View Compilation Error

0_0_13747455_28625.cpp:3:2: error: invalid preprocessing directive #a1
 #a1:hover{
  ^
0_0_13747455_28625.cpp:9:2: error: invalid preprocessing directive #a1
 #a1{
  ^
0_0_13747455_28625.cpp:15:2: error: invalid preprocessing directive #a2
 #a2{
  ^
0_0_13747455_28625.cpp:1:1: error: expected unqualified-id before '<' token
 <div id="a1"><div id="a2"></div>Click me</div>
 ^
0_0_13747455_28625.cpp:2:1: error: expected declaration before '}' token
 }
 ^