Check out example codes for "how to round the corners of a div outline in css". It will help you in understanding the concepts better.

Code Example 1

/* Use border-radius property */

.class {
  border-radius: 5px;
}

.circle {
  border-radius: 50%;
}

Code Example 2

/* Set rounded corners with border-radius property */

.class {
  border-radius: 4px;
}

.circle {
  border-radius: 50%;
}

Code Example 3

div {
  outline: auto;
  outline-style: round;
}

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