body {
    width: 800px;
    width: 90%;

}
@media (min-width: 640px) {
    html { background-color: #eaf6ff; }
  }
@media (max-width: 550px) {
    h1 {
        font-size: 1.5rem;
    }
}
@media (min-width: 640px) {
    h1 {
        font-size: 2.5rem;
    }
}

ul {
    display: flex;
    flex-wrap: wrap;
    list-style: none;

}
aside {
    width: 170px;
    margin: 10px;
    font-size: 0.8rem;
}

.stretchable-grid-items li {
    width: 100%;
}
@media (min-width:481) {
    .stretchable-grid-items li {
        width: 50%;
    }
}
@media (max-width: 640px) {
   .stretchable-grid-items li {
    width: 25%;
   }
 
}
.stretchable-grid-items aside {
    margin: 10px;
}
.stretchable-grid-items ul {
    margin-left: -10px;
    margin-right: -10px;
    margin-top: 1rem;
    margin-bottom: 1rem;
}