.site-header {
  position: fixed;
  z-index: 100;
  top: 0;
  left: 0;
  width: 100%;
  border-bottom: 1px solid transparent;
  background: var(--color-glass-soft);
  transition:
    background var(--transition-base),
    border-color var(--transition-base),
    box-shadow var(--transition-base);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.site-header.is-scrolled,
.site-header.is-menu-open {
  border-color: var(--color-line);
  background: var(--color-glass);
  box-shadow: 0 0.75rem 2.2rem rgba(0, 0, 0, 0.18);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.header-inner {
  min-height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
}

.site-logo {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  padding: 0.3rem;
}

.site-logo picture {
  display: block;
}

.site-logo img {
  width: auto;
  height: min(var(--logo-desktop-height, 52px), calc(var(--header-height) - 1rem));
  max-width: min(19rem, 31vw);
  object-fit: contain;
  object-position: left center;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: clamp(1.5rem, 3vw, 3rem);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(1.15rem, 2vw, 2rem);
}

.nav-list a {
  position: relative;
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  color: var(--color-paper-muted);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: color var(--transition-fast);
}

.nav-list a::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0.45rem;
  left: 0;
  height: 1px;
  transform: scaleX(0);
  transform-origin: right;
  background: var(--color-accent-light);
  transition: transform var(--transition-base);
}

.nav-link-icon {
  display: none;
  flex: 0 0 auto;
}

.menu-toggle {
  display: none;
}

.icon-button {
  min-width: 2.75rem;
  height: 2.75rem;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding-inline: 0.7rem;
  border: 1px solid var(--color-line);
  background: transparent;
  color: var(--color-paper);
  cursor: pointer;
}

.icon-button svg {
  width: 1.15rem;
  height: 1.15rem;
}

.icon-button [data-menu-icon] {
  display: grid;
  place-items: center;
}

.icon-button [data-menu-icon][hidden] {
  display: none;
}

.menu-button-label {
  color: var(--color-paper-muted);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.button {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.65rem;
  min-height: 3.25rem;
  padding: 0.85rem 1.15rem;
  border: 1px solid transparent;
  border-radius: var(--radius-xs);
  font-size: var(--text-sm);
  font-weight: 700;
  line-height: 1.2;
  cursor: pointer;
  transition:
    color var(--transition-fast),
    background var(--transition-fast),
    border-color var(--transition-fast),
    transform var(--transition-fast);
}

.button svg {
  width: 1.05rem;
  height: 1.05rem;
  transition: transform var(--transition-fast);
}

.button--compact {
  min-height: 2.75rem;
  padding: 0.65rem 0.9rem;
  font-size: var(--text-xs);
}

.button--accent {
  background: var(--color-accent);
  color: var(--color-ink);
}

.button--ghost {
  border-color: var(--color-line-strong);
  background: rgba(255, 255, 255, 0.025);
  color: var(--color-paper);
}

.button--disabled {
  border-color: var(--color-line);
  background: rgba(255, 255, 255, 0.04);
  color: var(--color-text-muted);
  cursor: not-allowed;
  opacity: 0.85;
}

.button--light {
  border-color: var(--color-ink);
  background: var(--color-ink);
  color: var(--color-paper);
}

@media (hover: hover) and (pointer: fine) {
  .nav-list a:hover {
    color: var(--color-paper);
  }

  .nav-list a:hover::after {
    transform: scaleX(1);
    transform-origin: left;
  }

  .button:not(:disabled):hover {
    transform: translateY(-0.12rem);
  }

  .button:not(:disabled):hover svg {
    transform: translate(0.1rem, -0.05rem);
  }

  .button--accent:hover {
    background: var(--color-accent-light);
  }

  .button--ghost:hover {
    border-color: var(--color-accent);
    color: var(--color-accent-light);
  }

  .button--light:hover {
    background: transparent;
    color: var(--color-ink);
  }
}

@supports not ((backdrop-filter: blur(1rem)) or (-webkit-backdrop-filter: blur(1rem))) {
  .site-header,
  .site-header.is-scrolled,
  .site-header.is-menu-open {
    background: var(--color-surface);
  }
}