Please help me out from 1 hour struggling.

[problem]

Without CSS, checkbox multiple will be displayed on the left top.

But applying CSS, the checkbox symbol is separated from checkbox value, located on CSS top and left (640, 390). But its value stays on the (0, 0).

[Code]

$dbc=....

 $query1 = "SELECT * FROM classroom_start";
 $result1= mysqli_query($con, $query1);
 
 if(mysqli_num_rows($result1)){
  $room_array = array();
 while($row1 = mysqli_fetch_array($result1))
   {  
     $room_array[] = $row1[1];
     
   } //while
 }

 for($i=0; $i<sizeof($room_array);$i++){

   $room_name = 'room' . $ room_array [$i];
   echo '<input id="checkbox' .  room_array[$i]  . '" type="checkbox" name="checkboxvar[]" value="' . $room_name . '"/>';     //$room_name value is display still on the left top after CSS. Just the checkbox symbol  is located on the top and left of CSS.
 }
 
 

[css]
 #checkbox1{
 
   position:fixed;
    left: 640px;
    top: 390px;
    background: green;
}