site: add RU/EN language toggle with full i18n on landing

server/site/css/style.css

@@ -104,6 +104,30 @@ ul { list-style: none; }
 
 .nav-cta:hover { background: var(--accent-soft); transform: translateY(-1px); }
 
+.nav-right {
+  display: flex;
+  align-items: center;
+  gap: 16px;
+}
+
+.lang-toggle {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  padding: 8px 12px;
+  border: 1px solid rgba(255, 255, 255, 0.12);
+  border-radius: 8px;
+  background: transparent;
+  color: var(--text-secondary);
+  font-size: 13px;
+  font-weight: 600;
+  letter-spacing: 0.4px;
+  cursor: pointer;
+  transition: color .2s ease, border-color .2s ease, background .2s ease;
+}
+
+.lang-toggle:hover { color: var(--text); border-color: rgba(255, 255, 255, 0.3); background: rgba(255, 255, 255, 0.04); }
+
 /* ---------- Hero ---------- */
 
 .hero {
@@ -804,6 +828,7 @@ ul { list-style: none; }
 
 @media (max-width: 720px) {
   .nav-links { display: none; }
+  .nav-cta { display: none; }
   .section { padding: 90px 20px; }
   .features-grid, .news-grid, .theme-grid { grid-template-columns: 1fr; }
   .server-stats { grid-template-columns: 1fr; }