如何在Sublime Text 3中自定义字符背景

"color_scheme": "Packages/Color Scheme - Default/Monokai.sublime-color-scheme",
"draw_white_space": "all",
"draw_indent_guides": true,
"highlight_line": true,
"line_padding_bottom": 1,
"line_padding_top": 1,
"caret_extra_bottom": 1,
"caret_extra_top": 1,
"caret_extra_width": 1,
"caret_style": "phase",
"highlight_modified_tabs": true,
"indent_guide_options": ["draw_normal", "draw_active"],
"indent_to_bracket": true,
"match_brackets": true,
"match_brackets_angle": true,
"match_brackets_braces": true,
"match_brackets_content": true,
"match_brackets_square": true,
"match_tags": true,
"rulers": [80],
"show_encoding": true,
"show_line_endings": true,
"show_panel_on_build": true,
"tab_size": 4,
"translate_tabs_to_spaces": true,
"trim_trailing_white_space_on_save": true,
"word_wrap": true