/* create custom CSS variables (also called custom properties) and apply them to the root of the page, making them accessible to all other CSS */
:root {
  /* declare a variable with `--` syntax */
  --dark: #13293d;
  --light: #fff;
  --navlink-color: #b9c6ae;
}

body {
  display: flex;
  flex-direction: column;
  line-height: 1.3;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1%;
  /* use CSS var() function to reference a variable created above */
  background-color: var(--dark);
  color: var(--light);
}

h1 {
  font-size: 200%;
}

h2 {
  margin: 2% 0;
  font-size: 250%;
}

a[href*='.css']::after {
  content: '📝';
  display: inline-block;
  margin-left: 3px;
}

nav ul {
  display: flex;
  justify-content: space-between;
  min-width: 300px;
}

nav a {
  background-color: unset;
  color: var(--navlink-color);
  font-weight: bold;
  text-decoration: none;
}

nav a:hover {
  color: var(--light);
}

main {
  display: flex;
  flex: 1 1 0;
  max-width: 96%;
  margin: 2% auto;
}

article {
  /* If we were to change the value of `--dark`, then all references to it would change automatically */
  border-bottom: 1px solid var(--dark);
}

article p {
  margin: 2% 0;
  font-size: 110%;
}

article ul {
  margin-left: 5%;
  font-size: 110%;
  list-style: circle;
}

footer {
  display: flex;
  justify-content: center;
  padding: 2%;
  background-color: var(--dark);
  color: var(--light);
}

@media screen and (max-width: 768px) {
  header {
    flex-direction: column;
  }

  main {
    max-width: 1200px;
  }
}