/* ============================================================
   Brain-site nav — hamburger + slide-from-left drawer.
   Pattern adapted from gabrielpenman.co.uk. Phosphor icons load
   from CDN; until they arrive, drawer items still render text.
   ============================================================ */

/* ---- Header line ---- */
.site-header {
  display: flex;
  align-items: center;
  gap: 12px;
}
.site-header .brand {
  font-family: var(--font-serif);
  font-size: 22px;
  text-decoration: none;
  color: var(--fg);
  letter-spacing: -0.005em;
}
.nav-spacer { flex: 1; }

/* Personal-site whisper-link, far right. */
.nav-personal {
  font-family: var(--font-sans);
  font-size: 11px;
  font-style: italic;
  color: var(--fg-faint);
  opacity: 0.55;
  text-decoration: none;
  white-space: nowrap;
  letter-spacing: 0.01em;
  transition: opacity 200ms, color 200ms;
}
.nav-personal:hover {
  opacity: 1;
  color: var(--fg-muted);
  text-decoration: none;
}
@media (max-width: 600px) {
  .nav-personal { display: none; }
}

/* ---- Hamburger — two-bar morph-to-X ---- */
.nav-burger {
  background: transparent;
  border: 0;
  padding: 6px 14px 6px 0;
  cursor: pointer;
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  gap: 6px;
  color: var(--fg);
  transition: color 160ms;
  margin-right: 4px;
}
.nav-burger:hover { color: var(--accent); }
.burger-bar {
  display: block;
  width: 22px;
  height: 1.5px;
  background: currentColor;
  border-radius: 1px;
  transition: transform 240ms cubic-bezier(0.2,0.6,0.2,1);
  transform-origin: center;
}
/* Shell renders three bars; third hidden so we get two-bar look
   without forking the shared template. */
.burger-bar:nth-child(3) { display: none; }
.nav-burger[aria-expanded="true"] .burger-bar:nth-child(1) {
  transform: translateY(3.75px) rotate(45deg);
}
.nav-burger[aria-expanded="true"] .burger-bar:nth-child(2) {
  transform: translateY(-3.75px) rotate(-45deg);
}

/* ---- Drawer (slide from left) ---- */
.nav-drawer {
  position: fixed;
  top: 0;
  left: 0;
  height: 100dvh;
  width: 320px;
  max-width: 86vw;
  background: var(--bg);
  border-right: 1px solid var(--rule);
  z-index: 100;
  transform: translateX(-100%);
  transition: transform 280ms cubic-bezier(0.2,0.6,0.2,1);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0;
  padding-bottom: 24px;
}
.nav-drawer:not([hidden]) { transform: translateX(0); }
.nav-drawer[hidden] {
  display: flex !important;
  visibility: hidden;
  pointer-events: none;
}

.nav-backdrop {
  position: fixed;
  inset: 0;
  background: color-mix(in oklch, var(--fg) 30%, transparent);
  z-index: 90;
  opacity: 0;
  transition: opacity 220ms;
  backdrop-filter: blur(2px);
}
.nav-backdrop:not([hidden]) { opacity: 1; }
.nav-backdrop[hidden] { display: block !important; pointer-events: none; visibility: hidden; opacity: 0; }

.nav-drawer-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px 6px;
  border-bottom: 1px solid var(--rule);
}
.nav-drawer-brand {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 18px;
  color: var(--accent);
}
.nav-drawer-close {
  background: transparent;
  border: 0;
  padding: 6px;
  font-size: 22px;
  color: var(--fg-muted);
  cursor: pointer;
  line-height: 1;
}
.nav-drawer-close:hover { color: var(--fg); }

.nav-drawer-section {
  display: flex;
  flex-direction: column;
  padding: 12px 6px;
  border-bottom: 1px solid var(--rule);
}
.nav-drawer-section:last-of-type { border-bottom: 0; }
.nav-drawer-section h3 {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: var(--ls-caps);
  color: var(--fg-faint);
  margin: 6px 12px 2px;
}
.nav-drawer-section a,
.nav-drawer-section button {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-sans);
  font-size: var(--t-sm);
  color: var(--fg);
  text-decoration: none;
  padding: 9px 12px;
  border: 0;
  background: transparent;
  border-radius: 2px;
  cursor: pointer;
  transition: background 120ms, color 120ms;
}
.nav-drawer-section a:hover,
.nav-drawer-section button:hover {
  background: var(--bg-sunk);
  color: var(--fg);
  text-decoration: none;
}
.nav-drawer-section a > i,
.nav-drawer-section button > i {
  font-size: 18px;
  width: 20px;
  text-align: center;
  flex-shrink: 0;
  color: var(--fg-muted);
}
.nav-drawer-section a:hover > i {
  color: var(--accent);
}

@media (prefers-reduced-motion: reduce) {
  .nav-burger .burger-bar,
  .nav-drawer { transition: none; }
}