CSS will not load Craft 3 + MAMP I'm a UX designer with some front end skills (though a complete novice with server config and Craft). I'm hoping someone can help me with something that seems rather basic.

Setup: 
Mac Book Pro running High Sierra (10.13.5).
Using MAMP 4.4.1 (free version)
PHP 7.2.1, MySQL, and Craft 3.
The site loads in a browser when I visit: http://localhost:8888/.

My craft files are here: Macintosh HD/Applications/MAMP/htdocs/.

The template file in question is here: Macintosh HD/Applications/MAMP/htdocs/templates/_layouts/base.html

In the base.html file, in the head section, I am attempting to link to several CSS files. Here's the entire head section:

&lt;head&gt;
    {% block head %}
      &lt;meta http-equiv="X-UA-Compatible" content="IE=edge"&gt;
      &lt;meta charset="utf-8"&gt;
      &lt;title&gt;{% if title is defined %}{{ title }} - {% endif %}{{ siteName }}&lt;/title&gt;
      &lt;meta name="viewport" content="width=device-width, initial-scale=1.0"&gt;
      {% css %}
        &lt;link rel="stylesheet" type="text/css" href="{{ siteUrl }}src/css/typeplate.css"&gt;
        &lt;link rel="stylesheet" type="text/css" href="{{ siteUrl }}src/css/grid.css"&gt;
        &lt;link rel="stylesheet" type="text/css" href="{{ siteUrl }}src/css/screen.css"&gt;
      {% endcss %}
    {% endblock %}
&lt;/head&gt;


The CSS files in question are here: Macintosh HD/Applications/MAMP/htdocs/src/css.

The Problem:
When I load the home page, the CSS does not load. 

Things I've Tried:


I've tried removing the siteURL bit, and just hardcoding things
instead (like this: http://localhost/src/css/typeplate.css), and I
get 404 errors for the 3 css files under the network tab in Chrome developer tools.
I've tried removing the {% css } brackets around the stylesheet links, and the network tab in Chrome dev tools just tells me "failed" when the links are hard coded. When the links have {{ siteUrl}} in them, I can see the browser looking for the files at www.mywebsite.com/src/css/typeplate.css. But the files aren't currently there - this is a local dev site only.
I've tried changing the dev siteUrl in general.php from "null" to
"http://localhost/", and the web page stops loading altogether.
I've tried different hard coded URL's, like
(../src/css/typeplate.css).
I've searched StackExchange for similar problems, but I can't seem to make sense of any of the answers.


Can anyone help? Thank you so much in advance.
After some searching, I decided to move my src/ folder into the web/ folder, since Craft seems to be looking only there and not at anything above that directory. Then, my CSS links were updated to relative paths like this: src/css/typeplate.css. And that worked.