<h3>Kuwait</h3>

<div class="flag kuwait"></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;
}
.kuwait {
  background: linear-gradient(#007a3d 33%, #fff 33%, #fff 66%, #ce1126 0);
}

.kuwait::before {
  position: absolute;
  content: "";
  background-color: #000;
  width: 100px;
  height: 100%;
  clip-path: polygon(0 0, 100% 33%, 100% 66%, 0% 100%);
}