:root{
  --nu-green:#006E4F;      /* NU Green */
  --nu-green-600:#005542;  /* 深めの緑 */
  --ink:#1a1a1a;
  --muted:#6b7280;
  --line:#e5e7eb;
  --surface:#f7f8f7;
  --radius:14px;
  --container:1120px;
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:"Noto Sans JP",system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue","Hiragino Kaku Gothic ProN","Hiragino Sans",Meiryo,sans-serif;
  color:var(--ink);
  background:#fff;
  line-height:1.7;
  font-size:16px;
}
h2,h3,h4{font-family:"Noto Serif JP","Noto Sans JP",serif;line-height:1.25;color:#111}
img{max-width:100%;display:block}

h1{font-family:"Noto Serif JP","Noto Sans JP",serif;line-height:1.25;color:#ffffff}
img{max-width:100%;display:block}

.container{max-width:var(--container);margin:auto;padding:0 20px}

.topbar{height:6px;background:var(--nu-green)}

.site-header{
  position:sticky;top:0;z-index:50;
  background:#fff;border-bottom:1px solid var(--line);
}
.hdr-inner{display:flex;align-items:center;gap:16px;min-height:64px}
.brand{display:flex;gap:12px;align-items:center;text-decoration:none;color:inherit}
.brand .brand-mark{
  width:32px;height:32px;border-radius:8px;
  background:var(--nu-green);
  box-shadow:inset 0 0 0 4px #fff, 0 0 0 1px #0d3b2f33;
}
.brand .brand-text{display:flex;flex-direction:column}
.brand .brand-text small{color:var(--muted);font-size:12px}

.site-nav ul{display:flex;gap:18px;list-style:none;margin:0 0 0 auto;padding:0}
.site-nav a{color:#0f172a;text-decoration:none;padding:10px 8px;border-radius:8px}
.site-nav a:hover{background:var(--surface)}
.nav-toggle{display:none;margin-left:auto}

@media (max-width:860px){
  .nav-toggle{display:inline-block;border:1px solid var(--line);border-radius:10px;background:#fff;padding:10px 14px}
  .site-nav{display:none;width:100%}
  .site-nav.open{display:block}
  .site-nav ul{flex-direction:column;gap:6px;margin-top:12px}
}

.hero{
  background:linear-gradient(180deg, var(--nu-green), var(--nu-green-600));
  color:#fff; padding:64px 0;
}
.hero-inner{padding:24px 0 8px}
.hero h1{font-size:clamp(28px,4.2vw,44px);margin:0 0 10px}
.hero p{opacity:.95;margin:0 0 18px}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 18px;border-radius:12px;text-decoration:none;border:1px solid transparent;
  font-weight:600;
}
.btn-solid{background:#fff;color:var(--nu-green)}
.btn-solid:hover{filter:brightness(.95)}
.btn-ghost{border-color:#ffffff66;color:#fff}
.btn-ghost:hover{background:#ffffff22}

.section{padding:56px 0}
.section-alt{background:var(--surface)}
.sec-title{font-size:clamp(22px,3vw,28px);margin:0 0 22px}

.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.card{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:18px;box-shadow:0 4px 10px #00000008;
}
.card-icon{font-size:28px}
.card h3{margin:8px 0 6px;font-size:20px}
.card p{margin:0;color:#374151}
@media (max-width:860px){.cards{grid-template-columns:1fr}}

.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.tile{
  background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px;
}
.tile h4{margin:0 0 4px}
@media (max-width:1024px){.grid{grid-template-columns:repeat(2,1fr)}}
@media (max-width:640px){.grid{grid-template-columns:1fr}}

.screens{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.screen{border:1px solid var(--line);border-radius:12px;overflow:hidden;background:#fff}
.note{color:var(--muted);font-size:14px;margin-top:10px}
@media (max-width:860px){.screens{grid-template-columns:1fr 1fr}}
@media (max-width:560px){.screens{grid-template-columns:1fr}}

.section-cta{background:linear-gradient(180deg,#f9fafb,#eef6f2)}
.cta-inner{display:flex;flex-direction:column;align-items:center;text-align:center;gap:8px}
.store-buttons{display:flex;gap:12px;margin-top:4px;flex-wrap:wrap}
.store-btn{display:inline-block;padding:12px 16px;border-radius:12px;border:1px solid var(--line);background:#fff;color:#111;text-decoration:none}
.store-btn:hover{border-color:#cbd5e1}

.site-footer{border-top:1px solid var(--line);padding:28px 0;background:#fff}
.footer-grid{display:flex;justify-content:space-between;align-items:flex-start;gap:16px}
.site-footer nav ul{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.brand.small .brand-mark{width:24px;height:24px}
.muted{color:var(--muted)}

/* Active nav look */
.site-nav a.active{
  background: var(--surface);
  color: var(--nu-green);
  font-weight: 700;
  box-shadow: inset 0 -2px 0 var(--nu-green);
}