/* ==========================================================
   subpage.css — 5サブページ共通スタイル
   対象: web/, ai/, data/, dx/, platform/ の各 index.html
   ========================================================== */

/* ========== 1. :root 変数 ========== */
:root {
  --color-bg: #000000;
  --color-bg-alt: #0A0A0A;
  --color-card: #111111;
  --color-elevated: #1A1A1A;
  --color-text: #EDEDED;
  --color-text-sub: #A1A1A1;
  --color-text-muted: #666666;
  --color-accent: #5F7A61;
  --color-border: rgba(255, 255, 255, 0.12);
  --font-serif: 'Cormorant', 'Noto Serif JP', serif;
  --font-sans: 'Inter', 'Noto Sans JP', sans-serif;
  --font-jp: 'Noto Sans JP', sans-serif;
  --font-en: 'Inter', sans-serif;
  --container-max: 1024px;
  --container-padding: 40px;
}

:root[data-theme="light"] {
  --color-bg: #F8F8F8;
  --color-bg-alt: #F0F0F0;
  --color-card: #FFFFFF;
  --color-elevated: #FFFFFF;
  --color-text: #111111;
  --color-text-sub: #555555;
  --color-text-muted: #999999;
  --color-accent: #4A7A4F;
  --color-border: rgba(0, 0, 0, 0.12);
}

/* ========== 2. リセット & ベース ========== */
html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ========== 3. ナビゲーション ========== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 24px var(--container-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--color-bg);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nav-anchors {
  display: flex;
  gap: 2px;
  align-items: center;
}

.nav-anchor {
  font-family: var(--font-serif);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--color-text-sub);
  text-decoration: none;
  padding: 4px 7px;
  transition: color 0.2s ease;
  font-feature-settings: 'lnum';
}

.nav-anchor:hover {
  color: var(--color-text);
}

.nav-back {
  font-family: var(--font-serif);
  font-size: 13px;
  letter-spacing: 0.15em;
  color: var(--color-text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 10px;
  transition: color 0.3s ease;
}

.nav-back:hover {
  color: var(--color-text);
}

/* ハンバーガーボタン (デスクトップ非表示) */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 6px;
  width: 30px;
  height: 30px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  position: relative;
  z-index: 101;
}

.nav-hamburger span {
  display: block;
  width: 30px;
  height: 2px;
  background: var(--color-text);
  transform-origin: center;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.nav-hamburger.active span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

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

.nav-hamburger.active span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}


/* ========== 4. 共通セクションスタイル ========== */

/* ヒーロー共通 */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: 0 var(--container-padding) 80px;
  max-width: calc(var(--container-max) + var(--container-padding) * 2);
  margin: 0 auto;
  width: 100%;
}

.hero-label {
  font-family: var(--font-en);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.3em;
  color: var(--color-text-muted);
  margin-bottom: 28px;
  font-feature-settings: 'lnum';
}

.hero-divider {
  width: 40px;
  height: 1px;
  background: var(--color-border);
}

/* セクション共通レイアウト（data / platform 共通） */
.section {
  padding: 120px var(--container-padding);
  max-width: calc(var(--container-max) + var(--container-padding) * 2);
  margin: 0 auto;
  width: 100%;
  border-top: 1px solid var(--color-border);
}

.section-label {
  font-family: var(--font-en);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.3em;
  color: var(--color-text-muted);
  margin-bottom: 16px;
}

.section-heading {
  font-family: var(--font-serif);
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 500;
  letter-spacing: 0.03em;
  color: var(--color-text);
  margin-bottom: 24px;
}

.section-en {
  font-family: var(--font-en);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--color-text-muted);
  margin-bottom: 48px;
}

.section-body {
  font-family: var(--font-jp);
  font-size: 15px;
  line-height: 1.9;
  color: var(--color-text);
  max-width: 680px;
}

/* ========== 5. フッター ========== */
.site-footer {
  padding: 48px var(--container-padding);
  max-width: calc(var(--container-max) + var(--container-padding) * 2);
  margin: 0 auto;
  width: 100%;
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-text {
  font-family: var(--font-serif);
  font-size: 12px;
  letter-spacing: 0.15em;
  color: var(--color-text-muted);
}

.footer-back {
  font-family: var(--font-serif);
  font-size: 12px;
  letter-spacing: 0.15em;
  color: var(--color-text-sub);
  text-decoration: none;
  transition: color 0.3s ease;
}

.footer-back:hover {
  color: var(--color-text);
}

/* ========== 6. 共通レスポンシブ ========== */
@media (max-width: 768px) {
  :root {
    --container-padding: 20px;
  }

  .nav {
    padding: 20px 24px;
  }

  .nav-hamburger {
    display: flex;
  }

  .nav-anchors {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 24px;
    z-index: 99;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
  }

  .nav-anchors.open {
    opacity: 1;
    visibility: visible;
  }

  .nav-anchors .nav-anchor {
    font-size: 20px;
    padding: 8px 16px;
  }

  .theme-toggle {
    z-index: 101;
  }

  .hero {
    min-height: 70vh;
    padding-bottom: 48px;
  }

  .section {
    padding-top: 64px;
    padding-bottom: 64px;
  }

  .site-footer {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }
}