Tax row is misaligned in order confirmation email

[thdoan]

Preconditions

1. Magento 2.1.5

Steps to reproduce

1. Set up tax rules.
2. Place an order.

Expected result

1. The Tax row should be aligned with the other rows in the order summary table.

Actual result

1. The Tax row is misaligned:

The reason this is happening is because the <tr> for the Tax row should have four <td> instead of two.

[thdoan]

Never mind -- this was caused by the custom theme.