halloween-poster-design

Halloween Premium Color Palette Poster Design Skill

1. Mission and Boundaries

Transform the user's poster requirements into an executable design plan, and deliver image generation Prompts as needed or call the image generation tools available in the current environment.

This Skill is not just a color palette table. It is responsible for the complete design decision chain:

Understand the design Brief and hard constraints.
Select or combine color strategies.
Establish color roles, HEX color values, and area allocation.
Plan the composition, subject, typography, graphics, and information hierarchy.
Compile the plan into a Prompt executable by the target image model.
Check whether the plan and generated results meet the requirements.
Iterate in a targeted manner based on the issues.

By default, communicate and output in Chinese. When the user explicitly requests another language, follow the user's request.

2. When to Invoke

Applicable to the following tasks:

Design Halloween-themed posters, event key visuals, brand marketing images, food and beverage promotional images, party invitations, cartoon posters, or trendy visuals.
Develop color schemes, color proportions, typography, and composition rules for posters.
Convert a design Brief into a Chinese or English image generation Prompt.
Extract color rules from reference images, preserve the composition, and adjust the style.
Review the color hierarchy, readability, and style consistency of existing posters.
Propose modification instructions with clear objectives based on generated results.

If the user only requests analysis or planning, do not generate images without authorization. Only when the user explicitly requests to create, generate, or edit an image, and the current environment provides available image tools, should that tool be invoked.

3. Design Principles

3.1 Determine the design goal first, then decide the color scheme

Do not directly equate "Halloween" with "orange background plus black bats." First identify:

The poster's purpose and distribution scenario;
The subject type (product, character, illustration, architecture, text, or combination);
The target temperament (minimalist, retro, rich, playful, mysterious, trendy, commercial, etc.);
Copy density and reading priority;
Brand colors, prohibited colors, reference images, and other hard constraints;
Aspect ratio and delivery requirements.

Use reasonable defaults when non-critical details are missing; do not ask repeated questions just to fill out a form. Only ask one direct question when the missing information would substantially change the design result.

3.2 User hard constraints take priority

Priority from high to low:

Content, brand, colors, reference images, aspect ratio, and output constraints explicitly specified by the user;
Design goals and distribution purpose;
The selected color strategy;
General aesthetic suggestions and defaults.

Do not override user-specified brand colors or reference image features that must be preserved in order to apply a certain strategy. When the reference image is a composition blueprint, clarify which elements need to be preserved and which elements need to be changed.

3.3 Color schemes must have role division

Each plan must at least clarify:

Primary color: establishes the main visual atmosphere;
Background color: carries the image and controls the light-dark structure;
Secondary color: builds layers or connects hues;
Accent color: guides the line of sight and marks key points;
Neutral color: carries text, negative space, and outlines.

A color can serve multiple roles, but its purpose must be stated. Color area percentages are design starting values, not a mechanical formula; the maximum values of each range cannot be taken at the same time, and the final proportions must be normalized and verified in combination with the layout.

3.4 "A sense of premium quality" needs an executable definition

Do not just write "premium, refined, cinematic." It should be translated into checkable design behaviors:

Limit the number of competing highly saturated colors;
Establish a clear lightness hierarchy and visual focus;
Control the density of decorative elements;
Keep typography, graphics, materials, and color strategy consistent;
Establish order through whitespace, proportion, and contrast;
Avoid having all elements compete for attention at the same time.

3.5 Decide color scheme, visual style, and layout separately

These three dimensions are related, but they cannot substitute for one another:

Color strategy: how colors are organized among themselves, such as accent colors, theme colors, analogous colors, or complementary colors.
Visual style: in what visual language the image is presented, such as editorial minimalism, retro print, playful cartoon, cinematic night scene, or modern product advertising.
Layout mode: how the subject, title, information area, and whitespace are organized.

Do not automatically choose strategy C just because the user says "cartoon," and do not automatically choose black gold or deep purple just because the user says "a sense of premium quality." The three dimensions should be judged separately, and then checked for whether they are coordinated.

4. Execution workflow

Step 1: Parse the Brief and delivery intent

Extract the purpose, subject, target temperament, audience, exact copy, brand assets, brand colors/prohibited colors, aspect ratio, reference image requirements, and delivery mode.

Identify what the user currently wants:

a design plan;
an image generation Prompt;
directly generating or editing an image;
review of an existing plan/image.

When there is an explicit request for final visual delivery such as "generate, draw one, output the image directly, edit this image," and the current environment has image tools, execute directly and do not just provide a Prompt. When there is an explicit request to "plan, analyze, design a plan, write a Prompt," do not generate an image without authorization. If the user says "make a poster" and the context clearly refers to the final visual product, handle it as direct generation by default; if the tool is unavailable, deliver a directly usable Prompt and explain the limitation.

Step 2: Assign a role to each reference image

Read references/reference-image-handling.md. Reference images may be used respectively for color scheme, composition, subject, style/material, or brand assets. Clarify which dimension each image is responsible for, and do not by default copy all features of one image into other dimensions.

Step 3: Choose a color strategy

Read references/palette-strategies.md and references/strategy-routing.md。

Four basic strategies:

A: Accent-color driven — a small area of highly saturated orange paired with a large area of achromatic color;
B: Theme-color driven — a large area of warm orange and red-brown builds a rich atmosphere;
C: Analogous-color driven — orange, golden orange, and bright yellow form a continuous warm color hierarchy;
D: Complementary-color contrast driven — orange, deep blue, and warm off-white form a warm-cool contrast.

The four strategies are design prototypes, not closed color palettes to be applied rigidly. If brand colors, user-specified colors, or reference image colors conflict with the standard palette, entercustom constrained color mode: First retain the user's hard constraints, then borrow suitable color relationships or layout logic. Only when the color relationship genuinely matches a certain strategy should that strategy be called the primary strategy; do not replace the user's primary color just to fit a category.

By default, choose only one primary strategy. When a combination is needed, explain what the primary strategy and secondary strategy are each responsible for; do not indiscriminately mix all four schemes.

Step 4: Establish color parameters and check contrast

Clarify the HEX, color roles, recommended area proportions, lightness/saturation relationships, warm/cool relationships, subject separation method, and text-bearing areas.

For area proportions, use the references/palette-strategies.md first-draft target values; the proportions of all colors must total 100%, then adjust according to the composition.
Distinguish between "explicit color values from the case," "recommended substitute colors," and "auxiliary colors estimated from the image."
Text color must be reviewed separately; do not assume that because two colors look good together as color blocks, they are suitable for overlaying small text.
For digital posters, WCAG AA contrast can be used as a readability reference: normal text should target at least 4.5:1, and large display text should target at least 3:1. This is a conservative check line, not an absolute aesthetic rule for all print and artistic design.
When contrast is insufficient, prioritize changing the text color, adding a separate backing plate for the text, or adjusting the text-bearing area; do not immediately overturn the entire color scheme.

Step 5: Plan the layout and information hierarchy

Clarify the first visual focal point, second visual focal point, main title, auxiliary copy, subject/background relationship, decorative density, information area, and whitespace. Establish the subject and information hierarchy first, then add decoration.

Step 6: Compile the Prompt

Read references/prompt-compiler.md. Output a complete design plan, copyable Prompt, negative constraints, or a Chinese-English bilingual version according to the user's needs. The Prompt should accurately express the determined subject, composition, color roles and proportions, text hierarchy, style, materials, aspect ratio, and hard constraints.

Step 7: Generate or deliver

Design plan mode: output color and layout decisions without generating an image.
Prompt mode: output a copyable Prompt without automatically generating an image.
Direct generation mode: when the user explicitly requests a final image and the current environment provides an image tool, call that tool.
Review mode: inspect the existing image/plan and provide prioritized correction suggestions.

The platform adaptation layer is responsible for defining how specific image tools are called. If no image tool is available, do not claim that an image has been generated.

Step 8: Review the actual output and iterate

Read references/quality-checklist.md. If the generated result can be inspected, you must check the hard constraints, color area proportions, text readability, composition, and style consistency based on the actual image; do not judge that the image is successful based only on the Prompt.

If the generated result cannot be accessed or viewed, clearly state that the visual review has not been completed; do not fabricate inspection results. In each round, prioritize fixing the 1–3 issues that most affect the goal, and describe the changes with observable modification instructions.

5. Standard output structure

When the user requests a complete design plan, output according to the following structure:

Design positioning: describe the design goal and visual strategy in one sentence.
Strategy selection: explain the reason for choosing A/B/C/D or a custom constrained color mode; if there is a mix, explain the primary and secondary.
Color asset table: Color name, HEX, role, recommended area, and usage location.
Color relationships: Lightness, saturation, warm/cool, and background/subject separation rules.
Composition and typography: Subject position, title, information area, decoration, and negative space.
Complete image generation Prompt: Can be copied directly; may be omitted when the user only wants a plan.
Negative constraints: List only failure risks relevant to the task.
Review focus: Give the 3--5 most important acceptance criteria.

When the user only asks for a Prompt, there is no need to repeat the full theory; directly provide an executable Prompt and the necessary constraints.

6. Image generation constraints

Do not treat color HEX as a guarantee that the model will execute it precisely; use it as a color anchor and assist the description with relative area, light/dark, and warm/cool relationships.
Do not guarantee that the image model can accurately generate long Chinese copy, QR codes, phone numbers, or complex Logos.
If accurate commercial copy is needed, prioritize suggesting generating the background and subject first, then overlaying text and brand assets with layout tools.
If the user provides reference images, follow the reference image priority requested by the user; do not treat details not specified in the reference image as facts.
Do not add brands, Logos, QR codes, URLs, or event information on your own when not requested.
Unwanted text, pseudo-text, watermarks, and meaningless marks in the image should be explicitly excluded in the constraints.

7. Default behavior

When the user only says "make a high-end Halloween poster" without giving more information:

Treat "make a poster / produce an image / directly output an image" as the final visual delivery intent; if an image tool is available, generate directly and do not only reply with a Prompt.
If the user explicitly asks to "give a plan first / write a Prompt first / help me analyze," deliver in the specified mode and do not generate an image without authorization.
If the current environment has no image tool, output a Prompt that can be copied and used directly, and clearly state that an image cannot be generated directly at present.
By default, choose one main color strategy; when the purpose is unclear, prioritize A (clear structure), and if the context is obviously lively and playful, C may be chosen.
By default, use a 4:5 vertical format; strictly follow the user's specified aspect ratio.
By default, use a limited set of festive graphic elements, clearly define the primary visual focus, and avoid piling up materials.
Use reasonable defaults when non-critical details are missing; ask only when key information is missing and would substantially change the result.

8. Reference module index

Read the following files as needed:

references/palette-strategies.md: Four color strategies, standard color values, and proportion recommendations.
references/strategy-routing.md: Strategy selection and combination rules.
references/layout-and-typography.md: Composition, typography, graphics, and information hierarchy.
references/prompt-compiler.md: Prompt compilation process and templates.
references/reference-image-handling.md: Reference image role breakdown and conflict handling.
references/quality-checklist.md: Quality review, scoring, and failure conditions.
examples/: Four sets of case asset cards and regression tests.