* {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

.box-sizing {
  background-color: aquamarine;
  height: 500px;
  width: 500px;
  margin: auto;
  gap: 10px;
  margin-bottom: 60px;

  /* ====using flex===== */
  display: flex;
  justify-content: center;
  align-items: center;

  /* ===========using grid========== */
  /* display: grid;
    place-content: center; */

  /* =============== Using position and transform ============== */
  /* position: relative; */
}

.content-box {
  background-color: blue;
  height: 200px;
  width: 200px;
  /* box-sizing: content-box; */
  padding: 40px;

  /* position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%); */
}

.border-box {
  background-color: green;
  height: 200px;
  width: 200px;
  box-sizing: border-box;
  padding: 40px;
}

/* Flag with Z-index */
.flag-green {
  height: 300px;
  width: 500px;
  background-color: green;
  position: relative;
}

.flag-rounded-red {
  height: 150px;
  width: 150px;
  background-color: red;
  border-radius: 50%;

  position: absolute;
  top: 50%;
  left: 40%;
  transform: translate(-50%, -50%);
  z-index: 3;
}

.flag-rounded-white {
  height: 150px;
  width: 150px;
  background-color: white;
  border-radius: 50%;

  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 2;
}