Creating modern forms with form.fscss — pure CSS

Floating labels. Inline validation. Custom checkboxes, radios, and a toggle switch. A gradient button with a press-down micro-interaction. Every bit of it below is CSS — no form library, no useState , no event listener wiring up a class toggle. That's form.fscss — the module in the FSCSS ecosystem. Same philosophy each time: solve the hard visual problem once, ship it as importable mixins, let the browser do the actual work. <script src= "https://cdn.jsdelivr.net/npm/fscss@1.1.24/exec.min.js" defer ></script> <style> @import (( * ) from form ) @ form-root () @ form-group (. form-group ) @ form-input (. form-input ) @ form-label (. form-label ) @ form-float (. form-group , . form-input , . form-label ) @ form-checkbox (. form-checkbox ) @ form-btn (. form-btn ) @ form-btn-primary (. form-btn-primary ) </style> <div class= "form-group" > <input class= "form-input" type= "text" placeholder= " " > <label class= "form-label" > Full name </label> </div> <label class= "form-checkbox" > <input type= "checkbox" checked ><span></span> I agree to the Terms </label> <button class= "form-btn form-btn-primary" > Create account </button> The two tricks doing all the work Forms feel like they need JavaScript because most tutorials reach for it immediately. Two native CSS mechanisms cover almost everything a "modern" form needs. Floating labels run entirely on :placeholder-shown . Give the input placeholder=" " — a literal space, not empty — and the browser now knows, purely in CSS, whether the field is empty and unfocused: .form-input :focus + .form-label , .form-input :not ( :placeholder-shown ) + .form-label { top : -9px ; font-size : 11px ; color : var ( --form-accent ); } No state, no class toggling on keyup. The label just reacts to what the browser already knows about the input. Checkboxes, radios, and the switch all use the classic checkbox-hack: the real <input> stays in the DOM (so it keeps native keyboard support and form submission) but is visually hidden, and a sibling