.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: var(--z-header);
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: transform var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}
.site-header.is-stuck { border-bottom-color: var(--line); }
.site-header.is-hidden { transform: translateY(-100%); }

.site-header__inner {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
}

/* Logo ---------------------------------------------------------------- */
.logo {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  font-family: var(--font-display);
  font-size: 1.3rem;
  letter-spacing: 0;
  line-height: 1;
}
.logo__mark {
  width: 26px; height: 26px;
  border: 1.5px solid var(--text);
  border-radius: 50%;
  position: relative;
  flex: none;
  transition: border-color var(--dur) var(--ease), transform var(--dur-slow) var(--ease-out);
}
.logo__mark::after {
  content: "";
  position: absolute;
  inset: 5px;
  background: var(--accent);
  border-radius: 50%;
  transform: scale(.75);
  transition: transform var(--dur) var(--ease-out);
}
.logo:hover .logo__mark { transform: rotate(180deg); }
.logo:hover .logo__mark::after { transform: scale(1); }

/* Desktop nav --------------------------------------------------------- */
.nav { display: none; }
@media (min-width: 1024px) {
  .nav { display: flex; align-items: center; gap: clamp(1rem, 2.2vw, 2.25rem); }
}

.nav__link {
  position: relative;
  font-size: var(--fs-sm);
  font-weight: 500;
  letter-spacing: .01em;
  padding-block: .35rem;
  color: var(--text-muted);
  transition: color var(--dur-fast) var(--ease);
}
.nav__link::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--dur) var(--ease-out);
}
.nav__link:hover { color: var(--text); }
.nav__link:hover::after { transform: scaleX(1); transform-origin: left; }
.nav__link.is-current { color: var(--text); }
.nav__link.is-current::after { transform: scaleX(1); background: var(--accent); }

/* Header actions ------------------------------------------------------ */
.header-actions { display: flex; align-items: center; gap: var(--space-3); }

.theme-toggle {
  width: 38px; height: 38px;
  display: grid; place-items: center;
  border: 1px solid var(--line);
  border-radius: var(--r-full);
  color: var(--text-muted);
  transition: color var(--dur-fast) var(--ease),
              border-color var(--dur-fast) var(--ease),
              transform var(--dur-fast) var(--ease);
}
.theme-toggle:hover { color: var(--text); border-color: var(--line-strong); transform: rotate(18deg); }
.theme-toggle svg { width: 17px; height: 17px; }
.theme-toggle .icon-moon { display: none; }
[data-theme="dark"] .theme-toggle .icon-moon { display: block; }
[data-theme="dark"] .theme-toggle .icon-sun  { display: none; }

.header-actions .btn { display: none; }
@media (min-width: 1024px) { .header-actions .btn { display: inline-flex; } }

/* Burger -------------------------------------------------------------- */
.burger {
  width: 38px; height: 38px;
  display: grid; place-items: center;
  border: 1px solid var(--line);
  border-radius: var(--r-full);
  position: relative;
  z-index: calc(var(--z-menu) + 1);
}
@media (min-width: 1024px) { .burger { display: none; } }

.burger__bars { width: 15px; height: 9px; position: relative; }
.burger__bars span {
  position: absolute; left: 0;
  width: 100%; height: 1.5px;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--dur) var(--ease-out), opacity var(--dur-fast) var(--ease);
}
.burger__bars span:nth-child(1) { top: 0; }
.burger__bars span:nth-child(2) { bottom: 0; }
.burger[aria-expanded="true"] .burger__bars span:nth-child(1) { transform: translateY(3.75px) rotate(45deg); }
.burger[aria-expanded="true"] .burger__bars span:nth-child(2) { transform: translateY(-3.75px) rotate(-45deg); }

/* Mobile menu --------------------------------------------------------- */
.mobile-menu {
  position: fixed;
  inset: 0;
  z-index: var(--z-menu);
  background: var(--bg);
  display: flex;
  flex-direction: column;
  padding: calc(var(--header-h) + 2rem) var(--gutter) var(--space-7);
  clip-path: inset(0 0 100% 0);
  transition: clip-path var(--dur-slow) var(--ease-out);
  visibility: hidden;
  overflow-y: auto;
}
.mobile-menu.is-open { clip-path: inset(0 0 0 0); visibility: visible; }

.mobile-menu__list { display: grid; gap: .35rem; margin-bottom: auto; }

.mobile-menu__link {
  display: flex;
  align-items: baseline;
  gap: var(--space-4);
  font-family: var(--font-display);
  font-size: clamp(2rem, 9vw, 3rem);
  line-height: 1.15;
  letter-spacing: 0;
  padding-block: .3rem;
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--dur) var(--ease) calc(var(--i, 0) * 55ms + 120ms),
              transform var(--dur-slow) var(--ease-out) calc(var(--i, 0) * 55ms + 120ms),
              color var(--dur-fast) var(--ease);
}
.mobile-menu.is-open .mobile-menu__link { opacity: 1; transform: translateY(0); }
.mobile-menu__link:hover { color: var(--accent); }
.mobile-menu__link.is-current { color: var(--accent); }
.mobile-menu__link span {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--text-muted);
  letter-spacing: .1em;
}

.mobile-menu__foot {
  border-top: 1px solid var(--line);
  padding-top: var(--space-5);
  display: grid;
  gap: var(--space-4);
  font-size: var(--fs-sm);
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.site-footer {
  background: var(--bg-alt);
  border-top: 1px solid var(--line);
  padding-block: var(--space-9) var(--space-6);
  margin-top: auto;
}

.footer-cta {
  display: grid;
  gap: var(--space-6);
  padding-bottom: var(--space-9);
  border-bottom: 1px solid var(--line);
  align-items: end;
}
@media (min-width: 900px) {
  .footer-cta { grid-template-columns: 1.5fr auto; gap: var(--space-8); }
}
.footer-cta__title { font-size: var(--fs-3xl); max-width: 14ch; }

.footer-grid {
  display: grid;
  gap: var(--space-7);
  padding-block: var(--space-8) var(--space-7);
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 170px), 1fr));
}
@media (min-width: 900px) {
  .footer-grid { grid-template-columns: 1.6fr repeat(3, 1fr); }
}

.footer-col__title {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-4);
}
.footer-col ul { display: grid; gap: .7rem; }
.footer-col a {
  font-size: var(--fs-sm);
  color: var(--text-muted);
  position: relative;
  transition: color var(--dur-fast) var(--ease);
}
.footer-col a:hover { color: var(--text); }

.footer-brand p {
  max-width: 34ch;
  font-size: var(--fs-sm);
  color: var(--text-muted);
  margin-top: var(--space-4);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4) var(--space-6);
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-5);
  border-top: 1px solid var(--line);
  font-size: var(--fs-xs);
  color: var(--text-muted);
}
.footer-bottom ul { display: flex; flex-wrap: wrap; gap: var(--space-5); }

.socials { display: flex; gap: var(--space-2); }
.socials a {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border: 1px solid var(--line);
  border-radius: var(--r-full);
  color: var(--text-muted);
  transition: all var(--dur-fast) var(--ease);
}
.socials a:hover {
  color: var(--accent-contrast);
  background: var(--text);
  border-color: var(--text);
  transform: translateY(-2px);
}
[data-theme="dark"] .socials a:hover { color: var(--bg); background: var(--text); }
.socials svg { width: 15px; height: 15px; }