Extending the height of Gallery to the top

Hello there! 

I'm trying to extend the Gallery: Slideshow Reel to the top of the page so that the menu bar area would not be white, I've attached the image of how I'd like it to look like.  

Currently, i've used this to remove the header background: 

// Invisible header background //
.tweak-fixed-header .header .header-announcement-bar-wrapper {
    background: transparent !important;
}

Appreciate if someone is able to help me with this. 

Add to Home > Design > Custom CSS

.homepage section:first-child {
    padding-top: 0 !important;
}

It works! Thank you so much @tuanphan Appreciate it!

How can I do the same but not for the home page, say a Portfolio landing page? I have no experience with coding.  @tuanphan Thanks!