:root {
  --etide-bg-color: rgb(15, 15, 15);
  --etide-color: rgb(235, 235, 235);
  --etide-enter-bg-color: rgb(255, 255, 255);
  --etide-title-height: 435px;
  --etide-nav-top: calc(var(--etide-title-height) + 235px);
  --etide-enter-top: calc(var(--etide-nav-top) - 75px);
}

body {
  background-color: var(--etide-bg-color);
  background-image: url('../img/bg.png');
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
  color: var(--etide-color);
  font-family: sans-serif;
  font-size: 18px;
  height: 100vh;
  margin: 0;
  padding: 0;
}

.etide-enter,
.etide-nav,
.etide-nav a,
.etide-title,
.etide-title-sub {
  display: flex;
  justify-content: center;
}

.etide-title {
  align-items: flex-end;
  font-size: 3ch;
  font-weight: 300;
  height: var(--etide-title-height);
  letter-spacing: clamp(1ch, 3ch, 5ch);
  position: relative;
  padding-right: 1ch;
  text-transform: uppercase;
  width: auto;
}

.etide-title::before,
.etide-title::after {
  background-image: linear-gradient(90deg, rgba(235, 235, 235, 0), rgba(235, 235, 235, .1), rgba(235, 235, 235, .3), rgba(235, 235, 235, .1), rgba(235, 235, 235, 0));
  bottom: -7.25%;
  content: '';
  left: 25%;
  position: absolute;
  right: 25%;
  top: 106.85%;
}

.etide-title::before {
  filter: blur(3px);
}

.etide-title-sub {
  align-items: center;
  background-color: rgb(15, 15, 15);
  border-radius: 8px;
  bottom: -27.35%;
  font-size: .735ch;
  font-weight: 300;
  letter-spacing: clamp(.5ch, 2.325ch, 3ch);
  margin-left: 2ch;
  padding: 1.935ch 1.325ch 1.935ch 1.395ch;
  position: absolute;
}

.etide-title img {
  margin-left: 0.5ch;
  position: absolute;
  top: 35%;
  width: 196px;
}

.etide-nav {
  align-items: center;
  left: 25%;
  position: absolute;
  right: 25%;
  top: var(--etide-nav-top);
}

a {
  color: var(--etide-color);
  text-decoration: none;
  transition: none;
}

.etide-nav a {
  border-radius: 100%;
  border: 3px solid rgba(235, 235, 235, 0);
  box-shadow: 0 3px 7px rgba(0, 0, 0, 0);
  box-sizing: border-box;
  height: 105px;
  justify-content: center;
  margin: 0 clamp(15px, 1.35vw, 45px);
  padding: 18px;
  transition: all .735s ease-in-out;
  width: 105px;
}

.etide-nav a:hover {
  background-color: rgba(15, 15, 15, .2);
  border: 3px solid rgba(235, 235, 235, .1);
  box-shadow: 0 3px 7px rgba(0, 0, 0, .2);
  padding: 5px;
  transition: all .376s ease-in-out;
}

.etide-nav img {
  border-radius: 100%;
  filter: grayscale(1) brightness(.735) contrast(1.5);
  height: auto;
  width: 100%;
}

.etide-enter {
  align-items: center;
  border: 1px solid rgba(235, 235, 235, .5);
  box-sizing: border-box;
  font-size: 1.35ch;
  height: 50px;
  left: 43.5%;
  letter-spacing: 1ch;
  padding: 0 2ch 0 2.845ch;
  position: absolute;
  right: 43.5%;
  text-transform: uppercase;
  top: var(--etide-enter-top);
  transition: all .5s ease-in-out;
}

.etide-enter:hover {
  background-color: var(--etide-enter-bg-color);
  color: var(--etide-bg-color);
  transition: all .25s ease-in-out;
}

.etide-enter:active {
  background-color: var(--etide-bg-color);
  color: var(--etide-color);
  transition: all .125s ease-in-out;
}

@media screen and (max-width: 758px) {
  .etide-nav a,
  .etide-nav a:hover {
    background-color: transparent;
    box-shadow: none;
    border: none;
    display: block;
    height: 100px;
    margin-top: 15px;
    padding: 0;
    transform-origin: center;
    width: 100px;
  }

  .etide-nav a:hover {
    transform: scale(1.235);
  }

  .etide-enter {
    left: 23.5%;
    right: 23.5%;
  }

  .etide-title {
    font-size: 2.136ch;
    letter-spacing: 2.135ch;
  }

  .etide-title-sub {
    font-size: 0.936ch;
    letter-spacing: 1.345ch;
  }
}