<form class="csb-bar" role="search">
  <label class="csb-sr" for="csb-bar-i">Search</label>
  <svg viewBox="0 0 24 24" aria-hidden="true">
    <circle cx="11" cy="11" r="7" />
    <path d="m20 20-3.5-3.5" />
  </svg>
  <input id="csb-bar-i" type="search" name="q" placeholder="Type to search..." />
  <span class="csb-bar-progress" aria-hidden="true"></span>
</form>

.csb-bar {
  position: relative; display: inline-flex; align-items: center; gap: 10px;
  padding: 11px 14px;
  background: #1a1a28;
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 10px;
  overflow: hidden;
}
.csb-bar:focus-within { border-color: #7c6cff; }
.csb-bar svg { width: 15px; height: 15px; fill: none; stroke: #7a7899; stroke-width: 2; stroke-linecap: round; }
.csb-bar input {
  width: 220px; padding: 0;
  border: 0; outline: none; background: transparent;
  color: #f0eeff; font: 500 14px/1 system-ui, sans-serif;
}
.csb-bar input::placeholder { color: #b8b6d4; }
.csb-bar-progress {
  position: absolute; bottom: 0; left: 0;
  height: 2px; width: 30%;
  background: linear-gradient(90deg, transparent, #7c6cff, transparent);
  transform: translateX(-100%);
  transition: opacity 0.2s;
  opacity: 0;
}
.csb-bar.is-loading .csb-bar-progress {
  opacity: 1;
  animation: csb-bar-slide 1.2s linear infinite;
}
@keyframes csb-bar-slide {
  0%   { transform: translateX(-100%); }
  100% { transform: translateX(400%); }
}

.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;
}

@media (prefers-reduced-motion: reduce) {
  .csb-bar,
  .csb-bar * {
    animation: none !important;
  }
}

document.querySelectorAll('.csb-bar').forEach(function(form) {
  var input = form.querySelector('input');
  var t;
  input.addEventListener('input', function() {
    form.classList.add('is-loading');
    clearTimeout(t);
    t = setTimeout(function() { form.classList.remove('is-loading'); }, 900);
  });
});