Indeterminate Checkbox Group: Custom CSS Checkbox

Indeterminate Checkbox Group

A parent row whose box mirrors its children: empty, a dash when some are checked, a check when all are. The dash folds away as the check draws in. Pure CSS: the parent reads them with :has().

Also known as: indeterminate checkbox css, select all checkbox css, tri-state checkbox.

Toppings

Cheese Basil Olives

Color Size 24px Dark background

HTML

<div class="chk-indeterminate-checkbox-group" role="group" aria-labelledby="chk-indeterminate-checkbox-group-title">
  <div class="chk-indeterminate-checkbox-group-head">
    <span class="chk-indeterminate-checkbox-group-box chk-indeterminate-checkbox-group-parent" aria-hidden="true"><i class="chk-indeterminate-checkbox-group-dash"></i><svg viewBox="0 0 24 24" aria-hidden="true"><path d="M5 12.5l4.5 4.5L19 7.5"/></svg></span>
    <span id="chk-indeterminate-checkbox-group-title">Toppings</span>
  </div>
  <div class="chk-indeterminate-checkbox-group-kids">
    <label class="chk-indeterminate-checkbox-group-item"><input type="checkbox" checked><span class="chk-indeterminate-checkbox-group-box"><svg viewBox="0 0 24 24" aria-hidden="true"><path d="M5 12.5l4.5 4.5L19 7.5"/></svg></span>Cheese</label>
    <label class="chk-indeterminate-checkbox-group-item"><input type="checkbox"><span class="chk-indeterminate-checkbox-group-box"><svg viewBox="0 0 24 24" aria-hidden="true"><path d="M5 12.5l4.5 4.5L19 7.5"/></svg></span>Basil</label>
    <label class="chk-indeterminate-checkbox-group-item"><input type="checkbox"><span class="chk-indeterminate-checkbox-group-box"><svg viewBox="0 0 24 24" aria-hidden="true"><path d="M5 12.5l4.5 4.5L19 7.5"/></svg></span>Olives</label>
  </div>
</div>

CSS

.chk-indeterminate-checkbox-group {
  --c: var(--chk-color, #3b82f6);
  font-size: var(--chk-size, 24px);
  display: grid;
  gap: 0.3em;
  line-height: 1.3;}
.chk-indeterminate-checkbox-group-head {
  display: flex;
  align-items: center;
  gap: 0.55em;
  font-weight: 600;
}
.chk-indeterminate-checkbox-group-kids {
  display: grid;
  gap: 0.2em;
  margin-left: 0.55em;
  padding-left: 1em;
  border-left: 0.08em solid color-mix(in srgb, currentColor 18%, transparent);
}
.chk-indeterminate-checkbox-group-item {
  position: relative;
  display: flex;
  align-items: center;
  gap: 0.55em;
  font-size: 0.9em;
  cursor: pointer;
  -webkit-user-select: none;
  user-select: none;
}
.chk-indeterminate-checkbox-group-item input {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  opacity: 0;
  cursor: pointer;
  z-index: 1;
}
.chk-indeterminate-checkbox-group-box {
  position: relative;
  display: grid;
  place-items: center;
  flex: none;
  width: 1.1em;
  height: 1.1em;
  border: 0.12em solid color-mix(in srgb, currentColor 38%, transparent);
  border-radius: 0.3em;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}
.chk-indeterminate-checkbox-group-box svg {
  grid-area: 1 / 1;
  width: 0.82em;
  height: 0.82em;
  fill: none;
  stroke: #fff;
  stroke-width: 3.6;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 20;
  stroke-dashoffset: 20;
  transition: stroke-dashoffset 0.2s ease-in;
}
.chk-indeterminate-checkbox-group-dash {
  grid-area: 1 / 1;
  width: 0.55em;
  height: 0.13em;
  border-radius: 1em;
  background: #fff;
  transform: scaleX(0);
  transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.chk-indeterminate-checkbox-group-item input:checked + .chk-indeterminate-checkbox-group-box,
.chk-indeterminate-checkbox-group:has(input:checked) .chk-indeterminate-checkbox-group-parent {
  background: var(--c);
  border-color: var(--c);
}
.chk-indeterminate-checkbox-group-item input:checked + .chk-indeterminate-checkbox-group-box svg {
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.3s ease-out 0.05s;
}
.chk-indeterminate-checkbox-group:has(input:checked) .chk-indeterminate-checkbox-group-dash {
  transform: scaleX(1);
}
.chk-indeterminate-checkbox-group:not(:has(input:not(:checked))) .chk-indeterminate-checkbox-group-dash {
  transform: scaleX(0);
  transition-duration: 0.15s;
}
.chk-indeterminate-checkbox-group:not(:has(input:not(:checked))) .chk-indeterminate-checkbox-group-parent svg {
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.3s ease-out 0.12s;
}
.chk-indeterminate-checkbox-group-item input:focus-visible + .chk-indeterminate-checkbox-group-box {
  outline: 0.12em solid var(--c);
  outline-offset: 0.18em;
}

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

Customizing this snippet

Color: set --chk-color on the element or a parent. Currently previewing #3b82f6.
Size: set --chk-size. Every other dimension is in em, so the whole thing scales together. Currently previewing 24px.
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.

Indeterminate Checkbox Group

HTML

CSS

Customizing this snippet

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