/* ============================================================================
   Topbar, nav, brand, search, theme toggle, footer, breadcrumb
   ============================================================================ */

.topbar {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: color-mix(in oklch, var(--bg-0) 82%, transparent);
  backdrop-filter: blur(20px) saturate(1.4);
  -webkit-backdrop-filter: blur(20px) saturate(1.4);
  box-shadow: 0 var(--hairline) 0 var(--border-1);
}
.topbar-inner {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 14px 28px;
  display: flex;
  align-items: center;
  gap: var(--s-6);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--s-2);
  font-weight: var(--w-semi);
  letter-spacing: var(--ls-snug);
  font-size: 14px;
  color: inherit;
  text-decoration: none;
  transition: opacity var(--dur-fast) ease;
}
@media (hover: hover) {
  .brand:hover { opacity: 0.75; }
}
.brand-mark {
  font-size: 14px;
  color: var(--accent);
  transform: translateY(-0.5px);
}
.brand-name { color: var(--text-0); }

/* Primary nav */
.nav {
  display: flex;
  gap: var(--s-1);
  margin-left: var(--s-2);
  align-items: center;
}
.nav-link {
  padding: 7px 12px;
  border-radius: var(--r-3);
  font-size: 13px;
  font-weight: var(--w-medium);
  color: var(--text-3);
  text-decoration: none;
  transition: background-color var(--dur-fast) ease, color var(--dur-fast) ease;
}
@media (hover: hover) {
  .nav-link:hover { color: var(--text-1); background: var(--bg-2); }
}
.nav-link.is-active { color: var(--text-0); background: var(--bg-2); }

/* "More" dropdown */
.nav-more { position: relative; }
.nav-more-toggle {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  border: 0;
  background: transparent;
  cursor: pointer;
  font-family: inherit;
}
.nav-more-toggle svg {
  transition: transform var(--dur-fast) var(--ease);
}
.nav-more.is-open .nav-more-toggle svg { transform: rotate(180deg); }

.nav-more-menu {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 180px;
  padding: 6px;
  background: var(--bg-1);
  box-shadow: var(--shadow-3), 0 0 0 var(--hairline) var(--border-1);
  border-radius: var(--r-4);
  z-index: var(--z-dropdown);
  animation: nav-more-in var(--dur-fast) var(--ease-out) both;
}
@keyframes nav-more-in {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: translateY(0); }
}

.nav-more-item {
  display: block;
  padding: 8px 12px;
  border-radius: var(--r-2);
  font-size: 13px;
  color: var(--text-2);
  text-decoration: none;
  transition: background-color var(--dur-fast) ease, color var(--dur-fast) ease;
}
@media (hover: hover) {
  .nav-more-item:hover { background: var(--bg-2); color: var(--text-0); }
}
.nav-more-divider {
  height: var(--hairline);
  background: var(--border-1);
  margin: 4px 8px;
}

/* Topbar tools cluster (search + theme toggle) */
.topbar-tools {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--s-2);
}

/* Search */
.search-box {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  width: 320px;
  background: var(--bg-1);
  box-shadow: inset 0 0 0 var(--hairline) var(--border-1);
  border-radius: var(--r-3);
  transition: box-shadow var(--dur-fast) ease, background-color var(--dur-fast) ease;
}
.search-box:focus-within {
  box-shadow: inset 0 0 0 var(--hairline) var(--border-3), var(--shadow-glow);
  background: var(--bg-0);
}
.search-box svg { color: var(--text-3); flex-shrink: 0; }
.search-box input {
  flex: 1;
  background: transparent;
  border: 0;
  color: var(--text-0);
  font-family: inherit;
  font-size: 14px;
  outline: none;
  min-width: 0;
}
.search-box input::placeholder { color: var(--text-3); }
.search-box kbd {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-3);
  padding: 2px 6px;
  box-shadow: inset 0 0 0 var(--hairline) var(--border-1);
  border-radius: 3px;
  background: var(--bg-0);
}

/* Theme toggle button */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  background: transparent;
  box-shadow: inset 0 0 0 var(--hairline) var(--border-1);
  border: 0;
  border-radius: var(--r-3);
  color: var(--text-2);
  cursor: pointer;
  transition: background-color var(--dur-fast) ease,
              color var(--dur-fast) ease,
              box-shadow var(--dur-fast) ease;
  flex-shrink: 0;
}
@media (hover: hover) {
  .theme-toggle:hover {
    background: var(--bg-2);
    color: var(--text-0);
    box-shadow: inset 0 0 0 var(--hairline) var(--border-2);
  }
}
.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.theme-icon { display: block; }
.theme-icon-sun  { display: none; }
.theme-icon-moon { display: block; }

[data-theme="dark"] .theme-icon-sun  { display: block; }
[data-theme="dark"] .theme-icon-moon { display: none; }


/* ============================================================================
   Main + Footer
   ============================================================================ */

.main {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 24px 28px 72px;
  position: relative;
  z-index: var(--z-base);
}

.footer {
  box-shadow: 0 calc(-1 * var(--hairline)) 0 var(--border-1);
  padding: 24px 28px;
  font-size: 12px;
  color: var(--text-3);
}
.footer-inner {
  max-width: var(--max-wide);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: var(--s-4);
}


/* ============================================================================
   Breadcrumb
   ============================================================================ */

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  color: var(--text-3);
  margin-bottom: 28px;
}
.breadcrumb .sep { color: var(--text-4); }
.breadcrumb .link { color: var(--text-2); text-decoration: none; transition: color var(--dur-fast) ease; }
@media (hover: hover) {
  .breadcrumb .link:hover { color: var(--accent); }
}


/* ============================================================================
   Global link + selection + small text helpers
   ============================================================================ */

a { color: inherit; text-decoration: none; }
.link {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--dur-fast) ease;
}
@media (hover: hover) {
  .link:hover { color: var(--accent-hover); }
}

strong { font-weight: var(--w-semi); }
/* Default <em>: italic in the body font — no typeface swap. */
em { font-style: italic; color: inherit; }
/* Opt-in editorial italic (serif). Reserve for hero headlines and prose. */
.ital {
  font-style: italic;
  font-family: var(--font-serif);
  color: var(--text-0);
}
.mono { font-family: var(--font-mono); font-feature-settings: "tnum", "ss01"; }
.smaller { font-size: 12px; }


/* ============================================================================
   Responsive topbar
   ============================================================================ */

@media (max-width: 900px) {
  .topbar-inner { flex-wrap: wrap; padding: 12px 18px; gap: var(--s-3); }
  .nav { order: 3; width: 100%; overflow-x: auto; scrollbar-width: none; }
  .nav::-webkit-scrollbar { display: none; }
  .topbar-tools { margin-left: auto; }
  .search-box { width: 200px; }
  .main { padding: 24px 18px 60px; }
}
@media (max-width: 560px) {
  .search-box { width: 140px; }
  .search-box kbd { display: none; }
}