CudaText

CudaText is a cross-platform text editor, written in Lazarus / Free Pascal.
It starts quite fast (0.5 sec with ~30 plugins on CPU Intel Core i3 3Hz).
It is extensible by Python add-ons (plugins, linters, code tree parsers, external tools).

Features include:

Syntax highlight for many languages: C, C++, JavaScript, HTML, CSS, PHP, Python, XML etc. 200+ syntax lexers exist.
Code tree (tree structure of functions/classes/etc in source).
Code folding.
Multi-carets and multi-selections.
Find/Replace with reg. ex.
Configs in JSON format. Including lexer-specific configs.
Tabbed UI.
Split each tab.
Split view for 2/3/4/6 files.
Simple auto-completion (fixed list) for some lexers.
Command palette (ST3 style).
Minimap.
Micromap.
Show unprinted whitespace.
Support for many encodings.
Customizable hotkeys.
Binary/Hex viewer for files of unlimited size.

Features for HTML/CSS coding:

Smart auto-completion for HTML, CSS.
HTML tags completion with Tab-key (Snippets plugin).
HTML color codes (#rgb, #rrggbb) underline.
Show pictures inside editor area (jpeg/png/gif/bmp/ico).
Show tooltip when mouse moves over picture tag, entity, color value.