From 56f02cc19e3fd5cb570fb1385029a4409d1e4adb Mon Sep 17 00:00:00 2001
From: "liu-yang.dz" <liu-yang@founder.com.cn>
Date: Fri, 22 May 2026 20:57:12 +0800
Subject: [PATCH] fix(theme-default): stabilize horizontal layout across pages
 with/without vertical scrollbar

On browsers using classic (space-occupying) vertical scrollbars, navigating
between a page that triggers the scrollbar and one that does not caused the
top nav, content area, and local nav to shift horizontally by ~15 px at
viewport widths >= 1440 px. The desktop layout's `100vw`-based centering
math is constant, but the container it applies to has `width: 100%` and
therefore tracks `html.clientWidth`, which shrinks when the scrollbar
appears.

Setting `overflow-y: scroll` on `html` reserves the scrollbar gutter at all
times, making `html.clientWidth` constant and the layout pixel-stable
across navigations. Overlay-scrollbar browsers (macOS Safari, mobile
Chrome) are unaffected since overlay scrollbars never consumed layout
space.

`scrollbar-gutter: stable` was considered but produced no effect in the
reporter's browser, suggesting incomplete propagation of the property to
viewport-relative measurements; `overflow-y: scroll` is the universal,
lowest-friction fix.
---
 src/client/theme-default/styles/base.css | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/client/theme-default/styles/base.css b/src/client/theme-default/styles/base.css
index 8041b6bc..d3b82973 100644
--- a/src/client/theme-default/styles/base.css
+++ b/src/client/theme-default/styles/base.css
@@ -22,6 +22,7 @@ html {
   line-height: 1.4;
   font-size: 16px;
   -webkit-text-size-adjust: 100%;
+  overflow-y: scroll;
 }
 
 html.dark {