/* ==========================================================================
   Header / nav / mobile menu / footer / persistent mobile CTA
   ========================================================================== */

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  background: oklch(13.5% 0.02 260 / 72%);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-bottom: 1px solid transparent;
  transition: border-color var(--d-med) var(--ease-soft),
              background var(--d-med) var(--ease-soft);
}

.site-header.is-stuck {
  border-bottom-color: var(--border);
  background: oklch(13.5% 0.02 260 / 92%);
}

.nav {
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-4);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--s-2);
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.brand img {
  height: 28px;
  width: 28px;
  border-radius: 8px;
  transition: transform var(--d-med) var(--ease-expo);
}
.brand:hover img { transform: rotate(-8deg) scale(1.08); }

.nav-links {
  display: none;
  align-items: center;
  gap: var(--s-8);
  font-size: var(--t-sm);
  font-weight: 500;
}

.nav-links a {
  position: relative;
  color: var(--muted);
  padding-block: var(--s-1);
  transition: color var(--d-fast) ease;
}

.nav-links a::after {
  content: '';
  position: absolute;
  left: 0; right: 100%;
  bottom: -3px;
  height: 1.5px;
  background: var(--accent);
  border-radius: 2px;
  transition: right var(--d-med) var(--ease-expo);
}

.nav-links a:hover { color: var(--text); }
.nav-links a[aria-current="true"] { color: var(--text); }
.nav-links a:hover::after,
.nav-links a[aria-current="true"]::after { right: 0; }

.nav-right { display: flex; align-items: center; gap: var(--s-3); }
.nav-right .nav-cta { display: none; }

/* Hamburger */
.burger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  border: 1px solid var(--border-2);
  border-radius: var(--r-sm);
  flex-shrink: 0;
  transition: border-color var(--d-fast) ease, background var(--d-fast) ease;
}
.burger:hover { border-color: var(--border-3); }

.burger span {
  width: 17px;
  height: 1.5px;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--d-med) var(--ease-expo), opacity var(--d-fast) ease;
}
.burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; transform: scaleX(0.4); }
.burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* Scroll progress */
.rail {
  position: absolute;
  left: 0; right: 0; bottom: -1px;
  height: 2px;
  pointer-events: none;
}
.rail-fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--accent-2), var(--accent));
  border-radius: 0 2px 2px 0;
}

/* ---------- Mobile menu ---------- */
.menu {
  position: fixed;
  inset: var(--header-h) 0 0 0;
  z-index: var(--z-menu);
  background: var(--bg);
  padding: var(--s-8) var(--edge) calc(var(--s-8) + env(safe-area-inset-bottom, 0px));
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: var(--s-8);
  overflow-y: auto;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: opacity var(--d-med) var(--ease-quart),
              transform var(--d-med) var(--ease-quart),
              visibility 0s var(--d-med);
}

.menu.is-open {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  transition: opacity var(--d-med) var(--ease-quart),
              transform var(--d-med) var(--ease-quart),
              visibility 0s;
}

.menu-links { display: flex; flex-direction: column; }

.menu-links a {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--s-4);
  padding-block: var(--s-5);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-display);
  font-size: 1.65rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--text);
  opacity: 0;
  transform: translateY(12px);
}

.menu.is-open .menu-links a {
  animation: menu-in 0.5s var(--ease-expo) forwards;
}

.menu-links a i {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-style: normal;
  color: var(--muted-2);
  letter-spacing: 0.06em;
}

.menu-foot { display: flex; flex-direction: column; gap: var(--s-4); }
.menu-foot .btn { width: 100%; justify-content: center; }
.menu-mail {
  font-family: var(--font-mono);
  font-size: var(--t-sm);
  color: var(--muted);
  letter-spacing: -0.03em;
}

@media (min-width: 900px) {
  .nav-links { display: flex; }
  .nav-right .nav-cta { display: inline-flex; }
  .burger, .menu { display: none; }
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  padding-block: var(--s-16) var(--s-10);
  background: var(--bg-2);
}

.foot-grid {
  display: flex;
  flex-direction: column;
  gap: var(--s-10);
}

.foot-brand-col { display: flex; flex-direction: column; gap: var(--s-4); align-items: flex-start; }

.foot-brand {
  display: flex;
  align-items: center;
  gap: var(--s-2);
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 600;
}
.foot-brand img { height: 24px; width: 24px; border-radius: 7px; }

.foot-tag { color: var(--muted); font-size: var(--t-sm); max-width: 34ch; }

.foot-mail {
  font-family: var(--font-mono);
  font-size: var(--t-sm);
  letter-spacing: -0.03em;
  color: var(--text-2);
  border-bottom: 1px solid var(--border-2);
  padding-bottom: 2px;
  transition: color var(--d-fast) ease, border-color var(--d-fast) ease;
}
.foot-mail:hover { color: var(--accent); border-color: var(--accent); }

.foot-nav { display: grid; grid-template-columns: 1fr 1fr; gap: var(--s-8); }
.foot-col { display: flex; flex-direction: column; gap: var(--s-3); align-items: flex-start; }

.foot-col h4 {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  font-weight: 500;
  color: var(--muted-2);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--s-1);
}

.foot-col a {
  font-size: var(--t-sm);
  color: var(--muted);
  transition: color var(--d-fast) ease, transform var(--d-fast) var(--ease-quart);
}
.foot-col a:hover { color: var(--accent); transform: translateX(3px); }

.to-top {
  margin-top: var(--s-2);
  display: inline-flex;
  align-items: center;
  gap: var(--s-2);
  font-family: var(--font-mono);
  font-size: var(--t-xs);
  letter-spacing: -0.03em;
  border: 1px solid var(--border-2);
  border-radius: var(--r-pill);
  padding: var(--s-2) var(--s-4);
}
.foot-col a.to-top:hover { transform: translateY(-2px); border-color: var(--accent-line); }

.foot-bottom {
  margin-top: var(--s-12);
  padding-top: var(--s-6);
  border-top: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: var(--s-2);
  font-family: var(--font-mono);
  font-size: var(--t-xs);
  letter-spacing: -0.03em;
  color: var(--muted-2);
}

@media (min-width: 760px) {
  .foot-grid { flex-direction: row; justify-content: space-between; align-items: flex-start; }
  .foot-nav { gap: var(--s-16); }
  .foot-bottom { flex-direction: row; justify-content: space-between; align-items: center; }
}

/* ---------- Persistent mobile CTA ---------- */
.cta-bar {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: var(--z-cta);
  display: flex;
  gap: var(--s-3);
  padding: var(--s-3) var(--edge);
  padding-bottom: calc(var(--s-3) + env(safe-area-inset-bottom, 0px));
  background: oklch(13.5% 0.02 260 / 90%);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-top: 1px solid var(--border);
  transition: transform var(--d-med) var(--ease-quart);
}

.cta-bar.is-down { transform: translateY(115%); }
.cta-bar .btn { flex: 1; justify-content: center; padding-inline: var(--s-3); }
.cta-bar .btn-ghost { flex: 0 0 auto; }

@media (min-width: 900px) {
  .cta-bar { display: none; }
}

@media (max-width: 899px) {
  body { padding-bottom: calc(74px + env(safe-area-inset-bottom, 0px)); }
}