No worries ??
REM is a relative value, whereas px (pixels) is static, meaning it will always be that size, but rem is relative. Being relative means that the size will self-adjust based on the window size the page is being viewed in. This helps make the sizing responsive.
I could give you a px value height for the banner image, but it would require more modifications, but let’s try this method first…
Copy and paste this into your Additional CSS tab of the Customizer:
#site-branding {
padding: calc(3rem + 7vw) 0;
}
The above code will still keep your banner responsive and auto-size the height based on what the person is viewing the page(s) on (desktop, phone, tablet, etc). You can still adjust that 7vw to whatever works best for you. For example, making it 6vw
.
ALTERNATIVE:
If you want to make sure your banner is always 400px, you can try this code:
@media (min-width: 1200px) {
#site-branding {
padding: 0;
height: 400px;
display: flex;
align-items: center;
flex-direction: column;
justify-content: center;
}
}
This makes the padding 0 pixels top, right, bottom, and left for the text area. Then, it will make that container always 400px in height–whether the page is being viewed on a desktop, phone, or tablet. The last few lines simply make the text stay centered and in the middle.
Try the first code option or if you want the fixed height, try the second code snippet above.