Theme development

Hello,

I'm new to drupal and i'm trying to get the option to login on a dedicated page.
I can't figure out how. 

I'm using drupal 7.59 and the nexus theme. 

Any solutions?

I'm using 8.5.3, and trying to follow the guide for creating a classy subtheme at https://www.drupal.org/node/2165673

I have created a sub-theme of classy, exactly as described, but with a different name. It doesn't appear in admin/appearance.

Here's the tree of my theme:

i've set the conditional-stylesheets settings in my info.yml file to spec (as per https://www.drupal.org/comment/reply/2659496) and cleared my caches, but there is no reference to my IE stylesheet in the browser. Made sure Drupal & browser cache cleared too, I even thought about the css file limit in IE and reduced to 20 files, and even tried turning on aggregation. no luck.

sHi everyone.

I am new in Drupal and trying to create my own theme.

After reading few articles from some websites, I am confusing to create my theme under which directory.

Some articles write should create under /core/themes and some write /themes, so where should I create my custom theme?

What the difference between these two directories?

I am building a theme where each page is unique but not repeatable content. I have to use Drupal 8 based on client request. The content is not repeatable only header and footer. I was going to set it up by creating a region for each page and put blocks in each region that are custom. I feel like this might not be the best way.. but I do not know. I would welcome feedback or sources for the best option to build a theme. I went thru a town of youtube videos and articles but they all build websites based on the content being repeatable like a grid or blog type page.

I bought a drupal theme from themeforest for my company, i uploaded files and sql as instructed by the author. I logged into backend to edit and add my contents, but everytime when i edited content and clicked save button, page was broken with error messages like below.