Sticky menu customizing.

Hi there,

try adding this CSS to change the site title and border colors on sticky nav:

.main-navigation.is_stuck .main-nav > ul > li:not(:first-child)::after {
    background-color: #000;
}
.main-navigation.is_stuck .navigation-branding .main-title a {
    color: #000 !important;
}

The bottom border color. You have this CSS:

@media (min-width: 769px) {
    #site-navigation .inside-navigation {
        border-bottom: 1px solid #f4f2f3;
    }
}

Change that to:

@media (min-width: 769px) {
    #site-navigation .inside-navigation {
        border-bottom: 1px solid #000;
    }
    .header-wrap #site-navigation .inside-navigation {
        border-bottom: 1px solid #f4f2f3;
    }

}

That way the light color only gets applied where the merged header is enabled.

On the blog page, on the main menu, is there a way to make the title and the border between menu black.?

Also, I have one more question.

When you see the border between menu, the thickness is different.
Can I make the thickness the same?

.main-navigation .main-nav > ul > li:not(:first-child):after {
content: "";
height: 50px;
width: 1px;
background-color: white;
position: absolute;
top: calc(40% - 10px);
}
.main-navigation .main-nav > ul > li {
position: relative;
}

This code is applied

is there a way to make the title and the border between menu black.?

The border is added using below CSS, you can simply change the white to black.
.main-navigation .main-nav > ul > li:not(:first-child):after {
content: "";
height: 50px;
width: 1px;
background-color: white;
position: absolute;
top: calc(40% - 10px);
}

Can I make the thickness the same?

They are the same, they are all 1px in width.

It has to be black only on blog page.
on other page, it has to be white.

This CSS:

.blog .main-navigation .main-nav > ul > li:not(:first-child):after {
    background-color: #000;
}

Thank you! It works!

Glad to hear that