Space between description and branding img

Hi everyone,

I am currently trying to reduce the space between site description and branding image in my site header, but can’t seem to find the relevant parameter in the css sheet. The code says as follows :

#site-description {
	color: #7a7a7a;
	font-size: 14px;
	margin: 0 270px 3.65625em 0;
}
#branding img {
	height: auto;
	margin-bottom: -7px;
	width: 100%;
}

Anyone has an idea on the subject ?
Thx !
https://www.levastemonde.org