Corner Brackets Button: CSS Button Style & Animation

Corner Brackets Button

Four corner brackets frame a tinted button. On hover they spring outward with a little overshoot, like a viewfinder widening, and the tint deepens. The brackets are eight gradients on one pseudo.

Also known as: corner border hover, viewfinder button, bracket corners css.

Color Base size 18px Dark background Hold hover state

HTML

<button class="btn-corner-brackets">Scan code</button>

CSS

.btn-corner-brackets {
  --c: var(--btn-color, #3b82f6);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  font: 600 var(--btn-size, 18px)/1.2 system-ui, sans-serif;
  cursor: pointer;
  position: relative;
  padding: 0.85em 1.8em;
  border: 0;
  border-radius: 0.2em;
  background-color: color-mix(in srgb, var(--c) 8%, transparent);
  color: var(--c);
  transition: background-color 0.3s ease;}
.btn-corner-brackets::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(var(--c) 0 0) top left / 0.75em 2px,
    linear-gradient(var(--c) 0 0) top left / 2px 0.75em,
    linear-gradient(var(--c) 0 0) top right / 0.75em 2px,
    linear-gradient(var(--c) 0 0) top right / 2px 0.75em,
    linear-gradient(var(--c) 0 0) bottom left / 0.75em 2px,
    linear-gradient(var(--c) 0 0) bottom left / 2px 0.75em,
    linear-gradient(var(--c) 0 0) bottom right / 0.75em 2px,
    linear-gradient(var(--c) 0 0) bottom right / 2px 0.75em;
  background-repeat: no-repeat;
  pointer-events: none;
  transition: inset 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.btn-corner-brackets:is(:hover, :focus-visible) { background-color: color-mix(in srgb, var(--c) 16%, transparent); }
.btn-corner-brackets:is(:hover, :focus-visible)::before { inset: -0.45em -0.6em; }

@media (prefers-reduced-motion: reduce) {
  .btn-corner-brackets, .btn-corner-brackets *, .btn-corner-brackets::before, .btn-corner-brackets::after, .btn-corner-brackets *::before, .btn-corner-brackets *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

Customizing this snippet

Color: set --btn-color on the element or a parent. Currently previewing #3b82f6.
Base size: set --btn-size. Every other dimension is in em, so the whole thing scales together. Currently previewing 18px.
Speed: change the duration on the transition or animation shorthand. 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.

Corner Brackets Button

HTML

CSS

Customizing this snippet

Similar buttons