Changing color of the line in the header

In logiscargo, there is a border in the header in default header type.  Please note the black arrows in below image.

To change its color, please put following style in themeoptions/customcss box.

#header:before { border-bottom:  1px solid #000000; }
#header:after { border-bottom:  1px solid #FFFFFF; }

As you note there are 2 border bottoms, the first one is a border of 1px and second line adds a shadow after first. Please change the color code to hex code of your desired color.

In case you want to remove this border at all, please use below style.

#header:before, #header:after { display: none; }

If you are using Header2 ...

then please use below styles to change the color.

.header_2 #top-bar, #header2 { border-bottom: 1px solid #000000; }

and below style to remove the border at all.

.header_2 #top-bar, #header2 { border-bottom: none;}