anchor.diff:          (:nav :class "navbar navbar-inverse navbar-fixed-top" :role "navigation"
             (:div :class "container"
               (:div :class "navbar-header"
  +              (:button :type "button" :class "navbar-toggle" :data-toggle "collapse" :data-target "#llthw-navbar-collapse-1"
  +                (:span :class "sr-only" "Toggle Navigation")
  +                (:span :class "icon-bar")
  +                (:span :class "icon-bar")
  +                (:span :class "icon-bar"))
                 (:a :class "navbar-brand" :href "/" (str (format nil "L(~C)THW" #\greek_small_letter_lamda))))
  -            (:ul :class "nav navbar-nav"
  -              (:li (:a :href "/" "Home"))
  -              (:li (:a :href "/book/" "Book"))
  -              (:li (:a :href "/resources/" "Resources"))
  -              (:li :class "active" (:a :href "/try-lisp/" "Try Lisp"))
  -              (:li (:a :href "/get-lisp/" "Get Lisp"))
  -              (:li (:a :href "/donate/" "Donations")))
  -          (:form :class "navbar-form navbar-right" :role "search"
  -            (:div :class "form-group"
  -              (:select :id "reference-search" :style "width: 325px; min-width: 325px;"
  -                (:option)
  -                (reference-search))))))
  +            (:div :class "collapse navbar-collapse" :id "llthw-navbar-collapse-1"
  +              (:ul :class "nav navbar-nav"
  +                (:li (:a :href "/" "Home"))
  +                (:li (:a :href "/book/" "Book"))
  +                (:li (:a :href "/resources/" "Resources"))
  +                (:li :class "active" (:a :href "/try-lisp/" "Try Lisp"))
  +                (:li (:a :href "/get-lisp/" "Get Lisp"))
  +                (:li (:a :href "/donate/" "Donations")))
  +              (:form :class "navbar-form navbar-right hidden-xs" :role "search"
  +                (:div :class "form-group"
  +                  (:select :id "reference-search" :style "width: 325px; min-width: 325px;"
  +                    (:option)
  +                    (reference-search)))))))
           (:div :class "jumbotron trylisphead" :id "overview"
             (:div :class "container"
               (:div :class "row"
                 (:div :class "col-md-12"
  -                (:h1 "L(λ)THW" (:small "Try Common Lisp"))
  +                (:h1 :class "hidden-xs" "L(λ)THW" (:small "Try Common Lisp"))
  +                (:h1 :class "visible-xs" "Try Common Lisp")
                   (:p "&nbsp;")))
  -            (:div :class "row"
  +            (:div :class "row visible-xs"
  +              (:div :class "col-xs-12"
  +                (:p :class "lead"
  +                  "The In-Browser REPL is not available on mobile phones.  Please visit this site on a tablet or desktop computer to use this feature.")))
  +            (:div :class "row hidden-xs"
                 (:div :class "col-md-6" :id "trylispbody"
                   ,@body)
                 (:div :class "col-md-6"
  
positive.code:         (:a :name "top" :id "top")
          (:div :class "jumbotron subhead" :id "overview"
            (:div :class "container"
              (:h1 :class "title" "L(λ)THW " (:small "Learn Lisp The Hard Way"))
              (:p :class "lead" ,subtitle)))
          (:div :class "container" :id "body"
            (:div :class "row"
  
negative.code:                   (:a :href "/get-lisp/" "Get Lisp"))
                  (:li :title "Donations" :class (str (if (string= ,section "donations") "active" " "))
                    (:a :href "/donate/" "Donations")))
                  (:form :class "navbar-form navbar-right hidden-xs" :role "search"
                    (:div :class "form-group"
                      (:select :id "reference-search" :style "width: 325px; min-width: 325px;"
                        (:option)
  