/* =========================================================
   mufu 1ページ版
   ========================================================= */

:root {
  --color-brand: #48504B;
  --color-text: #1b1b1b;
  --color-sub: #5c625e;
  --color-bg: #ffffff;
  --color-bg-sub: #f4f4f2;
  --color-c10: #b4c998;  /* 生ビタミンC10 のボトル色 */
  --color-c5: #bb766d;   /* 生ビタミンC5+レチノール のボトル色 */
  --header-height: 64px;
  /* 日本語は端末のフォント（Webフォントは重いため使わない） */
  --font-jp: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic", YuGothic, Meiryo, sans-serif;
  --font-en: "Alata", var(--font-jp);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-height);
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-jp);
  font-weight: 400;
  line-height: 1.9;
  letter-spacing: 0.04em;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: inherit;
}

h1,
h2,
h3,
h4,
p,
ul,
ol {
  margin: 0;
}

sup {
  font-size: 0.6em;
}

.en {
  font-family: var(--font-en);
}

.nowrap {
  white-space: nowrap;
}

/* PCだけ／スマホだけで改行 */
br.sp {
  display: none;
}

@media (max-width: 750px) {
  br.sp {
    display: inline;
  }
}

/* ---------- ボタン ---------- */
.button {
  display: block;
  padding: 16px;
  color: #ffffff;
  font-size: 15px;
  font-weight: 700;
  text-align: center;
  text-decoration: none;
  transition: opacity 0.2s;
}

.button:hover {
  opacity: 0.8;
}

.button--primary {
  display: inline-block;
  min-width: 240px;
  background: var(--color-brand);
}

/* Amazon本家と同じく、オレンジ地に黒文字（白文字は読みにくい） */
.button--amazon {
  background: #FF9900;
  color: #111111;
}

.button--rakuten {
  background: #a22041;
}

/* ---------- ヘッダー ---------- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  height: var(--header-height);
  padding: 0 32px;
  background: var(--color-brand);
}

.header__cta {
  padding: 6px 16px;
  border: 1px solid #ffffff;
  color: #ffffff;
  font-size: 13px;
  text-decoration: none;
}

.header__cta:hover {
  background: #ffffff;
  color: var(--color-brand);
}

@media (max-width: 750px) {
  .header {
    padding: 0 16px;
  }

  .header__logo {
    width: 64px;
  }
}

main {
  padding-top: var(--header-height);
}

/* ---------- メインビジュアル（写真の上にコピーを重ねる） ----------
   PC     : 半透明の板に全部載せて、写真の左側（ボトルにかからない位置）に重ねる
   タブレット・スマホ : 写真上部の白い余白にキャッチだけ重ね、価格とボタンは写真の下 */
.hero {
  position: relative;
}

.hero img {
  width: 100%;
}

.hero__copy {
  position: absolute;
  top: 50%;
  left: 4%;
  width: 32%;
  max-width: 420px;
  padding: 36px 36px 28px;
  background: rgba(255, 255, 255, 0.88);
  transform: translateY(-50%);
}

.hero__title {
  margin-bottom: 16px;
  font-size: clamp(22px, 2vw, 30px);
  font-weight: 700;
  line-height: 1.5;
}

.hero__lead {
  margin-bottom: 16px;
  color: var(--color-sub);
  font-size: 15px;
}

.hero__price {
  margin-bottom: 20px;
  font-size: 18px;
}

.hero__price small,
.option__price small {
  font-size: 0.7em;
}

.hero__note {
  margin-top: 12px;
  color: var(--color-sub);
  font-size: 11px;
}

@media (max-width: 1024px) {
  .hero__copy {
    position: static;
    width: auto;
    max-width: none;
    padding: 0;
    background: none;
    transform: none;
  }

  .hero__head {
    position: absolute;
    top: 0;
    right: 0;
    left: 0;
    padding: 20px 16px 40px;
    background: linear-gradient(rgba(255, 255, 255, 0.75), rgba(255, 255, 255, 0));
    text-align: center;
  }

  .hero__title {
    margin-bottom: 8px;
    font-size: 24px;
  }

  .hero__lead {
    margin-bottom: 0;
    font-size: 14px;
  }

  .hero__buy {
    padding: 28px 20px 40px;
    text-align: center;
  }
}

@media (max-width: 750px) {
  .hero__head {
    padding-top: 28px;
  }

  .hero__title {
    font-size: 22px;
  }

  .hero__lead {
    font-size: 13px;
  }

  .hero__price {
    margin-bottom: 16px;
    font-size: 16px;
  }

  .hero .button--primary {
    display: block;
    min-width: 0;
  }
}

/* ---------- セクション共通 ---------- */
.section {
  padding: 88px 24px;
}

.section--dark {
  background: var(--color-brand);
  color: #ffffff;
}

.section__inner {
  max-width: 680px;
  margin: 0 auto;
}

.section__inner p + p {
  margin-top: 1.2em;
}

.section__title {
  margin-bottom: 36px;
  font-size: 26px;
  font-weight: 700;
  line-height: 1.5;
}

.section__title--center {
  text-align: center;
}

.section p {
  font-size: 15px;
}

@media (max-width: 750px) {
  .section {
    padding: 56px 20px;
  }

  .section__title {
    margin-bottom: 24px;
    font-size: 20px;
  }

  .section p {
    font-size: 14px;
  }
}

/* ---------- 2段組（PC：左に見出し、右に本文） ---------- */
@media (min-width: 900px) {
  .split {
    display: grid;
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
    align-items: start;
    gap: 64px;
    max-width: 1040px;
  }

  .split__head .section__title,
  .split__head.section__title {
    margin-bottom: 20px;
    font-size: 30px;
  }

  .story__steps.split__body {
    margin-top: 0;
  }

  /* 写真＋本文 */
  .split--media {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: center;
  }
}

.split__media {
  width: 100%;
}

@media (max-width: 899px) {
  .split__media {
    margin-bottom: 32px;
  }
}

/* ---------- 悩み ---------- */
.problem {
  background: var(--color-bg-sub);
}

.problem__list {
  display: grid;
  gap: 12px;
  padding: 0;
  list-style: none;
}

.problem__list li {
  position: relative;
  padding: 18px 20px 18px 52px;
  background: #ffffff;
  font-size: 15px;
}

.problem__list li::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 20px;
  width: 18px;
  height: 18px;
  margin-top: -9px;
  border: 2px solid var(--color-brand);
  border-radius: 3px;
}

.problem__list li::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 26px;
  width: 6px;
  height: 11px;
  margin-top: -8px;
  border-right: 2px solid var(--color-brand);
  border-bottom: 2px solid var(--color-brand);
  transform: rotate(45deg);
}

@media (max-width: 750px) {
  .problem__list li {
    font-size: 14px;
  }
}

.section .problem__lead {
  margin: -16px 0 40px;
  color: var(--color-sub);
  font-size: 16px;
  text-align: center;
}

.section .problem__bridge {
  margin-bottom: 24px;
  font-size: 15px;
  font-weight: 700;
  text-align: center;
}

/* ---------- 作り手の話 ---------- */
.story {
  background: var(--color-bg-sub);
}

.story__label {
  margin-bottom: 8px;
  color: var(--color-brand);
  font-size: 13px;
  letter-spacing: 0.15em;
}

.section--dark .story__label {
  color: #ffffff;
  opacity: 0.7;
}

.story__steps {
  margin-top: 40px;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

/* 縦のライン＋番号でたどった道のりを表す */
.story__step {
  position: relative;
  padding: 0 0 32px 56px;
  counter-increment: step;
}

.story__step::before {
  content: counter(step);
  position: absolute;
  top: 0;
  left: 0;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--color-brand);
  color: #ffffff;
  font-family: var(--font-jp);
  font-size: 16px;
  font-weight: 700;
  line-height: 36px;
  text-align: center;
}

.story__step:not(:last-child)::after {
  content: "";
  position: absolute;
  top: 40px;
  bottom: 4px;
  left: 17px;
  border-left: 2px solid #c9ccc9;
}

.section .story__step-head {
  margin-bottom: 4px;
  font-size: 17px;
  font-weight: 700;
}

.section .story__step p + p {
  margin-top: 0;
}

@media (max-width: 750px) {
  .section .problem__lead {
    margin-bottom: 28px;
    font-size: 14px;
  }

  .section .problem__bridge {
    font-size: 14px;
  }

  .story__step {
    padding-left: 48px;
  }

  .section .story__step-head {
    font-size: 15px;
  }
}

/* ---------- 解決策 ---------- */
.solution__list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 40px;
  max-width: 1040px;
  margin: 0 auto 64px;
  padding: 0;
  list-style: none;
}

/* 英字フォント（Alata）は「1」が「I」に見えるため、数字は日本語フォントで */
.point__num {
  font-family: var(--font-jp);
  font-weight: 700;
  display: block;
  margin-bottom: 8px;
  color: var(--color-brand);
  font-size: 32px;
  line-height: 1;
}

.point__title {
  margin-bottom: 12px;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.5;
}

.section .point p {
  font-size: 14px;
  opacity: 0.85;
}

.section--dark .point__num {
  color: #ffffff;
  opacity: 0.6;
}

/* 図解（線画）。背景色は暗いセクションと同じ */
.point__visual {
  width: 100%;
  aspect-ratio: 670 / 534;
  margin-bottom: 20px;
  object-fit: contain;
}

/* 弱酸性の目盛り（他の図解と同じ白い線画の雰囲気で描く） */
.point__visual--ph {
  display: flex;
  align-items: center;
  justify-content: center;
}

.ph {
  position: relative;
  width: 80%;
  padding-top: 56px;
}

.ph__bar {
  display: block;
  height: 10px;
  border: 1.5px solid #ffffff;
  border-radius: 6px;
  background: linear-gradient(to right, rgba(255, 255, 255, 0.55), rgba(255, 255, 255, 0) 50%, rgba(255, 255, 255, 0.55));
}

.ph__marker {
  position: absolute;
  top: 0;
  left: 38%;
  padding: 4px 12px;
  border: 1.5px solid #ffffff;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 700;
  white-space: nowrap;
  transform: translateX(-50%);
}

.ph__marker::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  height: 22px;
  border-left: 1.5px solid #ffffff;
}

.ph__labels {
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
  font-size: 12px;
  opacity: 0.8;
}

/* 根拠のグラフ（画像の背景色 #48504B に合わせた枠） */
.evidence {
  max-width: 680px;
  margin: 0 auto;
  padding-top: 56px;
  border-top: 1px solid rgba(255, 255, 255, 0.25);
  color: #ffffff;
  text-align: center;
}

.evidence__title {
  margin-bottom: 8px;
  font-size: 20px;
  font-weight: 700;
  line-height: 1.5;
}

.section .evidence__label {
  margin-bottom: 24px;
  font-size: 13px;
  opacity: 0.8;
}

.evidence__chart {
  width: 100%;
  max-width: 510px;
  margin: 0 auto 16px;
}

/* 凡例（グラフ画像の線に合わせて CSS で描画） */
.evidence__legend {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin: 0 0 20px;
  padding: 0;
  list-style: none;
  font-size: 13px;
  font-weight: 700;
}

.evidence__legend-item {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 線 */
.evidence__legend-item::before {
  content: "";
  width: 48px;
  border-top: 2px dashed #ffffff;
}

.evidence__legend-item--mufu::before {
  border-top: 3px solid #ffffff;
}

/* 線の中央の点 */
.evidence__legend-item::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 20px;
  width: 8px;
  height: 8px;
  margin-top: -4px;
  border-radius: 50%;
  background: #ffffff;
}

@media (max-width: 750px) {
  .evidence__legend {
    gap: 20px;
    font-size: 12px;
  }

  .evidence__legend-item::before {
    width: 36px;
  }

  .evidence__legend-item::after {
    left: 14px;
  }
}

.section .evidence__note {
  font-size: 11px;
  opacity: 0.8;
}

@media (max-width: 750px) {
  .solution__list {
    grid-template-columns: 1fr;
    gap: 32px;
    margin-bottom: 40px;
  }

  .point__title {
    font-size: 16px;
  }

  .evidence {
    padding-top: 40px;
  }

  .evidence__title {
    font-size: 17px;
  }
}

/* ---------- 商品 ---------- */
.products {
  background: var(--color-bg-sub);
}

.products__list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  max-width: 1000px;
  margin: 0 auto;
}

/* PC: 左に商品情報、右に購入オプション */
.product {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.3fr);
  align-items: center;
  gap: 40px;
  padding: 40px;
  background: #ffffff;
}

/* 商品ごとにボトルの色で枠を付ける */
.product--c10 {
  border: 3px solid var(--color-c10);
}

.product--c5 {
  border: 3px solid var(--color-c5);
}

.section .product__for {
  display: inline-block;
  margin-bottom: 20px;
  padding: 4px 16px;
  background: var(--color-brand);
  color: #ffffff;
  font-size: 13px;
  font-weight: 700;
}

.product__name {
  font-size: 18px;
  font-weight: 700;
  line-height: 1.6;
}

.section .product__en {
  margin: 4px 0 16px;
  color: var(--color-sub);
  font-family: var(--font-en);
  font-size: 13px;
}

/* ファーストビューのお試し案内 */
.hero__trial {
  display: block;
  margin-top: 12px;
  color: var(--color-brand);
  font-size: 13px;
  font-weight: 700;
}

/* 全成分（折りたたみ） */
.product__ingredients {
  margin-top: 16px;
  font-size: 12px;
}

.product__ingredients summary {
  color: var(--color-brand);
  font-weight: 700;
  cursor: pointer;
}

.section .product__ingredients p {
  margin-top: 8px;
  color: var(--color-sub);
  font-size: 12px;
  line-height: 1.8;
  text-align: left;
}

/* 生ビタミンCの配合率 */
.section .product__vc {
  margin-bottom: 12px;
  padding: 8px 12px;
  border: 1px solid var(--color-brand);
  color: var(--color-brand);
  font-size: 14px;
  font-weight: 700;
  text-align: center;
}

.product__vc strong {
  font-size: 22px;
  line-height: 1;
}

.section .product__note {
  margin-top: 8px;
  color: var(--color-sub);
  font-size: 11px;
}

.section .products__lead {
  margin: -16px 0 40px;
  color: var(--color-sub);
  font-size: 14px;
  text-align: center;
}

/* 購入オプション（お試しパウチ／50mLボトル）: 同じ構成・同じボタン */
.product__options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.option {
  display: flex;
  flex-direction: column;
  padding: 16px;
  background: var(--color-bg-sub);
  text-align: center;
}

.option__img {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 180px;
  margin-bottom: 12px;
  background: #ffffff;
}

.option__img img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.option__name {
  font-size: 15px;
  font-weight: 700;
}

.section .option__spec {
  color: var(--color-sub);
  font-size: 12px;
}

.section .option__price {
  margin-top: 4px;
  font-size: 16px;
  font-weight: 500;
}

.option__buttons {
  display: grid;
  gap: 8px;
  margin-top: auto;
  padding-top: 14px;
}

.option__buttons .button {
  padding: 12px;
  font-size: 14px;
}

@media (max-width: 750px) {
  .products__list {
    gap: 24px;
  }

  .product {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .product__info {
    text-align: center;
  }

  .products {
    padding-right: 12px;
    padding-left: 12px;
  }

  .product {
    padding: 24px 12px;
  }

  .product__options {
    gap: 8px;
  }

  .option {
    padding: 12px 10px;
  }

  .option__img {
    height: 130px;
  }

  .product__name {
    font-size: 16px;
  }
}

/* ---------- よくある質問 ---------- */
.faq__item {
  border-bottom: 1px solid #dcdcd8;
}

.faq__item:first-of-type {
  border-top: 1px solid #dcdcd8;
}

.faq__q {
  position: relative;
  padding: 20px 40px 20px 0;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.6;
  list-style: none;
  cursor: pointer;
}

.faq__q::-webkit-details-marker {
  display: none;
}

/* 開閉の「＋／－」 */
.faq__q::before,
.faq__q::after {
  content: "";
  position: absolute;
  top: 50%;
  right: 8px;
  width: 14px;
  border-top: 2px solid var(--color-brand);
}

.faq__q::after {
  transform: rotate(90deg);
  transition: transform 0.2s;
}

.faq__item[open] .faq__q::after {
  transform: rotate(0deg);
}

.section .faq__a {
  padding: 0 0 20px;
  color: var(--color-sub);
  font-size: 14px;
}

@media (max-width: 750px) {
  .faq__q {
    font-size: 14px;
  }

  .section .faq__a {
    font-size: 13px;
  }
}

.header__home {
  display: block;
  line-height: 0;
}

/* ---------- フッター ---------- */
.footer {
  padding: 40px 24px;
  background: var(--color-brand);
  color: #ffffff;
  text-align: center;
}

.footer__brand {
  margin-bottom: 16px;
  font-size: 13px;
}

.footer__sns {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin-bottom: 16px;
}

.footer__sns a {
  font-family: var(--font-en);
  font-size: 13px;
  text-decoration: none;
}

.footer__copy {
  font-size: 11px;
}