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

html,
body {
  height: 100%;
  overflow: hidden;
}

body {
  background: #000;
  color: #26c6da;
  font-family: "Segoe UI", system-ui, sans-serif;
}

.layout {
  position: relative;
  display: flex;
  align-items: center;
  box-sizing: border-box;
  width: 100%;
  height: 100%;
  min-height: 0;
  padding: 0 6vw;
  overflow-x: hidden;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-y: contain;
  touch-action: pan-y;
}

.logo-panel {
  flex: 0 0 42%;
  display: flex;
  justify-content: center;
  opacity: 0;
  transform: translateX(29vw);
}

.logo {
  display: block;
  width: min(380px, 36vw);
  height: auto;
}

.index-panel {
  flex: 1;
  opacity: 0;
  padding-left: 2rem;
}

.index-panel.visible {
  opacity: 1;
}

.page-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.page-list a {
  color: #26c6da;
  text-decoration: none;
  font-size: 1.35rem;
  letter-spacing: 0.02em;
  transition: color 0.2s ease;
}

.page-list a:hover,
.page-list a:focus-visible {
  color: #0078d4;
  outline: none;
}

.youtube-link {
  position: absolute;
  bottom: 2rem;
  left: 0;
  right: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: #26c6da;
  font-size: 1.1rem;
  letter-spacing: 0.02em;
  opacity: 0;
  transition: opacity 0.6s ease, color 0.2s ease;
}

.youtube-link.visible {
  opacity: 1;
}

.youtube-link:hover,
.youtube-link:focus-visible {
  color: #0078d4;
  outline: none;
}

.youtube-icon {
  display: block;
  height: 2rem;
  width: auto;
}

body.intro-start .logo-panel {
  animation: logoIntro 2.1s ease forwards;
}

@keyframes logoIntro {
  0% {
    opacity: 0;
    transform: translateX(29vw);
  }

  57% {
    opacity: 1;
    transform: translateX(29vw);
  }

  100% {
    opacity: 1;
    transform: translateX(0);
  }
}

@media (max-width: 900px) {
  .layout {
    display: block;
    height: 100%;
    padding: 2rem 1.5rem calc(2rem + env(safe-area-inset-bottom, 0px));
    text-align: center;
  }

  .logo-panel {
    display: flex;
    justify-content: center;
    margin: 0 auto 2.5rem;
    transform: translateY(8vh);
  }

  .logo {
    width: min(280px, 70vw);
  }

  .index-panel {
    display: block;
    width: 100%;
    padding-left: 0;
    margin-bottom: 2.5rem;
    text-align: center;
  }

  .youtube-link {
    position: static;
    display: inline-flex;
    margin: 0 auto;
  }

  body.intro-start .logo-panel {
    animation: logoIntroMobile 2.1s ease forwards;
  }

  @keyframes logoIntroMobile {
    0% {
      opacity: 0;
      transform: translateY(8vh);
    }

    57% {
      opacity: 1;
      transform: translateY(8vh);
    }

    100% {
      opacity: 1;
      transform: translateY(0);
    }
  }
}