.scheme           { color: brown; margin: 4pt; }  /* background punctuation */
.scheme .keyword  { color: rgb(68,0,203); font-weight: bold; }
.scheme .builtin  { color: navy;   }
.scheme .variable { color: black;  }
.scheme .global   { color: purple; }
.scheme .selfeval { color: green;  }
.scheme .comment  { color: teal;   }