Change header height

Try this in Appearance->Customize->Additional CSS

.site-branding {
	padding-top: 10px;
	padding-bottom: 10px;
}

@omercakir it is usually better to start your own topic so that the original author doesn’t get emails.

If you can, please create your own thread here:

https://wordpress.org/support/theme/twentyseventeen/

Additionally, it also appears that your site has a coming soon screen and the normal design isn’t visible.