Use classless semantic HTML in the "simple" theme

[pauloxnet]

• [x] I have searched the issues (including closed ones) and believe that this is not a duplicate.
• [x] I have searched the documentation and believe that my question is not covered.
• [x] I am willing to lend a hand to help implement this feature.

Feature Request

Premise

Currently, in the "simple" theme there is no style sheet and it uses semantic HTML almost entirely, but not completely yet.

Proposal

I propose to remove any class references from the HTML code, which are not used anyway, and make the HTML code entirely semantic.

Feature

• [x] cleaner and lighter HTML code, thanks to the removal of unused parts (e.g. classes, ids, comments)
• [x] more accessible web pages, thanks to the use of only semantic HTML
• [x] responsive web pages with dark and light modes, thanks to the addition of just the URL of one of the many classless CSS frameworks available.
• [x] web pages more easily navigable by screen readers and assistive technologies, thanks to a correct hierarchy of components in the DOM

[avaris]

cleaner and lighter HTML code, thanks to the removal of unused parts (e.g. classes, ids, comments)

I get the other two but "comments"? Unused in rendering, yes, but they are not useless. Especially for a theme that's supposed to be a starter template for people to write their own.

[pauloxnet]

I provided the working PR #3234 (yet not tests complete)

[pauloxnet]

I tried the "simple" theme combined with some classless CSS frameworks found in this list: "Awesome Classless CSS" https://github.com/dbohdan/classless-css

Below are some screenshots of the various versions of my website using the updated "simple" theme, simply by providing a different URL in the STYLESHEET_URL setting, as shown in the example below

STYLESHEET_URL = "https://cdn.simplecss.org/simple.min.css"

[pauloxnet]

Bamboo

STYLESHEET_URL = "https://unpkg.com/bamboo.css"

dark	light

[pauloxnet]

Holiday

STYLESHEET_URL = "https://cdn.jsdelivr.net/npm/holiday.css@0.11.2"

dark	light

[pauloxnet]

Missing

STYLESHEET_URL = "https://unpkg.com/missing.css@1.1.1"

dark	light

[pauloxnet]

Pico

STYLESHEET_URL = "https://cdn.jsdelivr.net/npm/@picocss/pico@next/css/pico.classless.min.css"

dark	light

[pauloxnet]

Simple

STYLESHEET_URL = "https://cdn.simplecss.org/simple.min.css"

dark	light

[pauloxnet]

SpCSS

STYLESHEET_URL = "https://cdn.jsdelivr.net/npm/spcss@0.9.0"

dark	light

[pauloxnet]

Tufte CSS

STYLESHEET_URL = "https://unpkg.com/tufte-css@1.8.0/tufte.min.css"

dark	light

[pauloxnet]

Water

STYLESHEET_URL = "https://cdn.jsdelivr.net/npm/water.css@2/out/water.min.css"

dark	light

[pauloxnet]

Default

Web page as rendered by Firefox with no STYLESHEET_URL.