Project Guidelines

This skill provides project-specific guidelines for developing this Phoenix application.

Development Workflow

Pre-commit Checks

• Use mix precommit alias when done with all changes
• This runs: compile with warnings as errors, unlock unused deps, format, and test
• Fix any pending issues before committing

HTTP Client

• Use the already included :req (Req) library for HTTP requests
• Avoid :httpoison, :tesla, and :httpc
• Req is included by default and is the preferred HTTP client for Phoenix apps

# Use Req for HTTP requests
Req.get!("https://api.example.com/data")
Req.post!("https://api.example.com/users", json: %{name: "Alice"})

Phoenix v1.8 Conventions

Layout Components

• Always begin LiveView templates with <Layouts.app flash={@flash} ...> which wraps all inner content
• The MyAppWeb.Layouts module is aliased in the my_app_web.ex file—no need to alias it again

<Layouts.app flash={@flash} current_scope={@current_scope}>
  <%!-- Your content here --%>
</Layouts.app>

Current Scope Issues

When you encounter errors with no current_scope assign:

1. You failed to follow Authenticated Routes guidelines, OR
2. You failed to pass current_scope to <Layouts.app>

Fix by moving routes to proper live_session and ensure you pass current_scope as needed.

Flash Messages

• Phoenix v1.8 moved the <.flash_group> component to the Layouts module
• You are forbidden from calling <.flash_group> outside of the layouts.ex module

Icons

• Out of the box, core_components.ex imports <.icon name="hero-x-mark" class="w-5 h-5"/> for hero icons
• Always use the <.icon> component for icons
• Never use Heroicons modules or similar

<.icon name="hero-user" class="w-6 h-6" />
<.icon name="hero-envelope" class="w-5 h-5" />

Form Inputs

• Always use the imported <.input> component from core_components.ex when available
• Using <.input> will save steps and prevent errors

<.input field={@form[:email]} label="Email" type="email" />
<.input field={@form[:password]} label="Password" type="password" />

Class Override Warning: If you override default input classes with custom values, no default classes are inherited. Your custom classes must fully style the input.

JS and CSS Guidelines

Styling Philosophy

Use Tailwind CSS classes and custom CSS rules to create polished, responsive, and visually stunning interfaces.

Tailwind CSS v4

Tailwind CSS v4 no longer needs a tailwind.config.js and uses new import syntax in app.css:

@import "tailwindcss" source(none);
@source "../css";
@source "../js";
@source "../../lib/my_app_web";

Important:

• Always use and maintain this import syntax in app.css for projects generated with phx.new
• Never use @apply when writing raw CSS in Tailwind v4

UI Components

• Always manually write your own Tailwind-based components
• Never use daisyUI for a unique, world-class design
• Build custom components that match your brand and design system

Asset Bundling

Out of the box only the app.js and app.css bundles are supported:

• You cannot reference an external vendor'd script src or link href in the layouts
• You must import vendor deps into app.js and app.css to use them
• Never write inline <script>custom js</script> tags within templates

Example (in assets/js/app.js):

// Import vendor libraries
import Chart from "chart.js/auto"
import Alpine from "alpinejs"

// Make available globally if needed
window.Chart = Chart
window.Alpine = Alpine
Alpine.start()

UI/UX & Design Guidelines

Design Philosophy

Produce world-class UI designs with focus on:

• Usability
• Aesthetics
• Modern design principles

Micro-interactions

Implement subtle micro-interactions:

• Button hover effects
• Smooth transitions
• Loading states
• Focus states

<button class="
  px-4 py-2 bg-blue-600 text-white rounded-lg
  transition-all duration-200
  hover:bg-blue-700 hover:shadow-lg
  active:scale-95
  focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2
">
  Click me
</button>

Typography and Layout

Ensure clean typography, spacing, and layout balance for a refined, premium look:

• Use consistent spacing scales (Tailwind's spacing is great)
• Maintain visual hierarchy with font sizes and weights
• Use proper line heights for readability
• Ensure adequate contrast ratios

Delightful Details

Focus on delightful details:

• Hover effects on interactive elements
• Loading states for async operations
• Smooth page transitions
• Empty states with helpful guidance
• Success/error feedback with appropriate styling

Examples

Card with hover effect:

<div class="
  group p-6 bg-white rounded-xl shadow-sm
  transition-all duration-300
  hover:shadow-xl hover:-translate-y-1
">
  <h3 class="text-lg font-semibold text-gray-900 group-hover:text-blue-600 transition-colors">
    {@title}
  </h3>
  <p class="mt-2 text-gray-600">{@description}</p>
</div>

Loading state:

<div :if={@loading} class="flex items-center justify-center">
  <div class="animate-spin rounded-full h-8 w-8 border-b-2 border-blue-600"></div>
</div>

Summary

• Run mix precommit before committing
• Use Req library for HTTP requests
• Follow Phoenix v1.8 conventions (Layouts.app, icons, inputs)
• Use Tailwind v4 import syntax in app.css
• Never use @apply in raw CSS
• Build custom components, avoid daisyUI
• Import vendor deps into app.js/app.css
• Focus on world-class UI with micro-interactions and delightful details