diff --git a/scribble-doc/scribblings/scribble/core.scrbl b/scribble-doc/scribblings/scribble/core.scrbl
index e928d2d244..e8ae765011 100644
--- a/scribble-doc/scribblings/scribble/core.scrbl
+++ b/scribble-doc/scribblings/scribble/core.scrbl
@@ -597,6 +597,9 @@ The recognized @tech{style properties} are as follows:
        multiple @litchar{,}-separated labels and generate a suitable set of
        references. See also @racketmodname[scriblib/book-index].}
 
+ @item{@racket[initial-scale] structure --- For HTML, adjusts the initial
+       scale for responsive views, such as on mobile devices.}
+
 ]
 
 The @racket[to-collect] field contains @techlink{content} that is
@@ -1984,6 +1987,14 @@ via @racket[head-addition] appear before additions via @racket[head-extra].
 @history[#:added "1.38"]}
 
 
+@defstruct[initial-scale ([value (real-in 0.0 10.0)])]{
+
+Adjusts @litchar{initial-scale} in a @litchar{meta} tag with name
+@litchar{viewport}. The default is @racket[1.0].
+
+@history[#:added "1.61"]}
+
+
 @defstruct[render-convertible-as ([types (listof (or/c 'png-bytes 'svg-bytes 'gif-bytes))])]{
  For a @racket[part] that corresponds to an HTML page,
  controls how objects that subscribe to the @racketmodname[file/convertible]
diff --git a/scribble-doc/scribblings/scribble/manual.scrbl b/scribble-doc/scribblings/scribble/manual.scrbl
index 02655cb5d3..653a4932d2 100644
--- a/scribble-doc/scribblings/scribble/manual.scrbl
+++ b/scribble-doc/scribblings/scribble/manual.scrbl
@@ -4,7 +4,9 @@
           (for-label scribble/manual-struct
                      racket/list
                      version/utils
-                     syntax/quote))
+                     syntax/quote
+                     (only-in scribble/html-properties
+                              initial-scale)))
 
 @(define lit-ellipses (racket ...))
 @(define lit-ellipses+ (racket ...+))
@@ -2500,6 +2502,9 @@ For HTML rendering:
        @filepath{scribble} collection is added as a
        @racket[css-style-addition].}
 
+ @item{The document's initial scale (for responsive modes such as mobile
+       devices) via a @racket[(initial-scale "0.8")] style property.}
+
 ]
 
 To obtain this configuration without using @racket[@#,hash-lang[]
diff --git a/scribble-lib/scribble/html-properties.rkt b/scribble-lib/scribble/html-properties.rkt
index 25382f6f3a..23ccbe3bc8 100644
--- a/scribble-lib/scribble/html-properties.rkt
+++ b/scribble-lib/scribble/html-properties.rkt
@@ -33,4 +33,5 @@
 
  [head-extra ([xexpr xexpr/c])]
  [head-addition ([xexpr xexpr/c])]
+ [initial-scale ([value (real-in 0.0 10.0)])]
  [render-convertible-as ([types (listof (or/c 'png-bytes 'svg-bytes 'gif-bytes))])])
diff --git a/scribble-lib/scribble/html-render.rkt b/scribble-lib/scribble/html-render.rkt
index 8403ebce69..b5ba0fe10c 100644
--- a/scribble-lib/scribble/html-render.rkt
+++ b/scribble-lib/scribble/html-render.rkt
@@ -828,6 +828,9 @@
     (define/public (extract-show-language-family d ri)
       (extract-inherited d ri (lambda (v) (eq? v 'show-language-family)) values))
 
+    (define/public (extract-part-initial-scale d ri)
+      (extract-inherited d ri initial-scale? initial-scale-value))
+
     (define/public (part-nesting-depth d ri)
       0)
 
@@ -883,12 +886,17 @@
                  (copy-port in (current-output-port)))))
           (parameterize ([xml:empty-tag-shorthand xml:html-empty-tags])
             (xml:write-xexpr
+              ;; Adding newlines before `>` closers can make editing
+              ;; the generated HTML (for experiments) nicer:
+              ;; #:insert-newlines? #t
               `(html ,(style->attribs (part-style d))
                  (head ()
                    (meta ([http-equiv "content-type"]
                           [content "text/html; charset=utf-8"]))
                    (meta ([name "viewport"]
-                          [content "width=device-width, initial-scale=0.8"]))
+                          [content ,(format "width=device-width, initial-scale=~a"
+                                            (or (extract-part-initial-scale d ri)
+                                                "1.0"))]))
                    ,title
                    ,(scribble-css-contents scribble-css
                                            scribble-css-path
diff --git a/scribble-lib/scribble/manual-style.css b/scribble-lib/scribble/manual-style.css
index e30c4da1ed..752137225d 100644
--- a/scribble-lib/scribble/manual-style.css
+++ b/scribble-lib/scribble/manual-style.css
@@ -318,6 +318,7 @@ a:hover {
     position: sticky;
     top: 0;
     left: 100%;
+    width: 13em;
     margin-top: -4.75em;
     margin-right: -15em;
     font-size: 70%;
diff --git a/scribble-lib/scribble/private/manual-defaults.rkt b/scribble-lib/scribble/private/manual-defaults.rkt
index ce68f6507f..fae41c34ec 100644
--- a/scribble-lib/scribble/private/manual-defaults.rkt
+++ b/scribble-lib/scribble/private/manual-defaults.rkt
@@ -20,7 +20,8 @@
                               (css-style-addition
                                (scribble-file "manual-racket.css"))
                               (js-style-addition
-                               (scribble-file "manual-racket.js")))
+                               (scribble-file "manual-racket.js"))
+                              (initial-scale 0.8))
                 #t))
 
 (define-on-demand manual-doc-style
diff --git a/scribble-lib/scribble/scribble.css b/scribble-lib/scribble/scribble.css
index d465c2032d..28ae1d5faa 100644
--- a/scribble-lib/scribble/scribble.css
+++ b/scribble-lib/scribble/scribble.css
@@ -218,8 +218,8 @@ table td {
   white-space: nowrap;
   left: 2em;
   height: 0em;
-  width: 13em;
-  margin: 0em -13em 0em 0em;
+  width: 10.5em;
+  margin: 1.5em -13em 0em 0em;
   font-size: small;
 }
 
@@ -282,6 +282,15 @@ table td {
   margin: 0 0 0 0;
 }
 
+/* narrow display => inline right-hand margin notes */
+@media screen and (max-width: 55em) {
+    .refpara, .refelem, .reffootnote {
+        all: unset !important;
+        display: block !important;
+        margin: 1em 0 !important;
+        padding: 0.75em !important;
+    }
+}
 
 /* ---------------------------------------- */
 /* Table of contents, inline */