/* ---------- 顶栏 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: var(--stroke);
  background: var(--paper);
}

.site-header-inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.site-title {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-head);
  font-size: 24px;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--ink);
  text-decoration: none;
}

.logo-badge {
  width: 40px;
  height: 40px;
  flex: none;
  display: grid;
  place-items: center;
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 800;
  background: var(--accent);
  border: var(--stroke);
  box-shadow: var(--shadow-md);
  color: var(--on-accent);
}

.nav-desktop {
  display: none;
  flex: 1;
  min-width: 0;
  align-items: center;
  justify-content: flex-start;
  flex-wrap: wrap;
  gap: 2px;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.02em;
  padding: 8px 10px;
  text-decoration: none;
  border: 2px solid transparent;
  transition: background 0.12s ease, border-color 0.12s ease, box-shadow 0.12s ease;
}

.nav-link:hover,
.nav-link--active {
  background: var(--accent);
  border-color: var(--black);
  color: var(--on-accent);
}

.nav-link--active {
  box-shadow: var(--shadow-sm);
}

.nav-link--search {
  margin-left: auto;
}


.header-tools {
  display: flex;
  align-items: center;
  gap: 8px;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  color: var(--on-accent);
  background: var(--accent);
  border: var(--stroke);
  box-shadow: var(--shadow-md);
  padding: 0;
  text-decoration: none;
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}

.icon-btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: var(--shadow);
}

.icon-btn:active {
  transform: translate(3px, 3px);
  box-shadow: var(--shadow-press);
}

.icon-btn svg {
  width: 18px;
  height: 18px;
}

.icon-btn--menu svg {
  width: 20px;
  height: 20px;
}

.nav-mobile {
  border-top: var(--stroke);
  background: var(--paper);
}

.nav-mobile-link {
  display: block;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
  padding: 14px 16px;
  text-decoration: none;
  border-top: var(--stroke-thin);
  transition: background 0.12s ease;
}

.nav-mobile-link:first-child {
  border-top: none;
}

.nav-mobile-link:hover,
.nav-mobile-link--active {
  background: var(--accent);
  color: var(--on-accent);
}

@media (min-width: 768px) {
  .site-header-inner {
    min-height: 72px;
  }

  .site-title {
    font-size: 28px;
  }

  .logo-badge {
    width: 44px;
    height: 44px;
    font-size: 20px;
  }

  .nav-desktop {
    display: flex;
  }

  .header-tools,
  .nav-mobile {
    display: none;
  }
}