@font-face {
  font-family: "SFMono-Bold";
  src: url(../fonts/SFMono-Bold.otf) format("opentype");
}

.content {
  position: relative;
  overflow: hidden;
  width: 100%;
  height: 100vh;
  background: url(../images/index_bg.png) no-repeat center center/cover;
  font-family: "SFMono-Bold";
}

.bg-video {
  min-width: 100%;
  min-height: 100vh;
  position: absolute;
  top: 50%;
  left: 50%;
  transform : translate(-50%, -50%);
  z-index: 1;
}

.doctype {
  position: absolute;
  top: 5px;
  left: 5px;
  margin: 0;
  vertical-align: middle;
  white-space: nowrap;
  color: #fdfcf5; /* 白百合色 */
  text-shadow: #080000 5px 5px 5px; /* 漆黒 */
  font-size: 2vh;
  z-index: 2;
}

.menu {
  position: absolute;
  top: 50%;
  left: calc(50% + 8vh);
  transform : translate(-50%, -50%);
  transform-origin: -8vh center;
  animation: rotation 30s linear infinite;
  z-index: 3;
}

@keyframes rotation {
  from { transform: rotate(0deg); }
  to   { transform: rotate(-360deg); }
}

.tags {
  height: 0;
  font-size: 8vh;
  line-height: 0;
  white-space: nowrap;
  transform-origin: -8vh center;
  color: #7d7d7d; /* 鼠色 */
  text-shadow: #080000 1vh 1vh 1vh; /* 漆黒 */
  opacity: 0;
  animation: fadeIn 3s;
  animation-fill-mode: forwards;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.tags a {
  color: #ad002d; /* 真紅 */
  text-decoration-line: none;
}
.tags a:hover {
  color: #fdfcf5; /* 白百合色 */
}

.tags:nth-child(1) { transform: rotate(0deg);   }
.tags:nth-child(2) { transform: rotate(45deg);  }
.tags:nth-child(3) { transform: rotate(90deg);  }
.tags:nth-child(4) { transform: rotate(135deg); }
.tags:nth-child(5) { transform: rotate(180deg); }
.tags:nth-child(6) { transform: rotate(225deg); }
.tags:nth-child(7) { transform: rotate(270deg); }
.tags:nth-child(8) { transform: rotate(315deg); }

@media screen and (max-width:768px) {
  .menu {
    left: 10vw;
    transform-origin: -10vw center;
  }

  .tags {
    font-size: 10vw;
    transform-origin: -10vw center;
  }
}