I'm Not a Robot Checkbox
The verify-you're-human pattern: the box rounds into a spinner, turns twice, then shrinks away as a checkmark draws in and the shield fills. Only the look; real checks need a bot-detection service.
Also known as: captcha checkbox css, verify human checkbox, loading checkbox animation.
HTML
<label class="chk-not-a-robot">
<input type="checkbox">
<span class="chk-not-a-robot-slot">
<span class="chk-not-a-robot-box"></span>
<svg class="chk-not-a-robot-check" viewBox="0 0 24 24" aria-hidden="true"><path d="M4 12.5l5.5 5.5 11-11.5"/></svg>
</span>
<span class="chk-not-a-robot-text">I'm not a robot</span>
<svg class="chk-not-a-robot-shield" viewBox="0 0 24 24" aria-hidden="true"><path d="M12 3l7 2.8v5.4c0 4.3-2.9 8-7 9.8-4.1-1.8-7-5.5-7-9.8V5.8z"/></svg>
</label>CSS
.chk-not-a-robot {
--c: var(--chk-color, #3b82f6);
font-size: var(--chk-size, 24px);
position: relative;
display: inline-flex;
align-items: center;
gap: 0.6em;
line-height: 1.3;
cursor: pointer;
-webkit-user-select: none;
user-select: none;
-webkit-tap-highlight-color: transparent;
gap: 0.7em;
width: 13.5em;
padding: 0.8em 0.9em;
border: 0.08em solid color-mix(in srgb, currentColor 16%, transparent);
border-radius: 0.55em;
background: color-mix(in srgb, currentColor 4%, transparent);}
.chk-not-a-robot input {
position: absolute;
inset: 0;
width: 100%;
height: 100%;
margin: 0;
opacity: 0;
cursor: pointer;
z-index: 1;
}
.chk-not-a-robot-slot {
position: relative;
flex: none;
width: 1.45em;
height: 1.45em;
}
.chk-not-a-robot-box {
position: absolute;
inset: 0;
border: 0.14em solid color-mix(in srgb, currentColor 40%, transparent);
border-radius: 0.25em;
background: color-mix(in srgb, currentColor 3%, transparent);
transition: opacity 0.2s ease, transform 0.25s ease;
}
.chk-not-a-robot-check {
position: absolute;
inset: -0.1em;
width: calc(100% + 0.2em);
height: calc(100% + 0.2em);
fill: none;
stroke: var(--c);
stroke-width: 3;
stroke-linecap: round;
stroke-linejoin: round;
stroke-dasharray: 26;
stroke-dashoffset: 26;
transition: stroke-dashoffset 0.15s ease-in;
}
.chk-not-a-robot-text {
flex: 1;
font-weight: 500;
}
.chk-not-a-robot-shield {
flex: none;
width: 1.3em;
height: 1.3em;
fill: transparent;
stroke: color-mix(in srgb, currentColor 45%, transparent);
stroke-width: 1.6;
stroke-linejoin: round;
transition: fill 0.3s ease, stroke 0.3s ease;
}
.chk-not-a-robot:hover .chk-not-a-robot-box {
border-color: var(--c);
}
.chk-not-a-robot input:checked + .chk-not-a-robot-slot .chk-not-a-robot-box {
opacity: 0;
transform: rotate(0deg) scale(0.3);
animation: chk-not-a-robot-spin 1s linear;
}
.chk-not-a-robot input:checked + .chk-not-a-robot-slot .chk-not-a-robot-check {
stroke-dashoffset: 0;
transition: stroke-dashoffset 0.35s cubic-bezier(0.65, 0, 0.35, 1) 0.95s;
}
.chk-not-a-robot input:checked ~ .chk-not-a-robot-shield {
fill: color-mix(in srgb, var(--c) 25%, transparent);
stroke: var(--c);
transition-delay: 1.1s;
}
.chk-not-a-robot input:focus-visible + .chk-not-a-robot-slot {
outline: 0.12em solid var(--c);
outline-offset: 0.18em;
}
@keyframes chk-not-a-robot-spin {
0% { opacity: 1; transform: rotate(0deg) scale(1); border-radius: 0.25em; }
18% { opacity: 1; transform: rotate(60deg) scale(0.8); border-radius: 50%; border-color: color-mix(in srgb, var(--c) 22%, transparent); border-top-color: var(--c); background: transparent; }
82% { opacity: 1; transform: rotate(700deg) scale(0.8); border-radius: 50%; border-color: color-mix(in srgb, var(--c) 22%, transparent); border-top-color: var(--c); background: transparent; }
100% { opacity: 0; transform: rotate(760deg) scale(0.3); border-radius: 50%; border-color: color-mix(in srgb, var(--c) 22%, transparent); border-top-color: var(--c); background: transparent; }
}
@media (prefers-reduced-motion: reduce) {
.chk-not-a-robot, .chk-not-a-robot *, .chk-not-a-robot::before, .chk-not-a-robot::after, .chk-not-a-robot *::before, .chk-not-a-robot *::after {
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
transition-duration: 0.01ms !important;
}
}Customizing this snippet
- Color: set
--chk-coloron the element or a parent. Currently previewing#3b82f6. - Size: set
--chk-size. Every other dimension is inem, so the whole thing scales together. Currently previewing24px. - Speed: change the duration on the
transitionoranimationshorthand. Staggered delays are relative, so they keep their rhythm. - Reduced motion: the rule at the end of the CSS turns the motion off for people who asked their OS for less of it. Keep it.