.frame_center {
  width: 80%;
}

.frame_center_mini {
  width: 40%;
}

/* 開いて実行されるアニメーションを設定*/
details[open] .content {
  animation: fadeIn 2.0s ease-in-out;
}

@keyframes fadeIn {
  0% {
    opacity: 0;
    /* Transparent */
    transform: translateX(+100px);
    /* translateX(+100px)：右から表示 */
    /* translateX(-100px)：左から表示 */
    /* translateY(+100px)：下から表示 */
    /* translateY(-100px)：上から表示 */

  }

  100% {
    opacity: 1;
    transform: none;
  }
}

.area {
  width: 500px;
  margin: auto;
  flex-wrap: wrap;
  display: flex;
}

.tab_class {
  width: calc(100%/3);
  height: 50px;
  background-color: darkgrey;
  line-height: 50px;
  font-size: 15px;
  text-align: center;
  display: block;
  float: left;
  order: -1;
}

input[name="tab_name"] {
  display: none;
}

input:checked+.tab_class {
  background-color: cadetblue;
  color: aliceblue;
}

.content_class {
  display: none;
  width: 100%;
}

input:checked+.tab_class+.content_class {
  display: block;
  animation: fadeIn 2.0s ease-in-out;
}

center p {
  text-align: left;
}

center ul {
  text-align: left;
}

center ol {
  text-align: left;
}



ol.list_parentheses {
  text-align: left;
  padding: 0 0 0 2em;
  margin: 0;
}

ol.list_parentheses li {
  list-style-type: none;
  list-style-position: inside;
  counter-increment: cnt;
}

ol.list_parentheses li:before {
  display: marker;
  content: "(" counter(cnt) ") ";
}

.content_fadeIn {
  animation: fadeIn 2.0s ease-in-out;
  float: left;
}