Using google prettify in bootstrap website with php pages

Question

I have a bootstrap website with css built in and am trying to implement google prettify as described on this tutorial: http://www.techinfected.net/2016/12/syntax-highlighting-with-code-prettify.html

The problem is, that my website employs php main pages, and while certain sub pages are html, I want a way to add prettify in the css, so that everytime I use the < pre > and < / pre> tags, the code snippets will be formatted.

I have the following css files, and have tried changing the code where the "pre" tags are mentioned, but to no avail.

The pages that I wish to format include python code snippets inserted into html. (see format screenshot below) *for instance, the content file contains code snippets using the < pre > tag

These pages are "Controlled" by a php page in the main public_html, for example:

Can anyone provide some insight into how to go about adding css or automating the process of getting formatted code on using the pre tags, with or without google prettify.

Contents of the code.css file

   /* http://prismjs.com/download.html?themes=prism&languages=markup+css+clike+javascript+abap+actionscript+ada+apacheconf+apl+applescript+asciidoc+aspnet+autoit+autohotkey+bash+basic+batch+c+brainfuck+bro+bison+csharp+cpp+coffeescript+ruby+css-extras+d+dart+diff+docker+eiffel+elixir+erlang+fsharp+fortran+gherkin+git+glsl+go+graphql+groovy+haml+handlebars+haskell+haxe+http+icon+inform7+ini+j+jade+java+json+julia+keyman+kotlin+latex+less+livescript+lolcode+lua+makefile+markdown+matlab+mel+mizar+monkey+nasm+nginx+nim+nix+nsis+objectivec+ocaml+oz+parigp+parser+pascal+perl+php+php-extras+powershell+processing+prolog+properties+protobuf+puppet+pure+python+q+qore+r+jsx+rest+rip+roboconf+crystal+rust+sas+sass+scss+scala+scheme+smalltalk+smarty+sql+stylus+swift+tcl+textile+twig+typescript+verilog+vhdl+vim+wiki+xojo+yaml */
    /**
     * prism.js default theme for JavaScript, CSS and HTML
     * Based on dabblet (http://dabblet.com)
     * @author Lea Verou
     */

    code[class*="language-"],
    pre[class*="language-"] {
        color: black;
        background: none;
        text-shadow: 0 1px white;
        font-family: Consolas, Monaco, 'Andale Mono', 'Ubuntu Mono', monospace;
        text-align: left;
        white-space: pre;
        word-spacing: normal;
        word-break: normal;
        word-wrap: normal;
        line-height: 1.5;

        -moz-tab-size: 4;
        -o-tab-size: 4;
        tab-size: 4;

        -webkit-hyphens: none;
        -moz-hyphens: none;
        -ms-hyphens: none;
        hyphens: none;
    }

    pre[class*="language-"]::-moz-selection, pre[class*="language-"] ::-moz-selection,
    code[class*="language-"]::-moz-selection, code[class*="language-"] ::-moz-selection {
        text-shadow: none;
        background: #b3d4fc;
    }

    pre[class*="language-"]::selection, pre[class*="language-"] ::selection,
    code[class*="language-"]::selection, code[class*="language-"] ::selection {
        text-shadow: none;
        background: #b3d4fc;
    }

    @media print {
        code[class*="language-"],
        pre[class*="language-"] {
            text-shadow: none;
        }
    }

    /* Code blocks */
    pre[class*="language-"] {
        padding: 12em;
        margin: .5em 0;
        overflow: auto;
    }

    :not(pre) > code[class*="language-"],
    pre[class*="language-"] {
        background: #f5f2f0;
    }

    /* Inline code */
    :not(pre) > code[class*="language-"] {
        padding: .1em;
        border-radius: .13em;
        white-space: normal;
    }

    .token.comment,
    .token.prolog,
    .token.doctype,
    .token.cdata {
        color: slategray;
    }

    .token.punctuation {
        color: #999;
    }

    .namespace {
        opacity: .7;
    }

    .token.property,
    .token.tag,
    .token.boolean,
    .token.number,
    .token.constant,
    .token.symbol,
    .token.deleted {
        color: #905;
    }

    .token.selector,
    .token.attr-name,
    .token.string,
    .token.char,
    .token.builtin,
    .token.inserted {
        color: #690;
    }

    .token.operator,
    .token.entity,
    .token.url,
    .language-css .token.string,
    .style .token.string {
        color: #a67f59;
        background: hsla(0, 0%, 100%, .5);
    }

    .token.atrule,
    .token.attr-value,
    .token.keyword {
        color: #07a;
    }

    .token.function {
        color: #DD4A68;
    }

    .token.regex,
    .token.important,
    .token.variable {
        color: #e90;
    }

    .token.important,
    .token.bold {
        font-weight: bold;
    }
    .token.italic {
        font-style: italic;
    }

    .token.entity {
        cursor: help;
    }