/* ============================================================
   Hitokuchi (ひとくち) — Landing Page Stylesheet (v4)
   Design spec: designer-v4-section-blueprint.md
   Philosophy:
     - 静かな散歩 (quiet walk)
     - 朝の光 (morning light: warm but calm)
     - 和の佇まい (Japanese quietude)
     - 誠実な余白 (honest whitespace)
   No red, no orange-alert, no "!" marks, no fear framing.
   ============================================================ */

/* --- Reset (minimal, opinionated) ------------------------------ */
*,
*::before,
*::after {
  box-sizing: border-box;
}
html {
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
  scroll-behavior: smooth;
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}
body {
  margin: 0;
  font-family: var(--font-sans-ja);
  font-size: 1.0625rem; /* 17px baseline for P3 senior accessibility */
  line-height: 1.95;    /* v4: breathe longer */
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}
html[lang="en"] body { font-family: var(--font-sans-en); line-height: 1.75; }
img, svg, picture { max-width: 100%; height: auto; display: block; }
ul, ol { padding: 0; margin: 0; list-style: none; }
p { margin: 0; }
a {
  color: var(--accent-primary);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color 0.2s;
}
a:hover { color: var(--accent-primary-hover); }
a:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
  border-radius: 2px;
}

/* --- Design tokens (v5: water-blue palette, matches app default theme) --- */
:root {
  /* Color — Light (v5 水色基調) */
  --bg-primary:     #F4FBFD;  /* 白水 — main background */
  --bg-secondary:   #EAF5FA;  /* 薄水 — section / card bg */
  --bg-tertiary:    #D8ECF5;  /* 淡水 — stronger card bg */
  --text-primary:   #1E3A4D;  /* 深藍 — headings, body strong */
  --text-secondary: #5B7E94;  /* 鈍藍 — body, caption */
  --text-tertiary:  #8FAABD;  /* 霞藍 — sources, footnotes */
  --accent-primary: #5BADD6;  /* 水色 — CTA, links, frames */
  --accent-primary-hover: #3E93BF; /* 深水色 */
  --accent-secondary: #8FCFE8; /* 淡水色 — icon accent, number highlight */
  --accent-success:   #6BAE9E; /* 青緑 */
  --accent-soft-purple: #A9B7D4; /* 藍鼠 — quotes, tags (restrained) */
  --accent-sakura-ash:  #E8D3D1; /* 灰桜 — faint bg on FAQ emphasis */
  --border-default:   #CCE4EE; /* 細水 */
  --text-on-accent:   #FFFFFF; /* 白 on 水色 button */
  --shadow-subtle: 0 1px 3px rgba(30, 58, 77, 0.06);
  --shadow-medium: 0 2px 8px rgba(30, 58, 77, 0.10);

  /* Typography — v4 two-face system */
  --font-serif-ja: "Shippori Mincho B1", "BIZ UDPMincho",
                   "Hiragino Mincho ProN", "Yu Mincho", "YuMincho",
                   "Noto Serif JP", serif;
  --font-serif-en: "Playfair Display", "EB Garamond",
                   Georgia, "Times New Roman", serif;
  --font-sans-ja: "Noto Sans JP", "Hiragino Sans",
                  -apple-system, BlinkMacSystemFont, "Helvetica Neue",
                  Arial, sans-serif;
  --font-sans-en: "Inter", -apple-system, BlinkMacSystemFont,
                  "Helvetica Neue", Arial, sans-serif;
  /* Backward-compatible aliases */
  --font-sans:  var(--font-sans-ja);
  --font-serif: var(--font-serif-ja);

  /* Spacing — 8pt grid */
  --sp-3xs: 2px;
  --sp-2xs: 4px;
  --sp-xs:  8px;
  --sp-s:   12px;
  --sp-m:   16px;
  --sp-l:   24px;
  --sp-xl:  32px;
  --sp-2xl: 48px;
  --sp-3xl: 64px;
  --sp-4xl: 96px;
  --sp-5xl: 120px;

  /* Radius */
  --radius-s:  8px;
  --radius-m:  12px;
  --radius-l:  16px;
  --radius-xl: 20px;
  --radius-full: 999px;

  /* Layout */
  --content-max:    1120px;
  --content-narrow: 720px;
  --page-gutter:    24px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary:    #121C24;  /* 深藍墨 */
    --bg-secondary:  #1D2A34;  /* 藍鼠 */
    --bg-tertiary:   #253542;  /* 濃藍 */
    --text-primary:  #E8F4FC;  /* 白水 */
    --text-secondary:#9FBED1;  /* 薄水 */
    --text-tertiary: #6E8FA3;  /* 霞水 */
    --accent-primary:   #70BEDE; /* 明水色 */
    --accent-primary-hover: #8ACCE6; /* 淡水色 */
    --accent-secondary: #9FD5EC; /* 霞水色 */
    --accent-success:   #7DBAAB;
    --accent-soft-purple: #B8C5E0; /* 明藍鼠 */
    --accent-sakura-ash:  #38303A; /* 暗灰桜 */
    --border-default:   #2E4050; /* 暗細水 */
    --text-on-accent:   #121C24;
    --shadow-subtle: 0 1px 3px rgba(0, 0, 0, 0.28);
    --shadow-medium: 0 2px 8px rgba(0, 0, 0, 0.38);
  }
}

/* --- Typography scale (v4) ------------------------------------ */
h1, h2, h3, h4 {
  margin: 0;
  font-weight: 400; /* v4: 明朝 Regular only. Bold forbidden on serif. */
  color: var(--text-primary);
}
h1 {
  font-family: var(--font-serif-ja);
  font-size: 2.5rem;        /* 40px mobile */
  line-height: 1.45;
  letter-spacing: 0.05em;
}
h2 {
  font-family: var(--font-serif-ja);
  font-size: 1.75rem;       /* 28px mobile */
  line-height: 1.45;
  letter-spacing: 0.05em;
}
h3 {
  font-family: var(--font-sans-ja);
  font-size: 1.25rem;        /* 20px mobile */
  line-height: 1.5;
  font-weight: 500;
}
h4 {
  font-family: var(--font-sans-ja);
  font-size: 1.0625rem;
  line-height: 1.5;
  font-weight: 500;
}
html[lang="en"] h1,
html[lang="en"] h2 { font-family: var(--font-serif-en); letter-spacing: -0.01em; line-height: 1.3; }
html[lang="en"] h3,
html[lang="en"] h4 { font-family: var(--font-sans-en); }

@media (min-width: 768px) {
  h1 { font-size: 3rem; }     /* 48px */
  h2 { font-size: 2.125rem; } /* 34px */
  h3 { font-size: 1.375rem; }
  h4 { font-size: 1.125rem; }
}
@media (min-width: 1024px) {
  h1 { font-size: 3.75rem; }  /* 60px */
  h2 { font-size: 2.25rem; }  /* 36px */
}
p { max-width: 38em; }
p + p, p + ul, p + ol { margin-top: var(--sp-m); }
.lead {
  font-size: 1.0625rem;
  line-height: 1.95;
  color: var(--text-primary);
  max-width: 32em;
}
@media (min-width: 768px) {
  .lead { font-size: 1.125rem; }
}
@media (min-width: 1024px) {
  .lead { font-size: 1.1875rem; }
}
small, figcaption, .caption {
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--text-secondary);
}
@media (min-width: 768px) {
  small, figcaption, .caption { font-size: 0.875rem; }
}

/* --- Accessibility helpers ----------------------------------- */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--text-primary);
  color: var(--bg-primary);
  padding: var(--sp-xs) var(--sp-m);
  text-decoration: none;
  z-index: 100;
  border-radius: 0 0 var(--radius-s) 0;
}
.skip-link:focus { top: 0; }
.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0);
  white-space: nowrap; border: 0;
}

/* --- Container ---------------------------------------------- */
.container {
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--page-gutter);
}
.container.narrow {
  max-width: var(--content-narrow);
}

/* --- Site header (sticky) ----------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(244, 251, 253, 0.88); /* matches --bg-primary */
  -webkit-backdrop-filter: saturate(180%) blur(8px);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border-default);
}
@media (prefers-color-scheme: dark) {
  .site-header { background-color: rgba(18, 28, 36, 0.88); /* matches dark --bg-primary */ }
}
.site-header nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--page-gutter);
}
@media (min-width: 768px) {
  .site-header nav { height: 64px; }
}
.site-logo {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-xs);
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 500;
  font-family: var(--font-serif-ja);
  font-size: 1.125rem;
  letter-spacing: 0.05em;
}
html[lang="en"] .site-logo { font-family: var(--font-serif-en); letter-spacing: 0; }
.site-logo:hover { color: var(--text-primary); }
.site-logo img {
  width: 32px; height: 32px;
  border-radius: var(--radius-s);
}
.lang-link {
  font-family: var(--font-sans-ja);
  font-size: 0.9375rem;
  color: var(--text-secondary);
  text-decoration: none;
  padding: var(--sp-xs) var(--sp-s);
  border-radius: var(--radius-s);
}
.lang-link:hover {
  color: var(--accent-primary);
  background-color: var(--bg-secondary);
}
@media (max-width: 767px) {
  .lang-link { display: inline-flex; font-size: 0.875rem; }
}

/* --- Section base ------------------------------------------- */
main { display: block; }
section {
  padding-block: var(--sp-3xl);
}
@media (min-width: 768px) {
  section { padding-block: var(--sp-4xl); }
}
@media (min-width: 1024px) {
  section { padding-block: var(--sp-5xl); }
}
section + section { border-top: 1px solid transparent; }

/* Section eyebrow — small category label, neutral only */
.section-eyebrow {
  display: inline-block;
  font-family: var(--font-sans-ja);
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent-primary);
  font-weight: 500;
  margin-bottom: var(--sp-m);
}
html[lang="en"] .section-eyebrow { font-family: var(--font-sans-en); }

/* --- Hero (v4: brand heart) --------------------------------- */
.hero {
  padding-block: var(--sp-3xl) var(--sp-4xl);
  position: relative;
  background-color: var(--bg-primary);
}
@media (min-width: 768px) {
  .hero { padding-block: var(--sp-4xl) var(--sp-5xl); }
}
@media (min-width: 1024px) {
  .hero { padding-block: var(--sp-5xl) var(--sp-5xl); }
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--sp-2xl);
  align-items: center;
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--page-gutter);
}
@media (min-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1.1fr 0.9fr;
    gap: var(--sp-4xl);
  }
}
.hero h1 {
  margin-bottom: var(--sp-xl);
  max-width: 16ch;
}
html[lang="en"] .hero h1 { max-width: 22ch; }
.hero .lead {
  color: var(--text-secondary);
  margin-bottom: var(--sp-xl);
  max-width: 22em;
  font-family: var(--font-serif-ja);
  line-height: 1.8;
}
html[lang="en"] .hero .lead { font-family: var(--font-serif-en); line-height: 1.6; }
.hero-scroll-cue { margin-top: var(--sp-l); }
.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
  color: var(--accent-primary);
}
.hero-scene {
  width: 100%;
  max-width: 320px;
  height: auto;
}

/* --- Secondary button (scroll cue + quiet links) ------------ */
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-xs);
  padding: var(--sp-s) var(--sp-l);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--text-primary);
  font-family: var(--font-sans-ja);
  font-weight: 500;
  font-size: 0.9375rem;
  text-decoration: none;
  transition: border-color 0.2s, background 0.2s, color 0.2s;
  cursor: pointer;
}
html[lang="en"] .btn-secondary { font-family: var(--font-sans-en); }
.btn-secondary:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}
.btn-secondary:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
}
.btn-secondary .arrow,
.btn-secondary .arrow-down {
  display: inline-block;
  transition: transform 0.2s;
}
.btn-secondary:hover .arrow,
.btn-secondary:hover .arrow-down { transform: translateY(2px); }

/* --- Primary button (CTA: matcha-green) --------------------- */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-xs);
  padding: var(--sp-m) var(--sp-2xl);
  background: var(--accent-primary);
  color: var(--text-on-accent);
  font-family: var(--font-sans-ja);
  font-weight: 500;
  font-size: 1rem;
  border-radius: var(--radius-m);
  text-decoration: none;
  border: 1px solid transparent;
  transition: background 0.2s ease, transform 0.2s ease;
  letter-spacing: 0.04em;
}
html[lang="en"] .btn-primary { font-family: var(--font-sans-en); letter-spacing: 0.02em; }
.btn-primary:hover {
  background: var(--accent-primary-hover);
  color: var(--text-on-accent);
  transform: translateY(-1px);
}
.btn-primary:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
}
@media (prefers-reduced-motion: reduce) {
  .btn-primary { transition: none; }
  .btn-primary:hover { transform: none; }
}

/* --- App Store badge link ----------------------------------- */
.app-store-badge-link {
  display: inline-block;
  padding: 12px;
  border-radius: var(--radius-m);
  transition: background-color 0.2s, box-shadow 0.2s;
  text-decoration: none;
}
.app-store-badge-link:hover {
  background-color: var(--bg-secondary);
  box-shadow: var(--shadow-subtle);
}
.app-store-badge-link:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 4px;
}
.app-store-badge-link img {
  height: 48px;
  width: auto;
}
@media (min-width: 768px) {
  .app-store-badge-link img { height: 52px; }
}
.app-store-badge-link.large img {
  height: 56px;
}
@media (min-width: 768px) {
  .app-store-badge-link.large img { height: 60px; }
}

/* --- Cards (general 3-col / 2-col) -------------------------- */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--sp-l);
  margin-top: var(--sp-2xl);
}
@media (min-width: 768px) {
  .card-grid.three-col { grid-template-columns: repeat(3, 1fr); }
  .card-grid.two-col { grid-template-columns: repeat(2, 1fr); }
}
.card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-l);
  padding: var(--sp-xl);
  display: flex;
  flex-direction: column;
  gap: var(--sp-s);
}
.card h3 {
  font-family: var(--font-serif-ja);
  font-weight: 400;
  letter-spacing: 0.03em;
  color: var(--text-primary);
}
html[lang="en"] .card h3 { font-family: var(--font-serif-en); letter-spacing: 0; }
.card p {
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.85;
}
.card-icon {
  display: inline-flex;
  width: 48px;
  height: 48px;
  align-items: center;
  justify-content: center;
  color: var(--accent-secondary);
  margin-bottom: var(--sp-xs);
}

/* --- Empathy section ---------------------------------------- */
#empathy {
  background-color: var(--bg-primary);
}

/* --- Brand story (quiet centered essay) --------------------- */
#brand-story {
  background-color: var(--bg-secondary);
  text-align: center;
}
.brand-story-body {
  max-width: 30em;
  margin: var(--sp-2xl) auto 0;
  font-family: var(--font-serif-ja);
  line-height: 2.0;
  color: var(--text-primary);
  letter-spacing: 0.02em;
  display: flex;
  flex-direction: column;
  gap: var(--sp-l);
}
html[lang="en"] .brand-story-body { font-family: var(--font-serif-en); }
.brand-story-body p { margin: 0; max-width: none; }
.brand-story-body .brand-triplet p {
  color: var(--accent-primary);
}
.brand-story-body .brand-triplet {
  display: flex;
  flex-direction: column;
  gap: var(--sp-xs);
}
.brand-story-scene {
  margin: var(--sp-2xl) auto 0;
  color: var(--accent-primary);
  max-width: 400px;
}

/* --- Facts: quiet blockquote yardstick ---------------------- */
#facts {
  background-color: var(--bg-primary);
  text-align: center;
}
.facts-intro {
  max-width: 28em;
  margin: 0 auto var(--sp-2xl);
  color: var(--text-secondary);
  text-align: center;
}
.facts-mark {
  display: block;
  width: 3px;
  height: 48px;
  margin: 0 auto var(--sp-l);
  background-color: var(--accent-soft-purple);
  border-radius: var(--radius-full);
}
.blockquote-fact {
  margin: 0 auto;
  max-width: 560px;
  padding: var(--sp-xl) var(--sp-l);
  background-color: var(--bg-tertiary);
  border-left: 3px solid var(--accent-soft-purple);
  border-radius: var(--radius-m);
  text-align: left;
  font-family: var(--font-serif-ja);
  color: var(--text-primary);
  line-height: 1.95;
}
html[lang="en"] .blockquote-fact { font-family: var(--font-serif-en); }
.blockquote-fact p { margin: 0; max-width: none; }
.blockquote-fact .fact-figure {
  color: var(--accent-secondary);
  letter-spacing: 0.02em;
}
.blockquote-fact cite {
  display: block;
  margin-top: var(--sp-m);
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  font-style: normal;
  font-family: var(--font-sans-ja);
}
html[lang="en"] .blockquote-fact cite { font-family: var(--font-sans-en); }

/* --- Gap section (accepting — no cross marks) --------------- */
#gap {
  background-color: var(--bg-secondary);
}
#gap h2 {
  text-align: center;
  max-width: 20ch;
  margin-inline: auto;
  margin-bottom: var(--sp-2xl);
}
.gap-body {
  max-width: 30em;
  margin: 0 auto;
  color: var(--text-primary);
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: var(--sp-l);
}
.gap-body p { margin: 0; max-width: none; }
.gap-close {
  font-family: var(--font-serif-ja);
  color: var(--text-primary);
  line-height: 1.85;
}
html[lang="en"] .gap-close { font-family: var(--font-serif-en); }
.gap-trio {
  display: flex;
  justify-content: center;
  align-items: flex-end;
  gap: var(--sp-l);
  flex-wrap: wrap;
  margin: var(--sp-2xl) auto;
  max-width: 520px;
  color: var(--accent-primary);
}
.gap-trio figure {
  margin: 0;
  flex: 1 1 120px;
  min-width: 100px;
  max-width: 160px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-xs);
}
.gap-trio svg {
  width: 96px;
  height: auto;
}
.gap-trio figcaption {
  font-size: 0.875rem;
  color: var(--text-secondary);
  letter-spacing: 0.04em;
}

/* --- Solution (three small cards) --------------------------- */
#solution {
  background-color: var(--bg-primary);
  text-align: center;
}
.solution-lead {
  max-width: 30em;
  margin: 0 auto var(--sp-l);
  font-family: var(--font-serif-ja);
  color: var(--text-primary);
  line-height: 1.95;
  text-align: center;
}
html[lang="en"] .solution-lead { font-family: var(--font-serif-en); }
.solution-lead p { margin: 0; max-width: none; }
.solution-lead p + p { margin-top: var(--sp-s); }
.solution-sub {
  max-width: 28em;
  margin: 0 auto var(--sp-2xl);
  color: var(--text-secondary);
  line-height: 1.85;
  text-align: center;
}
.solution-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--sp-l);
  max-width: 760px;
  margin-inline: auto;
  padding: 0;
  list-style: none;
}
@media (min-width: 768px) {
  .solution-cards { grid-template-columns: repeat(3, 1fr); }
}
.solution-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-l);
  padding: var(--sp-xl) var(--sp-l);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-m);
  color: var(--accent-primary);
}
.solution-card svg {
  width: 64px;
  height: 64px;
}
.solution-card .solution-title {
  font-family: var(--font-serif-ja);
  font-size: 1.125rem;
  color: var(--text-primary);
  letter-spacing: 0.05em;
  line-height: 1.6;
  max-width: none;
}
html[lang="en"] .solution-card .solution-title { font-family: var(--font-serif-en); letter-spacing: 0; }

/* --- How it works (three steps with kanji numerals) --------- */
#how-it-works {
  background-color: var(--bg-secondary);
  text-align: center;
}
.steps-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--sp-l);
  margin-top: var(--sp-2xl);
  list-style: none;
  padding: 0;
}
@media (min-width: 768px) {
  .steps-grid { grid-template-columns: repeat(3, 1fr); }
}
.step {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-l);
  padding: var(--sp-xl) var(--sp-l);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-s);
}
.step-kanji {
  font-family: var(--font-serif-ja);
  font-size: 2rem;
  line-height: 1;
  color: var(--accent-secondary);
  letter-spacing: 0.05em;
  margin-bottom: var(--sp-xs);
}
@media (min-width: 768px) {
  .step-kanji { font-size: 2.5rem; }
}
.step-svg {
  color: var(--accent-primary);
  margin-bottom: var(--sp-xs);
}
.step-svg svg { width: 96px; height: 96px; }
.step-text {
  font-size: 1rem;
  color: var(--text-primary);
  line-height: 1.85;
  max-width: 16em;
}
.how-coda {
  margin-top: var(--sp-2xl);
  font-family: var(--font-serif-ja);
  font-size: 1.5rem;
  color: var(--text-primary);
  letter-spacing: 0.05em;
  text-align: center;
}
html[lang="en"] .how-coda { font-family: var(--font-serif-en); letter-spacing: 0; }
@media (min-width: 768px) {
  .how-coda { font-size: 1.75rem; }
}

/* --- Trust (honest list with middle-dot markers) ------------ */
#trust {
  background-color: var(--bg-secondary);
}
.trust-container {
  max-width: 640px;
  margin-inline: auto;
  text-align: center;
}
.trust-list {
  margin: var(--sp-2xl) auto 0;
  display: flex;
  flex-direction: column;
  gap: var(--sp-m);
  max-width: 28em;
  text-align: left;
}
.trust-list li {
  padding-left: 1.6em;
  position: relative;
  color: var(--text-primary);
  font-size: 1.0625rem;
  line-height: 2.0;
}
.trust-list li::before {
  content: "・";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent-primary);
  font-size: 1.125rem;
  line-height: 2.0;
}
.trust-line {
  margin-top: var(--sp-2xl);
  font-family: var(--font-serif-ja);
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.85;
  text-align: center;
  max-width: 36em;
  margin-inline: auto;
}
html[lang="en"] .trust-line { font-family: var(--font-serif-en); }

/* --- FAQ ---------------------------------------------------- */
#faq {
  background-color: var(--bg-secondary);
}
#faq h2 {
  text-align: center;
  margin-bottom: var(--sp-2xl);
}
.faq-list {
  max-width: var(--content-narrow);
  margin-inline: auto;
  margin-top: var(--sp-2xl);
}
.faq-item {
  border-top: 1px solid var(--border-default);
  padding-block: var(--sp-m);
}
.faq-item:last-of-type { border-bottom: 1px solid var(--border-default); }
.faq-item summary {
  cursor: pointer;
  font-family: var(--font-sans-ja);
  font-weight: 500;
  font-size: 1.0625rem;
  line-height: 1.65;
  list-style: none;
  position: relative;
  padding-right: 2em;
  color: var(--text-primary);
}
html[lang="en"] .faq-item summary { font-family: var(--font-sans-en); }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.25rem;
  color: var(--accent-primary);
  transition: transform 0.2s;
}
.faq-item[open] summary::after { transform: translateY(-50%) rotate(45deg); }
.faq-item summary:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 4px;
  border-radius: var(--radius-s);
}
.faq-answer {
  margin-top: var(--sp-s);
  color: var(--text-primary);
  line-height: 1.95;
}
.faq-answer p { margin: 0; max-width: none; }
.faq-answer p + p { margin-top: var(--sp-m); }
.faq-item.faq-highlight {
  background-color: rgba(232, 211, 209, 0.35);
  padding-inline: var(--sp-m);
  margin-inline: calc(-1 * var(--sp-m));
  border-radius: var(--radius-s);
}
@media (prefers-color-scheme: dark) {
  .faq-item.faq-highlight {
    background-color: rgba(68, 56, 52, 0.5);
  }
}

/* --- Closing (bookend with hero) ---------------------------- */
.closing {
  text-align: center;
  background-color: var(--bg-secondary);
}
.closing-scene {
  margin: 0 auto var(--sp-2xl);
  color: var(--accent-primary);
  max-width: 480px;
}
.closing h2 {
  font-family: var(--font-serif-ja);
  font-size: 2.25rem;
  margin-bottom: var(--sp-l);
  letter-spacing: 0.05em;
}
html[lang="en"] .closing h2 { font-family: var(--font-serif-en); letter-spacing: -0.01em; }
@media (min-width: 768px) {
  .closing h2 { font-size: 3rem; }
}
.closing .lead {
  max-width: 26em;
  margin-inline: auto;
  margin-bottom: var(--sp-2xl);
  font-family: var(--font-serif-ja);
  color: var(--text-secondary);
  line-height: 1.95;
}
html[lang="en"] .closing .lead { font-family: var(--font-serif-en); }

/* --- Fade-in on scroll (Intersection Observer) -------------- */
.fade-target {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.6s ease, transform 0.6s ease;
  will-change: opacity, transform;
}
.fade-target.is-visible {
  opacity: 1;
  transform: translateY(0);
}
@media (prefers-reduced-motion: reduce) {
  .fade-target,
  .fade-target.is-visible {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* --- Footer ------------------------------------------------- */
.site-footer {
  background-color: var(--bg-primary);
  border-top: 1px solid var(--border-default);
  padding-block: var(--sp-3xl) var(--sp-xl);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--sp-xl);
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--page-gutter);
}
@media (min-width: 640px) {
  .footer-grid { grid-template-columns: repeat(3, 1fr); }
}
.footer-col h4 {
  font-family: var(--font-sans-ja);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-bottom: var(--sp-m);
  font-weight: 500;
}
html[lang="en"] .footer-col h4 { font-family: var(--font-sans-en); }
.footer-col ul li {
  margin-bottom: var(--sp-xs);
}
.footer-col a {
  color: var(--text-primary);
  text-decoration: none;
  font-size: 0.9375rem;
}
.footer-col a:hover {
  color: var(--accent-primary);
  text-decoration: underline;
}
.lang-switcher {
  display: flex;
  gap: var(--sp-s);
  flex-wrap: wrap;
}
.lang-switcher a[aria-current="page"] {
  color: var(--accent-primary);
  font-weight: 500;
}
.footer-base {
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--page-gutter);
  margin-top: var(--sp-2xl);
  padding-top: var(--sp-l);
  border-top: 1px solid var(--border-default);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--sp-s);
  color: var(--text-secondary);
  font-size: 0.8125rem;
}
.footer-trademark {
  max-width: var(--content-max);
  margin-inline: auto;
  padding: var(--sp-m) var(--page-gutter) 0;
  font-size: 0.75rem;
  line-height: 1.65;
  color: var(--text-tertiary);
}
.footer-trademark p { margin: 0; max-width: 56em; }
.footer-trademark p + p { margin-top: var(--sp-2xs); }

/* --- Focus ring for key interactive targets ---------------- */
button:focus-visible,
[role="button"]:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
}

/* --- Legal pages (continuity with privacy/terms/support) --- */
.legal-content {
  max-width: var(--content-narrow);
  margin-inline: auto;
  padding-block: var(--sp-3xl);
  padding-inline: var(--page-gutter);
}
.legal-content h1 {
  font-size: 2rem;
  margin-bottom: var(--sp-s);
  letter-spacing: 0.04em;
}
.legal-content .updated {
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: var(--sp-2xl);
}
.legal-content h2 {
  font-size: 1.5rem;
  margin-top: var(--sp-2xl);
  margin-bottom: var(--sp-m);
}
.legal-content h3 {
  font-size: 1.1875rem;
  margin-top: var(--sp-xl);
  margin-bottom: var(--sp-s);
}
.legal-content h4 {
  font-size: 1.0625rem;
  margin-top: var(--sp-l);
  margin-bottom: var(--sp-xs);
}
.legal-content ul {
  list-style: disc;
  padding-left: 1.5em;
}
.legal-content ul li {
  margin-bottom: var(--sp-2xs);
}
.legal-content ol {
  list-style: decimal;
  padding-left: 1.5em;
}
.legal-content ol li {
  margin-bottom: var(--sp-2xs);
}
.legal-content a {
  word-break: break-word;
}

/* --- 404 page ---------------------------------------------- */
.error-404 {
  min-height: 70vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: var(--sp-3xl) var(--page-gutter);
  gap: var(--sp-l);
}
.error-404 h1 {
  max-width: 20em;
  font-size: 1.75rem;
}
.error-404 .error-eyebrow {
  font-family: var(--font-serif-ja);
  font-size: 3rem;
  font-weight: 400;
  color: var(--accent-primary);
  letter-spacing: 0.05em;
  margin: 0;
  line-height: 1;
}
html[lang="en"] .error-404 .error-eyebrow { font-family: var(--font-serif-en); }
.error-404 .lead {
  max-width: 36em;
  margin: 0 auto;
}
.error-404 .error-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-m);
  justify-content: center;
  margin-top: var(--sp-l);
}
.error-404 .error-note {
  margin-top: var(--sp-l);
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* ======================================================================
   v4 supplemental (classes referenced by index.html / index.en.html that
   did not yet have a CSS home). Keep tokens consistent with §B-1/B-2.
   ====================================================================== */

.hero-copy { display: flex; flex-direction: column; }
.empathy-close {
  margin-top: var(--sp-m);
  color: var(--text-primary);
  font-family: var(--font-serif-ja);
  font-style: normal;
}
html[lang="en"] .empathy-close { font-family: var(--font-serif-en); }

.solution-intro {
  color: var(--text-secondary);
  max-width: 34em;
  margin: 0 auto var(--sp-l);
  text-align: center;
}

/* Hero SVG decorative groups — inherit currentColor = water-tint ink. */
.hero-scene .sunrays,
.hero-scene .steam { stroke: currentColor; }

/* --- Screenshots section ------------------------------------- */
.screenshots {
  padding: var(--sp-4xl) 0;
  background-color: var(--bg-primary);
}
.screenshots .container { text-align: center; }
.screenshots h2 { margin-bottom: var(--sp-m); }
.screenshots-intro {
  color: var(--text-secondary);
  max-width: 34em;
  margin: 0 auto var(--sp-2xl);
  text-align: center;
}
.screenshots-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--sp-2xl);
  align-items: start;
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 0 var(--page-gutter);
}
.screenshot-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}
.screenshot-frame {
  width: 100%;
  max-width: 300px;
  margin-bottom: var(--sp-l);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-medium);
  background-color: var(--bg-secondary);
}
.screenshot-frame img {
  display: block;
  width: 100%;
  height: auto;
}
.screenshot-item h3 {
  font-family: var(--font-serif-ja);
  font-size: 1.125rem;
  color: var(--text-primary);
  margin: 0 0 var(--sp-xs);
}
html[lang="en"] .screenshot-item h3 {
  font-family: var(--font-serif-en);
}
.screenshot-item p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
  margin: 0;
  max-width: 22em;
}
@media (max-width: 760px) {
  .screenshots-grid {
    grid-template-columns: 1fr;
    gap: var(--sp-3xl);
  }
  .screenshot-frame { max-width: 260px; }
}