anchor.diff:  	    (:h1 :id "intro1" (:a :href "#" :onclick "hideDiv(\"intro\"); showDiv(\"info\"); showDiv(\"help\"); return false;"
   				 "In this lesson, you will learn the parts of a solar sail spacecraft that make it work."))
   	    ;; Skip intro
  -	    (:h2 :id "skip" (:a :href "#" :onclick "hideDiv(\"intro\"); showDiv(\"info\"); showDiv(\"help\"); return false;" "Skip intro")))
  +	    (:h3 :id "skip" (:a :href "#" :onclick "hideDiv(\"intro\"); showDiv(\"info\"); showDiv(\"help\"); return false;" "Skip intro")))
   
         (:div :id "info"
   	    (:h1 "Parts of a Solar Sail")
  -	    (:h2 "Challenges:")
  +	    (:h3 "Challenges:")
   	    (:ul
  -	     (:li "Click on " (:em "Help") " and learn how the interface works. Click on it again to make it disappear.")
  -	     (:li "Try to find the 4 major parts of the sail by clicking on different areas. Read about each one."))
  +	     ;;(:li "Click on " (:em "Help") " and learn how the interface works. Click on it again to make it disappear.")
  +	     (:li "Click on different areas of the sail to read about the 4 major parts."))
   	    (:div :id "sails" :class "hidden"
  -		  (:h2 "Sails")
  +		  (:h3 "Sails")
   		  (:ul
   		   (:li "The sails are large, thin, reflective sheets that are pushed by sunlight.")
   		   (:li "Current designs use a thin film of space qualified plastic like Kapton that is coated with a mirrored layer of aluminum.")
   		   (:li "For more information see: " (:a :target "_blank" :href "http://wiki.solarsails.info/index.php/Category:Sail_Film" "Sail Film"))))
   	    (:div :id "booms" :class "hidden"
  -		  (:h2 "Booms")
  +		  (:h3 "Booms")
   		  (:ul
  -		   (:li "Something needs to hold the sails flat so they don't collapse under the gentle pressure of sunlight.")
  -		   (:li "Many sail designs use structural booms in a kite-shape to keep the sail flat against the gentle pressure of sunlight.")
  +		   (:li "The booms are structural members that hold the sails flat so they can reflect sunlight without collapsing.")
   		   (:li (:a :target "_blank" :href "http://wiki.solarsails.info/index.php/IKAROS" "IKAROS") " spins, using centripetal acceleration to hold the sail flat.")
   		   (:li "For more information see: "
   			(:ul
   			 (:li (:a :target "_blank" :href "http://wiki.solarsails.info/index.php/Three-Axis_Stabilized" "Three-Axis Stabilized"))
   			 (:li (:a :target "_blank" :href "http://wiki.solarsails.info/index.php/Category:Spin_Stabilized" "Spin Stabilized"))))))
   	    (:div :id "bus" :class "hidden"
  -		  (:h2 "Spacecraft bus")
  +		  (:h3 "Spacecraft bus")
   		  (:p "The spacecraft bus houses all the systems required to operate the sail and carry out the mission. It typically contains:")
   		  (:ul
   		   (:li "Flight computer")
  
positive.code: 		   (:li "Scientific instruments and other payloads")
  		   (:li "Navigation and steering sensors")))
  	    (:div :id "vanes" :class "hidden"
  		  (:h2 "Steering vanes")
  		  (:ul
  		   (:li "Steering vanes are small sails at the boom tips that can rotate.")
  		   (:li "They push the main sail to point in the direction you want to go.")
  
negative.code: 		   (:li "For more information see: " (:a :target "_blank" :href "http://wiki.solarsails.info/index.php/Category:Attitude_Control" "Attitude Control")))))
        
        (:div :id "help"
  	    (:h2 (:a :href "#" :onclick "toggleDiv(\"helpText\"); toggleDiv(\"info\"); toggleDiv(\"nav\"); return false;" "Help"))
  	    (:div :id "helpText"
  		  (:ul
  		   (:li "Click or tap on the parts of the sail for a description.")
  		  (:li "Keyboard and Mouse:"
  		       (:ul
  			(:li "Zoom by rolling the mouse wheel up and down, or holding the middle mouse button and moving up and down.")
  			(:li "Rotate the view by holding the left mouse button, and moving the mouse left, right, up, and down.")))
  		  (:li "Touchscreen:"
  		       (:ul
  