fix CSS path in static <pkg>/doc/index.html and improve navigation

git-svn-id: https://svn.r-project.org/R/trunk@88230 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: smeyer

doc/manual/R-ints.texi

@@ -2558,8 +2558,9 @@ file name of the installed @R{} code, if present).
 
 All installed packages, whether they had any @file{.Rd} files or not,
 have @file{help} and @file{html} directories. The latter normally only
-contains the single file @file{00Index.html}, the package index which
-has hyperlinks to the help topics (if any).
+contains the files @file{00Index.html}, the package index which
+has hyperlinks to the help topics (if any), and @file{R.css},
+a copy of the default stylesheet.
 
 Directory @file{help} contains files @file{AnIndex}, @file{paths.rds}
 and @file{@var{pkgname}.rd[bx]}.  The latter two files are a lazy-load

src/library/tools/R/Vignettes.R

@@ -1,7 +1,7 @@
 #  File src/library/tools/R/Vignettes.R
 #  Part of the R package, https://www.R-project.org
 #
-#  Copyright (C) 1995-2024 The R Core Team
+#  Copyright (C) 1995-2025 The R Core Team
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by
@@ -1058,12 +1058,15 @@ function(x, ...)
 
 ### * .writeVignetteHtmlIndex
 
-## NB SamplerCompare has a .Rnw file which produces no R code.
 .writeVignetteHtmlIndex <-
 function(pkg, con, vignetteIndex = NULL)
 {
-    ## FIXME: in principle we could need to set an encoding here
-    html <- c(HTMLheader("Vignettes and other documentation"),
+    html <- c(HTMLheader("Vignettes and other documentation",
+                         up = "../html/00Index.html",
+                         css = "../html/R.css", # installed since R 2.13.0
+                         ## relative paths to 'top' and 'logo' will only work
+                         ## for the (site-)library in RHOME (or dynamic help)
+                         Rhome = "../../.."),
               paste0("<h2>Vignettes from package '", pkg,"'</h2>"),
               if(NROW(vignetteIndex) == 0L) ## NROW(NULL) = 0
                   "The package contains no vignette meta-information."