.header {
  position: fixed;
  width: 100%;
  background: var(--color-primary);
  box-shadow: var(--shadow-medium);
  z-index: 1000;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: var(--header-height-mobile);
  padding: var(--spacing-md);
}

.header-logo {
  height: calc(var(--header-height-mobile) * 0.6);
  width: auto;
}

.header-logo img {
  display: block;
  height: 100%;
  width: 100%;
  object-fit: contain;
}

.header-toggle {
  color: var(--color-primary-contrast);
  font-size: var(--font-size-xl);
  background: none;
  border: none;
  cursor: pointer;
}

.header-nav {
  position: fixed;
  top: 0;
  left: 0;
  height: 100vh;
  width: 75%;
  max-width: 300px;
  background: var(--color-secondary);
  box-shadow: var(--shadow-soft);
  transform: translateX(-110%);
  transition: transform var(--transition-base);
  padding: var(--spacing-lg);
  z-index: 100;
}

.header-nav.open {
  transform: translateX(0);
}

.header-nav ul {
  list-style: none;
}

.header-nav li {
  display: block;
  margin: var(--spacing-xxs) 0;
}

.header-nav li img {
  display: inline;
  height: 0.65em;
  width: 0.65em;
}

.header-nav a {
  display: block;
  padding: var(--spacing-sm);
  color: var(--color-primary-contrast);
  text-decoration: none;
  font-size: var(--font-size-lg);
  font-weight: 200;
  transition: background-color var(--transition-base);
}

.header-nav a:hover {
  background-color: var(--color-secondary-muted);
}

.header-backdrop {
  position: fixed;
  inset: 0;
  background: var(--color-backdrop);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
  z-index: 90;
}

.header-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

@media (prefers-reduced-motion: reduce) {
  .header-nav a {
    transition: none;
    transform: none;
  }
}

@media (min-width: 768px) {
  .header {
    position: sticky;
    top: 0;
  }

  .header-content {
    height: var(--header-height-desktop);
    max-width: 1024px;
    margin: 0 auto;
  }

  .header-toggle {
    display: none;
  }

  .header-nav {
    position: static;
    transform: none;
    height: auto;
    width: auto;
    max-width: none;
    padding: 0;
    background: transparent;
    box-shadow: none;
  }

  .header-nav a {
    font-weight: 400;
    font-size: var(--font-size-lg);
    position: relative;
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xxs);
    padding: var(--spacing-xs);
    opacity: 0.85;
    transform: scale(var(--scale-md));
    transition:
      opacity var(--duration-normal) var(--ease-soft),
      transform var(--duration-normal) var(--ease-soft),
      color var(--duration-fast) var(--ease-out);
  }

  .header-nav a:hover,
  .header-nav a:focus-visible {
    opacity: 1;
    transform: scale(var(--scale-lg));
  }

  .header-nav a::after {
    content: "";
    position: absolute;
    left: 50%;
    bottom: 0;
    width: 0;
    height: 2px;
    background-color: currentColor;
    opacity: 0.4;
    transform: translateX(-50%);
    transition:
      width var(--duration-fast) var(--ease-out),
      opacity var(--duration-fast) var(--ease-out);
  }

  .header-nav a:hover::after,
  .header-nav a:focus-visible::after {
    width: 100%;
    opacity: 0.8;
  }

  .header-nav ul {
    display: flex;
    align-items: center;
    gap: var(--spacing-xxs);
  }

  .header-nav li {
    margin: 0;
  }

  .header-nav li:first-child {
    display: none;
  }

  .header-nav a {
    font-size: var(--font-size-md);
    padding: var(--spacing-xs) var(--spacing-xs);
  }

  .header-nav li img {
    display: none;
  }

  .header-backdrop {
    display: none;
  }
}