/* ============================================================
   navigation.css — sticky site header + primary nav
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--rule-soft);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 1rem;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.site-header__mark {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
}
.site-header__mark img {
  width: 28px;
  height: 41px;
  display: block;
}
.site-header__mark span {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink-strong);
}

.site-nav {
  display: flex;
  gap: clamp(1rem, 2.5vw, 2.25rem);
  align-items: center;
}
.site-nav a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--ink-muted);
  transition: color 0.2s;
}
.site-nav a:hover { color: var(--accent); }
.site-nav a.cta {
  color: var(--paper);
  background: var(--ink-strong);
  padding: 0.5rem 0.875rem;
  border-radius: 1px;
  transition: background 0.2s;
}
.site-nav a.cta:hover { background: var(--accent-deep); color: var(--paper); }

@media (max-width: 640px) {
  .site-nav a:not(.cta) { display: none; }
}