/* Japanese Immersion — LP（静的ページ用。アプリの画面とは独立）
 *
 * 配色は日本の伝統色 3 色だけで組む（＋生成りの地色）。
 *   藍 #1E50A2 … 見出し・リンク・フッター・線
 *   朱 #D9381E … CTA・判子・強調（白文字とのコントラスト 4.6:1）
 *   山吹 #F8B500 … 明るさの差し色・淡い背景・印
 * 文字色や背景は、この 3 色の濃淡と生成りだけを使う。
 */
:root {
  /* 3 色 */
  --ai: #1e50a2;
  --shu: #d9381e;
  --yamabuki: #f8b500;
  /* 3 色の濃淡 */
  --ai-ink: #172a4e;        /* 本文（藍の濃） */
  --ai-muted: #46557a;      /* 補足文（藍の中間）。生成り上で 7:1 */
  --ai-line: #d7e0ef;       /* 罫線（藍の淡） */
  --ai-tint: #eef3fb;       /* 背景（藍のごく淡） */
  --ai-deep: #12306a;       /* フッター（藍の深） */
  --shu-deep: #b52c14;      /* CTA hover（朱の濃） */
  --yamabuki-tint: #fff6dd; /* 背景（山吹のごく淡） */
  --yamabuki-soft: #ffe7a3; /* 印・吹き出しの縁 */
  /* 地色 */
  --kinari: #fffdf7;        /* 生成り */
  --white: #ffffff;

  --radius: 14px;
  --wrap: 1120px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans",
    "Noto Sans KR", "Noto Sans SC", "Noto Sans Thai", sans-serif;
  --font-ja: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", "Noto Serif JP", serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--kinari);
  color: var(--ai-ink);
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.65;
  overflow-x: hidden;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--ai); text-underline-offset: 3px; }
a:hover { color: var(--ai-ink); }
:focus-visible { outline: 3px solid var(--ai); outline-offset: 3px; border-radius: 6px; }
h1, h2, h3 { line-height: 1.2; margin: 0; letter-spacing: -0.01em; text-wrap: balance; color: var(--ai-ink); }
p { margin: 0; }
ul { margin: 0; padding: 0; list-style: none; }
[lang="ja"] { font-family: var(--font-ja); letter-spacing: 0.04em; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 20px; }
.wrap.narrow { max-width: 760px; }
.center { text-align: center; }
.visually-hidden {
  position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;
}
.skip {
  position: absolute; left: 12px; top: -48px; z-index: 50; background: var(--ai); color: #fff;
  padding: 10px 14px; border-radius: 8px; text-decoration: none;
}
.skip:focus { top: 12px; color: #fff; }

/* ── Header ── */
.site-header {
  position: sticky; top: 0; z-index: 20;
  background: rgba(255, 253, 247, 0.94);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--ai-line);
}
/* 上端に山吹→朱の細い帯（のれんの縁のような差し色） */
.site-header::before {
  content: ""; display: block; height: 3px;
  background: linear-gradient(90deg, var(--yamabuki) 0 50%, var(--shu) 50% 100%);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ai-ink); text-decoration: none; font-weight: 700; }
.brand:hover { color: var(--ai-ink); }
/* 判子（落款）風のロゴ */
.brand-mark {
  display: inline-grid; place-items: center; width: 34px; height: 34px; border-radius: 6px;
  background: var(--shu); color: #fff; font-family: var(--font-ja); font-size: 1.1rem;
  box-shadow: inset 0 0 0 2px rgba(255, 255, 255, 0.55);
  transform: rotate(-3deg);
}
.brand-name { font-size: 1rem; white-space: nowrap; }
.header-nav { display: flex; align-items: center; gap: 6px; }
.login {
  white-space: nowrap;
  color: var(--ai); text-decoration: none; font-weight: 700; font-size: 0.95rem;
  padding: 8px 14px; border-radius: 999px; min-height: 44px; display: inline-flex; align-items: center;
  border: 1.5px solid var(--ai-line);
}
.login:hover { background: var(--ai-tint); color: var(--ai); }
.lang { position: relative; }
.lang summary {
  list-style: none; cursor: pointer; font-size: 0.9rem; font-weight: 600; color: var(--ai-muted);
  padding: 10px 12px; border-radius: 10px; min-height: 44px; display: inline-flex; align-items: center; gap: 6px;
}
.lang summary::-webkit-details-marker { display: none; }
.lang summary::after { content: "▾"; font-size: 0.75em; color: var(--shu); }
.lang summary:hover { background: var(--ai-tint); }
.lang ul {
  position: absolute; right: 0; top: calc(100% + 6px); background: var(--white); border: 1px solid var(--ai-line);
  border-radius: 12px; padding: 6px; min-width: 190px; box-shadow: 0 16px 40px rgba(23, 42, 78, 0.14);
  max-height: 70vh; overflow-y: auto;
}
.lang li a {
  display: block; padding: 10px 12px; border-radius: 8px; color: var(--ai-ink); text-decoration: none; font-size: 0.95rem;
}
.lang li a:hover { background: var(--ai-tint); }
.lang li a[aria-current="page"] { font-weight: 700; background: var(--yamabuki-tint); box-shadow: inset 3px 0 0 var(--yamabuki); }

/* ── Buttons ── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; min-height: 52px; padding: 14px 28px;
  border-radius: 999px; font-weight: 700; font-size: 1.05rem; text-decoration: none; text-align: center;
  transition: background-color 0.15s ease, transform 0.15s ease, box-shadow 0.15s ease;
}
.btn-primary { background: var(--shu); color: #fff; box-shadow: 0 6px 0 var(--shu-deep), 0 14px 24px rgba(217, 56, 30, 0.22); }
.btn-primary:hover { background: var(--shu-deep); color: #fff; transform: translateY(2px); box-shadow: 0 4px 0 #8f220f, 0 10px 18px rgba(217, 56, 30, 0.2); }
.btn-ghost { color: var(--ai); background: var(--white); border: 1.5px solid var(--ai-line); }
.btn-ghost:hover { background: var(--ai-tint); color: var(--ai); }
.cta-note { color: var(--ai-muted); font-size: 0.9rem; margin-top: 12px; }
.cta-block { margin-top: 40px; display: flex; flex-direction: column; align-items: center; text-align: center; }
.cta-block .btn { width: 100%; max-width: 360px; }

/* ── Hero ── */
.hero {
  position: relative; padding: 28px 0 56px; overflow: hidden;
  /* 青海波（せいがいは）の地紋をごく淡く */
  background-color: var(--kinari);
  background-image:
    radial-gradient(circle at 100% 150%, var(--kinari) 24%, var(--ai-line) 24.5%, var(--ai-line) 28%, var(--kinari) 28.5%, var(--kinari) 36%, var(--ai-line) 36.5%, var(--ai-line) 40%, transparent 40.5%),
    radial-gradient(circle at 0 150%, var(--kinari) 24%, var(--ai-line) 24.5%, var(--ai-line) 28%, var(--kinari) 28.5%, var(--kinari) 36%, var(--ai-line) 36.5%, var(--ai-line) 40%, transparent 40.5%),
    radial-gradient(circle at 50% 100%, var(--ai-line) 4%, var(--kinari) 4.5%, var(--kinari) 12%, var(--ai-line) 12.5%, var(--ai-line) 16%, var(--kinari) 16.5%, var(--kinari) 24%, var(--ai-line) 24.5%, var(--ai-line) 28%, var(--kinari) 28.5%, var(--kinari) 36%, var(--ai-line) 36.5%, var(--ai-line) 40%, transparent 40.5%),
    radial-gradient(circle at 100% 50%, var(--kinari) 16%, var(--ai-line) 16.5%, var(--ai-line) 20%, var(--kinari) 20.5%, var(--kinari) 28%, var(--ai-line) 28.5%, var(--ai-line) 32%, var(--kinari) 32.5%, var(--kinari) 40%, var(--ai-line) 40.5%, var(--ai-line) 44%, transparent 44.5%),
    radial-gradient(circle at 0 50%, var(--kinari) 16%, var(--ai-line) 16.5%, var(--ai-line) 20%, var(--kinari) 20.5%, var(--kinari) 28%, var(--ai-line) 28.5%, var(--ai-line) 32%, var(--kinari) 32.5%, var(--kinari) 40%, var(--ai-line) 40.5%, var(--ai-line) 44%, transparent 44.5%);
  background-size: 64px 32px;
}
/* 文字の下だけ地紋を消して読みやすくする */
.hero::before {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(255, 253, 247, 0.96) 0%, rgba(255, 253, 247, 0.9) 60%, rgba(255, 253, 247, 0.6) 100%);
}
.hero-inner { position: relative; display: grid; gap: 32px; align-items: center; }
.eyebrow { font-size: 0.85rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--ai); display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.eyebrow::before { content: ""; width: 22px; height: 3px; border-radius: 2px; background: var(--shu); }
.eyebrow [lang="ja"] { text-transform: none; letter-spacing: 0.12em; color: var(--ai-muted); font-weight: 600; }
.hero h1 { font-size: clamp(2.05rem, 7.6vw, 3.7rem); margin-top: 14px; font-weight: 800; letter-spacing: -0.02em; }
.hero-sub { font-size: clamp(1.05rem, 3.6vw, 1.25rem); color: var(--ai-muted); margin-top: 16px; max-width: 34em; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px 12px; margin-top: 26px; }
.hero-actions .btn-primary { flex: 1 1 220px; }
.hero-actions .btn-ghost { flex: 1 1 160px; }
.hero-points { margin-top: 22px; display: grid; gap: 8px; }
.hero-points li { position: relative; padding-left: 28px; color: var(--ai-ink); font-size: 0.98rem; }
.hero-points li::before {
  content: ""; position: absolute; left: 3px; top: 0.42em; width: 13px; height: 13px; border-radius: 50%;
  background: var(--yamabuki); box-shadow: 0 0 0 3px var(--yamabuki-tint);
}
.hero-visual { position: relative; display: flex; justify-content: center; padding: 8px 0 12px; }
/* 画面の後ろに山吹の日だまり */
.hero-visual::before {
  content: ""; position: absolute; left: 50%; top: 52%; width: min(86vw, 380px); aspect-ratio: 1; transform: translate(-50%, -50%);
  border-radius: 50%; background: radial-gradient(circle, var(--yamabuki-soft) 0%, var(--yamabuki-tint) 55%, transparent 70%);
}
.phone {
  position: relative; width: min(72vw, 300px); border-radius: 30px; overflow: hidden; background: var(--white);
  border: 8px solid var(--ai-ink); box-shadow: 0 30px 60px rgba(23, 42, 78, 0.2);
  aspect-ratio: 360 / 634;
}
.phone img { width: 100%; height: 100%; object-fit: cover; object-position: top; }
.phone.small { width: 100%; border-width: 6px; border-radius: 24px; }
/* 相づちの吹き出し（短冊のような角ばり） */
.bubble {
  position: absolute; background: var(--white); border: 1.5px solid var(--yamabuki-soft); border-radius: 12px 12px 12px 2px;
  padding: 8px 14px; font-size: 0.95rem; box-shadow: 0 10px 24px rgba(23, 42, 78, 0.1); white-space: nowrap; color: var(--ai-ink);
}
.bubble.b2 { border-color: #f4c3b8; border-radius: 12px 12px 2px 12px; color: var(--shu-deep); }
.bubble.b1 { left: 2%; top: 20%; }
.bubble.b2 { right: 2%; top: 46%; }
.bubble.b3 { left: 6%; bottom: 14%; }

/* ── Sections ── */
main { counter-reset: dan; }
.section { padding: 68px 0; position: relative; }
.section h2 { font-size: clamp(1.6rem, 5.2vw, 2.5rem); font-weight: 800; max-width: 22em; }
/* 見出しの前に漢数字（一・二・三…）を朱の小さな札で */
.section:not(.final) h2::before {
  counter-increment: dan;
  content: counter(dan, cjk-decimal);
  display: inline-grid; place-items: center; width: 1.5em; height: 1.5em; margin-right: 0.45em;
  vertical-align: 0.2em; border-radius: 4px; background: var(--shu); color: #fff;
  font-family: var(--font-ja); font-size: 0.5em; font-weight: 600;
}
.center h2 { margin: 0 auto; }
.lead { color: var(--ai-muted); font-size: 1.1rem; margin-top: 14px; max-width: 40em; }
.center .lead { margin-left: auto; margin-right: auto; }
.fine { color: var(--ai-muted); font-size: 0.875rem; margin-top: 14px; }

.cards { display: grid; gap: 14px; margin-top: 30px; }
.card {
  background: var(--white); border: 1px solid var(--ai-line); border-radius: var(--radius); padding: 22px;
  border-top: 4px solid var(--ai);
}
.card h3 { font-size: 1.15rem; }
.card p { color: var(--ai-muted); margin-top: 8px; }

/* 背景は 3 色の淡い色で交互に */
.problem { background: var(--ai-tint); }
.problem .card { border-top-color: var(--shu); }
.approach { background: var(--kinari); }
.how { background: var(--yamabuki-tint); }
.how .card { border-top-color: var(--yamabuki); }
.experience { background: var(--kinari); }
.who { background: var(--ai-tint); }
.benefits { background: var(--kinari); }
.benefits .card { border-top-color: var(--ai); }
.pricing { background: var(--yamabuki-tint); }
.faq { background: var(--kinari); }

.compare { display: grid; gap: 12px; margin-top: 30px; align-items: stretch; }
.compare-card { margin: 0; border-radius: var(--radius); padding: 22px; border: 1px solid var(--ai-line); background: var(--white); }
.compare-card.enter { border: 2px solid var(--shu); box-shadow: 0 12px 30px rgba(217, 56, 30, 0.12); }
.compare-label { font-size: 0.8rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--ai-muted); }
.compare-card.enter .compare-label { color: var(--shu-deep); }
.compare-card .jp { font-size: clamp(1.35rem, 5vw, 1.75rem); margin-top: 12px; }
.compare-card.study .jp { color: var(--ai-muted); }
.compare-card.enter .jp { color: var(--ai-ink); }
.compare-caption { color: var(--ai-muted); margin-top: 10px; font-size: 0.98rem; }
.compare-arrow { justify-self: center; font-size: 1.6rem; color: var(--shu); transform: rotate(90deg); }

.how-card .jp-word {
  font-size: 1.6rem; color: var(--ai); margin-bottom: 6px;
  display: inline-block; border-bottom: 3px solid var(--yamabuki); line-height: 1.3;
}

.gallery {
  display: flex; gap: 16px; overflow-x: auto; scroll-snap-type: x mandatory; padding: 28px 20px 8px;
  scroll-padding: 20px; -webkit-overflow-scrolling: touch;
}
.gallery:focus-visible { outline-offset: -3px; }
.shot { flex: 0 0 min(62vw, 240px); scroll-snap-align: start; margin: 0; }
.shot figcaption { text-align: center; font-weight: 700; margin-top: 12px; font-size: 0.98rem; color: var(--ai-ink); }

.checklist { display: grid; gap: 10px; margin-top: 24px; }
.checklist li { position: relative; padding-left: 34px; }
.checklist li::before {
  content: "✓"; position: absolute; left: 0; top: 0; width: 24px; height: 24px; border-radius: 50%;
  background: var(--yamabuki); color: var(--ai-ink); font-weight: 800; font-size: 0.8rem;
  display: grid; place-items: center; margin-top: 0.1em;
}
.who .checklist { max-width: 760px; }

.price-card {
  margin-top: 30px; border: 2px solid var(--ai); border-radius: var(--radius); padding: 28px; background: var(--white);
  max-width: 640px; position: relative;
}
/* 料金カードの角に山吹の小さな札 */
.price-card::after {
  content: "月額"; position: absolute; top: -14px; right: 20px; background: var(--yamabuki); color: var(--ai-ink);
  font-family: var(--font-ja); font-size: 0.85rem; font-weight: 700; padding: 4px 12px; border-radius: 4px;
}
.price { display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px; }
.amount { font-size: 2.8rem; font-weight: 800; letter-spacing: -0.02em; color: var(--ai); }
.per { color: var(--ai-muted); }
.price-card .checklist { margin-top: 18px; }
.operator { margin-top: 22px; color: var(--ai-muted); font-size: 0.95rem; overflow-wrap: anywhere; }
.legal-links { display: flex; flex-wrap: wrap; gap: 4px 18px; margin-top: 10px; font-size: 0.92rem; }
.legal-links a { display: inline-block; padding: 6px 0; }

.faq-item { border-bottom: 1px solid var(--ai-line); }
.faq-item:first-of-type { margin-top: 20px; }
.faq-item summary {
  list-style: none; cursor: pointer; padding: 18px 40px 18px 0; position: relative;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+"; position: absolute; right: 4px; top: 50%; transform: translateY(-50%);
  width: 26px; height: 26px; border-radius: 50%; display: grid; place-items: center;
  background: var(--ai-tint); color: var(--ai); font-size: 1.2rem; font-weight: 600; line-height: 1;
}
.faq-item[open] summary::after { content: "−"; background: var(--yamabuki); color: var(--ai-ink); }
.faq-item summary h3 { font-size: 1.08rem; font-weight: 700; }
.faq-item p { color: var(--ai-muted); padding: 0 0 20px; }

.final {
  padding: 84px 0 104px;
  background:
    radial-gradient(circle at 50% 0%, var(--yamabuki-tint) 0%, transparent 60%),
    var(--kinari);
  border-top: 1px solid var(--ai-line);
}
.final-jp { font-size: clamp(1.7rem, 6.4vw, 2.6rem); color: var(--shu); margin-bottom: 12px; }

/* ── Footer ── */
.site-footer { background: var(--ai-deep); color: #e7edf8; padding: 44px 0 120px; position: relative; }
.site-footer::before {
  content: ""; position: absolute; left: 0; right: 0; top: 0; height: 4px;
  background: linear-gradient(90deg, var(--yamabuki) 0 33.3%, var(--shu) 33.3% 66.6%, var(--ai) 66.6% 100%);
}
.site-footer a { color: #e7edf8; }
.site-footer a:hover { color: var(--yamabuki); }
.footer-brand { font-weight: 700; color: #fff; }
.footer-brand [lang="ja"] { margin-left: 8px; color: var(--yamabuki-soft); font-weight: 400; }
.footer-langs { display: flex; flex-wrap: wrap; gap: 4px 14px; margin-top: 18px; font-size: 0.92rem; }
.footer-langs a { display: inline-block; padding: 6px 0; text-decoration: none; }
.footer-langs a[aria-current="page"] { text-decoration: underline; text-decoration-color: var(--yamabuki); text-decoration-thickness: 2px; font-weight: 700; }
.site-footer .legal-links { margin-top: 14px; }
.site-footer .fine { color: #b9c6e0; }

/* ── Sticky CTA（スマホのみ。JS が表示を切り替える） ── */
.sticky-cta {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 30; padding: 10px 16px calc(12px + env(safe-area-inset-bottom));
  background: rgba(255, 253, 247, 0.96); border-top: 1px solid var(--ai-line); backdrop-filter: blur(8px);
}
.sticky-cta .btn { width: 100%; }
.sticky-cta[hidden] { display: none; }

/* 狭い画面では、ヘッダーのブランド名を隠してロゴだけにする（リンクの aria-label は残る） */
@media (max-width: 399px) {
  .brand-name { display: none; }
  .lang summary { white-space: nowrap; max-width: 46vw; overflow: hidden; text-overflow: ellipsis; }
}

/* ── Larger screens ── */
@media (min-width: 720px) {
  .wrap { padding: 0 32px; }
  .cards.three { grid-template-columns: repeat(3, 1fr); }
  .cards.two { grid-template-columns: repeat(2, 1fr); }
  .cards.four { grid-template-columns: repeat(2, 1fr); }
  .compare { grid-template-columns: 1fr auto 1fr; align-items: center; }
  .compare-arrow { transform: none; }
  .who .checklist { grid-template-columns: repeat(2, 1fr); column-gap: 32px; }
  .gallery { justify-content: center; overflow-x: visible; padding: 32px; }
  .shot { flex: 0 1 240px; }
}
@media (min-width: 900px) {
  .hero { padding: 60px 0 80px; }
  .hero-inner { grid-template-columns: 1.15fr 0.85fr; gap: 48px; }
  /* 縦書きの「日本語に浸る」を右端に（装飾） */
  .hero-inner::after {
    content: "日本語に浸る"; position: absolute; right: -8px; top: 0;
    writing-mode: vertical-rl; font-family: var(--font-ja); font-size: 1.05rem; letter-spacing: 0.5em;
    color: var(--ai); opacity: 0.55;
  }
  .phone { width: 320px; }
  .cards.four { grid-template-columns: repeat(4, 1fr); }
  .section { padding: 92px 0; }
  .sticky-cta { display: none !important; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn { transition: none; }
  .btn-primary:hover { transform: none; }
}