body {
  margin: 0;
  padding: 0;
  max-width: 100%;
  overflow: hidden;
  font-family: Noto Sans JP;
  animation: fadeIn 2.5s cubic-bezier(0.33, 1, 0.68, 1) forwards;
  background-color: #212121;
}

p, h1 {
  color: #FFFFFF;
}

.header-iframe {
  width: 100%;
  height: 100px;
  border: none;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1000;
}

.welcome {
  font-weight: normal;
  text-align: center;
  margin-top: 125px;
}

.explanation {
  margin-top: 10px;
  text-align: center;
}

.windowsbox, .applebox, .googlebox {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 0.5em 1em;
  margin: 0 auto;
  font-weight: bold;
  background: #EEEEEE;
  border-radius: 10px;
  max-width: 375px;
  width: 80%;
  overflow: hidden;
  margin-bottom: 10px;
  background-color: #808080;
}

.windowsbox {
  color: #0078D7;
  border: solid 3px #0078D7;
}

.applebox {
  color: #696969;
  border: solid 3px #696969;
}

.googlebox {
  color: #3DDC84;
  border: solid 3px #3DDC84;
}

/* aタグをflex中央揃え＆範囲限定 */
.link {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  text-decoration: none;
  color: inherit;
}

.windows-logo,
.google-logo {
  width: 37.5px;
  height: 37.5px;
}

.apple-logo {
  margin-left: 3.51px;
  margin-right: 3.51px;
  height: 37.5px;
}

.ostext {
  font-size: 20px;
  font-weight: normal;
}


.windows-logo, .google-logo {
  width: 37.5px;
  height: 37.5px;
  float: left;
}

.apple-logo {
  margin-left: 3.51px;
  margin-right: 3.51px;
  height: 37.5px;
  float: left;
}

.ostext {
  margin: auto;
  font-size: 20px;
  font-weight: normal;
}

.link {
  text-decoration: none;
}

.sorry {
  text-align: center;
}

.copyright, .form {
  text-align: center;
  text-decoration: none;
}

footer {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  background-color: #171717;
}

@keyframes fadeIn {
  0% {
    opacity: 0;
  }

  100% {
    opacity: 1;
  }
}