How to transparent header background only on one page?

I know I can make a transparent header background by editing the design in wix editor. But I want to make a transparent header background only on the main page using velo.
I know how to change the color. But I can’t make it transparent.

This code can change the color and work only on one page.
$w ( “#header1” ). style . backgroundColor = “#516298” ;

Color code transparent doesn’t work (#xxxxxx00)( rgba (x, x, x, 0 ))
$w ( “#header1” ). style . backgroundColor = “#51629800” ;
$w ( “#header1” ). style . backgroundColor = " rgba ( 100 , 100 , 100 , 0 );

Please help me.

(I’m Japanese. My English may be wrong.)

Also, this doesn’t work
$w ( “#header1” ). style . backgroundColor =col ;

maybe you should change your code from

$w ( “#header1” ). style . backgroundColor = " rgba ( 100 , 100 , 100 , 0 );

to

$w ( “#header1” ). style . backgroundColor = " rgba ( 100 , 100 , 100 , 0 )";