fix: change units of max content width from vw to %

This is necessary to correctly calculate the width
of the content container.

Author: alsolovyev

src/frontend/styles/layout.pcss

@@ -30,7 +30,7 @@
     @media (--desktop) {
       max-width: min(
         calc(var(--layout-width-main-col) + var(--max-space-between-cols) + var(--layout-sidebar-width)),
-        calc(100vw - var(--layout-sidebar-width))
+        calc(100% - var(--layout-sidebar-width))
       );
       margin-left: max(var(--main-col-min-margin-left), calc(50vw - var(--layout-sidebar-width) - var(--layout-width-main-col) / 2) - var(--layout-padding-horizontal));
       margin-right: auto;