Margin Note — Back to Top Button

Source Code

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

<!-- TB-2050 / Margin Note | paste before closing body -->
<button class="backtop tb-btt-button w2050" type="button" aria-label="Back to top"><span class="w50bar"></span><span class="w50arrow">↗</span><span class="w50copy">To the top</span></button>

/* TB-2050 / Margin Note */
.backtop{box-sizing:border-box;position:fixed;z-index:50;cursor:pointer;opacity:0;visibility:hidden;pointer-events:none;transform:translateY(12px);text-align:center;transition:opacity .24s, transform .28s, visibility .24s}.backtop.is-visible{opacity:1;visibility:visible;pointer-events:auto;transform:translateY(0)}.backtop.w2055.is-visible{transform:translate(-50%,0)}.backtop:focus-visible{outline:3px solid #e7ab4c;outline-offset:4px}
.w2050{left:28px;bottom:29px;min-width:118px;height:45px;display:flex;align-items:center;gap:11px;padding:0 7px;background:transparent;color:#352e29;border:0;filter:drop-shadow(0 1px 1px #fff)}.w50bar{width:26px;height:1px;background:currentColor;transition:width .34s}.w50arrow{font:400 18px/1 Georgia,serif;transform:rotate(-45deg);display:inline-block}.w50copy{font:italic 15px Georgia,serif;white-space:nowrap}.w2050:hover .w50bar{width:45px}.w2050:hover .w50arrow{transform:rotate(-45deg) translate(2px,-2px)}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{transition-duration:.01ms!important;animation-duration:.01ms!important}}
/* POLISH PASS 2026-10-18: alignment, tactile size, emphasis & individual character */
.backtop{isolation:isolate;-webkit-tap-highlight-color:transparent;}
.backtop:focus-visible{outline:3px solid #f0af42;outline-offset:4px;}
@media(prefers-reduced-motion:reduce){.backtop,.backtop *{transition-duration:.01ms!important;animation-duration:.01ms!important}}

.w2050{left:clamp(22px,4vw,70px);bottom:clamp(29px,5vh,65px);min-width:142px;height:51px;padding:0 10px;gap:14px;color:#302d2a;background:#f8f4eddc;border-bottom:1px solid #a59989;filter:none;text-align:left;}
.w2050 .w50copy{white-space:nowrap;}
.w2050:hover{background:#e7ded1;transform:translateY(-3px)}
@media(max-width:650px){.w2050{left:18px;bottom:24px;min-width:128px;height:48px}}

(()=>{'use strict';const button=document.querySelector('.backtop');if(!button)return;const footerOnly=button.classList.contains('footer-backtop');const reduced=matchMedia('(prefers-reduced-motion: reduce)');let scheduled=false;function update(){scheduled=false;if(footerOnly)return;const shown=window.scrollY>160;button.classList.toggle('is-visible',shown);button.classList.toggle('is-hidden',!shown);button.tabIndex=shown?0:-1;button.setAttribute('aria-hidden',String(!shown));if(button.classList.contains('w2056')){const max=Math.max(1,document.documentElement.scrollHeight-innerHeight);button.style.setProperty('--progress',(Math.round(Math.min(100,scrollY/max*100)))+'%');}}function onScroll(){if(!scheduled){scheduled=true;requestAnimationFrame(update)}}button.addEventListener('click',()=>window.scrollTo({top:0,behavior:reduced.matches?'instant':'smooth'}));addEventListener('scroll',onScroll,{passive:true});addEventListener('resize',onScroll,{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

Editorial publications, journals and long-form reading layouts.

Technical Notes

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

Mobile：Check tap target and placement on mobile devices.

Browser：Test in your supported browsers.

Reduced Motion：CSS respects prefers-reduced-motion.