🎨 Autumn theme, "How chimera works"-guide and improved :focus styling

What's Changed

• Update README.md by @MarkusJohansen in #76
• feat: better structure that explains theme files by @MarkusJohansen in #75
• 🔥 remove empty file by @SindreKjelsrud in #79
• 💄 added new theme "Chimera-autumn" by @SindreKjelsrud in #78
• 🚑 Consistent :focus with new modern look by @MarkusJohansen in #81

Full Changelog: 1.4.0...1.4.1