/* ============================================
   大松 / 清流館 LP - BALMUDAスタイル
   白基調・ミニマル・余白重視
   ============================================ */

/* --- リセット・ベース --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: "Hiragino Mincho ProN", "Noto Serif JP", "Yu Mincho", serif;
  color: #1a1a1a;
  background-color: #fff;
  line-height: 1.9;
  letter-spacing: 0.06em;
}

a {
  color: inherit;
  text-decoration: none;
}

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

/* --- タイポグラフィ --- */
.heading-xl {
  font-size: clamp(1.75rem, 4vw, 3rem);
  font-weight: 400;
  line-height: 1.5;
  letter-spacing: 0.12em;
}

.heading-lg {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 400;
  line-height: 1.5;
  letter-spacing: 0.1em;
}

.heading-md {
  font-size: clamp(1.125rem, 2vw, 1.5rem);
  font-weight: 400;
  line-height: 1.6;
  letter-spacing: 0.08em;
}

.text-body {
  font-size: clamp(0.9rem, 1.2vw, 1.05rem);
  line-height: 2;
  letter-spacing: 0.05em;
  color: #444;
}

.text-sm {
  font-size: 0.825rem;
  color: #888;
  letter-spacing: 0.04em;
}

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

/* --- レイアウト --- */
.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 120px 0;
}

.section--hero {
  padding: 160px 0 120px;
}

.section--compact {
  padding: 80px 0;
}

/* --- ヘッダー --- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
  transition: transform 0.4s ease;
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

.header__logo {
  font-size: 0.9rem;
  letter-spacing: 0.15em;
  font-weight: 400;
}

.header__nav {
  display: flex;
  gap: 32px;
}

.header__nav a {
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  color: #666;
  transition: color 0.3s ease;
  position: relative;
}

.header__nav a::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: #1a1a1a;
  transition: width 0.3s ease;
}

.header__nav a:hover {
  color: #1a1a1a;
}

.header__nav a:hover::after,
.header__nav a.is-active::after {
  width: 100%;
}

.header__nav a.is-active {
  color: #1a1a1a;
}

/* --- ハンバーガーメニュー（モバイル） --- */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: #1a1a1a;
  transition: all 0.3s ease;
}

.hamburger.is-active span:nth-child(1) {
  transform: rotate(45deg) translate(4px, 4px);
}

.hamburger.is-active span:nth-child(2) {
  opacity: 0;
}

.hamburger.is-active span:nth-child(3) {
  transform: rotate(-45deg) translate(4px, -4px);
}

/* --- ヒーローセクション --- */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero__catch {
  font-size: clamp(1.75rem, 5vw, 3.2rem);
  font-weight: 300;
  letter-spacing: 0.2em;
  line-height: 1.7;
  margin-bottom: 32px;
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp 1s ease 0.3s forwards;
}

.hero__sub {
  font-size: clamp(0.8rem, 1.2vw, 0.95rem);
  color: #888;
  letter-spacing: 0.15em;
  line-height: 2;
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp 1s ease 0.6s forwards;
}

.hero__scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  opacity: 0;
  animation: fadeUp 1s ease 1s forwards;
}

.hero__scroll span {
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  color: #aaa;
}

.hero__scroll-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, #ccc, transparent);
  animation: scrollLine 2s ease infinite;
}

/* --- カードUI --- */
.cards {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  margin-top: 80px;
}

.card {
  background: #fafafa;
  border: 1px solid rgba(0, 0, 0, 0.06);
  padding: 56px 36px 48px;
  text-align: center;
  transition: all 0.4s ease;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: #1a1a1a;
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 0.4s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.06);
}

.card:hover::before {
  transform: scaleX(1);
}

.card__number {
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: #bbb;
  margin-bottom: 24px;
  font-family: "Helvetica Neue", Arial, sans-serif;
}

.card__title {
  font-size: 1.25rem;
  letter-spacing: 0.12em;
  margin-bottom: 16px;
  font-weight: 400;
}

.card__desc {
  font-size: 0.875rem;
  color: #888;
  line-height: 1.8;
  margin-bottom: 36px;
  letter-spacing: 0.04em;
}

/* --- ボタン --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: inherit;
  font-size: 0.825rem;
  letter-spacing: 0.12em;
  padding: 16px 40px;
  border: 1px solid #1a1a1a;
  background: transparent;
  color: #1a1a1a;
  cursor: pointer;
  transition: all 0.35s ease;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: #1a1a1a;
  transform: translateX(-101%);
  transition: transform 0.35s ease;
  z-index: -1;
}

.btn:hover {
  color: #fff;
}

.btn:hover::before {
  transform: translateX(0);
}

.btn--arrow::after {
  content: "→";
  transition: transform 0.3s ease;
}

.btn:hover .btn--arrow::after,
.btn--arrow:hover::after {
  transform: translateX(4px);
}

/* プライマリボタン（LINE用） */
.btn--primary {
  background: #06C755;
  border-color: #06C755;
  color: #fff;
  font-size: 0.95rem;
  padding: 20px 48px;
}

.btn--primary::before {
  background: #05b34c;
}

.btn--primary:hover {
  color: #fff;
}

/* ラージボタン */
.btn--lg {
  font-size: 0.95rem;
  padding: 20px 56px;
}

/* --- セクション画像 --- */
.section-image {
  max-width: 360px;
  margin: 0 auto 64px;
  overflow: hidden;
}

.section-image img {
  width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

/* --- 展覧会概要 --- */
.exhibition-info {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.exhibition-info__inner {
  margin-top: 32px;
}

.exhibition-info__title {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  letter-spacing: 0.1em;
  line-height: 1.8;
  margin-bottom: 32px;
}

.exhibition-info__dl {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 16px 24px;
  text-align: left;
  max-width: 400px;
  margin: 0 auto;
}

.exhibition-info__dl dt {
  font-size: 0.85rem;
  color: #888;
  letter-spacing: 0.08em;
}

.exhibition-info__dl dd {
  font-size: 0.95rem;
  letter-spacing: 0.04em;
}

/* --- 体験ブロック --- */
.experience-block {
  max-width: 720px;
  margin: 80px auto 0;
  padding: 64px 0;
  border-top: 1px solid rgba(0, 0, 0, 0.06);
  text-align: center;
}

.experience-block__label {
  font-family: "Helvetica Neue", Arial, sans-serif;
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: #bbb;
  margin-bottom: 24px;
  text-transform: uppercase;
}

/* --- 特徴リスト --- */
.feature-list {
  list-style: none;
  max-width: 400px;
  margin: 2em auto 0;
  text-align: left;
}

.feature-list li {
  position: relative;
  padding-left: 20px;
  font-size: 0.95rem;
  color: #444;
  line-height: 2.2;
  letter-spacing: 0.04em;
}

.feature-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.9em;
  width: 8px;
  height: 1px;
  background: #1a1a1a;
}

/* --- 縦型ステップ --- */
.steps-vertical {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 56px 0 80px;
}

.step-v {
  display: flex;
  align-items: center;
  gap: 20px;
}

.step-v__number {
  width: 40px;
  height: 40px;
  border: 1px solid #ddd;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Helvetica Neue", Arial, sans-serif;
  font-size: 0.8rem;
  color: #999;
  flex-shrink: 0;
}

.step-v__text {
  font-size: 0.95rem;
  letter-spacing: 0.06em;
  color: #444;
}

.step-v__line {
  width: 1px;
  height: 32px;
  background: #ddd;
  margin: 8px 0 8px 20px;
}

/* --- 価値グリッド --- */
.value-grid {
  margin-top: 100px;
}

.value-grid__items {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 40px;
}

.value-grid__item {
  text-align: center;
  padding: 40px 20px;
  background: #fafafa;
  border: 1px solid rgba(0, 0, 0, 0.06);
}

.value-grid__text {
  font-size: 0.95rem;
  line-height: 1.8;
  letter-spacing: 0.06em;
  color: #444;
}

/* --- おすすめ --- */
.recommend {
  margin-top: 80px;
}

.recommend__list {
  list-style: none;
  max-width: 400px;
  margin: 32px auto 0;
  text-align: left;
}

.recommend__list li {
  position: relative;
  padding-left: 20px;
  font-size: 0.95rem;
  color: #444;
  line-height: 2.4;
  letter-spacing: 0.04em;
}

.recommend__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.95em;
  width: 8px;
  height: 1px;
  background: #1a1a1a;
}

/* --- 最終CTA --- */
.final-cta {
  margin-top: 120px;
  padding-top: 80px;
  border-top: 1px solid rgba(0, 0, 0, 0.06);
  text-align: center;
}

/* --- ステップUI --- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 48px;
  margin: 80px 0;
  counter-reset: step;
}

.step {
  text-align: center;
  position: relative;
}

.step__number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border: 1px solid #ddd;
  border-radius: 50%;
  font-family: "Helvetica Neue", Arial, sans-serif;
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  color: #999;
  margin-bottom: 28px;
}

.step__title {
  font-size: 1rem;
  letter-spacing: 0.1em;
  margin-bottom: 12px;
  font-weight: 400;
}

.step__desc {
  font-size: 0.85rem;
  color: #888;
  line-height: 1.8;
}

/* ステップ間の線 */
.step:not(:last-child)::after {
  content: "";
  position: absolute;
  top: 28px;
  right: -24px;
  width: 48px;
  height: 1px;
  background: #ddd;
}

/* --- コンテンツセクション（独立ページ用） --- */
.content {
  max-width: 720px;
  margin: 0 auto;
}

.content__heading {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 300;
  letter-spacing: 0.15em;
  text-align: center;
  margin-bottom: 56px;
  line-height: 1.6;
}

.content__body {
  font-size: clamp(0.9rem, 1.2vw, 1.05rem);
  line-height: 2.2;
  color: #444;
  letter-spacing: 0.04em;
}

.content__body p + p {
  margin-top: 2em;
}

.content__cta {
  text-align: center;
  margin-top: 80px;
}

/* --- 区切り線 --- */
.divider {
  width: 40px;
  height: 1px;
  background: #ccc;
  margin: 0 auto 48px;
}

/* --- セクション区切り（1ページ構成用） --- */
.section--border {
  border-top: 1px solid rgba(0, 0, 0, 0.06);
}

/* --- ページヒーロー（インライン版） --- */
.page-hero--inline {
  text-align: center;
  margin-bottom: 56px;
}

/* --- フッター --- */
.footer {
  padding: 60px 0;
  text-align: center;
  border-top: 1px solid rgba(0, 0, 0, 0.06);
}

.footer__logo {
  font-size: 0.85rem;
  letter-spacing: 0.15em;
  margin-bottom: 16px;
}

.footer__copy {
  font-size: 0.7rem;
  color: #aaa;
  letter-spacing: 0.08em;
}

/* --- ページヒーロー（サブページ用） --- */
.page-hero {
  padding: 160px 0 80px;
  text-align: center;
}

.page-hero__label {
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: #bbb;
  margin-bottom: 20px;
  font-family: "Helvetica Neue", Arial, sans-serif;
}

/* --- アニメーション --- */
@keyframes fadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scrollLine {
  0% {
    transform: scaleY(0);
    transform-origin: top;
  }
  50% {
    transform: scaleY(1);
    transform-origin: top;
  }
  51% {
    transform-origin: bottom;
  }
  100% {
    transform: scaleY(0);
    transform-origin: bottom;
  }
}

/* スクロール連動フェードイン */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.fade-in.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- 動画セクション --- */
.video-section {
  text-align: center;
  margin-top: 64px;
}

.video-placeholder {
  position: relative;
  width: 100%;
  max-width: 720px;
  margin: 0 auto 48px;
  aspect-ratio: 16 / 9;
  background: #f5f5f5;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.video-placeholder__play {
  width: 72px;
  height: 72px;
  border: 2px solid #1a1a1a;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s ease;
}

.video-placeholder__play::after {
  content: "";
  display: block;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent #1a1a1a;
  margin-left: 4px;
}

.video-placeholder:hover .video-placeholder__play {
  background: #1a1a1a;
}

.video-placeholder:hover .video-placeholder__play::after {
  border-color: transparent transparent transparent #fff;
}

/* --- レスポンシブ --- */
@media (max-width: 768px) {
  .section {
    padding: 80px 0;
  }

  .section--hero {
    padding: 120px 0 80px;
  }

  .cards {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
    margin-top: 56px;
  }

  .card {
    padding: 40px 28px 36px;
  }

  .steps {
    grid-template-columns: 1fr;
    gap: 40px;
    margin: 56px 0;
  }

  .step:not(:last-child)::after {
    display: none;
  }

  .value-grid__items {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .experience-block {
    margin-top: 56px;
    padding: 48px 0;
  }

  .header__nav {
    display: none;
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.98);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 40px;
  }

  .header__nav.is-open {
    display: flex;
  }

  .header__nav a {
    font-size: 1rem;
  }

  .hamburger {
    display: flex;
  }

  .page-hero {
    padding: 120px 0 56px;
  }

  .content__heading {
    margin-bottom: 40px;
  }

  .content__cta {
    margin-top: 56px;
  }

  .btn--lg {
    padding: 16px 40px;
    font-size: 0.875rem;
  }
}

@media (max-width: 480px) {
  .cards {
    grid-template-columns: 1fr;
  }

  .hero__catch {
    letter-spacing: 0.12em;
  }

  .btn {
    padding: 14px 32px;
    font-size: 0.8rem;
  }

  .btn--primary {
    padding: 16px 36px;
    font-size: 0.875rem;
  }
}