.site-header {
  position: relative;
  z-index: 1000;
  background-color: var(--color-background-primary);
  border-bottom: 1px solid var(--color-border-subtle);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--container-max-width);
  margin-inline: auto;
  padding: var(--space-3) var(--space-4);
  min-height: 72px;
}

.site-header__brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--color-text-primary);
  flex-shrink: 0;
}

.site-header__logo {
  width: 48px;
  height: 48px;
  object-fit: contain;
  display: block;
}

.site-header__brand-text {
  font-family: var(--font-heading);
  font-size: var(--font-size-h3);
  font-weight: var(--font-weight-bold);
  letter-spacing: var(--letter-spacing-heading);
  color: var(--color-accent-primary);
  white-space: nowrap;
}

.site-header__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-small);
  cursor: pointer;
  transition: border-color var(--transition-duration) var(--transition-ease),
    box-shadow var(--transition-duration) var(--transition-ease);
}

.site-header__toggle:hover {
  border-color: var(--color-accent-primary);
}

.site-header__toggle:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(var(--color-accent-glow-rgb), 0.25);
}

.site-header__toggle-line {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-text-primary);
  border-radius: 1px;
  transition: transform var(--transition-duration) var(--transition-ease),
    opacity var(--transition-duration) var(--transition-ease);
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(2) {
  opacity: 0;
}

.site-header__toggle[aria-expanded="true"] .site-header__toggle-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.site-header__nav {
  display: flex;
  align-items: center;
}

.site-header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-header__nav-item {
  margin: 0;
  padding: 0;
}

.site-header__nav-link {
  display: inline-block;
  padding: var(--space-2) 0;
  font-size: var(--font-size-body);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  text-decoration: none;
  position: relative;
  transition: color var(--transition-duration) var(--transition-ease);
  white-space: nowrap;
}

.site-header__nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-accent-primary);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-duration) var(--transition-ease);
}

.site-header__nav-link:hover {
  color: var(--color-accent-primary);
}

.site-header__nav-link:hover::after,
.site-header__nav-link:focus-visible::after {
  transform: scaleX(1);
}

.site-header__nav-link:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
  border-radius: var(--radius-small);
}

@media (max-width: 991px) {
  .site-header__inner {
    flex-wrap: wrap;
  }

  .site-header__toggle {
    display: flex;
  }

  .site-header__nav {
    display: none;
    width: 100%;
    order: 3;
    background-color: var(--color-background-primary);
    border-top: 1px solid var(--color-border-subtle);
    padding: var(--space-3) var(--space-4);
    max-height: calc(100vh - 72px);
    overflow-y: auto;
  }

  .site-header__nav.is-open {
    display: block;
  }

  .site-header__nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-2);
  }

  .site-header__nav-link {
    display: block;
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-small);
  }

  .site-header__nav-link::after {
    display: none;
  }

  .site-header__nav-link:hover {
    background-color: rgba(var(--color-accent-primary-rgb), 0.1);
  }
}

@media (max-width: 575px) {
  .site-header__inner {
    padding: var(--space-2) var(--space-3);
    min-height: 64px;
  }

  .site-header__logo {
    width: 40px;
    height: 40px;
  }

  .site-header__brand-text {
    display: none;
  }

  .site-header__nav {
    max-height: calc(100vh - 64px);
  }
}