diff --git a/bc.css b/bc.css
index 6a9b8e5..1e59045 100644
--- a/bc.css
+++ b/bc.css
@@ -30,6 +30,7 @@ h1,h2,h3{
   color:gray;
   font-style:italic;
 }
+.main{position:absolute;width:100%;height:100%;margin:0;padding:0;}
 /* BG START */
 .bg-white,.hover-bg-white:hover{background-color:white;color:black;}
 .bg-black,.hover-bg-black:hover{background-color:black;color:white;}
@@ -103,6 +104,7 @@ h1,h2,h3{
 .true-serif{font-family:serif;}
 .true-center{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);}
 .left-center{position:absolute;left:50%;transform:translate(-50%);}
+.top-center{top:50%;transform:translate(0,-50%);}
 .full-width{position:absolute;width:100%;}
 .text-left{text-align:left;}
 .text-right{text-align:right;}
@@ -111,3 +113,6 @@ h1,h2,h3{
 .no-select{user-select:none;}
 .point{cursor:pointer;}
 .relative{position:relative;}
+.absolute{position:absolute;}
+.fixed{position:fixed;}
+