* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  
  border: 0.1rem solid black;
  border-radius: 0.5rem;
}

:root {
  --a-bg: ;
  --b-bg: ;
  --c-bg: ;
  --border-clr: ;
  --font-clr: ;
  --font-spcl: ;

  font-size: small;
}

body {
  display: grid;
  place-items: center;
  grid-template-areas: 
    ". head ."
    ". main ."
    ". foot .";
  grid-template-columns: auto 1fr auto;
  grid-template-rows: auto 1fr auto;

  line-height: 1.3;
  padding: 2vw;
  gap: .1vw;

  header { grid-area: head; }
  nav { grid-area: nav; }
  main { grid-area: main; }
  footer { 
    grid-area: foot;
    details { margin: 15px; }
  }
  #adbnr { grid-area: ad; }
  #alertbnr { grid-area: alrt; }
}

section, article, aside {
  padding: 2vw;
  gap: 2vw;
}

ul {
  display: flex;
  list-style-type: none;
}

#heros {
  display: grid;
  place-items: center;
  grid-template-areas: 
    "h3    h3   h3"
    "prev hero next"
    ".    p    . ";
  grid-template-columns: auto 1fr auto;
  grid-template-rows: auto 1fr auto;

  h3 {
    grid-area: h3;
  }
  input {
    width: 55px;
  }
  img {
    max-width: 60vw;
    max-height: 40vw;
  }
  p {
    grid-area: p;
    padding: 2%;
  }
  .hero {
    display: none;
    grid-area: hero;
  }
  #prevBtn { grid-area: prev; }
  #nextBtn { grid-area: next; }
}