Easily generate cross-browser compatible CSS for the Flexbox gap property. Create margin-based workarounds for legacy browsers with this free, instant tool.
AI Generation Prompt
Free Online Flexbox Gap Polyfill CSS Generator
This application is a specialized development utility designed to help front-end developers generate CSS "margin-hack" polyfills for the Flexbox gap property. It provides an intuitive interface to configure layout spacing and instantly exports the necessary CSS code.
Core Features
- Live Configuration: Adjust gap size (px, rem, em), layout direction (row or column), and child element selection.
- Instant Code Generation: Generates clean, ready-to-copy CSS rules based on input parameters.
- Copy to Clipboard: One-click functionality to copy the generated code block.
- Visual Preview: A lightweight, non-interactive visual representation of how the generated CSS applies spacing to container children.
- Legacy Support: Explicitly focuses on generating negative-margin wrappers, which is the industry-standard workaround for the lack of
gapsupport in legacy browser engines.
UI/UX Specification
- Layout: A "split-screen" layout. The left pane contains the configuration form (controls, inputs), and the right pane displays the generated code and the visual preview.
- Mobile Responsiveness: On smaller screens, the layout stacks vertically, with the code output appearing below the inputs.
- Aesthetics:
- Theme: Strictly vibrant light mode. Use high-contrast grays for text (#1f2937) and white backgrounds (#ffffff).
- Primary Accent: Use a professional "SaaS" blue (#2563eb) for primary buttons and interactive elements.
- Shadows: Use soft, subtle box-shadows on card elements to denote depth (e.g.,
box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1)).
Color Palette
- Background: #f9fafb
- Card Background: #ffffff
- Primary Blue: #2563eb
- Border Color: #e5e7eb
- Text Primary: #111827
- Text Secondary: #6b7280
Animations & Transitions
- Buttons: All buttons should have a 150ms ease-in-out transition on hover states (subtle scale or brightness shift).
- Code Reveal: When parameters change, the code block should smoothly fade-in the new syntax rather than jarringly swapping text.
Technical Constraints & Requirements
- Single File: All HTML, CSS, and Vanilla JavaScript must be contained in one index.html file.
- Sandboxed Iframe Compatibility:
- Zero Persistence: Absolutely NO
localStorage,sessionStorage, or cookies. Use global JavaScript variables for in-memory state management. - No Popups: Do not use
alert(),confirm(), orprompt(). Use custom HTML elements (modals) for user feedback if necessary.
- Zero Persistence: Absolutely NO
- Dependencies: Use Tailwind CSS via CDN for styling. Use a lightweight icon library like Lucide-Icons (via CDN) for visual indicators.
- Clean Code: Ensure the JS logic is modular, even within the single file, to keep the output maintainable.
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Frequently Asked Questions
Everything you need to know about using this application.
Why do I need a Flexbox gap polyfill?
While modern browsers support the gap property in Flexbox, older browsers like Internet Explorer and legacy versions of Safari require margin-based hacks to achieve the same spacing between elements.
Is this tool compatible with all CSS frameworks?
Yes, the generated CSS is standard, pure CSS that can be applied to any HTML project, whether you are using Bootstrap, Tailwind CSS, or custom stylesheets.
Does this tool store my generated CSS?
No. This tool operates entirely client-side. It does not use cookies, local storage, or server-side saving. All data is cleared when the page is refreshed.
