body{
    width: 90%;
    max-width:800px;
    margin-left: auto;
    margin-right: auto;
}

@media (min-width: 640px) {

    #stretchable-grid-items li{
        width: 25%;
    }
    
    body {
        background-color: #eaf6ff;
    }

    h1 {
        font-size: 2.5rem;
    }

}

@media (max-width: 500px) {
    h1 {
        font-size: 1.5rem;
    }
}

@media (min-width: 480px) {

    @media (max-width: 640px) {
        #stretchable-grid-items li{
            width: 50%;
        } 
    }
}


#fixed-size-grid-items aside{
    width: 170px; 
    margin: 10px;
    font-size: 0.8rem;
}

#fixed-size-grid-items ul{
    display: flex;
    flex-wrap: wrap;
    list-style-type: none;
    padding: 0;
}


#stretchable-grid-items ul {
    display: flex;
    flex-wrap: wrap;
    padding: 0;
    list-style: none;
    font-size: 0.8rem;
    margin-left: -10px;
    margin-right: -10px;
    margin-top: 1rem;
    margin-bottom: 1rem;
  }


  
  #stretchable-grid-items aside {
    margin: 10px;
  }