It seemed to work now. I could set top and bottom padding to 100px and the slogan narrowed nicely:
padding: 100px 0 100px 0; /* Vary the padding for greater or lesser height */
However, when the slogan narrows, it does not maintain the background parallax image vertically centered. That is, when the slogan section is now not so high, it is showing the upper part of the background image, but I would like the background image to also remain centred.
I would like to have a look at the actual page to decide on the exact code which can achieve this. We can use media queries to change the height (padding) so that the image remains centered to the extent possible. Will need to reduce the text size as well. Can you pls post a private message with a link to the page. Thanks!