<section>
  <div class="grid__container">
    <div class="grid__item"></div>
    <div class="grid__item"></div>
    <div class="grid__item"></div>
    <div class="grid__item"></div>
    <div class="grid__item"></div>
    <div class="grid__item"></div>
    <div class="grid__item"></div>
    <div class="grid__item"></div>
    <div class="grid__item"></div>
  </div>
</section>

<form action="">
  <label for="gap">gap:</label>
  <input type="range" name="gap" id="gap" min="0" max="40" steps="2" value="20px" />
  <output>20px</output>
</form>

@import url("https://fonts.googleapis.com/css2?family=Exo:wght@600&display=swap");

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

body {
  width: 100vw;
  min-height: 100vh;

  display: flex;
  justify-content: center;
  flex-direction: column;
  gap: 20px;
  font-family: "Exo", Arial, sans-serif;
  background-color: #f7f7f7;

  padding: 20px;
}

section {
  margin: 0 auto;

  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  box-shadow: 0 0 0 6px rgb(0 0 0 / 13%);
  border-radius: 3px;
  gap: 20px;
  min-width: 80vw;
}

.grid__container {
  width: 100%;
  box-shadow: 0 0 0 1px #f36;
  position: relative;
  /*   min-width: 20vmin; */
  /*   min-height: 20vmin; */
}

.grid__item {
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #f7f7f7;
  position: relative;
  counter-increment: item;
  padding: 10px;
}

.grid__item::before {
  content: "i" counter(item);
  color: #fff;
  font-size: 1.2rem;
  padding: 10px;
  text-shadow: 1px 1px 0 rgba(0 0 0 / 0.25);
  background-color: rgb(0 0 0 / 0.6);
  background-image: conic-gradient(
    from 90deg at 40% -25%,
    #ffd700,
    #f79d03,
    #ee6907,
    #e6390a,
    #de0d0d,
    #d61039,
    #cf1261,
    #c71585,
    #cf1261,
    #d61039,
    #de0d0d,
    #ee6907,
    #f79d03,
    #ffd700,
    #ffd700,
    #ffd700
  );
  width: 32px;
  aspect-ratio: 1 / 1;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  border-radius: 50%;
  filter: drop-shadow(0 0 3px rgb(255 255 255 / 0.5));
}

.grid__item:nth-child(n + 1) {
  background-color: #f1c2c6;
}

.grid__item:nth-child(2n + 1) {
  background-color: #dac2f1;
}

.grid__item:nth-child(3n + 1) {
  background-color: #ccf1c2;
}

.grid__item:nth-child(4n + 1) {
  background-color: #c2e9f1;
}

.grid__item:nth-child(5n + 1) {
  background-color: #f1ebc2;
}
.grid__item:nth-child(6n + 1) {
  background-color: #09f;
}

.grid__item:nth-child(7n + 1) {
  background-color: #ff5722;
}

.grid__item:nth-child(8n + 1) {
  background-color: #8bc34a;
}

.grid__item:nth-child(9n + 1) {
  background-color: #f66803;
}
1 .grid__item:nth-child(10n + 1) {
  background-color: #0d815f;
}
.grid__item:nth-child(11n + 1) {
  background-color: #28d1c2;
}
.grid__item:nth-child(12n + 1) {
  background-color: #4a28d1;
}
h3 {
  margin: 20px auto;
}

form {
  width: 100%;
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-top: 20px;
}

.grid__container {
  display: grid;
  grid-template-columns: [aside-start] 1fr [center-start] 4fr [center-end] 1fr [aside-end];
  grid-template-rows: [top] 1fr [main-start] auto [main-end] 1fr [bottom];
  --gap: 20px;
  gap: var(--gap);
}

.grid__item:nth-child(1) {
  grid-column: aside-start / center-end;
}

.grid__item:nth-child(2) {
  grid-column: center-end / aside-end;
  grid-row: top / bottom;
}

.grid__item:nth-child(3) {
  grid-row: main-start / bottom;
}

.grid__item:last-child {
  grid-column: aside-start / aside-end;
}

const gridContainer = document.querySelector(".grid__container");
const input = document.querySelector("input[type='range']");
const output = document.querySelector("output");

input.addEventListener("input", (etv) => {
  gridContainer.style.setProperty("--gap", `${etv.target.value}px`);
  output.textContent = `${etv.target.value}px`;
});