.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 40;
  backdrop-filter: blur(18px);
  background: linear-gradient(
    to bottom,
    rgba(5, 5, 12, 0.96),
    rgba(5, 5, 12, 0.88),
    rgba(5, 5, 12, 0.78),
    transparent
  );
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-normal), background-color var(--transition-normal),
    box-shadow var(--transition-normal), transform 0.25s ease-out;
}

.site-header.is-sticky {
  background: rgba(5, 5, 12, 0.98);
  border-bottom-color: var(--color-border-subtle);
  box-shadow: 0 14px 30px rgba(0, 0, 0, 0.75);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 15px 1.5rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

/* Fill the box with the logo content; crop any extra padding in the image file */
.brand-logo {
  width: 140px;
  height: 56px;
  border-radius: 10px;
  object-fit: cover;
  object-position: center center;
  display: block;
}

.primary-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 1.7rem;
  margin: 0;
  padding: 0;
}

.nav-link {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  position: relative;
  padding-bottom: 4px;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(
    90deg,
    oklch(60% 0.16 264.665),
    oklch(46% 0.15 264.665)
  );
  transition: width var(--transition-fast);
}

.nav-link:hover::after {
  width: 100%;
}

.nav-link:hover {
  color: #fff;
}

.nav-link.nav-active {
  color: #fff;
}

.nav-link.nav-active::after {
  width: 100%;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
  border: none;
  background: transparent;
  cursor: pointer;
  transition: transform 0.2s ease;
}

.nav-toggle-bar {
  width: 22px;
  height: 2px;
  background: #f5f5f5;
  border-radius: 999px;
  transition: transform 0.25s ease, opacity 0.2s ease;
}

/* Close button: only visible inside the mobile drawer */
.nav-close {
  display: none;
}

@media (max-width: 768px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav-close {
    display: flex;
    align-items: center;
    justify-content: center;
    position: absolute;
    top: max(1rem, env(safe-area-inset-top));
    right: max(1rem, env(safe-area-inset-right));
    width: 44px;
    height: 44px;
    padding: 0;
    border: none;
    background: transparent;
    color: var(--color-text-muted);
    cursor: pointer;
    font-size: 1.35rem;
    transition: color var(--transition-fast), transform var(--transition-fast);
    z-index: 1;
  }

  .nav-close:hover {
    color: #fff;
  }

  .nav-close:active {
    transform: scale(0.95);
  }

  .brand-logo {
    width: 110px;
    height: 44px;
  }

  .header-inner {
    padding: 12px 1.5rem;
  }

  .primary-nav {
    position: fixed;
    left: -320px;
    top: 0;
    bottom: 0;
    width: 300px;
    max-width: calc(100vw - 2rem);
    z-index: 50;
    padding: 80px 1.5rem 2rem;
    padding-left: max(1.5rem, env(safe-area-inset-left));
    margin: 0;
    background: rgba(8, 8, 14, 0.98);
    visibility: hidden;
    pointer-events: none;
    transition: left 0.5s cubic-bezier(0.4, 0, 0.2, 1),
      visibility 0.5s step-end;
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.5);
    border: none;
    overflow-y: auto;
    overflow-x: visible;
    box-sizing: border-box;
    /* Ensure panel is anchored to viewport left (nav is outside header to avoid backdrop-filter containing block) */
  }

  .primary-nav.is-open {
    left: 0;
    visibility: visible;
    pointer-events: auto;
    transition: left 0.5s cubic-bezier(0.4, 0, 0.2, 1),
      visibility 0s step-start;
  }

  /* When drawer is open: remove backdrop-filter (so fixed nav is viewport-relative) and raise z-index so drawer is above the overlay and links are clickable */
  body.nav-open .site-header {
    backdrop-filter: none;
    z-index: 50;
  }

  body.nav-open::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: 45;
    background: rgba(0, 0, 0, 0.45);
    pointer-events: auto;
    animation: nav-overlay-fade 0.35s ease forwards;
  }

  .primary-nav .nav-list {
    margin: 0;
    padding: 0;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-list li {
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    margin: 0;
  }

  .nav-list li:first-child .nav-link {
    padding-top: 0;
  }

  .nav-list li:last-child {
    border-bottom: none;
  }

  .nav-list .nav-link {
    display: block;
    padding: 0.85rem 0;
    font-size: 1rem;
  }
}

@media (max-width: 480px) {
  .header-inner {
    padding: 12px 1rem;
  }

  .primary-nav {
    left: -300px;
    width: 280px;
    max-width: calc(100vw - 2rem);
    padding: 72px 1.25rem 1.5rem;
    padding-left: max(1.25rem, env(safe-area-inset-left));
  }

  .primary-nav.is-open {
    left: 0;
  }
}

@keyframes nav-overlay-fade {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}