*{
    margin:0;
    padding: 0;
    box-sizing: border-box;
}
body { 
  display: grid;
  grid-template-areas: 
    "header header header"
    "galeria galeria galeria"
    "footer footer footer";
  grid-template-rows: 15% 1fr 15%;
  grid-template-columns: 20% 1fr 15%;
  grid-gap: 10px;
  height: 100vh;
  margin: 0;
  }


body {
  background: #e9e3ff;
  color: #000;
  font-family: 'Roboto', sans-serif;
  }

.header {
 background: #12203E; 
 color: #fff;
padding: 10px;
grid-area: header;
}

.footer {
   background: #12203E; 
   color: #fff;
  text-align: center;
  font-size: 12px;
  padding: 15px;
  width:100%; 
  grid-area: footer;
}
.galeria{
    font-family: 'open sans';
    grid-area: galeria;
}

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

.linea{
    border-top: 5px solid #0077C0;
    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{
   grid-template-columns: repeat(3,33.3%);
    }
}

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

@media screen and (max-width:450px){
   body{background-color: #3f888f;
              }
    h1{
        font-size:22px;
    }
    .contenedor-imagenes{
        width: 98%;
    }
    .contenedor-imagenes .imagen{
        width: 80%;
        grid-template-columns: repeat(1,98%);
    }
    
    
}