.site {
   display: grid;
   grid-template-columns:  2fr 1fr 1fr;
   grid-template-rows:  auto 1fr 2fr 3fr 1fr 1fr 1fr;
   grid-template-areas:  
      "masthead masthead masthead"
      "header header header"
      "hero hero hero"
      "main main sidebar"
      "cta cta cta"
      "subfooter subfooter subfooter"
      "footer footer footer";
}

.masthead {
    grid-area: masthead;
}

.header {
   grid-area: header;
}

.hero {
   grid-area: hero;
}

.main-content {
   grid-area: main;
}

.sidebar {
   grid-area: sidebar;
}

.cta {
   grid-area: cta;
}

.subfooter {
   grid-area: subfooter;
}

.footer {
   grid-area: footer;
}