* {
   font-family: Arial, Helvetica, sans-serif;
   margin: 0;
   color: #fff;
   padding: 0;
   box-sizing: border-box;
}
.flex {
   display: flex;
   flex-wrap: wrap;
   justify-content: space-between;
}
section {
   flex: 1;
}
main {
   background: #000;
   padding: 3rem 3rem 3rem 0;
}

nav {
   /* just decreasing the padding sometime helps in responsiveness */
   padding: 1rem 2rem;
   background: #333;
   align-items: center;
   display: flex;
   justify-content: space-evenly;
}
nav span {
   border-radius: 50%;
   padding: 1rem;
   background: #fff;
}
nav h2 {
   font-size: 3rem;
}
nav span {
   font-size: 2.5rem;
}
nav h3 {
   font-size: 1.5rem;
   color: #888;
}
.box {
   display: flex;
   justify-content: space-evenly;
   padding: 1.4rem 0;
   background: #555;
   margin: 1rem 0;
}
.box h3 {
   font-size: 2rem;
}
.box p {
   font-size: 1.2rem;
}
.box span {
   font-size: 4rem;
}

aside {
   width: 40%;
   height: 90vh;
}

aside img {
   object-fit: cover;
   height: 100%;
   width: 100%;
}

@media screen and (max-width: 768px) {
   main {
      flex-direction: column;
      padding-right: 0;
   }
   aside,
   main {
      /* height: auto; same as below:*/
      height: fit-content;
      width: 100%;
   }
}