.answer {font-weight:bolder;font-color:blue;}
  #a1, #a2, #a3, #a4, #a5, #a6, #a7, #a8, #a9, #a10, #a11, #a12, #a13 {display:none;}
  #button_answer {display:none;}
  .secondbg {background-color: #cccccc;}
  #result, #result2, #result3, #result4,#result5, #result6, #result7, #result8, #result9, #result10, #result11, #result12, #result13 {font-weight:bold;color:blue}