HTML Template milestone objects (such as lines and designs) not appearing in the email

Hello Community,

As the title says, i have HTML template that is used in a send an email task.
When i view the code in a html viewer it loads correctly without any issues, but when it's being viewed from the user prespective , in the sent email, its totally different, missing css elements and not alligned well.

Can it be something related to the .html code am using, or can't be due to the way different email clients handle CSS, especially for HTML emails.

Is there any limitations from appsheet side when it comes to using CSS elements as an email template ?

If needed, i can provide the .html code if needed.

html Viewer: