<form class="csb-scope" role="search">
  <button type="button" class="csb-scope-btn" aria-haspopup="listbox" aria-expanded="false">
    <span>All</span>
    <svg viewBox="0 0 12 12" aria-hidden="true"><path d="M3 5l3 3 3-3" /></svg>
  </button>
  <ul class="csb-scope-list" role="listbox" hidden>
    <li role="option" aria-selected="true">All</li>
    <li role="option">People</li>
    <li role="option">Posts</li>
    <li role="option">Files</li>
  </ul>
  <label class="csb-sr" for="csb-scope-i">Search</label>
  <input id="csb-scope-i" type="search" name="q" placeholder="Search workspace..." />
</form>

.csb-scope {
  position: relative; display: inline-flex; align-items: stretch;
  background: #1a1a28;
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 10px;
}
.csb-scope:focus-within { border-color: #7c6cff; }
.csb-scope-btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 0 14px;
  border: 0; border-right: 1px solid rgba(255,255,255,0.08);
  background: transparent; cursor: pointer;
  color: #a78bfa; font: 600 12px/1 system-ui, sans-serif;
}
.csb-scope-btn svg { width: 10px; height: 10px; fill: none; stroke: #a78bfa; stroke-width: 1.5; }
.csb-scope-list {
  position: absolute; top: calc(100% + 4px); left: 0;
  margin: 0; padding: 4px;
  list-style: none;
  background: #1a1a28;
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 8px;
  z-index: 10;
  min-width: 120px;
}
.csb-scope-list li {
  padding: 7px 10px;
  font: 500 13px/1 system-ui, sans-serif;
  color: #cbd5e1; cursor: pointer;
  border-radius: 5px;
}
.csb-scope-list li[aria-selected="true"] { color: #a78bfa; }
.csb-scope-list li:hover { background: rgba(124,108,255,0.12); }
.csb-scope input {
  flex: 1; padding: 11px 14px;
  border: 0; outline: none; background: transparent;
  color: #f0eeff; font: 500 14px/1 system-ui, sans-serif;
  min-width: 200px;
}
.csb-scope input::placeholder { color: #b8b6d4; }

.csb-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;
}

document.querySelectorAll('.csb-scope').forEach(function(form) {
  var btn  = form.querySelector('.csb-scope-btn');
  var list = form.querySelector('.csb-scope-list');
  var label = btn.querySelector('span');
  btn.addEventListener('click', function(e) {
    e.stopPropagation();
    var open = list.hidden;
    list.hidden = !open;
    btn.setAttribute('aria-expanded', open ? 'true' : 'false');
  });
  list.addEventListener('click', function(e) {
    var li = e.target.closest('li[role="option"]');
    if (!li) return;
    list.querySelectorAll('li').forEach(function(x){ x.removeAttribute('aria-selected'); });
    li.setAttribute('aria-selected', 'true');
    label.textContent = li.textContent;
    list.hidden = true;
    btn.setAttribute('aria-expanded', 'false');
  });
  document.addEventListener('click', function() {
    list.hidden = true;
    btn.setAttribute('aria-expanded', 'false');
  });
});