:root{--night:#0d1a38;--night-2:#15284f;--ink:#f4f1ea;--muted:#aab4cc;--lamp:#f3c56b;--lamp-deep:#e0a43c;--line:rgba(244,241,234,.16);--card:rgba(255,255,255,.05);--font:'Portfolio English',"Hiragino Kaku Gothic ProN","Yu Gothic","Noto Sans JP",sans-serif}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;min-height:100vh;background:radial-gradient(120% 70% at 20% 0%,#1d3466 0%,var(--night) 55%) fixed,var(--night);color:var(--ink);font-family:var(--font);line-height:1.8;-webkit-text-size-adjust:100%}
a,button{-webkit-tap-highlight-color:transparent}
a:focus-visible,button:focus-visible{outline:3px solid var(--lamp);outline-offset:4px}
.snow{position:fixed;inset:0;width:100%;height:100%;pointer-events:none;z-index:0}
body>*:not(.snow){position:relative;z-index:1}

.portfolio-return{margin:0 5%;padding:16px 0 0}
.portfolio-return a{display:inline-flex;align-items:center;min-height:44px;padding:10px 18px;border:1px solid var(--line);border-radius:10px;background:rgba(255,255,255,.06);color:var(--ink);font-size:14px;font-weight:700;text-decoration:none}
.portfolio-return a:hover{background:rgba(255,255,255,.12)}

.eyebrow{margin:0 0 14px;font-size:11px;font-weight:700;letter-spacing:.24em;color:var(--lamp)}
h1,h2,h3{font-weight:700;letter-spacing:.04em;margin:0}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5em;min-height:48px;padding:12px 22px;border-radius:999px;font:inherit;font-size:14px;font-weight:700;text-decoration:none;cursor:pointer;border:1px solid transparent;transition:transform .15s,background .2s,color .2s,border-color .2s}
.btn:active{transform:translateY(2px)}
.btn-primary{background:var(--lamp);color:#1a1606}
.btn-primary:hover{background:#f7d58e}
.btn-ghost{background:transparent;color:var(--ink);border-color:rgba(244,241,234,.4)}
.btn-ghost:hover,.btn-ghost[aria-pressed="true"]{border-color:var(--lamp);color:var(--lamp)}
.btn-small{min-height:42px;padding:9px 18px;font-size:13px}

/* hero */
.hero{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,520px);gap:64px;align-items:center;max-width:1180px;margin:0 auto;padding:56px 32px 72px}
.hero h1{font-size:clamp(2rem,4.4vw,3.4rem);line-height:1.4}
.hero h1 em{font-style:normal;color:var(--lamp)}
.lead{margin:28px 0 36px;color:var(--muted);font-size:15px;line-height:2.1}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px}

.art{margin:0}
.art-frame{position:relative;border-radius:6px;overflow:hidden;box-shadow:0 30px 80px rgba(0,0,0,.45),0 0 0 10px rgba(244,241,234,.06)}
.art-frame img{display:block;width:100%;height:auto}
.art figcaption{margin-top:20px;font-size:12px;color:var(--muted);letter-spacing:.08em;display:flex;gap:14px;align-items:baseline}
.art figcaption span{color:var(--ink);font-size:14px;font-weight:700}

/* answer overlay */
.qr-reveal{position:absolute;inset:0;opacity:0;transition:opacity .5s;pointer-events:none}
.qr-area{position:absolute;left:18%;top:23.3%;width:63.2%;height:43.3%;box-shadow:0 0 0 2000px rgba(6,12,30,.62);outline:2px dashed rgba(243,197,107,.9);outline-offset:4px}
.finder{position:absolute;width:15.6%;height:15.6%;border:3px solid var(--lamp);border-radius:4px;box-shadow:0 0 18px rgba(243,197,107,.8)}
.f-tl{left:0;top:0}.f-tr{right:0;top:0}.f-bl{left:0;bottom:0}
.art-frame.is-revealed .qr-reveal{opacity:1}
.art-frame.is-revealed .finder{animation:pulse 1.6s ease-in-out infinite}
@keyframes pulse{50%{box-shadow:0 0 4px rgba(243,197,107,.3)}}

/* mobile note */
.mobile-note{max-width:1180px;margin:0 auto 40px;padding:0 20px}
.mobile-note-inner{border:1px solid rgba(243,197,107,.5);background:rgba(243,197,107,.08);border-radius:16px;padding:20px}
.mobile-note p{margin:0 0 14px;font-size:14px;color:var(--ink)}
.mobile-note .mobile-note-title{font-weight:700;color:var(--lamp);margin-bottom:6px}

main{max-width:1180px;margin:0 auto;padding:0 32px 40px}
main section{padding:72px 0;border-top:1px solid var(--line)}
main h2{font-size:clamp(1.6rem,3vw,2.2rem);margin-bottom:32px}

/* caution */
.caution{display:flex;gap:18px;align-items:flex-start;padding:24px 26px;border-radius:16px;background:#f4f1ea;color:#1b2440;margin-bottom:28px}
.caution p{margin:0;font-size:14px;line-height:1.9;color:#4a5370}
.caution .caution-title{font-size:17px;font-weight:700;color:#1b2440;margin-bottom:6px;line-height:1.6}
.caution strong{background:linear-gradient(transparent 60%,#f7d58e 60%)}
.caution-icon{flex:none;display:grid;place-items:center;width:44px;height:44px;border-radius:50%;background:#1b2440}
.caution-icon svg{width:24px;height:24px;fill:none;stroke:var(--lamp);stroke-width:2;stroke-linejoin:round;stroke-linecap:round}

/* devices */
.device-cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
.device-card{background:var(--card);border:1px solid var(--line);border-radius:20px;padding:26px;transition:border-color .3s}
.device-card.is-current{order:-1;border-color:var(--lamp);background:rgba(243,197,107,.06)}
.device-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}
.device-label{font-size:13px;font-weight:700;letter-spacing:.18em;color:var(--muted)}
.device-badge{font-size:11px;font-weight:700;padding:4px 10px;border-radius:999px;background:var(--lamp);color:#1a1606}
.app-icon-wrap{display:flex;align-items:center;gap:18px;padding-bottom:22px;border-bottom:1px solid var(--line)}
.app-icon{flex:none;width:76px;height:76px;filter:drop-shadow(0 6px 14px rgba(0,0,0,.35))}
.app-name{margin:0;font-size:18px;font-weight:700}
.app-sub{margin:2px 0 0;font-size:12px;color:var(--muted)}
.steps{list-style:none;margin:20px 0 0;padding:0;counter-reset:step}
.steps li{counter-increment:step;display:grid;grid-template-columns:auto 1fr;gap:4px 14px;padding:12px 0;font-size:14px}
.steps li::before{content:counter(step);grid-row:span 2;display:grid;place-items:center;width:30px;height:30px;border-radius:50%;border:1px solid var(--lamp);color:var(--lamp);font-size:13px;font-weight:700}
.steps b{font-size:12px;letter-spacing:.12em;color:var(--lamp)}
.steps span{color:var(--ink);line-height:1.8}
.steps strong{color:var(--lamp)}
.card-note{margin:14px 0 0;font-size:11px;color:var(--muted)}

.tips{margin-top:28px;padding:22px 26px;border-radius:16px;border:1px dashed var(--line)}
.tips-title{margin:0 0 8px;font-weight:700}
.tips ul{margin:0;padding-left:1.2em;color:var(--muted);font-size:14px}
.tips strong{color:var(--ink)}

/* mechanism */
.mech-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}
.mech-item{padding:26px;border-radius:20px;background:var(--card);border:1px solid var(--line)}
.mech-num{font-size:12px;letter-spacing:.2em;color:var(--lamp);font-weight:700}
.mech-item h3{font-size:17px;margin:10px 0 10px}
.mech-item p{margin:0;font-size:14px;color:var(--muted)}
.usecases{margin-top:36px;display:flex;flex-wrap:wrap;align-items:center;gap:12px 18px}
.usecases p{margin:0;font-size:13px;font-weight:700;color:var(--lamp)}
.usecases ul{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:8px}
.usecases li{font-size:13px;padding:6px 14px;border-radius:999px;border:1px solid var(--line)}

footer{text-align:center;padding:30px 20px 40px;font-size:11px;color:var(--muted)}

@media (max-width:900px){
  .hero{grid-template-columns:1fr;gap:40px;padding:36px 20px 48px}
  .art{max-width:480px;width:100%;margin:0 auto}
  .pc-br{display:none}
  main{padding:0 20px 30px}
  main section{padding:56px 0}
  .device-cards,.mech-grid{grid-template-columns:1fr}
}
@media (max-width:480px){
  .hero-actions .btn{width:100%}
  .caution{flex-direction:column;padding:20px}
  .device-card,.mech-item{padding:20px}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .art-frame.is-revealed .finder{animation:none}
}