- Modify color of dark theme, so it will darker and less warm.
- Remove the color `--color-fav-x` and replace with colors those
defined in dark or light
- set paginate to 4 to show the pager in example site.
Fix the appear of image in content so it wouldn't overflow the content
card.
Note that the inline image cannot be displayed in the same line as text,
because the image is centered by display:block and set margin-x as auto.
