付箋がぺたっと貼られたようなポップな見出し

<div class="sticky-note-heading">
  <h2>重要なお知らせ</h2>
</div>

.sticky-note-heading {
  position: relative;
  background: #fffbcc;
  padding: 20px 24px;
  margin: 40px 0;
  border: 2px solid #f1c40f;
  border-radius: 8px;
  box-shadow: 4px 4px 0 #f1c40f;
  width: fit-content;
  transform: rotate(-1.5deg);
}

.sticky-note-heading::before {
  content: "";
  position: absolute;
  top: 8px;
  left: 50%;
  transform: translateX(-50%);
  width: 30px;
  height: 10px;
  background: #999;
  border-radius: 5px;
}

.sticky-note-heading h2 {
  margin: 0;
  font-size: 20px;
  font-weight: bold;
  color: #333;
  font-family: 'Arial', sans-serif;
}