/* Shared PhotonBrief navigation.  It inherits LiGRP's blue, gold, measured
   spacing and bilingual hierarchy without importing or changing main-site CSS. */
:root {
  --pb-nav-primary: #00356b;
  --pb-nav-accent: #c09d63;
  --pb-nav-ink: #1d2b3a;
  --pb-nav-muted: #607080;
  --pb-nav-line: rgba(0, 53, 107, 0.12);
  --pb-nav-surface: rgba(255, 255, 255, 0.97);
}

.pb-site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  min-height: 80px;
  border-bottom: 1px solid var(--pb-nav-line);
  background: var(--pb-nav-surface);
  box-shadow: 0 2px 12px rgba(0, 31, 66, 0.05);
  backdrop-filter: blur(12px);
}

.pb-site-nav-shell {
  width: min(1280px, calc(100% - 48px));
  min-height: 80px;
  margin: 0 auto;
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 28px;
}

.pb-site-brand {
  display: inline-flex;
  flex: 0 0 auto;
  flex-direction: column;
  justify-content: center;
  min-width: max-content;
  color: var(--pb-nav-primary);
  text-decoration: none;
}

.pb-site-brand-cn {
  font-family: "Noto Serif SC", "Songti SC", "STSong", Georgia, serif;
  font-size: 19px;
  font-weight: 750;
  letter-spacing: 0.01em;
  line-height: 1.12;
}

.pb-site-brand-en {
  margin-top: 4px;
  color: #66798a;
  font-family: Inter, ui-sans-serif, system-ui, sans-serif;
  font-size: 9px;
  font-weight: 760;
  letter-spacing: 0.1em;
  line-height: 1.15;
  text-transform: uppercase;
}

.pb-primary-nav {
  display: flex;
  align-items: stretch;
  justify-content: flex-end;
  gap: 4px;
}

.pb-primary-nav a {
  position: relative;
  display: inline-flex;
  min-width: 68px;
  flex-direction: column;
  justify-content: center;
  padding: 0 13px;
  color: #2b3d4d;
  font-family: Inter, "Noto Sans SC", "Microsoft YaHei", sans-serif;
  font-size: 13px;
  font-weight: 720;
  line-height: 1.12;
  text-align: center;
  text-decoration: none;
  transition: color 150ms ease, background-color 150ms ease;
}

.pb-primary-nav a > small {
  display: block;
  margin-top: 4px;
  color: #7b8994;
  font-size: 8px;
  font-weight: 650;
  letter-spacing: 0.055em;
  line-height: 1;
  text-transform: uppercase;
}

.pb-primary-nav a::after {
  position: absolute;
  right: 13px;
  bottom: 0;
  left: 13px;
  height: 3px;
  background: transparent;
  content: "";
  transition: background-color 150ms ease;
}

.pb-primary-nav a:hover,
.pb-primary-nav a:focus-visible {
  color: var(--pb-nav-primary);
  background: rgba(0, 53, 107, 0.035);
  outline: none;
}

.pb-primary-nav a:hover::after,
.pb-primary-nav a:focus-visible::after,
.pb-primary-nav a[aria-current="page"]::after {
  background: var(--pb-nav-accent);
}

.pb-primary-nav a[aria-current="page"] {
  color: var(--pb-nav-primary);
}

.pb-primary-nav .pb-main-link {
  min-width: 96px;
  margin-left: 8px;
  color: var(--pb-nav-primary);
  border-left: 1px solid var(--pb-nav-line);
}

.pb-primary-nav .pb-main-link::after {
  display: none;
}

.pb-nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  align-self: center;
  padding: 11px 9px;
  border: 1px solid var(--pb-nav-line);
  background: #fff;
  color: var(--pb-nav-primary);
  cursor: pointer;
}

.pb-nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  margin: 3px 0;
  background: currentColor;
}

.pb-nav-toggle:focus-visible {
  outline: 3px solid rgba(192, 157, 99, 0.45);
  outline-offset: 2px;
}

@media (max-width: 840px) {
  .pb-site-nav-shell {
    width: min(100% - 32px, 1280px);
    min-height: 70px;
  }

  .pb-site-header { min-height: 70px; }
  .pb-nav-toggle { display: block; }
  .pb-primary-nav {
    position: absolute;
    top: 100%;
    right: 0;
    left: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 16px 14px;
    border-bottom: 1px solid var(--pb-nav-line);
    background: #fff;
    box-shadow: 0 8px 16px rgba(0, 31, 66, 0.09);
  }

  .pb-site-header[data-pb-open="true"] .pb-primary-nav { display: flex; }
  .pb-primary-nav a,
  .pb-primary-nav .pb-main-link {
    min-height: 47px;
    min-width: 0;
    align-items: flex-start;
    padding: 8px 14px;
    text-align: left;
    border-left: 0;
    border-bottom: 1px solid rgba(0, 53, 107, 0.08);
  }

  .pb-primary-nav .pb-main-link { margin-left: 0; }
  .pb-primary-nav a::after { right: auto; left: 0; width: 3px; height: auto; top: 8px; bottom: 8px; }
}

@media (max-width: 430px) {
  .pb-site-nav-shell { width: min(100% - 24px, 1280px); }
  .pb-site-brand-cn { font-size: 17px; }
}