:root {
  --bg: #575757;
  --neomBglight: #646464;
  --neomBgdark: #4a4a4a;
  --upMatrix: 5px 5px 10px;
  --downMatrix: -5px -5px 10px;
  --neomUpShadow: var(--upMatrix) var(--neomBgdark),
    var(--downMatrix) var(--neomBglight);
  --neomDownShadow: inset var(--upMatrix) var(--neomBgdark),
    inset var(--downMatrix) var(--neomBglight);
  --text-color: #e0e0e0;
}

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

iframe {
  display: none;
}

html {
  font-size: 62.5%;
  /* background: blue; */
}

body {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  background: var(--bg);
  font-size: 1.6rem;
  color: var(--text-color);
}

h1 {
  font-size: 2rem;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 80%;
  margin-top: 40px;
}

header nav ul {
  display: flex;
  justify-content: flex-end;
  margin: 0;
  gap: 14px;
}

header nav ul > li {
  width: fit-content;
  height: fit-content;
  padding: 16px 24px;
}

ul {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 3rem;
  justify-content: space-evenly;
  align-items: center;
  margin-top: 10rem;
}

li {
  position: relative;
  list-style: none;
  width: 220px;
  height: 220px;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: all 0.15s ease-in-out;

  border-radius: 50px;
  background: var(--bg);
  box-shadow: var(--neomUpShadow);
}

main ul li:nth-child(2n + 1) {
  /* height: 200px; */
}

li.active,
li.active a {
  background: none;
  box-shadow: none;
}

li > a {
  text-decoration: none;
}

.hover_bg {
  position: absolute;
  width: 0;
  height: 0;
  left: 0;
  top: 0;
  /* background: crimson;
  border: 1px solid #f1f1f1; 
  box-shadow: inset 0 0 12px #999; */
  transition: all 0.3s ease-in-out;
  border-radius: 50px;
  background: var(--bg);
  box-shadow: var(--neomDownShadow);
}

footer {
  position: relative;
  margin-top: 40px;
  bottom: 20px;
}