html, body {
  width: 100%;
  margin: 0;
}

.main {
  width: 100%;
  display: flex;
  flex-flow: column wrap;
  justify-content: center;
}

footer {
  margin: auto 2em;
  text-align: center;
}

img {
  display: block;
  width: auto;
  height: auto;
  max-width: 100%;
  max-height: 90%;
  margin: 20px auto;
}

.advert {
  display: flex;
  flex-flow: row wrap;
  justify-content: center;
}
.advert .heading {
  display: flex;
  flex-grow: 2;
  height: 40px;
  width: 100%;
  justify-content: center;
}
.advert .child {
  display: flex;
  flex-grow: 1;
  width: 40%;
  margin: 0 20px 0 20px;
  justify-content: flex-end;
  align-items: center;
}
.advert .child:not(.label) {
  justify-content: flex-start;
}