body {
   font-family: Arial, sans-serif;
   line-height: 1.6;
   margin: 0;
   padding: 0;
   background-color: #f4f4f4;
}
header {
   background: #333;
   color: #fff;
   text-align: center;
   padding: 1rem 0;
}
h1 {
   margin: 0;
}
main {
   padding: 20px;
}
h2 {
   color: #333;
}

#intro {
    text-align: center;
    margin-left: 5%; margin-right: 5%;
}

#title {
    text-align: center;
}

 /* Three image containers (use 25% for four, and 50% for two, etc) */
.column {
  float: left;
  width: 33%;
  text-align: center;
}

/* Clear floats after image containers */
.row::after {
  content: "";
  clear: both;
  display: table;
}