Input Focus Border
An input whose border draws itself around the field when it gets focus, with a soft ring fading in behind. It erases the same way on blur, because it is a transition on an SVG stroke.
Also known as: css input border animation, input box border animation css, input focus animation.
HTML
<label class="bdr-input-focus-border">
<span class="bdr-input-focus-border-label">Email</span>
<span class="bdr-input-focus-border-field">
<input type="email" placeholder="you@example.com">
<svg class="bdr-input-focus-border-svg" aria-hidden="true"><rect width="100%" height="100%" pathLength="100"/></svg>
</span>
</label>CSS
.bdr-input-focus-border {
--c: var(--bdr-color, #3b82f6);
font-size: var(--bdr-size, 16px);
display: grid;
gap: 0.45em;
align-content: start;
width: 15em;
font-family: system-ui, sans-serif;
}
.bdr-input-focus-border-label {
font-size: 0.8em;
font-weight: 600;
opacity: 0.75;
transition: color 0.3s ease, opacity 0.3s ease;
}
.bdr-input-focus-border-field {
position: relative;
border-radius: 0.6em;
transition: box-shadow 0.4s ease;
}
.bdr-input-focus-border input {
display: block;
box-sizing: border-box;
width: 100%;
padding: 0.75em 0.9em;
border: 1px solid color-mix(in srgb, var(--c) 35%, transparent);
border-radius: 0.6em;
background: color-mix(in srgb, var(--c) 5%, transparent);
color: inherit;
font: inherit;
outline: none;
transition: border-color 0.3s ease;
}
.bdr-input-focus-border input::placeholder { color: inherit; opacity: 0.45; }
.bdr-input-focus-border-field:hover input { border-color: color-mix(in srgb, var(--c) 70%, transparent); }
.bdr-input-focus-border-svg {
position: absolute;
inset: 0;
width: 100%;
height: 100%;
overflow: visible;
pointer-events: none;
}
.bdr-input-focus-border-svg rect {
rx: 0.6em;
fill: none;
stroke: var(--c);
stroke-width: 0.13em;
stroke-dasharray: 100 100;
stroke-dashoffset: 100;
transition: stroke-dashoffset 0.7s cubic-bezier(0.65, 0, 0.35, 1);
}
.bdr-input-focus-border:focus-within .bdr-input-focus-border-label { color: var(--c); opacity: 1; }
.bdr-input-focus-border-field:focus-within { box-shadow: 0 0 0 0.3em color-mix(in srgb, var(--c) 18%, transparent); }
.bdr-input-focus-border-field:focus-within rect { stroke-dashoffset: 0; }
@media (prefers-reduced-motion: reduce) {
.bdr-input-focus-border, .bdr-input-focus-border *, .bdr-input-focus-border::before, .bdr-input-focus-border::after, .bdr-input-focus-border *::before, .bdr-input-focus-border *::after {
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
transition-duration: 0.01ms !important;
}
}Tailwind CSS version
The same effect using Tailwind utility classes. No custom CSS or config needed.
<label class="group grid w-60 gap-2 text-base">
<span class="text-sm font-semibold opacity-75 transition group-focus-within:text-blue-500 group-focus-within:opacity-100">Email</span>
<span class="relative rounded-[0.6em] transition-shadow duration-300 group-focus-within:shadow-[0_0_0_0.3em_rgb(59_130_246/0.18)]">
<input type="email" placeholder="you@example.com" class="block w-full rounded-[0.6em] border border-blue-500/35 bg-blue-500/5 px-3.5 py-3 outline-none transition-colors placeholder:opacity-45 hover:border-blue-500/70">
<svg class="pointer-events-none absolute inset-0 h-full w-full overflow-visible" aria-hidden="true"><rect width="100%" height="100%" pathLength="100" class="fill-none stroke-blue-500 [rx:0.6em] [stroke-dasharray:100_100] [stroke-dashoffset:100] [stroke-width:0.13em] transition-[stroke-dashoffset] duration-700 ease-[cubic-bezier(.65,0,.35,1)] group-focus-within:[stroke-dashoffset:0]"/></svg>
</span>
</label>Customizing this snippet
- Color: set
--bdr-coloron the element or a parent. Currently previewing#3b82f6. - Base size: set
--bdr-size. Every other dimension is inem, so the whole thing scales together. Currently previewing16px. - 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.