diff --git a/doc/Makefile.am b/doc/Makefile.am
index 62f3ae2b6a27..c1a518af2714 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -10,7 +10,7 @@
 # never built as part of a regular build. They are only built when explicitly
 # asked for. See comment further down.
 SUBDIRS = manpages user
-AM_MAKEFLAGS = DESTDIR=${DESTDIR} infodir=${infodir}
+AM_MAKEFLAGS = DESTDIR=${DESTDIR} infodir=${infodir} doczdir=${abs_srcdir}
 
 MANPAGE_BUILDDIR = manpages/_build/man
 
diff --git a/doc/developer/Makefile b/doc/developer/Makefile
index 9807a750bf7d..a3b90656b1e5 100644
--- a/doc/developer/Makefile
+++ b/doc/developer/Makefile
@@ -1 +1 @@
-include ../frr-sphinx.mk
+include $(doczdir)/frr-sphinx.mk
diff --git a/doc/developer/conf.py b/doc/developer/conf.py
index 3f531c14b081..e2293b2a6b01 100644
--- a/doc/developer/conf.py
+++ b/doc/developer/conf.py
@@ -157,7 +157,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'classic'
+html_theme = 'default'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
diff --git a/doc/manpages/Makefile b/doc/manpages/Makefile
index ebbbc31009af..1950b76fc9cd 100644
--- a/doc/manpages/Makefile
+++ b/doc/manpages/Makefile
@@ -1,4 +1,4 @@
-include ../frr-sphinx.mk
+include ${doczdir}/frr-sphinx.mk
 
 # -----------------------------------------------------------------------------
 # Automake requires that 3rd-party Makefiles recognize these targets.
diff --git a/doc/manpages/conf.py b/doc/manpages/conf.py
index 50331b6f0ace..a78e1a2c3892 100644
--- a/doc/manpages/conf.py
+++ b/doc/manpages/conf.py
@@ -159,7 +159,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'classic'
+html_theme = 'default'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
diff --git a/doc/user/Makefile b/doc/user/Makefile
index ad2abb25c19e..697c3f86fb0f 100644
--- a/doc/user/Makefile
+++ b/doc/user/Makefile
@@ -1,4 +1,4 @@
-include ../frr-sphinx.mk
+include ${doczdir}/frr-sphinx.mk
 
 # -----------------------------------------------------------------------------
 # Automake requires that 3rd-party Makefiles recognize these targets.
diff --git a/doc/user/conf.py b/doc/user/conf.py
index 817a6d83bb8a..efe10237402b 100644
--- a/doc/user/conf.py
+++ b/doc/user/conf.py
@@ -157,7 +157,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'classic'
+html_theme = 'default'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the