Update training site style guide

[marisalim]

• [x] add text highlight syntax

Text highlighting is specified in the "extra.css" file with this block:

.highlight_txt {
  color: #9f0bde;
  background-color: #ededed;
  padding: .25em;
}

The color is set to purple website-wide. Use this syntax in markdown files, where the highlighted text here is "File Repository":

<span class="highlight_txt">File Repository</span> 

[s-canchi]

Would it be worthwhile to add a new section that lists our flyers and other documents we generate for our workshops ? The color and font info are below. Flyers have been created in Canva.

The Hex color codes for the CFDE palette from the training website:

• Main Headers: #336699
• Table headings/ landing page : #C3E1E6
• Footer: #204060

Fonts Used So Far & Sizes

• Workshop Header: Lora 37.5 Font
• Title: Lora 60 Font
• Date & Time: Montserrat 42.7 Font
• Brought to you By: Lora 35.4 Font
• Contact Training E-mail: Lora 30.5 Font

---> since we don't use these for the training website itself, i think these details can go to our Training Org google drive, where we keep workshop surveys/notes/schedule

[marisalim]

• [x] add emoji syntax

e.g., :fontawesome-regular-trash-alt:

specified in mkdocs.yml by:

- pymdownx.emoji:
     emoji_index: !!python/name:materialx.emoji.twemoji
     emoji_generator: !!python/name:materialx.emoji.to_svg

[s-canchi]

• [x] add header syntax style

Use the === under the titles for landing page. To ensure the contents occupy the full width of the page use

hide:
   - toc

in the yaml format on top of the page.