* {
  box-sizing: border-box;
}

:root {
  --content-width: 72ch;
  --content-padding: 1rem;
}

body {
  margin: 0;
  padding: 0;
  line-height: 1.5;
}

header,
main,
footer {
  width: 100%;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: var(--content-padding);
}

header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1.5rem;
}

header > div {
  flex: 1 1 12rem;
}

header nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
}

main nav {
  margin: 0 0 1rem;
}

main nav a,
main nav span {
  display: inline-block;
  margin-right: 0.5rem;
}

section {
  margin: 1.5rem 0;
}

article {
  margin: 1rem 0 2rem;
}

article h1,
article h2,
article h3 {
  margin-top: 0;
}

ol,
ul {
  padding-left: 1.25rem;
  margin: 0.5rem 0 1rem;
}

li {
  margin: 0.25rem 0;
}

footer {
  margin-top: 2rem;
}

@media (min-width: 768px) {
  :root {
    --content-padding: 1.5rem;
  }
}

@media (min-width: 1024px) {
  :root {
    --content-width: 80ch;
  }
}