*{
  margin: 0;
  padding: 0;
  color: inherit;
  text-decoration: none;
  font-style: normal;
  font-family: inherit;
  font-size: inherit;
  list-style: none;
  box-sizing: border-box;
  border-collapse: collapse;
  outline: inherit;
}

:root{
  --blue:#2E5077;
  --green:#4DA1A9;
  --deep-green:#1c7178;
  --light-green:#79D7BE;
  --bright-green:#c5e8df;
  --ivory:#F6F4F0;
  --accent-color:#ffa200;
  --invalid-color: #b4b4b4;
  --invalid-back-color: #fbfbfb;
}

html{
  width: 100%;
  height: 100%;
  height: -webkit-fill-available;
  font-size: 10px;
}

body{
  min-height: 100vh;
  color: #000;
  line-height: 1.8;
  font-family: "Noto Sans JP", sans-serif;
  background: var(--green);
}

.container{
  width: 600px;
  height: 100%;
  height: 100dvh;
  margin: 0 auto;
  position: relative;
}

.flex{
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
}

a{
  display: block;
}

img{
  max-width: 100%;
}

/* -----------------------ヘッダー----------------------- */
header {
  width: 600px;
  height: 60px;
  background: var(--green);
  color: var(--ivory);
  display: flex;
  justify-content: left;
  align-items: center;
  position: fixed;
  top: 0;
  z-index: 100;
}

.header_inner{
  width: 100%;
  position: relative;
  user-select: none;
}

.header_inner h1 {
  font-size: 2rem;
  padding-left: 10px;
}

/* -----------------------メニュー----------------------- */
.menu-wrapper{
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
}

/* メニュー非表示用 */
.menu-toggle {
  display: none;
}

/* ハンバーガーの見た目 */
.hamburger {
  cursor: pointer;
  display: flex;
  flex-direction: column;
  width: 45px;
  height: 45px;
  justify-content: center;
  align-items: center;
  position: relative;
  padding: 10px;
  z-index: 200;
}

/* ハンバーガーの線 */
.hamburger span {
  width: 25px;
  height: 3px;
  background: var(--ivory);
  transition: 0.3s;
  position: absolute;
}

/* 1本目（上の線） */
.hamburger span:nth-child(1) {
  top: 12px;
}

/* 2本目（中央の線） */
.hamburger span:nth-child(2) {
  top: 50%;
  transform: translateY(-50%);
}

/* 3本目（下の線） */
.hamburger span:nth-child(3) {
  bottom: 12px;
}

/* チェック時のアニメーション */
.menu-toggle:checked + .hamburger{
  background: none;
}

.menu-toggle:checked + .hamburger span{
  background: var(--deep-green);
}

.menu-toggle:checked + .hamburger span:nth-child(1) {
  transform: translateY(9px) rotate(45deg);
  right: 10px;
}

.menu-toggle:checked + .hamburger span:nth-child(2) {
  opacity: 0;
}

.menu-toggle:checked + .hamburger span:nth-child(3) {
  transform: translateY(-9px) rotate(-45deg);
  right: 10px;
}

/* メニューの表示 */
.menu {
  display: none;
  color: var(--deep-green);
}

.menu-toggle:checked ~ .menu {
  display: block;
  position: absolute;
  right: 0;
  top: 0;
  width: 600px;
  background: var(--ivory);
  border: 4px solid var(--deep-green);
  border-radius: 10px;
  font-size: 1.8rem;
  font-weight: bold;
  text-align: center;
  padding-top: 40px;
  animation: slideIn 0.3s ease-in-out forwards;
}
@keyframes slideIn {
  from {
    transform: translateY(-100%);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.menu li a {
  padding: 15px 0;
}

.menu li a:hover {
  background: var(--deep-green);
  color: var(--ivory);
  transition: 0.2s linear;
}

/* -----------------------問題スタート画面----------------------- */
.question_inner{
  width: 100%;
  height: 100%;
  min-height: 100vh;
  min-height: 100dvh;
  background: #fff;
  font-size: 1.8rem;
  display: flex;
  justify-content: center;
  align-items: center;
}

.question_start{
  width: 100%;
  height: 100%;
  color: var(--deep-green);
  text-align: center;
  padding-top: 60px;
}

.question_start h2{
  font-size: 2.5rem;
}

.question_start ul{
  width: 250px;
  margin: 50px auto 0;
  justify-content: center;
}

.question_start li{
  width: 100%;
}

.question_start li a{
  font-size: 1.8rem;
  font-weight: bold;
  background: var(--bright-green);
  color: var(--deep-green);
  border-radius: 10px;
  padding: 10px 0;
  margin: 15px 0;
  position: relative;
  box-shadow: 0px 0px 3px rgba(0, 0, 0, 0.5);
  user-select: none;
}

.invalid_btn{
  background: #ddd!important;
  color: gray!important;
  cursor: inherit;
}

.question_start li a:hover{
  background: var(--green);
  color: var(--ivory);
}

.question_start li a i{
  color: var(--deep-green);
  font-size: 3rem;
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
}

.question_start li a:hover i{
  background: var(--green);
  color: var(--ivory);
}

.question_start li.start_btn a{
  background: var(--accent-color);
  color: #fff;
}

.question_start li.start_btn a:hover{
  background: #de8d01;
}

.question_start li.start_btn a i{
  color: #fff;
}

.question_start li.start_btn a:hover i{
  background: #de8d01;
}


@media screen and (max-width: 768px) {
  .container{
    width: 485px;
  }
  
  /* -----------------------ヘッダー----------------------- */
  header {
    width: 485px;
    height: 50px;
  }

  .header_inner h1 {
    font-size: 1.8rem;
  }

  /* -----------------------メニュー----------------------- */
  .menu-toggle:checked ~ .menu {
    width: 485px;
    font-size: 1.6rem;
  }

  /* -----------------------問題スタート画面----------------------- */
  .question_inner{
    font-size: 1.6rem;
  }

  .question_start h2{
    font-size: 2.2rem;
  }

  .question_start ul{
    width: 200px;
    margin: 40px auto 0;
  }

  .question_start li a{
    font-size: 1.6rem;
  }
}

@media screen and (max-width: 500px) {
  .container{
    width: 100%;
  }
  
  /* -----------------------ヘッダー----------------------- */
  header {
    width: 100%;
  }

  /* -----------------------メニュー----------------------- */
  .menu-toggle:checked ~ .menu {
    width: 100vw;
  }
}