    margin: auto;	
	border-radius: 10px;
	
	
	background-size: 100% 100%;
	
	animation-name: banner;
	animation-duration: 40s;
	animation-iteration-count: infinite;
	
	
}

	@keyframes banner {
		0%, 10% {
				background-image: url(../imagenes/1.jpg);
		}
		15%, 25%{
			background-image: url(../imagenes/2.jpg);
		}
		30%, 40% {
			background-image: url(../imagenes/3.jpg);
		}
		45%, 55% {
			background-image: url(../imagenes/4.jpg);
		}
		60%, 70% {
			background-image: url(../imagenes/5.jpg);
		}
		75%, 85% {
			background-image: url(../imagenes/6.jpg);
		}
		90%, 100% {
			background-image: url(../imagenes/7.jpg);
		}
	}
	
	body{
	
	background:#F2F4F4;
	
}
header, .main, footer{
	
	width: 1000px;
	font-family:Arial;
	margin: auto;
	
	
}
	
	header nav {
		
		background:#CFCFCF;
		
	}
	header nav ul {
		list-style:none;
		
	} 
	
	
	
	header nav ul li a{
		padding:10px 30px;
		display:block;
		color:black;
		text-decoration:none;
		
	}
	
	header nav ul li a:hover{
		background:#CFCFCF;
	}
	.nav li ul {
		
		display:none;
		position:absolute;
		min-width:140px;
	}
	
	.nav li:hover > ul {
		display:block; 
	}
	
	
	.nav > li {
		
		Float:Left;
	}
	
	footer{
		width:600px;
		background:#000;
		color:#fff;
		clear:both;
		padding:10px 0px;
		text-align:center;
	}
	
	.galeria{
    font-family: 'open sans';
}

.galeria h1{
    text-align: center;
    margin:20px 0 15px 0;
    font-weight: 300;
}

.linea{
    border-top: 5px solid #CCC;
    margin-bottom: 40px;
	
}

.contenedor-imagenes{
    display:flex;
    width: 85%;
    margin: auto;
    justify-content: space-around;
    flex-wrap: wrap;
    border-radius:3px;
}

.contenedor-imagenes .imagen{
    width: 32%;
    position: relative;
    height:250px;
    margin-bottom:5px;
    box-shadow: 0px 0px 3px 0px rgba(0, 0, 0, .75)
}
.imagen img{
    width: 100%;
    height:100%;
    object-fit: cover;
}

.overlay{
    position: absolute;
    bottom: 0;
    left: 0;
    background:rgba(0, 118, 192, 0.781) ;
    width: 100%;
    height: 0;
    overflow: hidden;
    transition: .5s ease;
}

.overlay h2{
    color: #fff;
    font-weight: 300;
    font-size:30px;
    position: absolute;
    top: 50%;
    left:50%;
    text-align: center;
    transform: translate(-50%, -50%);
}

.imagen:hover .overlay{
    height:100%;
    cursor: pointer;
}

@media screen and (max-width:1000px){
    .contenedor-imagenes{
        width: 95%;
    }
}

@media screen and (max-width:700px){
    .contenedor-imagenes{
        width: 90%;
    }
    .contenedor-imagenes .imagen{
        width: 48%;
    }
}

@media screen and (max-width:450px){
    h1{
        font-size:22px;
    }
    .contenedor-imagenes{
        width: 98%;
    }
    .contenedor-imagenes .imagen{
        width: 80%;
    }
}