How to make header transparent

Hi,

I already made a transparent (text) png logo. I’m still trying to find the best size for my header. This is not the problem.

I’ve been searching the web for houres to find a CSS code to make the header transparent.

Here is my site.

These are all the Custom CSS codes I filled in. Maybe because one of these codes the transparent header doesn’t work. The last 2 codes, #wrapper and #main, I filled in I saw on other sites and it should work… :

`.page-template-template-no-sidebars-php #wrapper,
.page-template-template-blog-no-sidebars-php #wrapper,
.page-template-template-portfolio-no-sidebars-php #wrapper {
max-width:810px;
}

aside.entry-meta {
display:none;
}

#sidebar-header {
float: right;
height: 260px;
margin: -80px 0;
overflow: hidden;width: 728px;
opacity:0.4;
}

#site-title,
#site-description {
margin:30;
font-weight:300;
float:left;
line-height:75px;
}
/*
#wrapper {
position:relative;
max-width:1140px; margin:0 auto;
box-shadow:0 0 18px rgba(0, 0, 0, .4);
overflow:hidden;
/*opacity:0.4;
filter:alpha(opacity=40);*/ /* For IE8 and earlier */
}

#wrapper {
margin-top: 0px;

padding: 0 0px;
}

#main {
background: #fff;
}`