/* Fixed-size display unit: reserve its full height even when blocked or unfilled. */
.ad-space {
  box-sizing: border-box;
  width: 100%;
  max-width: 720px;
  margin: 96px auto;
  padding: 24px 8px;
  border-top: 1px solid #e6dcd5;
  color: #75675f;
  text-align: center;
  clear: both;
}
.ad-label { display: block; margin-bottom: 12px; font: 12px/20px system-ui, sans-serif; }
.ad-reserved { width: 250px; height: 250px; margin: 0 auto; }
/* Keep the introduction's reservation below the initial viewport on wide screens too. */
.landing-page ~ .ad-space { margin-top: max(96px, 30vh); }