50 Dark Themes · 47 / 50

Undertow

A cool accent, #A8D8E8, on a #151E23 terminal. Primary text reads at 14.21:1 and secondary text at 7.02:1, measured against that background. Free and MIT licensed, one of the 50 Dark Themes for Claude Code.

Undertow

#A8D8E8
✻ Claude Code · undertow
● Applied theme “Undertow”
  3 files changed · staged
> show me the diff
>theme undertow
/theme  ·  ⏎ send  ·  esc to interrupt

Install Undertow.

Requires Claude Code v2.1.118 or later. The marketplace command is needed once per machine; the plugin command installs the whole 50 Dark Themes pack, and /theme inside Claude Code switches to this one.

$ claude plugin marketplace add notgabriels-sys/claude-code-50-dark-themes
$ claude plugin install 50-dark-themes@notgabriels-themes
$ /theme undertow

Plugin themes are read-only. Press Ctrl+E on one in /theme for an editable copy in ~/.claude/themes/.

Or copy just this file.

One theme, no plugin: fetch undertow.json from the repository into your themes folder. If that folder did not exist when Claude Code started, restart it once.

$ mkdir -p ~/.claude/themes && curl -fsSL https://raw.githubusercontent.com/notgabriels-sys/claude-code-50-dark-themes/main/undertow.json -o ~/.claude/themes/undertow.json

Terminal background: #151E23.

Claude Code colours its own interface; the terminal application owns the canvas behind it. Every figure below is measured against #151E23, so set that as the terminal background for the result the numbers describe. On a different background the ratios move.

Palette.

The thirteen overrides Claude Code reads from the theme file. Success, error, warning and diff colours are deliberately not overridden, so status meaning stays the same across every theme in the pack.

ColourTokenRole
#A8D8E8claudeClaude's mark and accent
#E9F5F9claudeShimmerAccent highlight while Claude works
#E8ECEDtextPrimary text
#9DA9AFinactiveSecondary text
#263136subtleDecorative hairlines (reserved, carries no meaning)
#A8D8E8suggestionAutocomplete suggestions
#3E7A9EpermissionPermission prompt border and indicator
#A8D8E8promptBorderInput prompt border
#E9F5F9promptBorderShimmerPrompt border highlight
#3E7A9EplanModePlan mode indicator
#1D2930userMessageBackgroundSurface behind your messages
#25343DuserMessageBackgroundHoverThat surface, hovered
#A8D8E8rate_limit_fillUsage meter fill

Measured contrast.

Computed from the hex values above with the WCAG 2 relative-luminance formula, by the same script that gates every change to this repository. Figures are truncated, never rounded up. Each row meets its floor.

PairColoursRatioFloorStandard
text on terminal background#E8ECED on #151E2314.21:17:1WCAG AAA, normal text
text on your-message surface#E8ECED on #1D293012.50:17:1WCAG AAA, normal text
inactive on terminal background#9DA9AF on #151E237.02:14.5:1WCAG AA, normal text
inactive on your-message surface#9DA9AF on #1D29306.18:14.5:1WCAG AA, normal text
claude on terminal background#A8D8E8 on #151E2310.99:14.5:1WCAG AA, normal text
claudeShimmer on terminal background#E9F5F9 on #151E2315.21:14.5:1WCAG AA, normal text
suggestion on terminal background#A8D8E8 on #151E2310.99:14.5:1WCAG AA, normal text
permission on terminal background#3E7A9E on #151E233.60:13:1WCAG AA, non-text
planMode on terminal background#3E7A9E on #151E233.60:13:1WCAG AA, non-text
promptBorder on terminal background#A8D8E8 on #151E2310.99:13:1WCAG AA, non-text
promptBorderShimmer on terminal background#E9F5F9 on #151E2315.21:13:1WCAG AA, non-text
rate_limit_fill on terminal background#A8D8E8 on #151E2310.99:13:1WCAG AA, non-text
your-message surface against the terminal#1D2930 on #151E231.13:11.08:1visibly distinct surface
hovered surface against the resting one#25343D on #1D29301.15:11.08:1visibly distinct surface