body > header {
  --menu-transition-duration: var(--duration-300);
  --menu-transition-easing: ease-in-out;
  border-bottom: var(--border-width) dashed var(--color-primary);
  display: flex;
  flex-direction: column;
  width: 100%;
}

body > header a {
  text-decoration: none;
}

body > header .nav-bar {
  align-items: center;
  display: flex;
  justify-content: space-between;
  padding: 0.5em var(--page-padding);
}

body > header .logo {
  align-items: center;
  display: flex;
  column-gap: 0.125em;
  margin-right: 1em;
}

body > header .logo svg {
  --left-logo-margin-ratio: 160 / 1024;
  --size: 2.5em;
  color: var(--color-text);
  height: var(--size);
  flex-shrink: 0;
  margin-left: calc(-1 * var(--left-logo-margin-ratio) * var(--size));
}

body > header nav {
  flex-shrink: 0;
  overflow: hidden;
  max-height: 0;
  transition: max-height var(--menu-transition-duration)
    var(--menu-transition-easing);
}

body > header nav ul {
  display: flex;
  flex-direction: column;
  list-style-type: none;
  margin: 0;
  padding: 0;
}

body > header nav a {
  --border-width: 0.25em;
  border-color: transparent;
  border-width: var(--border-width);
  border-left-style: solid;
  border-right-style: solid;
  display: flex;
  padding: 1em calc(var(--page-padding) - var(--border-width));
}

body > header nav .current a {
  border-top-color: var(--color-secondary);
  border-left-color: var(--color-secondary);
}

@media (hover: hover) {
  body > header nav a:hover {
    border-top-color: var(--color-primary);
    border-left-color: var(--color-primary);
  }
}

body > header .hamburger {
  /* use `calc(sqrt(2))` if browser support is good enough */
  --sqrt-of-2: 1.4142135623730951;
  align-items: center;
  display: flex;
  flex-direction: column;
  font-size: 75%;
  row-gap: calc(6em / 16);
  width: 2em;
}

body > header .hamburger .line {
  background-color: black;
  border-radius: 0.125em;
  height: 0.25em;
  display: block;
  transition: all var(--menu-transition-duration) var(--menu-transition-easing);
  width: 100%;
}

@media (hover: hover) {
  body > header .hamburger:hover {
    cursor: pointer;
  }
}

#main-menu-checkbox:checked ~ .nav-bar .hamburger .line:nth-child(1),
#main-menu-checkbox:checked ~ .nav-bar .hamburger .line:nth-child(3) {
  width: calc(var(--sqrt-of-2) * 0.75em + 0.25em);
}

#main-menu-checkbox:checked ~ .nav-bar .hamburger .line:nth-child(1) {
  transform: translate(0.5em, 0.25em) rotate(45deg);
}

#main-menu-checkbox:checked ~ .nav-bar .hamburger .line:nth-child(3) {
  transform: translate(0.5em, -0.25em) rotate(-45deg);
}

#main-menu-checkbox {
  display: none;
}

#main-menu-checkbox:checked ~ nav {
  max-height: initial;
}

@media (min-width: 48rem) {
  body > header {
    flex-direction: row;
    justify-content: space-between;
    padding: 0 var(--page-padding);
  }

  body > header .hamburger {
    display: none;
  }

  body > header .nav-bar {
    padding-left: 0;
    padding-right: 0;
  }

  body > header nav {
    align-self: stretch;
    font-size: 75%;
    max-height: initial;
  }

  body > header nav ul {
    flex-direction: row;
    height: 100%;
  }

  body > header nav a {
    align-items: center;
    border-left-style: initial;
    border-right-style: initial;
    border-top-style: solid;
    border-bottom-style: solid;
    display: flex;
    padding: 0 0.75em;
    height: 100%;
  }
}

@media (min-width: 64rem) {
  body > header nav {
    font-size: 100%;
  }

  body > header nav a {
    align-items: center;
    display: flex;
    padding: 0 1em;
    height: 100%;
  }
}