/* reset CSS */
*,
::after,
::before {
  -webkit-box-sizing: border-box;
  box-sizing: border-box
}

body {
  margin: 0
}

img {
  border-style: none;
  height: auto;
  max-width: 100%;
  display: block;
  vertical-align: middle
}

/* --- 基本スタイル --- */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  margin: 0;
  padding: 0;
  background-color: #f4f4f4;
  color: #2D2D2D;
  font-size: 1rem;
}

.container {
  max-width: 1000px;
  margin: auto;
  background-color: #fff;
  overflow: hidden;
  background: #D7ECE7;
}

h1,
h2,
h3 {
  color: #2c3e50;
  margin: 0;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0 auto;
}

img.img-responsive {
  width: 100%;
}

/* --- クイズ --- */
#quiz-container {
  background: url(../img/bg_stripe.png), #FEF532;
  background-size: 92px 92px;
  padding: 50px 15px 30px;
}

.quiz-inner {
  position: relative;
  background: #fff;
  padding: 40px 7%;
  box-shadow: 5px 5px 0px #00000029;
  border-radius: 8px;
  min-height: 300px;
  max-width: 800px;
  margin: auto;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

#start-section {
  text-align: center;
}

#quiz-list {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
}

.quiz-item {
  display: none;
  max-width: 600px;
  margin: auto;
}

.quiz-item.active {
  display: block;
}

i.quiz-num {
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;
  top: -30px;
  left: 0;
  right: 0;
  margin: auto;
  width: 60px;
  height: 60px;
  border-radius: 50%;
  background: #02777F;
  color: #fff;
  font-family: "century-gothic", sans-serif;
  font-size: 1.6rem;
  line-height: 1em;
  font-weight: bold;
  font-style: normal;
}

.quiz-item h3 {
  text-align: center;
  margin: .8em 0;
  font-size: clamp(1.125rem, 3vw, 1.625rem);
  font-feature-settings: "palt";
  letter-spacing: .05em;
  line-height: 1.3em;
}

.quiz-item img {
  margin: 10px auto;
  max-width: 400px;
}

.quiz-item p {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.accordion-toggle {
  position: relative;
  margin-top: 10px;
  cursor: pointer;
  padding: .7em 1em;
  width: 100%;
  border: none;
  text-align: left;
  outline: none;
  font-size: 1em;
  border-radius: 6px;
  transition: 0.3s;
}

.accordion-toggle:after {
  content: "";
  display: block;
  position: absolute;
  right: 15px;
  top: calc(50% - 5px);
  width: 8px;
  height: 8px;
  border-top: 1px solid #2D2D2D;
  border-right: 1px solid #2D2D2D;
  -webkit-transform: rotate(135deg);
  transform: rotate(135deg);
}

.accordion-toggle.-hint {
  border: 1px solid #D1D1D1;
  background-color: #fff;
}

.accordion-toggle.-hint:hover {
  background-color: #dfdfdf;
}

.accordion-toggle.-answer {
  background-color: #02777F;
  color: white;
  font-weight: bold;
}

.accordion-toggle.-answer:after {
  border-color: #fff;
  border-width: 2px;
}

.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.1s ease-out;
}

.quiz-answer strong {
  font-size: 120%;
}

.accordion-content .content-inner {
  padding: 15px 0;
}

.answer-prompt-text {
  font-size: .875rem;
  text-align: center;
}

/* --- ボタン --- */
.btn {
  display: block;
  width: 95%;
  max-width: 300px;
  margin: 0 auto;
  padding: .7em 1em;
  font-size: 1.2em;
  font-weight: bold;

  background-color: #fff;
  border: 2px solid #2d2d2d;
  box-shadow: 2px 5px 0px #2d2d2d;
  border-radius: 32px;
  cursor: pointer;
  text-align: center;
  transition: background-color 0.3s;
  box-sizing: border-box;
  text-decoration: none;
  color: #2d2d2d;
}

.quiz-intro {
  margin-top: 0.5em;
  line-height: 1.4em;
}

.quiz-intro em {
  font-style: normal;
  font-size: 150%;
}

.btn-primary {
  background-color: #EA6101;
  box-shadow: 2px 5px 0px #9D4100;
  border-color: #E96002;
  color: #fff;

}

.prev-question-btn {
  position: relative;
  display: block;
  margin: 30px auto 0;
  color: #30678C;
  border: none;
  background: none;
  line-height: 1em;
  font-size: 1rem;
}

.prev-question-btn:before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: .3em;
  vertical-align: .1em;
  border-top: 1px solid #30678C;
  border-right: 1px solid #30678C;
  -webkit-transform: rotate(-135deg);
  transform: rotate(-135deg);
}

/* --- 概要 --- */
#campaign-summary {
  padding: 30px 15px 0;
}

.inner {
  background: #fff;
  padding: 40px 7%;
  border-radius: 8px;
  max-width: 800px;
  margin: auto;
}

#campaign-summary h2 {
  text-align: center;
}

.summery-list h3 {
  margin: 1em 0 .3em;
  color: #139286;
}

.summery-list p {
  margin: 0.3em 0;
  font-size: .875rem;
}

.related-books {
  display: flex;
  justify-content: space-around;
  flex-direction: row;
  flex-wrap: wrap;
  margin-top: 40px;
  border-top: 1px solid #ddd;
  padding-top: 40px;
}

.book-item {
  flex-basis: 45%;
  text-align: center;
  margin-bottom: 20px;
}
.book-item dt {
  font-weight: bold;
  margin-bottom: 0.4em;
  line-height: 1.4em;
}

.book-item dd {
  font-size: clamp(.75rem, 2vw, .875rem);
  padding: 0;
  margin: 0;
  line-height: 1.2em;
  margin-top: 0.2em;
}

.btn-buy {
  background: #2d2d2d;
  color: #fff;
  box-shadow: none;
  border: none;
  font-size: clamp(.875rem, 2vw, 1rem);
}

@media screen and (min-width: 769px) {
  .container {
    border-radius: 8px;
  }

  .related-books-container {
    flex-direction: row;
  }
}

#footer {
  text-align: center;
  padding: 30px 10px;
}

#footer .copyright {
  font-size: 10px;
}