Untitled

<?php
  include("includes/connect.php");
  $error = "";

  if($_SERVER["REQUEST_METHOD"] == "POST") {
    $User = mysqli_real_escape_string($db,$_POST['User']);
    $Email = mysqli_real_escape_string($db,$_POST['Email']);
    $Pass = mysqli_real_escape_string($db,$_POST['Pass']);
    $RPass = mysqli_real_escape_string($db,$_POST['RPass']);
    if ($Pass == $RPass) {
      $sqlquery = "SELECT ID FROM users WHERE Email='$Email'";
      $sqlresult = $db->query($sqlquery);
      $sqlquery1 = "SELECT ID FROM users WHERE User='$User'";
      $sqlresult1 = $db->query($sqlquery1);
      if ($sqlresult->num_rows == 0) {
        if ($sqlresult1->num_rows == 0) {
          $options = [
              'cost' => 12,
          ];
          $hash = password_hash($Pass, PASSWORD_BCRYPT, $options);
          $sqlinsert = "INSERT INTO users (User, Pass, Email) VALUES ('$User', '$hash', '$Email')";
          $db->query($sqlinsert);
          header("location: login.php");
        }else {
          $error = "Username is already in use";
        }
      } else {
        $error = "Email is already in use";
      }

    } else {
      $error = "Passwords didnt match";
    }
  }
 ?>
<html>
  <head>
    <title>ASG | Signup</title>
      <style type = "text/css">
         body {
            font-family:Arial, Helvetica, sans-serif;
            font-size:14px;
         }
         label {
            font-weight:bold;
            width:100px;
            font-size:14px;
         }
         .box {
            border:#666666 solid 1px;
            margin: 1px;
         }
         .submit {
           border: lightgray solid 1px;
           background-color: white;
           color: black;
           text-align: center;
           text-decoration: none;
           display:inline-block;
           font-size: 16px;
           padding: 4px 12px 4px 12px;
           margin-top: 4px;
         }
         .submit:hover{
           background-color: lightgray;
           border: black solid 1px;
         }
      </style>
  </head>
  <body>
    <form action="" method="post">
      <label>Username: </label><input type="text" name="User" class="box"><br>
      <label>E-mail: </label><input type="email" name="Email" class="box"><br>
      <label>Password: </label><input type="password" name="Pass" class="box"><br>
      <label>Repeat Password: </label><input type="password" name="RPass" class="box"><br>
      <input type="submit" class="submit"><p style = "font-size:15px; color:#cc0000; margin-top:10px; font-weight: bold;"><?php echo $error; ?></p>
    </form>
  </body>
</html>