Terminal

Canonical specification

Purpose

The reference for terminal text: the surface, the default foreground, the cursor, the selection, the six attributes and the sixteen slots the workstation froze in Xresources. The slots are the origin of the theme and are carried exactly; what a program does with a slot is that program’s choice, and the theme documents where a choice fails rather than quietly fixing it.

Anatomy

Root .terminal (the <pre>) with a variant class .terminal-transcript, .terminal-ansi-grid or .terminal-attributes. Parts .terminal-<part>: -line, -prompt with -prompt-path, -prompt-branch and -prompt-arrow, -cursor, -sel, -label, -fail (the ✕), and the attributes -bold, -dim, -italic, -underline, -inverse, -strike. Slot classes are .terminal-fg-0 … .terminal-fg-15 and .terminal-bg-0 … .terminal-bg-15, each a single role variable color.terminal.ansi.0 … color.terminal.ansi.15, so the profile switch on the specimen recolours the grid without touching the markup. The foreground is color.terminal.fg on color.terminal.bg; the prompt path segment is color.terminal.selection-text on color.terminal.ansi.4 and the branch segment color.terminal.bg on color.terminal.ansi.3, the two agnoster backgrounds the workstation used.

States

The cursor never blinks in the reference. A host keeps the user’s own blink setting and stops blinking under reduced motion; the theme never turns it on.

Keyboard

The emulator and the shell own every key, including Tab, Escape and the selection modifiers. The reference transcript is a single focus stop that consumes nothing. The theme draws the ring when the host reports focus, the fill when the host reports a selection, and the block cursor where the host puts it.

Accessibility

The transcript is role=log so new output is announced politely; the grid and the attribute sheet are plain <pre> elements with a label. The sixteen slots are exact in every profile: slots 2, 3, 5, 7 and 11 reach 4.5:1 on the terminal background; slots 1, 4, 6, 8, 9, 10, 12, 13 and 14 do not (1.86:1–4.43:1), and the grid marks each of them with a ✕ after its number so the failure is visible, not implied. Two more are marked on the same evidence: slot 15 measures 4.45:1 and slot 0 is the background itself. The extended overlay reassigns the slots to a semantic sixteen that all reach 4.5:1; the site’s profile control shows the grid under it. The background row is legible only with a foreground the program chooses: with the default foreground only slots 0 and 8 pass, which is why the row is shown and not declared as a contract. Two escape families bypass the slots entirely and are outside the theme: bold-as-bright, which substitutes slots 8–15 for 0–7 and must be off for the slots to hold, and 256-colour or 24-bit sequences, which carry their own values. Attributes are attributes: dim uses color.text.muted (5.81:1) rather than a slot, inverse swaps foreground and background (8.65:1), and bold, italic, underline and strikethrough are text styles a screen reader can expose.

Portability

Every emulator with a sixteen-slot palette can hold these values byte for byte; the port’s evidence records whether bold-as-bright is off and whether the cursor and selection keys exist. Programs that pick slot 4 or 12 for directories inherit the documented failure; a port may recommend LS_COLORS or a prompt configuration but never changes the slots to compensate. The cursor shape (block, bar, underline) is the user’s setting; the theme only supplies its colour.

Non-examples

Normalising the heritage slots so every one reaches 4.5:1 and calling it heritage-ansi. A blinking cursor in the reference. A cursor that is a glowing bar. Bold rendered as bright, which silently swaps the slots. A purple or cyan slot borrowed from another scheme. Wrapping the transcript at narrow widths and breaking the prompt segments. A selection drawn as a ring instead of a fill. Rounded prompt segments or a gradient prompt.