/* ================== tokens ================== */
:root{
  --text:#1d1d1f;
  --muted:#5f6772;
  --dim:#767b82;          /* WCAG AA on --bg #f7f5f0 (≈4.6:1) */
  --line:rgba(0,0,0,.08);
  --bg:#f7f5f0;
  --surface:#ffffff;
  --amber:#FFAB00;
  --amber-deep:#E69500;
  --violet:#5d50a8;
  --green:#3a9a64;
  --sans:"Inter","Noto Sans JP","Hiragino Sans","Yu Gothic UI",system-ui,sans-serif;
}
@media (prefers-color-scheme: dark){
  :root{
    --text:#f2f2f4;
    --muted:#b0b3b9;
    --dim:#8e9197;        /* WCAG AA on --bg #15131e (≈5.5:1) */
    --line:rgba(255,255,255,.10);
    --bg:#15131e;
    --surface:rgba(255,255,255,.04);
    --amber:#FFC04D;
    --amber-deep:#FFAB00;
    --violet:#b8a8ff;
  }
}

/* ================== base ================== */
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:var(--sans);
  font-size:16px;line-height:1.7;color:var(--text);
  background:var(--bg);
  -webkit-font-smoothing:antialiased;
  min-height:100vh;overflow-x:hidden;
  position:relative;
}
/* one subtle amber blob top-right */
body::before{
  content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;
  background:radial-gradient(38% 50% at 92% -2%, rgba(255,171,0,.32), transparent 70%);
}
@media (prefers-color-scheme: dark){
  body::before{background:radial-gradient(38% 50% at 92% -2%, rgba(255,171,0,.18), transparent 70%)}
}

a{color:inherit;text-decoration:none}
a.ilink{
  color:var(--violet);
  text-decoration:underline;
  text-decoration-thickness:1px;
  text-underline-offset:3px;
  text-decoration-color:rgba(93,80,168,.40);
}
a.ilink:hover{text-decoration-color:currentColor}
@media (prefers-color-scheme: dark){
  a.ilink{text-decoration-color:rgba(184,168,255,.40)}
}
:focus-visible{outline:2px solid var(--violet);outline-offset:3px;border-radius:4px}
::selection{background:rgba(255,171,0,.20);color:var(--text)}

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

/* Firefox does not support ::-webkit-details-marker, so we hide the marker via list-style.
   Applies to all <details> globally (FAQ + any future use). */
details summary{list-style:none}
details summary::-webkit-details-marker{display:none}

/* ================== layout ================== */
main{max-width:760px;margin:0 auto;padding:48px 24px 0}
@media (max-width:560px){main{padding:32px 20px 0}}

section{margin-top:64px}
section:first-of-type{margin-top:0}
@media (max-width:560px){section{margin-top:48px}}

h2{
  margin:0 0 18px;font-size:22px;font-weight:700;
  letter-spacing:-.005em;line-height:1.35;color:var(--text);
}
p{margin:0 0 14px;color:var(--muted);line-height:1.85}
p:last-child{margin-bottom:0}
p b, p strong{color:var(--text);font-weight:600}

/* ================== back link (sub-pages) ================== */
.back-link{
  display:inline-flex;align-items:center;gap:6px;
  margin-bottom:28px;
  padding:6px 12px;border-radius:999px;
  background:rgba(0,0,0,.04);
  color:var(--muted);
  font-size:13px;font-weight:500;
  transition:background .15s, color .15s;
}
.back-link:hover{background:rgba(255,171,0,.14);color:var(--amber-deep)}
@media (prefers-color-scheme: dark){
  .back-link{background:rgba(255,255,255,.06)}
  .back-link:hover{background:rgba(255,192,77,.16);color:var(--amber)}
}

/* ================== hero (main LP only) ================== */
.hero{
  text-align:center;
  padding:24px 0 8px;
}
.hero .icon{
  width:128px;height:128px;
  border-radius:28px;
  margin:0 auto 24px;
  box-shadow:0 8px 32px -8px rgba(255,171,0,.40), 0 2px 8px rgba(0,0,0,.08);
}
@media (prefers-color-scheme: dark){
  .hero .icon{box-shadow:0 12px 36px -8px rgba(255,171,0,.30), 0 2px 8px rgba(0,0,0,.30)}
}
.hero h1{
  margin:0;font-size:clamp(28px, 4.6vw, 38px);
  font-weight:700;letter-spacing:-.02em;line-height:1.18;color:var(--text);
}
.hero .sub{
  margin:8px auto 0;max-width:480px;
  color:var(--muted);font-size:15px;line-height:1.65;
}
.hero .pill{
  display:inline-flex;align-items:center;gap:8px;
  margin-top:20px;padding:6px 14px;
  border-radius:999px;
  background:rgba(255,171,0,.12);
  color:var(--amber-deep);
  font-size:12.5px;font-weight:600;letter-spacing:.01em;
}
@media (prefers-color-scheme: dark){
  .hero .pill{background:rgba(255,192,77,.14);color:var(--amber)}
}
.hero .pill .dot{
  display:inline-block;width:6px;height:6px;border-radius:50%;
  background:currentColor;
}
.hero .badges{
  margin-top:24px;
  display:flex;flex-wrap:wrap;justify-content:center;gap:12px;
}
.hero .badges a{
  display:inline-block;
  transition:transform .15s, filter .15s;
}
.hero .badges a:hover{transform:translateY(-1px);filter:drop-shadow(0 6px 16px rgba(0,0,0,.15))}
.hero .badges img{height:52px;width:auto}
@media (prefers-color-scheme: dark){
  .hero .badges .apple img{filter:invert(1) hue-rotate(180deg) brightness(1.05)}
}
.hero .meta{
  margin-top:14px;color:var(--dim);font-size:12.5px;
}

/* ================== sub-page hero (privacy/terms/support) ================== */
.page-hero{padding:0 0 8px}
.page-hero h1{
  margin:0 0 8px;
  font-size:clamp(26px, 4vw, 34px);
  font-weight:700;letter-spacing:-.015em;line-height:1.25;color:var(--text);
}
.page-hero .for-app{
  display:inline-flex;align-items:center;gap:10px;
  font-size:13px;color:var(--muted);
}
.page-hero .for-app .mini-icon{
  width:24px;height:24px;border-radius:6px;
  box-shadow:0 1px 4px rgba(255,171,0,.40);
}
.page-hero .for-app a{
  color:var(--violet);
  text-decoration:underline;
  text-decoration-color:rgba(93,80,168,.30);
  text-underline-offset:3px;
}

/* ================== lead (main LP) ================== */
.lead{
  text-align:center;
  margin:48px auto 0;max-width:560px;
  color:var(--muted);font-size:16px;line-height:1.85;
}
.lead b{color:var(--text);font-weight:600}

/* ================== features (main LP) ================== */
.features{
  display:grid;
  grid-template-columns:repeat(3, 1fr);
  gap:24px 28px;
}
@media (max-width:640px){
  .features{grid-template-columns:1fr;gap:24px 0}
}
.feat h3{
  margin:0 0 6px;font-size:15px;font-weight:700;color:var(--text);line-height:1.4;
}
.feat .sym{
  display:inline-flex;align-items:center;justify-content:center;
  width:32px;height:32px;border-radius:10px;
  background:rgba(255,171,0,.14);color:var(--amber-deep);
  font-weight:700;font-size:14px;
  margin-bottom:12px;
}
@media (prefers-color-scheme: dark){
  .feat .sym{background:rgba(255,192,77,.16);color:var(--amber)}
}
.feat p{margin:0;font-size:14px;line-height:1.7;color:var(--muted)}

/* ================== checklist (main LP) ================== */
.chklist{margin:0;padding:0;list-style:none}
.chklist li{
  padding:14px 0;
  border-top:1px solid var(--line);
}
.chklist li:first-child{border-top:0;padding-top:0}
.chk-name{
  font-size:15px;font-weight:600;color:var(--text);
  margin:0 0 4px;
}
.chk-desc{
  margin:0;font-size:14px;color:var(--muted);line-height:1.7;
}
.chk-src{
  display:inline-block;margin-top:2px;
  font-size:11.5px;color:var(--dim);font-style:italic;
}
.chk-src::before{content:"出典: "}
.disclaimer{
  margin-top:18px;font-size:12.5px;color:var(--dim);line-height:1.7;
}
.disclaimer b{color:var(--amber-deep);font-weight:600}
@media (prefers-color-scheme: dark){
  .disclaimer b{color:var(--amber)}
}

/* ================== download CTA ================== */
.download-cta{text-align:center}
.download-cta .badges{
  display:flex;flex-wrap:wrap;justify-content:center;gap:12px;
  margin-bottom:12px;
}
.download-cta .badges a{
  display:inline-block;transition:transform .15s, filter .15s;
}
.download-cta .badges a:hover{transform:translateY(-1px);filter:drop-shadow(0 6px 16px rgba(0,0,0,.15))}
.download-cta .badges img{height:52px;width:auto}
@media (prefers-color-scheme: dark){
  .download-cta .badges .apple img{filter:invert(1) hue-rotate(180deg) brightness(1.05)}
}
.download-cta .note{margin:0;font-size:13px;color:var(--dim)}

/* ================== legal links (main LP) ================== */
.legal-links{
  display:grid;gap:0;
}
.legal-links a{
  display:flex;align-items:center;gap:14px;
  padding:18px 4px;
  border-top:1px solid var(--line);
  font-size:15px;color:var(--text);font-weight:500;
  transition:color .15s, padding .15s;
}
.legal-links a:last-child{border-bottom:1px solid var(--line)}
.legal-links a:hover{color:var(--amber-deep);padding-left:8px}
@media (prefers-color-scheme: dark){
  .legal-links a:hover{color:var(--amber)}
}
.legal-links a .ic{
  width:28px;height:28px;flex-shrink:0;
  display:inline-flex;align-items:center;justify-content:center;
  border-radius:8px;
  background:rgba(255,171,0,.14);color:var(--amber-deep);
  font-size:14px;font-weight:700;
}
@media (prefers-color-scheme: dark){
  .legal-links a .ic{background:rgba(255,192,77,.16);color:var(--amber)}
}
.legal-links a .arrow{margin-left:auto;color:var(--dim);transition:transform .15s, color .15s}
.legal-links a:hover .arrow{transform:translateX(3px);color:currentColor}
.legal-links a .desc{
  display:block;font-size:12.5px;color:var(--dim);font-weight:400;margin-top:2px;
}

/* ================== button ================== */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 20px;border-radius:999px;
  background:var(--amber);color:#1d1d1f;
  font-size:14px;font-weight:700;text-decoration:none;
  transition:transform .15s, background .15s, box-shadow .15s;
  box-shadow:0 4px 14px -4px rgba(255,171,0,.55);
}
.btn:hover{transform:translateY(-1px);background:var(--amber-deep);box-shadow:0 6px 18px -4px rgba(255,171,0,.65)}
/* alt-text "" suppresses screen-reader announcement of the decorative arrow */
.btn::after{content:"↗" / ""}
@media (prefers-color-scheme: dark){
  .btn{color:#1a1410}
}

/* ================== document body (privacy/terms) ================== */
.doc h2{
  margin:32px 0 8px;font-size:18px;font-weight:700;color:var(--text);
  padding-bottom:6px;border-bottom:1px solid var(--line);
}
.doc h2:first-child{margin-top:0}
.doc h3{
  margin:18px 0 6px;font-size:15px;font-weight:600;color:var(--text);
}
.doc h3::before{
  content:"";display:inline-block;width:3px;height:0.85em;
  background:var(--amber);margin-right:8px;border-radius:2px;vertical-align:-1px;
}
.doc p{
  margin:8px 0;font-size:14.5px;color:var(--muted);line-height:1.85;
}
.doc strong, .doc p strong, .doc p b{color:var(--text);font-weight:700}
.doc ul{
  margin:8px 0;padding-left:22px;font-size:14.5px;color:var(--muted);line-height:1.85;
}
.doc ul li{margin:4px 0}
.doc ul li b{color:var(--text);font-weight:600}
.doc .meta{
  margin-top:24px;padding-top:12px;border-top:1px solid var(--line);
  font-size:11.5px;color:var(--dim);
}
.doc .meta b{color:var(--muted);font-weight:500}

/* ================== FAQ (support page) ================== */
.faq{margin:0;padding:0;list-style:none}
.faq details{
  border-top:1px solid var(--line);
}
.faq details:last-child{border-bottom:1px solid var(--line)}
.faq details summary{
  cursor:pointer;list-style:none;
  padding:16px 0;
  font-size:15px;font-weight:600;color:var(--text);
  display:flex;align-items:center;gap:12px;
  user-select:none;
}
.faq details summary::-webkit-details-marker{display:none}
.faq details summary::before{
  content:"+";flex-shrink:0;
  width:22px;height:22px;
  display:inline-flex;align-items:center;justify-content:center;
  border-radius:6px;
  background:rgba(255,171,0,.14);color:var(--amber-deep);
  font-size:15px;font-weight:700;line-height:1;
  transition:transform .2s, background .15s;
}
.faq details[open] summary::before{content:"−"}
.faq details summary:hover::before{background:rgba(255,171,0,.24)}
@media (prefers-color-scheme: dark){
  .faq details summary::before{background:rgba(255,192,77,.18);color:var(--amber)}
  .faq details summary:hover::before{background:rgba(255,192,77,.28)}
}
.faq details .answer{
  padding:0 0 18px 34px;
  font-size:14px;color:var(--muted);line-height:1.85;
}
@media (max-width:560px){
  .faq details .answer{padding-left:0}
}

/* ================== related links (sub-page bottom) ================== */
.related{
  margin-top:48px;padding-top:24px;
  border-top:1px solid var(--line);
}
.related h2{
  margin:0 0 14px;font-size:14px;font-weight:600;color:var(--muted);
  letter-spacing:.02em;
}
.related-list{
  display:grid;gap:8px;
  grid-template-columns:repeat(auto-fit, minmax(180px, 1fr));
}
.related-list a{
  display:flex;align-items:center;gap:8px;
  padding:12px 14px;border-radius:10px;
  background:var(--surface);
  border:1px solid var(--line);
  font-size:14px;color:var(--text);font-weight:500;
  transition:border-color .15s, background .15s;
}
.related-list a:hover{border-color:var(--amber);color:var(--amber-deep)}
.related-list a::after{content:"→";margin-left:auto;color:var(--dim)}
.related-list a:hover::after{color:currentColor}
@media (prefers-color-scheme: dark){
  .related-list a:hover{color:var(--amber)}
}

/* ================== support (sub-page) ================== */
.support-card{
  padding:24px;border-radius:14px;
  background:var(--surface);
  border:1px solid var(--line);
  margin-bottom:18px;
}
.support-card h3{
  margin:0 0 10px;font-size:15px;font-weight:700;color:var(--text);
}
.support-card p{margin:0 0 14px;font-size:14px;color:var(--muted);line-height:1.8}
.support-card p:last-child{margin-bottom:0}

/* ================== operator (main LP) ================== */
.operator p{
  font-size:14px;color:var(--muted);line-height:1.85;margin:0 0 6px;
}
.operator a{color:var(--violet);text-decoration:underline;text-decoration-color:rgba(93,80,168,.30);text-underline-offset:3px}
.operator a:hover{text-decoration-color:currentColor}

/* ================== footer ================== */
/* footer is intentionally placed OUTSIDE <main> for the contentinfo landmark.
   Layout (max-width / padding) mirrors main so the visual stays identical. */
footer{
  max-width:760px;margin:80px auto 0;
  padding:24px 24px 80px;
  border-top:1px solid var(--line);
  font-size:12px;color:var(--dim);
  line-height:1.75;
}
@media (max-width:560px){
  footer{padding:24px 20px 64px}
}
footer .row{
  display:flex;flex-wrap:wrap;gap:8px 18px;align-items:center;
  margin-bottom:14px;
}
footer .row a{color:var(--dim)}
footer .row a:hover{color:var(--amber-deep)}
@media (prefers-color-scheme: dark){
  footer .row a:hover{color:var(--amber)}
}
footer .spacer{flex:1}
footer .tm{
  font-size:11px;color:var(--dim);line-height:1.7;
}

/* ================== reduced motion ================== */
@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{transition:none !important;animation:none !important}
}