dark-theme-no-banding

dark-theme-no-banding is a cursor rule for Cursor from ASHR12/iris. It costs 0 tokens per session (590 once invoked), scanned A, original, MIT.

A set of design rules for dark user interfaces that avoids visible contour lines in gradients, known as colour banding. It also defines background tones, surface layering, borders, and the use of a single light source.

In plain words
What is it for?
Use it when designing dark screens, backgrounds, panels, cards, buttons, vignettes, overlays, and glowing canvas effects.
Why use it?
It prevents dark gradients from appearing as flat steps and keeps depth from depending on large washes or unnecessary outlines.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/ashr12/iris/dark-theme-no-banding
Clone the repo
git clone --depth 1 https://github.com/ASHR12/iris

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for dark-theme-no-banding

README.md
[![agentmods](https://agentmods.dev/badge/rules/ashr12/iris/dark-theme-no-banding.svg)](https://agentmods.dev/rules/ashr12/iris/dark-theme-no-banding)
Your own site
<a href="https://agentmods.dev/rules/ashr12/iris/dark-theme-no-banding"><img src="https://agentmods.dev/badge/rules/ashr12/iris/dark-theme-no-banding.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 590 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00590
Opus 5 $0.00000 $0.00295
Sonnet 5 $0.00000 $0.00118
Haiku 4.5 $0.00000 $0.00059

Measured 4d ago against content hash 149d75a57b3b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dark-theme-no-banding scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/dark-theme-no-banding.mdc · 50 lines

How it starts

The opening of the file, as written. The whole thing — 50 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Dark surfaces must not band

Contour lines in a dark UI come from 8-bit quantization: sRGB has very few code levels near black, so a wide soft gradient has nothing to put between its steps and renders as flat plateaus with hard edges. Below the sRGB toe brightness is proportional to code value, so one step at value 7 is a ~14% brightness jump; at value 21 it is ~5% and stops reading as a line. Full explanation in README.md → "Dark UI without colour banding".

Rules

  1. A gradient that crosses more pixels than it has code levels is not a gradient — it is plateaus with visible edges. Use a flat fill.
  2. Never take a surface below --bg-0 (#0b111c). Vignettes, scrims and overlays must land above that floor too, or they drag their region back into the crush zone.
  3. Gradients on dark surfaces must be small and steep — a 40px button fade is fine, a 900px wash is not.
  4. Depth = one step of fill tone + spacing. Not washes, not outlines. Surfaces nest by tone (background → panel → card) and carry no border; borders are only for things that float (menus, popovers).
  5. One light source. Only the reactor canvas glows. Note the trap: on a flat background a lone soft halo becomes the only brightness variation, which is exactly what vignetting looks like.
/* ❌ BAD — 2 levels of green stretched over 860px, plus window-sized washes */
background:
  radial-gradient(92% 78% at 50% 30%, rgba(18, 36, 68, 0.55), transparent 74%),
  linear-gradient(180deg, #05070d 0%, #030509 100%);

/* ✅ GOOD */
background: var(--bg-1);

Do not "fix" banding with these

  • Noise/dither overlays. Cannot remove a staircase already baked into a rasterized layer, and backdrop-filter averages any dither beneath it away, so banding returns inside blurred glass.
  • mix-blend-mode: overlay. Resolves to 2 × backdrop × source below mid-grey, so on dark surfaces its effect is a fraction of one code level.
  • More gradient stops. The limit is quantization, not stop count.

Read the full file on GitHub · 50 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 50 lines · 0 tokens per session scan A 149d75a57b3b

Subscribe to this mod's changes

dark-theme-no-banding is a cursor rule published in the GitHub repository ASHR12/iris (194 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 590 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.