Sticky Day Groups

<div class="nuda-nc2-day-sticky" role="region" aria-label="Notifications grouped by day">
  <ul class="nuda-nc2-day-sticky__list">
    <li class="nuda-nc2-day-sticky__head">Today</li>
    <li class="nuda-nc2-day-sticky__row is-unread">
      Build #291 succeeded
      <span class="nuda-nc2-day-sticky__sr"> — Unread</span>
    </li>
    <li class="nuda-nc2-day-sticky__row">Invitation accepted</li>
    <li class="nuda-nc2-day-sticky__row">Weekly digest ready</li>
    <li class="nuda-nc2-day-sticky__head">Yesterday</li>
    <li class="nuda-nc2-day-sticky__row">3 new comments on #design</li>
    <li class="nuda-nc2-day-sticky__row">Storage 80% full</li>
  </ul>
</div>

.nuda-nc2-day-sticky {
  width: 100%;
  max-width: 260px;
  background: rgba(255,255,255,.02);
  border: 1px solid rgba(255,255,255,.06);
  border-radius: 12px;
  padding: 4px 6px;
}

.nuda-nc2-day-sticky__list {
  list-style: none;
  margin: 0;
  padding: 0;
  max-height: 190px;
  overflow-y: auto;
}

.nuda-nc2-day-sticky__head {
  position: sticky;
  top: 0;
  z-index: 1;
  padding: 8px 8px 5px;
  background: #131316;
  color: #63636e;
  font-size: 9px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  font-family: ui-monospace,SFMono-Regular,Menlo,monospace;
  border-bottom: 1px solid rgba(255,255,255,.06);
}

.nuda-nc2-day-sticky__row {
  position: relative;
  padding: 8px 10px 8px 20px;
  color: #a0a0a8;
  font-size: 12px;
  border-radius: 6px;
  cursor: pointer;
  animation: _nuda-nc2day-sticky-in .35s cubic-bezier(.16,1,.3,1) both;
  transition: background .2s,color .2s;
}

.nuda-nc2-day-sticky__row:hover {
  background: rgba(255,255,255,.04);
  color: #fafafa;
}

.nuda-nc2-day-sticky__row.is-unread {
  color: #fafafa;
}

.nuda-nc2-day-sticky__row.is-unread::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: #e4ff54;
}

.nuda-nc2-day-sticky__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

@keyframes _nuda-nc2day-sticky-in {
  from {
    opacity: 0;
    transform: translateX(-4px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion:reduce) {
  .nuda-nc2-day-sticky__row {
    animation: none;
  }
}