html {
  overflow: visible;
  background-color: #f4f4f5;
}
body {
  overflow: visible;
  min-width: 320px;
  background-color: white;
}
header {
  padding: 8px;
  height: 64px;
  position: relative;
  text-align: left;
}
header img, nav img {
  display: inline;
}
header hr {
  clear: both;
}
main {
  display: block;
  width: calc(100vw - 28px);
  max-width: 940px;
  white-space: normal;
  min-height: calc(100vh - 80px - 20px - 96px);
  margin: 0 20px 20px 8px;
}
footer {
  text-align: left;
  width: 100%;
  height: 96px;
  margin: 0;
  white-space: normal;
  background-color: #95928d;
  color: white;
}
nav > ul, footer > ul, header > ul {
  list-style-type: none;
  justify-content: left;
  padding-left: 0;
  display: inline-block;
}
footer > ul > li {
  display: inline-block;
  vertical-align: bottom;
}
footer > ul > li > a {
  color: white;
  font-weight: normal;
  margin: 4px 8px;
}
nav {
  margin: 8px 0 0 0;
  display: block;
  white-space: normal;
  font-size: 10pt;
  text-align: center;
}
nav > ul {
  display: inline-block;
  text-align: left;
}
nav > ul > li {
  display: inline-block;
  vertical-align: bottom;
  width: 98px;
  text-align: center;
}
nav > ul > li > a {
  display: inline-block;
  margin: 4px 8px;
}

/* pseudo select box */
input[type='checkbox'].select, input[type='checkbox'].select + ul {
  display: none;
}
input[type='checkbox'].select:checked + ul {
  display: inline;
  list-style-type: none;
  justify-content: left;
  padding-left: 0;
}
.select + ul > li {
  display: block;
}
.select + ul > li > a {
  padding: 0px;
}

#language_label {
  position: absolute;
  display: inline-block;
  top: 12px;
  right: 12px;
  font-weight: bold;
  border-radius: 8px;
  border: 1px solid silver;
  background-color: white;
  font-family: Menlo, 'Lucida Console', monospace;
}
#language_label a {
  font-family: Menlo, 'Lucida Console', monospace;
}

#copyright {
  font-size: x-small;
  float: right;
  width: 340px;
  padding: 0 4px;
}

label.gif {
  display: block;
  cursor: pointer;
}
input[type='checkbox'].gif {
  display: none;
}
input[type='checkbox'].gif:checked + img {
  display: none;
}

@media screen and (min-width: 640px) {
  .mobile {
    display: none;
  }
}
@media screen and (max-width: 640px) {
  .pc {
    display: none;
  }
  header {
    height: 96px;
  }
  main {
    min-height: calc(100vh - 120px - 20px - 96px);
  }
}