Not even James Webb can find it.
We looked 13.8 billion years into the past and this page isn’t in a single image.
Back to EarthHTML + CSS404
James Webb 404
The James Webb mirror: 18 gold hexagons light up one by one, with the 404 sitting in the central gap.
Settings
1x
Code
<!doctype html>
<html lang="es">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta name="robots" content="noindex" />
<title>404 · Page not found</title>
<style>
body { margin: 0; background: #000; }
.n4-webb {
--accent: #ffcc4d;
--k: 1;
position: fixed;
inset: 0;
z-index: 0;
overflow: hidden;
container-type: size;
display: grid;
place-items: center;
background: #000;
color: #f5f5f7;
font-family: -apple-system,BlinkMacSystemFont,"SF Pro Display","Inter","Segoe UI",system-ui,sans-serif;
-webkit-font-smoothing: antialiased;
text-align: center;
line-height: 1.4;
}
.n4-webb *,.n4-webb *::before,.n4-webb *::after {
box-sizing: border-box;
}
.n4-webb .n4-copy {
position: relative;
z-index: 5;
display: flex;
flex-direction: column;
align-items: center;
gap: 1.6cqmin;
width: 100%;
max-width: 680px;
padding: 0 6cqw;
}
.n4-webb .n4-title {
margin: 0;
font-size: clamp(17px,4.2cqmin,36px);
font-weight: 600;
letter-spacing: -.02em;
line-height: 1.15;
text-wrap: balance;
}
.n4-webb .n4-sub {
margin: 0;
max-width: 34em;
font-size: clamp(13px,2.4cqmin,18px);
color: #a1a1a6;
text-wrap: balance;
}
.n4-webb .n4-tag {
font: 600 clamp(10px,1.9cqmin,13px)/1 ui-monospace,"SF Mono",Menlo,Consolas,monospace;
letter-spacing: .16em;
text-transform: uppercase;
color: var(--accent);
}
.n4-webb .n4-cta {
margin-top: 1.8cqmin;
display: inline-flex;
align-items: center;
gap: .5em;
padding: .85em 1.5em;
border-radius: 999px;
background: #f5f5f7;
color: #000;
font-size: clamp(13px,2.2cqmin,16px);
font-weight: 600;
text-decoration: none;
transition: transform .3s cubic-bezier(.25,.1,.25,1),box-shadow .3s cubic-bezier(.25,.1,.25,1);
}
.n4-webb .n4-cta:hover {
transform: translateY(-2px);
box-shadow: 0 12px 32px -10px var(--accent);
}
.n4-webb .n4-cta:focus-visible {
outline: 2px solid var(--accent);
outline-offset: 3px;
}
.n4-webb .n4-stars,.n4-webb .n4-stars2 {
position: absolute;
inset: -4%;
pointer-events: none;
}
.n4-webb .n4-stars {
background-image: radial-gradient(1px 1px at 8% 12%,#fff 60%,transparent),radial-gradient(1px 1px at 22% 68%,#fff 60%,transparent),radial-gradient(1.5px 1.5px at 35% 24%,#fff 60%,transparent),radial-gradient(1px 1px at 48% 82%,#fff 60%,transparent),radial-gradient(1px 1px at 57% 9%,#fff 60%,transparent),radial-gradient(1.5px 1.5px at 66% 44%,#fff 60%,transparent),radial-gradient(1px 1px at 74% 72%,#fff 60%,transparent),radial-gradient(1px 1px at 86% 18%,#fff 60%,transparent),radial-gradient(1.5px 1.5px at 93% 58%,#fff 60%,transparent),radial-gradient(1px 1px at 14% 42%,#fff 60%,transparent),radial-gradient(1px 1px at 40% 55%,#fff 60%,transparent),radial-gradient(1px 1px at 81% 90%,#fff 60%,transparent),radial-gradient(1px 1px at 4% 88%,#fff 60%,transparent),radial-gradient(1px 1px at 62% 30%,#fff 60%,transparent);
opacity: .75;
animation: n4-webb-tw calc(5s / var(--k)) ease-in-out infinite alternate;
}
.n4-webb .n4-stars2 {
background-image: radial-gradient(2px 2px at 18% 30%,rgba(255,255,255,.9) 50%,transparent),radial-gradient(1.5px 1.5px at 72% 20%,rgba(255,255,255,.8) 50%,transparent),radial-gradient(2px 2px at 30% 85%,rgba(255,255,255,.7) 50%,transparent),radial-gradient(1.5px 1.5px at 88% 70%,rgba(255,255,255,.8) 50%,transparent),radial-gradient(2px 2px at 52% 60%,rgba(255,255,255,.6) 50%,transparent),radial-gradient(1.5px 1.5px at 6% 55%,rgba(255,255,255,.8) 50%,transparent);
opacity: .55;
animation: n4-webb-tw calc(7s / var(--k)) ease-in-out infinite alternate-reverse;
}
.n4-webb [data-depth] {
transition: transform .9s cubic-bezier(.2,.7,.2,1);
}
@keyframes n4-webb-tw {
from {
opacity: .3;
}
}
@keyframes n4-webb-spin {
to {
transform: rotate(1turn);
}
}
@keyframes n4-webb-fade {
from {
opacity: 0;
transform: translateY(10px);
}
}
@media (prefers-reduced-motion:reduce) {
.n4-webb *,.n4-webb *::before,.n4-webb *::after {
animation: none!important;
transition: none!important;
}
}
.n4-webb {
background: #02010a;
}
.n4-webb .n4-neb {
position: absolute;
inset: 0;
background: radial-gradient(40% 30% at 20% 25%,rgba(120,60,200,.25),transparent 70%),radial-gradient(35% 28% at 82% 70%,rgba(255,120,40,.18),transparent 70%),radial-gradient(30% 22% at 70% 18%,rgba(60,140,255,.14),transparent 70%);
}
.n4-webb .n4-mirror {
--s: clamp(14px,4.6cqmin,50px);
position: relative;
width: calc(var(--s) * 9.4);
height: calc(var(--s) * 8.6);
margin-bottom: 1cqmin;
}
.n4-webb .n4-hex {
position: absolute;
left: 50%;
top: 50%;
width: calc(var(--s) * 1.732);
height: calc(var(--s) * 2);
margin: calc(var(--s) * -1) 0 0 calc(var(--s) * -.866);
transform: translate(calc(var(--x) * var(--s) * 1.07),calc(var(--y) * var(--s) * 1.07));
clip-path: polygon(50% 0,100% 25%,100% 75%,50% 100%,0 75%,0 25%);
background: linear-gradient(135deg,#fff3c4,color-mix(in srgb,var(--accent) 85%,#b8860b) 35%,#7a4f06 62%,color-mix(in srgb,var(--accent) 70%,#fff) 82%,#5c3a03);
animation: n4-webb-pop calc(.7s / var(--k)) calc(var(--d) * .06s / var(--k)) cubic-bezier(.2,.9,.3,1.2) both;
}
.n4-webb .n4-hex::after {
content: "";
position: absolute;
inset: 0;
background: linear-gradient(115deg,transparent 38%,rgba(255,255,255,.85) 50%,transparent 62%);
background-size: 320% 100%;
background-position: 120% 0;
animation: n4-webb-sheen calc(6s / var(--k)) calc(var(--d) * .08s / var(--k)) ease-in-out infinite;
}
.n4-webb .n4-core {
position: absolute;
left: 50%;
top: 50%;
translate: -50% -50%;
font: 700 calc(var(--s) * .62)/1 ui-monospace,"SF Mono",Menlo,monospace;
letter-spacing: .04em;
color: var(--accent);
text-shadow: 0 0 .4em var(--accent),0 0 1.2em color-mix(in srgb,var(--accent) 60%,transparent);
animation: n4-webb-pulse calc(2.6s / var(--k)) ease-in-out infinite;
}
.n4-webb .n4-copy>:not(.n4-mirror) {
animation: n4-webb-fade calc(1s / var(--k)) calc(1.2s / var(--k)) cubic-bezier(.2,.7,.2,1) both;
}
@keyframes n4-webb-pop {
from {
opacity: 0;
transform: translate(calc(var(--x) * var(--s) * 1.5),calc(var(--y) * var(--s) * 1.5)) scale(.6);
}
}
@keyframes n4-webb-sheen {
0%,55% {
background-position: 120% 0;
}
100% {
background-position: -20% 0;
}
}
@keyframes n4-webb-pulse {
50% {
opacity: .55;
}
}
</style>
</head>
<body>
<main class="n4-webb">
<div class="n4-stars" aria-hidden="true"></div>
<div class="n4-neb" aria-hidden="true"></div>
<div class="n4-copy">
<div class="n4-mirror" aria-hidden="true"><i class="n4-hex" style="--x:1.732;--y:0.000;--d:0"></i><i class="n4-hex" style="--x:0.866;--y:-1.500;--d:1"></i><i class="n4-hex" style="--x:-0.866;--y:-1.500;--d:2"></i><i class="n4-hex" style="--x:-1.732;--y:0.000;--d:3"></i><i class="n4-hex" style="--x:-0.866;--y:1.500;--d:4"></i><i class="n4-hex" style="--x:0.866;--y:1.500;--d:5"></i><i class="n4-hex" style="--x:3.464;--y:0.000;--d:6"></i><i class="n4-hex" style="--x:2.598;--y:-1.500;--d:7"></i><i class="n4-hex" style="--x:1.732;--y:-3.000;--d:8"></i><i class="n4-hex" style="--x:0.000;--y:-3.000;--d:9"></i><i class="n4-hex" style="--x:-1.732;--y:-3.000;--d:10"></i><i class="n4-hex" style="--x:-2.598;--y:-1.500;--d:11"></i><i class="n4-hex" style="--x:-3.464;--y:0.000;--d:12"></i><i class="n4-hex" style="--x:-2.598;--y:1.500;--d:13"></i><i class="n4-hex" style="--x:-1.732;--y:3.000;--d:14"></i><i class="n4-hex" style="--x:0.000;--y:3.000;--d:15"></i><i class="n4-hex" style="--x:1.732;--y:3.000;--d:16"></i><i class="n4-hex" style="--x:2.598;--y:1.500;--d:17"></i><span class="n4-core">404</span></div>
<h1 class="n4-title">Not even James Webb can find it.</h1>
<p class="n4-sub">We looked 13.8 billion years into the past and this page isn’t in a single image.</p>
<a class="n4-cta" href="/">Back to Earth</a>
</div>
</main>
</body>
</html>
Prompt for AI
Paste it into ChatGPT, Claude or Cursor and it will adapt the block to your project with these settings, even if you don’t use React.
More in 404
Where to use it
The joke is right there: not even the James Webb can find this page. The mirror lights up segment by segment, which gives visitors a few pleasant seconds before they read the way back. It works for an astronomy blog, a data or optics company, or a science outreach site that wants a clever 404 page.
Gold on black is close to the real telescope, so change it only if it clashes with your palette. The line about looking back 13.8 billion years lands well; if you rewrite it, keep the number, because that is what makes people smile.