style.css

:root {
  --yangColor: #d8c21e;
  --yinColor: #111111;
}

body {
  box-sizing: border-box;
  width: 100%;
  height: 100%;
  background: var(--yinColor);
}

*,
*::before,
*::after {
  font-size: inherit;
  font-family: inherit;
  box-sizing: inherit;
  margin: 0;
  padding: 0;
}

.container {
  display: grid;
  place-items: center;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}

.emblem {
  display: flex;
  flex-wrap: wrap;
  width: 45vw;
  height: 45vw;
}

.square {
  position: relative;
  border: 2px solid var(--yangColor);
  width: calc(100% / 3);
  height: calc(100% / 3);
}

.square:nth-child(1) {
  border-top: 4px solid var(--yangColor);
  border-left: 4px solid var(--yangColor);
}

.square:nth-child(2) {
  border-top: 4px solid var(--yangColor);
}

.square:nth-child(3) {
  border-top: 4px solid var(--yangColor);
  border-right: 4px solid var(--yangColor);
}

.square:nth-child(4) {
  border-left: 4px solid var(--yangColor);
}

.square:nth-child(6) {
  border-right: 4px solid var(--yangColor);
}

.square:nth-child(7) {
  border-bottom: 4px solid var(--yangColor);
  border-left: 4px solid var(--yangColor);
}

.square:nth-child(8) {
  border-bottom: 4px solid var(--yangColor);
}

.square:nth-child(9) {
  border-bottom: 4px solid var(--yangColor);
  border-right: 4px solid var(--yangColor);
}

.square:nth-child(2)::after,
.square:nth-child(6)::after,
.square:nth-child(7)::after,
.square:nth-child(8)::after,
.square:nth-child(9)::after {
  content: '';
  position: absolute;
  width: 75%;
  height: 75%;
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: var(--yangColor);
}

@media (max-width: 768px) {
  .emblem {
    width: 75vw;
    height: 75vw;
  }
}

@media (min-width: 769px) and (max-width: 1280px) {
  .emblem {
    width: 50vw;
    height: 50vw;
  }
}