I decided to try using CSS Grid for my portfolio instead of Bootstrap. Feedback?

I’ve finally finished my portfolio after weeks of nitpicking. At some point you just have to set it free! I decided to use CSS grid for parts of it instead of Bootstrap. I would appreciate any feedback offered to help me improve! Thank you!

Never used CSS grid but I know I should.

You should remove the fixed height from the header (from the media query as well), it causes your about section to slide down by a lot when you resize the window. You could make use of flexbox to have the text easily centered in the header. Try styling it like this:

.header {
    background: url(https://res.cloudinary.com/desertdesigns/image/upload/v1503863490/cactus_vytluc.jpg) no-repeat center center;
    background-size: cover;
    background-attachment: fixed;
    padding: 40px;
    margin-top: 88px;
    display: flex;
    align-items:center;
    justify-content: center;
    text-align:center;
}

As for your navbar, I think you can mantain those three links side by side while reducing the font-size a little; they will look better. (Suggestion: instead of making them wrap, you could hide them and show an icon instead).

Aside from that, I like the rest. The portfolio section looks nice. Good work!