Hello,

Please check below the steps taken to fix your issues:
-Logo: i added this custom css into your custom css box:

 #logo img.dark {
    display: block !important;
    visibility: visible !important;
}

-Links: I resetted permalinks in Settings > Permalinks from “Day and Name” to “Postname”. I checked they are ok now. Please clear cache and refresh pages.
-Portfolio items grid: i added this code into your custom css box:

.three-cols .portfolio-item {
    min-height: 390px !important;
}

Let us know if you need further help.

Best regards!

Hello,

You are using a codeless slider in home page. The white opaque strip is the place where the title and text of the slide would be. But you have not added any content to it. Check it at Codeless Slider Options > Slide > Content (screenshot).

To remove it, i changed the opacity of the color to full transparent by adding this custom css Into your custom css box:

.codeless_slider .swiper-slide .content.vertical_centered {
    opacity: 0;
}

Let us know.

Best regards!