QA: Chat Customization (CSS) — LangGraph (Python)

Prerequisites

• Demo is deployed and accessible at /demos/chat-customization-css on the dashboard host
• Agent backend is healthy (/api/health); OPENAI_API_KEY is set on Railway; LANGGRAPH_DEPLOYMENT_URL points at a LangGraph deployment exposing the neutral sample_agent graph
• The demo wires agent="chat-customization-css" at /api/copilotkit (neutral assistant cell)
• Note: the demo source contains no data-testid attributes. Checks below rely on CopilotKit built-in class names (copilotKitChat, copilotKitMessages, copilotKitMessage, copilotKitUserMessage, copilotKitAssistantMessage, copilotKitInput) scoped under the .chat-css-demo-scope wrapper defined in theme.css

Test Steps

1. Basic Functionality

• Navigate to /demos/chat-customization-css; verify the page renders within 3s with a single centered <CopilotChat /> container inside a .chat-css-demo-scope wrapper (max-width 4xl, rounded corners via rounded-2xl)
• Verify the chat input is visible with a textarea placeholder (default CopilotKit placeholder, e.g. "Type a message")
• Send "Hello" and verify an assistant text response appears within 10s
• Verify the input clears after send and a user-message bubble is appended to the transcript

2. Feature-Specific Checks

Theme Applied On Load (CopilotKit CSS Variables)

• In DevTools, inspect the .chat-css-demo-scope element and verify getComputedStyle(el).getPropertyValue('--copilot-kit-primary-color').trim() equals #ff006e
• Verify --copilot-kit-background-color is #fff8f0, --copilot-kit-secondary-color is #fde047, and --copilot-kit-separator-color is #ff006e
• Verify the .copilotKitChat background renders the themed cream color #fff8f0 (not the default white/neutral)

User Message Bubble (hot pink gradient, serif, bold)

• Send "Hi there"; locate the newly rendered .copilotKitMessage.copilotKitUserMessage bubble
• Verify its background-image computed style starts with linear-gradient(135deg, rgb(255, 0, 110) (i.e. #ff006e) and its text color is rgb(255, 255, 255)
• Verify font-family contains Georgia, font-weight is 700, and border-radius is 22px 22px 4px 22px
• Verify the bubble has a 2px solid border in #ff6fa5 and a pink drop shadow (box-shadow includes rgba(255, 0, 110, 0.35))

Assistant Message Bubble (amber, monospace, boxy)

• After the agent responds, locate the .copilotKitMessage.copilotKitAssistantMessage bubble
• Verify its background-color computed style is rgb(253, 224, 71) (i.e. #fde047) and text color is rgb(30, 27, 75) (i.e. #1e1b4b)
• Verify font-family contains JetBrains Mono / Fira Code / Menlo / Consolas (monospace stack)
• Verify the bubble uses a boxy shape with border-radius: 4px 22px 22px 22px, a 2px solid rgb(30, 27, 75) border, and a hard offset shadow 4px 4px 0 rgb(30, 27, 75)

Input Area (cream background, dashed pink border, serif)

• Verify the .copilotKitInput element has background-color: rgb(254, 243, 199) (i.e. #fef3c7), a 3px dashed rgb(255, 0, 110) border, and border-radius: 18px
• Verify the inner textarea uses a Georgia serif font at 1.1rem, with text color #2c1810
• Verify the placeholder text renders in italic #c2185b (type-drain the textarea to expose the placeholder)

Theme Persists Across Message Rounds

• Send a second message ("Tell me a joke"); wait for the assistant reply
• Verify both the new user bubble (pink gradient, serif) and the new assistant bubble (amber, monospace, boxy) retain the same computed styles as round 1 — no fallback to default CopilotKit theme between rounds
• Verify the .copilotKitMessages container continues to use the Georgia serif font family and the #fff8f0 background through scrolling

Chat Functions Identically To Default

• Type a multi-line message using Shift+Enter and verify Enter submits, Shift+Enter inserts a newline (same as a default <CopilotChat />)
• Verify the agent's response streams token-by-token into the amber assistant bubble without the theme resetting mid-stream

3. Error Handling

• Attempt to send an empty message; verify it is a no-op (no user bubble added)
• Send a ~500-character message; verify it wraps inside the pink user bubble without horizontal scroll, and the bubble still respects the hot-pink gradient + serif styling
• With the backend stopped, send a message; verify a visible error path surfaces in the UI and DevTools → Console shows no uncaught errors caused by the themed styles

Expected Results

• Chat loads within 3 seconds; plain-text response within 10 seconds
• All eight --copilot-kit-* CSS variables from theme.css resolve on .chat-css-demo-scope
• User bubbles: hot pink gradient, white bold serif text, asymmetric rounded corners, 2px pink border, shadow
• Assistant bubbles: amber #fde047 background, monospace dark text, boxy corners, 2px dark border, hard offset shadow
• Input: cream background, 3px dashed pink border, serif font, italic pink placeholder
• No flash of unstyled content between the default CopilotKit stylesheet and theme.css; no uncaught console errors