PHP login system

when i trying to insert username/password(already created them on database MySql) get a lot of errors:

Notice: Undefined variable: password in C:\xampp\htdocs\One1\login.php on line 11

Notice: Undefined variable: db in C:\xampp\htdocs\One1\login.php on line 19

Notice: Undefined variable: sq1 in C:\xampp\htdocs\One1\login.php on line 19

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\One1\login.php on line 19

Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, null given in C:\xampp\htdocs\One1\login.php on line 20 YOu didn't enter the correct details! this is my code: