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title: "Themes" sidebar_position: 2

Themes

A theme is a terminal color scheme: the 16 ANSI colors plus a background, a foreground and a selection color, the same shape Ghostty, kitty, iTerm2, Alacritty and VHS themes have. 012 has no theme format of its own to learn: any scheme works, and so does any Ghostty theme file.

# ~/.config/012/config
theme = terminal                                   # the default
theme = Dracula                                    # one scheme
theme = light:Catppuccin Latte,dark:Catppuccin Mocha  # follow the terminal
  • terminal (the default) draws with the terminal's own palette, as ANSI color numbers, with a dark and a light variant picked from the terminal's background. It looks the way your terminal is set up.
  • Any other name is a color scheme. 012 draws its roles in the scheme's colors (true color), fills the whole screen with the scheme's background, and draws the menu bar, the column headers and the status line as solid bands, in the manner of 1-2-3 and classic terminal programs. The terminal's own palette is never changed.
  • high-contrast is white on black on a dark terminal and black on white on a light one, switching when the terminal does, with every role at WCAG AAA contrast (see High contrast).
  • light:A,dark:B picks A on a light terminal and B on a dark one, and switches when the terminal does (for example with the system's appearance, in terminals that report it).

At startup the screen stays blank until the terminal says its background, so a light terminal never shows a frame in dark colors, even over SSH; a terminal that doesn't answer is waited for at most half a second.

File > Settings > Theme opens a picker: type to search the names. A search starting with "dark" or "light" lists only the schemes of that kind (by meta.isDark, so "light" leaves out dark schemes such as Bright Lights), the rest of it searching their names: "light sol" finds Solarized Light. The highlighted theme is drawn live, Enter keeps it and writes theme = ... to the config file, and Esc goes back to the theme you had. With a light:/dark: pair, the picker changes the one in use. In terminals that say when a key is let go (Keys the terminal has to tell apart), holding Space before typing a search hides the list to show the whole sheet in the highlighted theme, until Space is let go. 012 config themes lists every theme, with a * on the current one.

The theme picker previewing 1-2-3 Classic

Built-in schemes

012 embeds the 348 schemes of VHS (Dracula, Nord, Gruvbox, Catppuccin, Solarized, Tokyo Night, One Dark, Rose Pine and hundreds more), so names are the ones VHS's Set Theme takes, plus 1-2-3 Classic: CGA colors on a blue screen. Names match without regard to case, and then without regard to spaces, hyphens and underscores, so tokyo-night finds TokyoNight.

High contrast

theme = high-contrast draws with two built-in schemes, High Contrast Dark and High Contrast Light, picked by the terminal's background; name one of them (theme = high-contrast-light) to keep it. They hold every role to WCAG AAA rather than AA: 7:1 for all text, hints and muted text included, and 4.5:1 for lines, borders, chart axes and unavailable menu items. The pointer is black on cyan, the selection white on blue, errors a light red on black (a dark red on white).

States never rest on color alone in any theme: each also shows as text, a glyph or an attribute such as reverse video or an underline (Reading without color).

Your own schemes

Put a file in the themes directory next to the config file (~/.config/012/themes/ on Linux; 012 config path shows where the config is) and use its file name as the theme. A file with a built-in's name replaces it. Three formats are read:

  • Ghostty (copy any Ghostty theme unchanged):

    palette = 0=#1d1f21
palette = 1=#cc6666
# ... through 15
background = #1d1f21
foreground = #c5c8c6
selection-background = #373b41

  • kitty: color0 #1d1f21 through color15, background, foreground and selection_background.

  • VHS JSON: one scheme or a list, with black ... brightWhite, background, foreground, selection and meta.isDark (a .json file; purple and selectionBackground are accepted too).

A scheme needs a background and a foreground; ANSI colors it leaves out are xterm's. Other keys (fonts, cursor colors) are ignored.

How roles get their colors

Every role in internal/ui/theme (the cell pointer, selection, headers, menus, errors, links, chart series and so on) is defined on the ANSI colors and the background and foreground: the pointer is black on cyan, headers are bright white on bright black (black on white on light terminals), errors are red. The terminal theme sends those color numbers; a scheme replaces each with its own color. Then, so every scheme reads well:

  • the selection uses the scheme's selection color, when it has one;
  • the menu bar and status line are the background moved 12% toward the text color; the column header row is filled with the header color;
  • a background role too close to the screen's background is moved apart;
  • text below its contrast minimum against its background (WCAG 4.5:1 for text, 3:1 for hints, lines and chart axes, 2:1 for unavailable items; the high-contrast schemes' AAA minimums above) is moved toward the scheme's text color, or toward black or white, just far enough to reach it.

A test runs every built-in scheme through this and checks those minimums for cell text, text on the bars, the selection, the headers and every other role (TestEveryThemeReadable, and TestHighContrast for AAA). Charts, as text and as kitty images, use the scheme's colors too.

Conditional formats (Conditional formatting and data validation) name their colors (red, yellow, green, cyan, blue, magenta) rather than giving RGB, and each is an ANSI slot, so they follow the theme too: a text color is the slot on the cell (RuleText), a fill the slot as a background with black or bright white text, whichever reads better (RuleFill), and a text color on a fill (RuleOn) takes the fill's ink where it wouldn't read on it. These roles are corrected and checked like the others, and the terminal theme's are checked against the two reference palettes. A color scale blends the slots of its points, the scheme's colors or the terminal's own (asked for with OSC 4 at startup, xterm's when it doesn't answer), in 32 shades between two points; text on a shade is the scheme's text or background color (the terminal's bright white or black), whichever reads better, or pure black or white where neither reaches 4.5:1. A test checks the shades of every pair of colors under every scheme.

The roles for the bars are MenuBarRow, FormulaBarRow, ContextRow, ColumnHeaderRow and StatusBarRow (a background and a text color for the whole line, out to the terminal's edge, under overlays too), with RowHeader for the row numbers and Screen for everything else. The terminal theme leaves them empty, so it looks as it always has.

Credits

The built-in schemes are VHS's themes.json (MIT License, Copyright (c) 2022-2023 Charmbracelet, Inc.; see NOTICE), which credits each scheme's authors in its meta.credits. The contrast correction is adapted from the theme package of puzzletea, by the same author.