Theme development

I'm trying out Drupal theme in D7 and after reading some posts about responsive, recommended Drupal themes, I installed the latest Xen for Drupal 7.
I'm a little familiar with SASS and got my gulp running, and don't see much docs of the recent versions. Due to streaming issues, I haven't been able to get through the latest John Albin video which is three years old.

I created a sub-theme through Drush and copied some of the template files from the parent theme.

My first Q is it normal for this D7 theme to have .twig files alongside the .scss files?

Templating using Foundation 6 sub-theme

html.html.twig

I am noticing some unexpected behavior where DIV sections are appear between head and body sections.

I am still totally new to Drupal. I have installed Drupal 8.3.2 so the latest Version. I have installed the Bootstrap Theme and activated it. I now want the Front Page to look different to the Layout of the other Pages meaning I would like:

A image slider, below that 3 Boxes with Content while 1 will be Latest News and 2 with static content below that a full width box then a Gallery with multiple images in 2 rows.

Hi
I have not used Drupal in some years and I am finding it a little hard to work out the CSS structure
Could someone please tell me what CSS document change and what ID to use to change the fontsize of the site.name.
I am using the business responsive theme
<div id="block-business-responsive-theme-branding" class="contextual-region site-branding block block-system block-system-branding-block">

Hi everyone,

I'm not pretty sure, if this question is correctly placed within the theming-forum – but since I hope, the fix for it is a little bit of Twig-Magic, I thought it would be =)

Since my forum- and even Google-search takes me more than one day without solving my problem now, I decided to ask you directly.

Hi I’m helping out my running club by making some changes to their website.
Although I have an IT background, it’s not web development and am a little stuck.

Hoping this is the right thread / if not please point me in the right direction.

My objective is to update our home page so that instead of showing just one static image it changes every few seconds to show a new image.