CSS overscroll-behavior-x Property - Playground Example

<!DOCTYPE html><html><head><style type="text/css">/* Layout for the outer horizontal scroller */
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  background: #f6f8fb;
  padding: 20px;
}
.outer-scroll {
  width: 160vw; /* make the container wider than the viewport so it can scroll */
  display: flex;
  gap: 24px;
  padding: 20px;
  overflow-x: auto;
  align-items: flex-start;
}
.demo {
  flex: 0 0 48%;
  min-width: 420px;
  background: #ffffff;
  border-radius: 10px;
  padding: 16px;
  box-shadow: 0 6px 18px rgba(16, 24, 40, 0.06);
}
.demo h2 {
  margin: 0 0 12px 0;
  font-size: 16px;
  color: #0f172a;
}
.inner-scroll {
  overflow-x: auto;
  white-space: nowrap;
  padding: 12px;
  border-radius: 8px;
  background: linear-gradient(180deg, #eef7ff 0%, #f7fbff 100%);
  border: 1px solid rgba(2,6,23,0.06);
}
.inner-scroll .item {
  display: inline-block;
  width: 160px;
  height: 96px;
  margin-right: 12px;
  border-radius: 8px;
  background: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
  color: #ffffff;
  font-weight: 700;
  font-size: 20px;
  line-height: 96px;
  text-align: center;
  user-select: none;
}
/* Default demo uses normal scroll chaining */
.default {
  /* no explicit overscroll-behavior set */
}
/* Prevent horizontal scroll chaining from the inner scroller to the outer scroller */
.contain {
  overscroll-behavior-x: contain;
}

/* Small responsive tweak */
@media (max-width: 640px) {
  .outer-scroll {
    width: 240vw;
  }
  .demo {
    min-width: 320px;
  }
}
</style></head><body><div class="outer-scroll">
  <div class="demo">
    <h2>Default (scroll chaining)</h2>
    <div class="inner-scroll default">
      <div class="item">1</div>
      <div class="item">2</div>
      <div class="item">3</div>
      <div class="item">4</div>
      <div class="item">5</div>
      <div class="item">6</div>
      <div class="item">7</div>
      <div class="item">8</div>
    </div>
  </div>

  <div class="demo">
    <h2>overscroll-behavior-x: contain</h2>
    <div class="inner-scroll contain">
      <div class="item">1</div>
      <div class="item">2</div>
      <div class="item">3</div>
      <div class="item">4</div>
      <div class="item">5</div>
      <div class="item">6</div>
      <div class="item">7</div>
      <div class="item">8</div>
    </div>
  </div>
</div></body></html>