FOUR CORNERS — Back to Top

Source Code

Copy the HTML, CSS or JavaScript you need for your project.

<button type="button" class="tb-btt-button tb-btt-2008 is-hidden" aria-label="Back to the top of the page" title="Back to Top"><span class="art art-corners"><svg viewBox="0 0 100 100" focusable="false" aria-hidden="true" xmlns="http://www.w3.org/2000/svg"><path class="corner-piece c1" d="M19 38V19H38"/><path class="corner-piece c2" d="M62 19H81V38"/><path class="corner-piece c3" d="M81 62V81H62"/><path class="corner-piece c4" d="M38 81H19V62"/><path class="corner-arrow" d="M50 66V35M38 47 50 35 62 47"/></svg></span></button>

/* TB-2008 — Back to Top button. */
.tb-btt-2008{--selectedtone:#8a6b5a;color:#8a6b5a;position:fixed;right:max(18px,env(safe-area-inset-right));bottom:max(18px,env(safe-area-inset-bottom));z-index:1000;border:0;background:transparent;padding:5px;display:flex;align-items:center;justify-content:center;min-width:48px;min-height:48px;cursor:pointer;font-family:Arial,"Noto Sans JP",sans-serif;line-height:normal;box-sizing:border-box;-webkit-tap-highlight-color:transparent;transition:opacity .24s ease, transform .35s ease,visibility .24s ease}
.tb-btt-2008:is(:focus-visible){outline:2px solid currentColor;outline-offset:4px}
.tb-btt-2008.is-hidden{opacity:0;transform:translateY(10px);visibility:hidden;pointer-events:none}
.tb-btt-2008 *{box-sizing:border-box}
.tb-btt-2008 .art{display:flex;position:relative;align-items:center;justify-content:center;flex-shrink:0}
.tb-btt-2008 .art svg{display:block;overflow:visible;width:100%;height:100%}

.tb-btt-2008 .art-corners{width:59px;height:59px}
.tb-btt-2008 .art-corners svg path{stroke:currentColor;stroke-width:2.4;fill:none;stroke-linecap:square;stroke-linejoin:miter}
.tb-btt-2008 .art-corners .corner-arrow{stroke-width:2.5}

.tb-btt-2008 .corner-piece{transition:transform .48s ease}
.tb-btt-2008:is(:hover,:focus-visible) .c1{transform:translate(-5px,-5px)}
.tb-btt-2008:is(:hover,:focus-visible) .c2{transform:translate(5px,-5px)}
.tb-btt-2008:is(:hover,:focus-visible) .c3{transform:translate(5px,5px)}
.tb-btt-2008:is(:hover,:focus-visible) .c4{transform:translate(-5px,5px)}
.tb-btt-2008:is(:hover,:focus-visible) .corner-arrow{animation:tb_btt_2008_cornerDraw .55s ease-out}
@keyframes tb_btt_2008_cornerDraw{0%{stroke-dasharray:80;stroke-dashoffset:80}100%{stroke-dashoffset:0}}

.tb-btt-2008 .art{color:var(--selectedtone,#465b53)}
@media(prefers-reduced-motion:reduce){.tb-btt-2008,.tb-btt-2008 *, .tb-btt-2008 *::before,.tb-btt-2008 *::after{animation-duration:0.01ms!important;animation-iteration-count:1!important;transition-duration:0.01ms!important}}

/* TB-2008 | Back to Top | No external libraries required. */
(() => {
  'use strict';

  const button = document.querySelector('.tb-btt-2008');
  if (!button) return;

  const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)');
  let scheduled = false;

  function update() {
    scheduled = false;
    const visible = window.scrollY > 160;
    button.classList.toggle('is-hidden', !visible);
    button.tabIndex = visible ? 0 : -1;
    button.setAttribute('aria-hidden', String(!visible));
  }

  function requestUpdate() {
    if (scheduled) return;
    scheduled = true;
    requestAnimationFrame(update);
  }

  button.addEventListener('click', () => {
    window.scrollTo({ top: 0, behavior: reduceMotion.matches ? 'auto' : 'smooth' });
  });
  window.addEventListener('scroll', requestUpdate, { passive: true });
  window.addEventListener('resize', requestUpdate, { passive: true });
  update();
})();

How to Use

Insert the HTML button near the end of body, load the CSS, and include JavaScript using defer. Test scrolling, returning to the top, and positioning on mobile.

Use Case

Geometric and grid-based websites

Technical Notes

Keep controls usable on touch devices. Test keyboard focus and reduced-motion preferences.

Mobile：Works with tap and keyboard. Check the lower-right offset against other fixed controls.

Browser：Uses standard HTML, CSS and JavaScript. Install all three together; no external library is required.

Reduced Motion：Reduces transitions and smooth scrolling when reduced motion is requested.