<h3>Tonga</h3>

<div class="flag tonga">
  <div class="tonga__white_box">
    <div class="tonga__plus"></div>
  </div>
</div>

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

body {
  width: 100%;
  height: 100vh;
  background-color: rgb(221, 239, 255);
  display: grid;
  place-items: center;
  font-family: cursive;
  font-weight: bold;
}

h3 {
  position: absolute;
  text-align: center;
  top: 20px;
}

/* Main Style Stars from here  */
.flag {
  position: relative;
  width: 300px;
  height: 200px;
  box-shadow: 0 0 1px rgba(0, 0, 0, 0.5);
  overflow: hidden;
}

.tonga {
  background-color: #c10000;
}

.tonga__white_box {
  width: 146px;
  height: 90px;
  background-color: white;
  display: grid;
  place-items: center;
}
.tonga__plus {
  height: 50px;
  aspect-ratio: 1;
  background: #c10000;
  clip-path: polygon(
    0 35%,
    35% 35%,
    35% 0%,
    65% 0%,
    65% 35%,
    100% 35%,
    100% 65%,
    65% 65%,
    65% 100%,
    35% 100%,
    35% 65%,
    0 65%
  );
}