Reworked the login page
- Simplified some of the HTML and CSS
- Removed some `aria-label`s
- Added alt text for the logo
- Added a label for the input field
- Added subtle borders to otherwise flat elements

Reviewed-on: https://codeberg.org/superseriousbusiness/masto-fe-standalone/pulls/76
Co-authored-by: Zoë Bijl <code@moiety.me>
Co-committed-by: Zoë Bijl <code@moiety.me>
Fixes#9
- Cute styling, combination of Mastodon and GTS
- Short description of the project
- Error and status messages (temporarily) appear in disabled button with correct ARIA attributes
- Sufficient contrast (WCAG AAA)
Let me know if using `login.scss` both as an index file and for adding custom styling is okay. I figured this might be preferred over creating an extra folder and file.
Reviewed-on: https://codeberg.org/superseriousbusiness/masto-fe-standalone/pulls/19
Co-authored-by: vyxen <vyxen@tutamail.com>
Co-committed-by: vyxen <vyxen@tutamail.com>