/* ==========================================================================
   Navigation Header
   Breakpoint: nav mobile ≤ 39.99rem | desktop ≥ 40rem
   ========================================================================== */

.header {
  position: fixed;
  top: 1rem;
  left: var(--padding);
  right: var(--padding);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0;
  box-sizing: border-box;
  z-index: 100;
}

.logo {
  padding: 1rem 0;
  display: flex;
  align-items: center;
  font-weight: 600;
  cursor: pointer;
}

.menu {
  display: flex;
}

.menu a {
  padding: 1rem;
  display: block;
}

.menu a[aria-current] {
  text-decoration: underline;
}

.burger-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  padding: 0;
  margin: 0;
  cursor: pointer;
  width: 24px;
  height: 24px;
  position: relative;
  z-index: 200;
}

.burger-line {
  position: absolute;
  left: 0;
  width: 24px;
  height: 2px;
  background-color: var(--color-black);
  transform-origin: center center;
  transition: transform 0.25s var(--ease-out),
              top 0.25s var(--ease-out);
}

.line-1 { top: 7px; }
.line-2 { top: 15px; }

.burger-menu-toggle[aria-expanded="true"] .line-1 {
  top: 11px;
  transform: rotate(45deg);
}

.burger-menu-toggle[aria-expanded="true"] .line-2 {
  top: 11px;
  transform: rotate(-45deg);
}

@media screen and (max-width: 39.99rem) {
  .burger-menu-toggle {
    display: block;
  }

  .nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background-color: var(--color-background);
    padding: 8rem var(--padding) 4rem var(--padding);
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: flex-start;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, visibility 0.25s ease;
    z-index: 150;
  }

  .nav-overlay.is-active {
    opacity: 1;
    visibility: visible;
  }

  .menu {
    flex-direction: column;
    width: 100%;
  }

  .menu a {
    font-size: 2rem;
    font-weight: 600;
    padding: 1rem 0;
  }
}

@media screen and (min-width: 40rem) {
  .nav-overlay {
    display: flex;
    align-items: center;
    gap: 1.5rem;
  }
}