.theme-base,:root{--bg:#ffffff;--surface:#ffffff;--text-primary:#111827;--text-secondary:#6B7280;--border-soft:#e5e7eb;--shadow-dark:0 1px 3px rgba(0,0,0,0.1);--shadow-light:0 1px 2px rgba(0,0,0,0.06)}.theme-base,.theme-vocab,:root{--accent-50:#eff6ff;--accent-500:#3B82F6;--accent-600:#2563EB}.theme-grammar{--accent-50:#ecfdf5;--accent-500:#10B981;--accent-600:#059669}.theme-legacy{--bg:#ffffff;--surface:#ffffff;--text-primary:#111827;--text-secondary:#6B7280;--border-soft:#e5e7eb;--shadow-dark:0 1px 3px rgba(0,0,0,0.1);--shadow-light:0 1px 2px rgba(0,0,0,0.06);--accent-50:#eff6ff;--accent-500:#3B82F6;--accent-600:#2563EB}