/* ============ CSS VARIABLES (Dart配色寄せ) ============ */
:root{
  --bg: #ffffff;
  --text: #0F172A;           /* slate-900 */
  --muted: #475569;          /* slate-600 */
  --line: #E2E8F0;           /* slate-200 */

  --primary: #0175C2;        /* Dart Blue */
  --primary-2: #13B9FD;      /* Light Cyan */
  --teal: #00C4B3;           /* accent */
  --ghost: #F8FAFC;          /* slate-50 */

  --shadow: 0 10px 30px rgba(2,32,71,0.06);
  --radius: 14px;
}

/* ダークモード（任意） */
@media (prefers-color-scheme: dark){
  :root{
    --bg: #0B1220;
    --text: #E5EEFF;
    --muted: #A7B1C2;
    --line: #1E293B;

    --ghost: #0F172A;
    --shadow: 0 10px 30px rgba(0,0,0,0.35);
  }
}

/* ============ RESET / BASE ============ */
* { box-sizing: border-box; }
html, body { height: 100%; }
body{
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, "Helvetica Neue", Arial, "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", "YuGothic", Meiryo, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img{max-width:100%;height:auto;display:block;}
a{color:inherit;text-decoration:none;}
.visually-hidden{position:absolute!important;width:1px;height:1px;overflow:hidden;clip:rect(1px,1px,1px,1px);}
.skip-link{
  position:absolute;left:-9999px;top:auto;width:1px;height:1px;overflow:hidden;
}
.skip-link:focus{
  left:16px;top:16px;width:auto;height:auto;background:#000;color:#fff;padding:.5rem 1rem;border-radius:8px;z-index:1000;
}

/* Containers */
.container{width:100%;max-width:1120px;margin-inline:auto;padding-inline:24px;}
.center{text-align:center;}
.br-md{display:none;}
@media (min-width: 860px){ .br-md{display:inline;} }

/* ============ HEADER ============ */
.site-header{
  position: sticky; top: 0; z-index: 50;
  background: linear-gradient(180deg, rgba(255,255,255,.85), rgba(255,255,255,.70));
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
@media (prefers-color-scheme: dark){
  .site-header{
    background: linear-gradient(180deg, rgba(11,18,32,.85), rgba(11,18,32,.60));
  }
}
.header-inner{
  display:flex; align-items:center; gap:16px; padding-block:14px;
}
.brand{display:flex; align-items:center; gap:10px; font-weight:700;}
.logo{width:28px;height:28px;position:relative;display:grid;place-items:center;}
.logo-dot{
  width:10px;height:10px;border-radius:50%;
  background: radial-gradient(circle at 35% 35%, var(--primary-2), var(--primary));
  box-shadow: 0 0 0 4px rgba(19,185,253,.12), 0 0 0 10px rgba(1,117,194,.08);
  animation: pulse 2.4s ease-in-out infinite;
}
@keyframes pulse{
  0%,100%{box-shadow: 0 0 0 4px rgba(19,185,253,.12), 0 0 0 10px rgba(1,117,194,.08);}
  50%    {box-shadow: 0 0 0 8px rgba(19,185,253,.16), 0 0 0 16px rgba(1,117,194,.12);}
}
.brand-name{display:block; height: 30px;}
.brand-name img{height:100%;}
.site-nav{margin-left:auto;display:none;gap:18px;}
.site-nav a{color:var(--muted);}
.site-nav a:hover{color:var(--text);}
.cta-wrap{display:flex;gap:10px;margin-left:auto;}
@media (min-width: 980px){
  .site-nav{display:flex;margin-left:48px;}
  .cta-wrap{margin-left:0;}
}

/* Buttons */
.btn{
  --_bg: transparent;
  --_fg: var(--text);
  --_bd: var(--line);
  display:inline-flex; align-items:center; justify-content:center;
  padding:.65rem 1rem; border-radius:12px; border:1px solid var(--_bd);
  font-weight:600; transition: all .2s ease; box-shadow:none;
}
.btn:hover{transform: translateY(-1px);}
.btn-primary{ --_bg: linear-gradient(135deg, var(--primary), var(--primary-2)); --_fg: #fff; --_bd: transparent; color:var(--_fg); background:var(--_bg); }
.btn-primary:hover{ filter: brightness(1.05); }
.btn-outline{ --_fg: var(--primary); --_bd: rgba(1,117,194,.35); color:var(--_fg); }
.btn-outline:hover{ background: rgba(1,117,194,.08); }
.btn-ghost{ border-color: transparent; background: transparent; color: var(--primary); }
.btn-lg{ padding:.9rem 1.25rem; border-radius:14px; }

/* ============ HERO ============ */
.hero{
  position: relative; isolation: isolate;
  padding: 88px 0 72px;
}
.hero-bg{
  position: absolute; inset: 0; z-index: -1; overflow:hidden;
  background:
    radial-gradient(60vw 60vw at 70% -10%, rgba(19,185,253,.25), transparent 60%),
    radial-gradient(50vw 50vw at -10% 20%, rgba(1,117,194,.18), transparent 55%),
    radial-gradient(40vw 40vw at 110% 100%, rgba(0,196,179,.12), transparent 55%);
}
.ripple{
  position:absolute; left:50%; top:48%; transform:translate(-50%,-50%);
  width:120vmax; height:120vmax; border-radius:50%;
  background: radial-gradient(circle, rgba(255,255,255,.25), rgba(255,255,255,0) 50%);
  opacity:.25; animation: ripple 8s ease-in-out infinite;
}
.ripple-2{ animation-delay: .8s; opacity:.20;}
.ripple-3{ animation-delay: 1.6s; opacity:.18;}
@keyframes ripple{
  0%{transform:translate(-50%,-50%) scale(.9);}
  50%{transform:translate(-50%,-50%) scale(1.05);}
  100%{transform:translate(-50%,-50%) scale(.9);}
}

.hero-inner{ text-align:center; }
.hero-title{
  font-size: clamp(28px, 4vw, 48px);
  line-height:1.15; letter-spacing:.2px; margin:0 0 16px;
}
.highlight{
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
  -webkit-background-clip:text; background-clip:text; color:transparent;
}
.hero-lead{
  color: var(--muted);
  font-size: clamp(15px, 1.8vw, 18px);
  margin: 0 auto 28px; max-width: 840px;
}
.hero-lead .sub{opacity:.9;}
.hero-cta{display:flex; gap:12px; justify-content:center; flex-wrap:wrap;}

/* ============ SECTIONS ============ */
.section{ padding: 72px 0; }
.section-tint{ background:
  linear-gradient(180deg, rgba(1,117,194,.04), rgba(19,185,253,.04)); }
.eyebrow{
  text-transform: uppercase; letter-spacing:.2em; font-weight:700; color: var(--primary);
  font-size: 12px; margin:0 0 12px;
}
.section-title{
  font-size: clamp(22px, 3vw, 34px);
  line-height:1.25; margin:0 0 14px;
}
.section-copy{ color: var(--muted); margin: 8px 0 0; }
.grid-2{ display:grid; gap:26px; align-items:start; }
@media (min-width: 920px){
  .grid-2{ grid-template-columns: 1.1fr 1fr; gap:40px; }
}

/* Lists */
.bullets{margin:0;padding:0;list-style:none;display:grid;gap:12px;color:var(--muted);}
.bullets li{position:relative;padding-left:28px;}
.bullets li::before{
  content:""; position:absolute; left:0; top:.55em; width:14px; height:14px; border-radius:50%;
  background: radial-gradient(circle at 35% 35%, var(--primary-2), var(--primary));
  box-shadow: 0 0 0 3px rgba(1,117,194,.12);
}

/* Cards / Features */
.card{
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
}
.callout{ position: relative; overflow:hidden; }
.callout-quote{
  font-size: clamp(18px, 2.4vw, 24px); line-height:1.4; margin:0 0 8px;
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
  -webkit-background-clip:text; background-clip:text; color:transparent;
}
.callout::after{
  content:""; position:absolute; inset:auto -20% -35% -20%;
  height:60%; background: radial-gradient(50% 60% at 50% 100%, rgba(19,185,253,.15), transparent 70%);
  pointer-events:none;
}

.features{
  display:grid; gap:16px; margin-top:24px;
  grid-template-columns: repeat(1, minmax(0,1fr));
}
@media (min-width: 760px){
  .features{ grid-template-columns: repeat(2, minmax(0,1fr)); }
}
@media (min-width: 1100px){
  .features{ grid-template-columns: repeat(4, minmax(0,1fr)); }
}
.feature{
  background: var(--ghost); border:1px solid var(--line);
  border-radius: var(--radius); padding:20px 18px; box-shadow: var(--shadow);
}
.feature-ico{
  width:40px;height:40px;display:grid;place-items:center;border-radius:12px;margin-bottom:10px;
  background: linear-gradient(135deg, var(--primary), var(--primary-2)); color:#fff; font-weight:700;
}
.feature h4{ margin: 0 0 6px; }
.feature p{ margin: 0; color: var(--muted); }

/* Vision */
.vision-card{
  background: var(--bg);
  border:1px solid var(--line);
  border-radius: var(--radius);
  padding:24px;
  box-shadow: var(--shadow);
}
.ticks{ list-style: none; margin:0; padding:0; display:grid; gap:10px; color:var(--muted); }
.ticks li{ position: relative; padding-left:28px; }
.ticks li::before{
  content:"✓"; position:absolute; left:0; top:0; color: var(--teal); font-weight:700;
}

/* CTA / Notify */
.section-cta{
  background:
    radial-gradient(80vw 60vw at 50% 130%, rgba(19,185,253,.15), transparent 60%),
    radial-gradient(60vw 40vw at -10% 0%, rgba(1,117,194,.10), transparent 60%);
}
.notify-form{
  display:flex; gap:10px; justify-content:center; flex-wrap:wrap; margin-top:18px;
}
.notify-form input{
  width:min(420px, 90vw);
  border:1px solid var(--line); border-radius:12px; padding:.9rem 1rem;
  background:#fff; color:#0b1220; outline:none;
}
@media (prefers-color-scheme: dark){
  .notify-form input{
    background:#0E1627; color:#E5EEFF; border-color:#1E2A3C;
  }
}
.notify-form input:focus{ box-shadow: 0 0 0 3px rgba(19,185,253,.25); }
.privacy-note{ color: var(--muted); font-size: 14px; margin-top: 10px; }

/* ============ FOOTER ============ */
.site-footer{
  border-top:1px solid var(--line);
  padding: 24px 0;
}
.footer-inner{
  display:flex; gap:12px; align-items:center; justify-content:space-between;
}
.footer-link{ color: var(--muted); }
.footer-link:hover{ color: var(--text); }
.footer-logo{ display: flex; justify-content: center; align-items: center; width: 200px; margin : 0 auto; }