Underline Link

<a class="kodza-underline" href="#">Read the docs</a>

<a class="kodza-underline kodza-underline--retract" href="#">Nobody reads the docs</a>

/* Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license */
/* Kodza — Underline Link
   The underline slides in from the left and leaves through the right.
   The --retract variant does the opposite: visible at rest, it pulls away on hover.
   It is drawn as a background, so it follows the text across several lines, like a pen.
   Everything is tuned with the --kz-underline-* variables. */
.kodza-underline {
  --kz-underline-text: currentColor;
  --kz-underline-color: currentColor;
  --kz-underline-thickness: 0.07em;
  --kz-underline-offset: 0.08em;
  --kz-underline-duration: 0.6s;
  --kz-underline-ease: cubic-bezier(0.76, 0, 0.24, 1);

  color: var(--kz-underline-text);
  text-decoration: none;
  background-image: linear-gradient(var(--kz-underline-color), var(--kz-underline-color));
  background-repeat: no-repeat;
  background-position: 100% 100%;
  background-size: 0% var(--kz-underline-thickness);
  padding-bottom: var(--kz-underline-offset);
  /* Only the width moves: the anchor flips instantly, while it changes nothing on screen */
  transition: background-size var(--kz-underline-duration) var(--kz-underline-ease);
}

.kodza-underline:hover,
.kodza-underline:focus-visible {
  background-position: 0 100%;
  background-size: 100% var(--kz-underline-thickness);
}

.kodza-underline--retract {
  background-position: 0 100%;
  background-size: 100% var(--kz-underline-thickness);
}

.kodza-underline--retract:hover,
.kodza-underline--retract:focus-visible {
  background-position: 100% 100%;
  background-size: 0% var(--kz-underline-thickness);
}

.kodza-underline:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 4px;
  border-radius: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .kodza-underline {
    transition-duration: 0.01ms;
  }
}

/* kodza-guard 8d0c30debe74 — generated by Kodza, do not edit.
   Theme guard: keeps a site's own CSS (WordPress themes, Bootstrap, CSS resets…) off this
   component. :not(#_) is always true and weighs as much as an id, so these lines win over
   theme rules made of classes and tags. Customise the component through its --kz-* variables. */

/* What the browser gives, where the component sets it only in some states: at the lowest weight, so its own rules below put it back */

:where(.kodza-underline):not(#_) {
  border-radius: revert;
  outline: revert;
  outline-offset: revert;
}

/* What the browser gives, on everything the component leaves to it */

.kodza-underline:not(#_) {
  border: revert;
  list-style: revert;
  box-sizing: revert;
  position: revert;
  padding-top: revert;
  padding-right: revert;
  padding-left: revert;
  background-color: revert;
  box-shadow: revert;
  appearance: revert;
  max-height: revert;
  font-family: revert;
  font-size: revert;
  font-weight: revert;
  font-style: revert;
  line-height: revert;
  letter-spacing: revert;
  text-transform: revert;
  text-underline-offset: revert;
  text-align: revert;
  text-indent: revert;
  text-shadow: revert;
  vertical-align: revert;
}

.kodza-underline:not(#_):where(:not([hidden])) {
  display: revert;
}

.kodza-underline:not(#_):where([hidden]) {
  display: none;
}

/* The component's own rules, one step stronger: real buttons and fields, what it sets on tags themes style (links, lists, headings, images…), and the root width (a theme may narrow it, never widen it) */

.kodza-underline:not(#_) {
  color: var(--kz-underline-text);
  text-decoration: none;
  background-image: linear-gradient(var(--kz-underline-color), var(--kz-underline-color));
  padding-bottom: var(--kz-underline-offset);
  transition: background-size var(--kz-underline-duration) var(--kz-underline-ease);
}

.kodza-underline:focus-visible:not(#_) {
  outline: 2px solid currentColor;
  outline-offset: 4px;
  border-radius: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .kodza-underline:not(#_) {
    transition-duration: 0.01ms;
  }
}

'use client';
// Kodza — Underline Link, for React. From https://kodza.dev/components/hover-link-text-underline/
// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Next to this file: hover-link-text-underline.css, the component's CSS from Kodza, as they are.
// Yours to edit: the markup is plain JSX below.
import { useRef, type ComponentPropsWithoutRef, type ComponentRef, type CSSProperties } from 'react';
import './hover-link-text-underline.css';

type Variant = "retract";

export type UnderlineLinkProps = Omit<ComponentPropsWithoutRef<'a'>, "children" | "variant" | "vars"> & {
  /** Modifier class(es): .kodza-underline--retract */
  variant?: Variant | Variant[];
  /** Settings, as CSS variables on the root */
  vars?: {
    /** default: currentColor */
    "--kz-underline-text"?: string | number;
    /** default: currentColor */
    "--kz-underline-color"?: string | number;
    /** default: 0.07em */
    "--kz-underline-thickness"?: string | number;
    /** default: 0.08em */
    "--kz-underline-offset"?: string | number;
    /** default: 0.6s */
    "--kz-underline-duration"?: string | number;
    /** default: cubic-bezier(0.76, 0, 0.24, 1) */
    "--kz-underline-ease"?: string | number;
  };
  /** The text */
  children?: string;
  className?: string;
};

export function UnderlineLink({ variant, vars, children = "Read the docs", className, style, ...rest }: UnderlineLinkProps) {
  const ref = useRef<ComponentRef<'a'>>(null);
  const classes = ["kodza-underline", ...([] as string[]).concat(variant ?? []).map((v) => `kodza-underline--${v}`), className].filter(Boolean).join(' ');
  // Everything the markup is made of: when it changes, React gets a fresh element (see the top)
  const key = JSON.stringify([classes, vars, children, style, rest]);

  return (
    <a href="#" key={key} {...rest} className={classes} style={{ ...vars, ...style } as CSSProperties} ref={ref}>{children}</a>
  );
}