CSS resize Property Demo - Online User‑Resizable Element
Make an element resizable horizontally, vertically, or both. See the handle and code. Useful for textareas.
UD5 Toolkit
I change based on my container's size, not the viewport.
inline-size queries width only; size enables both width and height queries.inline-size establishes a container that supports queries on the inline axis (usually width). size enables queries on both the inline and block (usually height) axes. Use inline-size for most layout cases; size when you need height‑based rules.cqw, cqh, cqi, cqb, cqmin, and cqmax. They are relative to the query container’s size, enabling precise proportional sizing inside components.@container style()) allow styling based on computed values of an ancestor (e.g., custom properties). This feature is still experimental and has very limited browser support at the moment.Make an element resizable horizontally, vertically, or both. See the handle and code. Useful for textareas.
Type a few words and see them rendered at every heading size (h1–h6) with your chosen font. Perfect for design systems.
Select any element on the test page and monitor its size changes with ResizeObserver. See log of all entries.
Enter two tire sizes and see a side‑by‑side comparison of diameter, width, and speedometer error. Local math.
Toggle print‑specific styles like removing backgrounds, showing link URLs, and adding page breaks. Generate a complete print stylesheet instantly.
Add print styles like removing backgrounds, adding page breaks, setting margins. See print preview instantly.
Drag to resize a box and see the Resize Observer callback fire. Get contentRect and borderBoxSize. Learn the API.
Upload a small image and generate the CSS code for a custom cursor. Test it live on the page. Tiny but useful.
Estimate your one‑rep max from weight and reps. Supports Epley, Brzycki, Lombardi formulas. See your strength level.
Add appliances with running and starting watts to estimate needed generator capacity. Prevent overload.
Type a password and see a bar that fills based on estimated bits of entropy. Color‑coded feedback. No storage.
Enter a chemical formula (e.g., H2O, C6H12O6) and calculate its molar mass. Handles parentheses and hydrates. Pure frontend.
Estimate your one‑rep max (1RM) from weight and reps. Supports multiple formulas (Epley, Brzycki). Training percentages table.
Paste a raw WebAuthn attestation response (CBOR) and decode its fields: format, authenticator data, and extensions. Debug passkeys locally.
Find your healthy weight range using multiple medical formulas (Hamwi, Devine, Robinson, Miller). Frame size adjustment included. Instant local computation.
Calculate your one-rep max using Epley, Brzycki, Lombardi or O'Conner formulas. Predict maximum lifting capacity and plan progressive overload. 100% local processing.
Visually configure scroll‑snap containers and items. Adjust alignment, stop behavior, and padding. Copy the clean CSS instantly.
Create complex linear gradients with any number of color stops, exact angles, and length units. Live preview and CSS code.
Style underlines, overlines, and strike-throughs with colors, wavy styles, and thickness. Modern CSS text‑decoration.
Design a fully styled scrollbar with colors, width, radius, and hover effects. Supports both ::-webkit‑scrollbar and Firefox scrollbar‑width.
Create CSS clamp() values for fluid typography. Enter min and max font sizes and viewport widths. Modern responsive design.
Create CSS mask‑image effects with custom shapes, gradients, and SVGs. Visually see the mask applied to an image. Copy the CSS.
Paste your CSS and sort the properties of each rule alphabetically or by concentric groups. Keep your stylesheets consistent without a build step.
Create a customizable checkerboard or grid background using pure CSS gradients. Adjust cell size and colors. Copy the code.
Upload two images and apply CSS blend modes (multiply, screen, overlay, etc.). See the result and copy the filter CSS. Pure frontend.
Write a media query and instantly see if it matches your current viewport. Width, height, orientation, and more.
Paste your CSS and strip all `!important` declarations in one click. See a list of affected rules. Local tool.
Paste HTML/CSS snippets or enter properties to test how z‑index and stacking contexts interact. Real‑time example.
Adjust margin, border, padding, and content sizes interactively and see the rendered box model. Get the exact CSS. Teach or learn layout.
Design a pure CSS tooltip with custom text, position (top/bottom/left/right), and arrow. Copy the clean code.