.site-nav { position: sticky; top: 0; z-index: 100; background: var(--color-bg); border-bottom: 1px solid var(--color-border); }
.site-nav-inner { display: flex; align-items: center; justify-content: space-between; height: var(--nav-height); }
.site-nav-logo img { height: 36px; width: auto; }
.site-nav-dropdown { position: relative; }
.site-nav-submenu {
  display: none; position: absolute; top: 100%; left: -16px; min-width: 200px; padding: 8px 0;
  background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius);
}
.site-nav-submenu a { display: block; padding: 8px 16px; }
.site-nav-dropdown:hover .site-nav-submenu, .site-nav-dropdown:focus-within .site-nav-submenu { display: block; }
.site-nav-links { display: flex; align-items: center; gap: 32px; font-size: 15px; font-weight: 500; }
.site-nav-links > a:not(.btn):hover, .site-nav-dropdown > a:hover { color: var(--color-accent); }
.site-nav-toggle { display: none; flex-direction: column; gap: 5px; }
.site-nav-toggle span { width: 24px; height: 2px; background: var(--color-text); }

@media (max-width: 768px) {
  .site-nav-toggle { display: flex; }
  .site-nav-links {
    display: none; position: absolute; top: var(--nav-height); left: 0; right: 0;
    flex-direction: column; gap: 20px; padding: 24px var(--gutter);
    background: var(--color-bg); border-bottom: 1px solid var(--color-border);
  }
  .site-nav-links.is-open { display: flex; }
  .site-nav-links { align-items: flex-start; }
  .site-nav-submenu { display: block; position: static; border: 0; padding: 8px 0 0 16px; min-width: 0; }
  .site-nav-submenu a { padding: 6px 0; }
}

/* EN / 中文 switch */
.lang-switch { padding: 6px 12px; border: 1px solid var(--color-border); border-radius: 999px; font-size: 13px; line-height: 1; color: var(--color-muted); transition: border-color .2s, color .2s; }
.lang-switch:hover { border-color: var(--color-primary); color: var(--color-primary); }
.site-nav-links > a.lang-switch::after { display: none; }