How to Make Child Elements Respect Curved Borders in CSS: A Question of Overflow?

Solving the Child-Parent Border Obedience Dilemma in CSS

When dealing with nested elements in CSS, it's often necessary for the child element to adhere to the curved borders of its parent element. However, this can sometimes be an issue, resulting in the child element extending beyond its parent's limits.

The Problem:

Consider the following HTML and CSS code:

<code class="html"><div id="outer">
  <div id="inner"></div>
</div></code>

<code class="css">#outer {
  display: block;
  width: 200px;
  background-color: white;
  overflow: hidden;
  border-radius: 10px;
}

#inner {
  background-color: green;
  height: 10px;
}</code>

In this scenario, the #inner div will extend beyond the curved borders of the #outer div, creating an unwanted overlap.

The Solution:

According to the CSS3 specifications, elements such as block-level elements are clipped to the curve of their parent's border. However, there are some exceptions, one of which is replaced elements.

Replaced Elements:

Replaced elements, such as and