The property allows the radius of the bottom left border of any element.
border-bottom-left-radius: value or percentage;
Example:
border-bottom-left-radius: 20%;
border-bottom-left-radius: 20% 10%;
border-bottom-left-radius: 5px;
As a radius, any value allowed in CSS (px, cm, in, em, etc.) is specified, as well as percentages, in this case the rounding radius is calculated from the width of the block.
The optional second value is for creating an elliptical corner, with the first value setting the horizontal radius and the second setting the vertical radius.
<div class="example">solid</div>
.example {
border: 1px solid blue;
border-bottom-left-radius: 10px;
margin: 20px;
padding: 10px;
}