Ink Drop
A drop of ink falls from above and fills the circle on selection — uses a clip-path to animate the liquid level from empty to full.
Ink Drop the 4th of 18 designs in the 18 CSS Radio Button Designs collection. The design is implemented in pure CSS — no JavaScript required. Copy the HTML and CSS panels below into your project. Because the demo is pure CSS, it works in any framework or templating engine you happen to use. The design honours prefers-reduced-motion and uses real semantic markup, so it ships accessibility-ready out of the box.
Live preview
The code
<fieldset class="crb-ink"> <legend class="crb-sr">Theme</legend> <label><input type="radio" name="crb-ink" /><span></span>Light</label> <label><input type="radio" name="crb-ink" checked /><span></span>Dark</label> <label><input type="radio" name="crb-ink" /><span></span>Auto</label> </fieldset>
.crb-ink { display: flex; flex-direction: column; gap: 10px; border: 0; padding: 0; }
.crb-ink label {
display: flex; align-items: center; gap: 10px;
font: 500 13px/1 system-ui, sans-serif; color: #cbd5e1; cursor: pointer;
}
.crb-ink input { appearance: none; -webkit-appearance: none; position: absolute; opacity: 0; }
.crb-ink span {
width: 18px; height: 18px; border-radius: 50%;
border: 2px solid #444461; background: transparent;
position: relative; overflow: hidden;
transition: border-color 0.25s;
}
.crb-ink span::before {
content: ''; position: absolute; inset: 0;
background: linear-gradient(180deg, #06b6d4, #0ea5e9);
transform: translateY(-100%);
transition: transform 0.5s cubic-bezier(0.65,0,0.35,1);
}
.crb-ink input:checked + span { border-color: #06b6d4; }
.crb-ink input:checked + span::before { transform: translateY(0); }
.crb-sr {
position: absolute !important;
width: 1px;
height: 1px;
padding: 0;
margin: -1px;
overflow: hidden;
clip: rect(0, 0, 0, 0);
white-space: nowrap;
border: 0;
}