diff --git a/collects/scribble/html-render.ss b/collects/scribble/html-render.ss
index fe8f4525..fddce7da 100644
--- a/collects/scribble/html-render.ss
+++ b/collects/scribble/html-render.ss
@@ -130,7 +130,8 @@
                   `((,(case (length number)
                         [(0) 'h2]
                         [(1) 'h3]
-                        [else 'h4])
+                        [(2) 'h4]
+                        [else 'h5])
                      ,@(format-number number '((tt nbsp)))
                      ,@(if (part-tag d)
                            `((a ((name ,(format "~a" `(part ,(part-tag d)))))))
diff --git a/collects/scribble/manual.ss b/collects/scribble/manual.ss
index d01ed7af..521add3b 100644
--- a/collects/scribble/manual.ss
+++ b/collects/scribble/manual.ss
@@ -180,7 +180,8 @@
 
   ;; ----------------------------------------
 
-  (provide defproc defproc* defstruct defthing defform defform* defform/subs defform*/subs defform/none
+  (provide defproc defproc* defstruct defthing defparam
+           defform defform* defform/subs defform*/subs defform/none
            specform specform/subs 
            specsubform specsubform/subs specspecsubform specspecsubform/subs specsubform/inline
            schemegrammar schemegrammar*
@@ -240,8 +241,10 @@
                  (lambda () (list desc ...)))]))
   (define-syntax defstruct
     (syntax-rules ()
+      [(_ name fields #:immutable desc ...)
+       (*defstruct (quote-syntax name) 'name 'fields #t (lambda () (list desc ...)))]
       [(_ name fields desc ...)
-       (*defstruct (quote-syntax name) 'name 'fields (lambda () (list desc ...)))]))
+       (*defstruct (quote-syntax name) 'name 'fields #f (lambda () (list desc ...)))]))
   (define-syntax (defform*/subs stx)
     (syntax-case stx ()
       [(_ #:literals (lit ...) [spec spec1 ...] ([non-term-id non-term-form ...] ...) desc ...)
@@ -342,6 +345,10 @@
     (syntax-rules ()
       [(_ id result desc ...)
        (*defthing (quote-syntax id) 'id 'result (lambda () (list desc ...)))]))
+  (define-syntax defparam
+    (syntax-rules ()
+      [(_ id arg contract desc ...)
+       (defproc* ([(id) contract] [(id [arg contract]) void?]) desc ...)]))
   (define-syntax schemegrammar
     (syntax-rules ()
       [(_ #:literals (lit ...) id clause ...) (*schemegrammar '(lit ...) 
@@ -587,7 +594,7 @@
                                          (map symbol->string (car wrappers)))))))
          (cdr wrappers))))
 
-  (define (*defstruct stx-id name fields content-thunk)
+  (define (*defstruct stx-id name fields immutable? content-thunk)
     (define spacer (hspace 1))
     (make-splice
      (cons
@@ -613,10 +620,13 @@
                                  (map (lambda (f)
                                         (list name '- (car f)))
                                       fields)
-                                 (map (lambda (f)
-                                        (list 'set- name '- (car f) '!))
-                                      fields)))))
-                            ,(map car fields))))))))
+                                 (if immutable?
+                                     null
+                                     (map (lambda (f)
+                                            (list 'set- name '- (car f) '!))
+                                          fields))))))
+                     ,(map car fields)
+                     ,@(if immutable? '(#:immutable) null))))))))
         (map (lambda (v)
                (cond
                 [(pair? v)
diff --git a/collects/scribble/scheme.ss b/collects/scribble/scheme.ss
index c820bad7..c762f205 100644
--- a/collects/scribble/scheme.ss
+++ b/collects/scribble/scheme.ss
@@ -111,7 +111,7 @@
       (define advance
         (case-lambda
          [(c init-line! delta)
-          (let ([c (+ delta (syntax-column c))]
+          (let ([c (+ delta (or (syntax-column c) 0))]
                 [l (syntax-line c)])
             (let ([new-line? (and l (l . > . line))])
               (when new-line?
diff --git a/collects/scribble/scribble.css b/collects/scribble/scribble.css
index 887ca883..2310f499 100644
--- a/collects/scribble/scribble.css
+++ b/collects/scribble/scribble.css
@@ -69,10 +69,6 @@
                 margin-right: 0em;
                }
 
-               h1,h2,h3,h4,h5,h6 {
-               margin-top: .5em;
-               }
-
                .toclink { 
                text-decoration: none;
                color: blue;