how can I make the login form transparent?

This is how you can make the Login Form transparent:

1. Add this css to Server Module-> Custom css:

.frmLogin .x-window-body
{
  background-color: transparent !important;
}

2. Make the form color in design time to 'clNone'.

3. Form Login->ClientEvents->UniEvents->BeforeInit:

function window.beforeInit(sender, config)
{
  config.baseCls='frmLogin';
}

It will make totally transparent with no border, only controls will appear.  

I use Extjs 6.5