Sections with fixed height

Hello,

All the pages on my website start with a "Hero" section.
That is, a section with a background image and a title plus a supporting tagline.

I need to create a class suffix so that all Hero sections have the same height (for example, 70vh).

I managed to do that with this CSS, but the content inside the section is not vertically centered — it stays at the top, so I have to manually add padding:

.hero-fixed-height {
height: 70vh;
position: relative;
overflow: hidden;
}

How can I center it?
Thank you.