Baseline joint fit to fundamental-mode, first-overtone RR Lyrae, and type-II Cepheids in Galactic GC. Colors indicate different stellar types: blue for RRab, green for RRc, yellow for T2Cep, and red for stars excluded by the outlier rejection. Circles mark stars in hosts, while downward-pointing triangles denote stars in anchors. Top: absolute magnitudes, corrected for metallicity, plotted against log P. For hosts, $M_{i,j}^W=m_{i,j}^W-{\mu }_{0,i}-{\alpha }_M({[\mathrm{Fe}/\mathrm{H}]}_{i,j}-{[\mathrm{Fe}/\mathrm{H}]}_0)$; for anchors, an additional −Δ μ_{0, i} term applies. Colored dashed lines show the fitted PLR. Bottom: residuals between the corrected magnitudes and the fitted PLR, with dashed lines marking the residual standard deviation. The inset (bottom right) shows the residual distributions.