/* ===== reset ===== */
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
img{max-width:100%;display:block}
a{text-decoration:none;color:inherit}
ul,ol{list-style:none}
body{-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
@media (prefers-reduced-motion: reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
:focus-visible{outline:3px solid var(--accent);outline-offset:2px}

/* ===== tokens ===== */
:root{
  --bg:#0d1424;
  --panel:#141d33;
  --ink:#e8eefc;
  --muted:#93a2c4;
  --line:#243350;
  --accent:#3d8bff;
  --accent2:#5fd0ff;
  --accent-soft:#182746;
  --card:#111a2e;
  --maxw:1180px;
  --ff-head:'Zen Kaku Gothic New',sans-serif;
  --ff-body:'Zen Kaku Gothic New',sans-serif;
  --radius:18px;
}

body{font-family:var(--ff-body);background:var(--bg);color:var(--ink);line-height:1.9;font-size:16px;
  background-image:radial-gradient(circle at 15% -10%,rgba(61,139,255,.14),transparent 45%),radial-gradient(circle at 90% 0%,rgba(95,208,255,.10),transparent 40%);
  background-attachment:fixed}

/* ===== top bar ===== */
.topbar{position:sticky;top:0;z-index:80;display:flex;align-items:center;gap:18px;
  padding:0 26px;height:66px;background:rgba(13,20,36,.82);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line)}
.brand{display:flex;align-items:center;gap:11px;font-family:var(--ff-head);font-weight:700;font-size:18px;letter-spacing:.02em}
.brand .mark{width:30px;height:30px;flex:none;display:grid;place-items:center;border-radius:9px;
  background:linear-gradient(135deg,var(--accent),var(--accent2));color:#06101f;font-size:17px}
.brand b{color:var(--accent2)}
.nav-main{margin-left:auto}
.nav-main ul{display:flex;gap:6px}
.nav-main a{display:inline-block;padding:9px 15px;border-radius:10px;font-size:13.5px;font-weight:500;color:var(--muted);transition:.2s}
.nav-main a:hover{color:var(--ink);background:var(--accent-soft)}
.nav-main a.is-active{color:var(--accent2);background:var(--accent-soft)}
.nav-toggle{display:none;width:44px;height:44px;margin-left:auto;border:1px solid var(--line);border-radius:11px;
  background:var(--panel);color:var(--ink);cursor:pointer;flex-direction:column;justify-content:center;align-items:center;gap:5px}
.nav-toggle span{display:block;width:20px;height:2px;background:currentColor;transition:.3s}
.nav-toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
.nav-mobile{display:none}

/* ===== home hero ===== */
.hero{max-width:var(--maxw);margin:0 auto;padding:78px 26px 40px;display:grid;grid-template-columns:1.15fr .85fr;gap:40px;align-items:center}
.hero .kicker{display:inline-block;font-family:var(--ff-head);font-size:12px;letter-spacing:.28em;color:var(--accent2);
  padding:6px 14px;border:1px solid var(--line);border-radius:30px;margin-bottom:22px}
.hero h1{font-family:var(--ff-head);font-weight:700;font-size:clamp(30px,5.2vw,50px);line-height:1.3;letter-spacing:.01em;margin-bottom:20px}
.hero h1 em{font-style:normal;background:linear-gradient(120deg,var(--accent),var(--accent2));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p{color:var(--muted);font-size:16.5px;max-width:52ch}
.hero-visual{position:relative;aspect-ratio:1/1;max-width:340px;margin-left:auto;width:100%}
.bt-ring{position:absolute;inset:0;border-radius:50%;border:1px solid var(--line);display:grid;place-items:center}
.bt-ring::before{content:"";position:absolute;inset:14%;border-radius:50%;border:1px solid var(--line)}
.bt-ring::after{content:"";position:absolute;inset:28%;border-radius:50%;
  background:radial-gradient(circle,var(--accent-soft),transparent 70%)}
.bt-glyph{position:relative;z-index:2;font-size:clamp(70px,16vw,130px);color:var(--accent2);
  filter:drop-shadow(0 0 26px rgba(95,208,255,.45))}
.pulse{position:absolute;inset:0;border-radius:50%;border:2px solid var(--accent);opacity:0;animation:pulse 3.4s ease-out infinite}
.pulse:nth-child(2){animation-delay:1.7s}
@keyframes pulse{0%{transform:scale(.55);opacity:.55}100%{transform:scale(1.05);opacity:0}}
@media(max-width:860px){.hero{grid-template-columns:1fr;padding-top:54px}.hero-visual{max-width:250px;margin:8px auto 0}}

/* ===== home step nav ===== */
.home-steps{max-width:var(--maxw);margin:0 auto;padding:44px 26px 96px}
.home-steps h2{font-family:var(--ff-head);font-size:22px;text-align:center;margin-bottom:8px}
.home-steps .sub{text-align:center;color:var(--muted);font-size:14.5px;margin-bottom:40px}
.step-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:18px}
.step-card{position:relative;display:block;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:28px 24px 26px;transition:.25s;overflow:hidden}
.step-card::before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:linear-gradient(var(--accent),var(--accent2));
  transform:scaleY(0);transform-origin:top;transition:.3s}
.step-card:hover{transform:translateY(-5px);border-color:var(--accent)}
.step-card:hover::before{transform:scaleY(1)}
.step-card .no{font-family:var(--ff-head);font-size:13px;letter-spacing:.2em;color:var(--accent2);margin-bottom:12px}
.step-card h3{font-family:var(--ff-head);font-size:18px;margin-bottom:10px}
.step-card p{color:var(--muted);font-size:14px;line-height:1.8}
.step-card .go{display:inline-block;margin-top:16px;font-size:13px;font-weight:700;color:var(--accent2)}

/* ===== article pages ===== */
.wrap{max-width:var(--maxw);margin:0 auto;padding:56px 26px 20px;display:grid;grid-template-columns:1fr 240px;gap:52px}
@media(max-width:900px){.wrap{grid-template-columns:1fr;gap:0}}
.article{min-width:0}
.crumb{font-size:12.5px;color:var(--muted);margin-bottom:22px}
.crumb a:hover{color:var(--accent2)}
.crumb span{margin:0 8px;opacity:.5}
.art-head{margin-bottom:40px;padding-bottom:26px;border-bottom:1px solid var(--line)}
.art-head .tag{display:inline-block;font-family:var(--ff-head);font-size:11px;letter-spacing:.22em;color:var(--accent2);
  padding:5px 12px;border-radius:20px;background:var(--accent-soft);margin-bottom:18px}
.art-head h1{font-family:var(--ff-head);font-weight:700;font-size:clamp(26px,4.6vw,40px);line-height:1.34}
.art-head .lead{margin-top:16px;color:var(--muted);font-size:16px;max-width:60ch}
.article h2{font-family:var(--ff-head);font-weight:700;font-size:clamp(20px,3vw,27px);margin:46px 0 18px;
  padding-left:16px;border-left:5px solid var(--accent);line-height:1.4}
.article h2:first-of-type{margin-top:0}
.article p{margin-bottom:18px;color:#d4ddf2}
.callout{background:var(--card);border:1px solid var(--line);border-left:4px solid var(--accent2);
  border-radius:12px;padding:20px 22px;margin:26px 0}
.callout p{margin:0;color:var(--muted);font-size:14.5px}
.callout strong{color:var(--accent2);font-weight:700}

/* pager */
.pager{display:flex;gap:14px;margin:52px 0 20px;flex-wrap:wrap}
.pager a{flex:1 1 0;min-width:220px;background:var(--card);border:1px solid var(--line);border-radius:14px;
  padding:16px 20px;transition:.22s}
.pager a:hover{border-color:var(--accent);transform:translateY(-3px)}
.pager .dir{font-size:11.5px;letter-spacing:.18em;color:var(--accent2);font-family:var(--ff-head)}
.pager .ttl{display:block;margin-top:5px;font-weight:700;font-size:14.5px}
.pager .next{text-align:right}

/* side toc */
.side{position:sticky;top:90px;align-self:start}
@media(max-width:900px){.side{display:none}}
.side .box{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:20px}
.side h4{font-family:var(--ff-head);font-size:12px;letter-spacing:.16em;color:var(--muted);margin-bottom:14px}
.side ul{display:flex;flex-direction:column;gap:2px}
.side a{display:block;padding:8px 12px;border-radius:9px;font-size:13.5px;color:var(--muted);transition:.2s}
.side a:hover{background:var(--accent-soft);color:var(--ink)}
.side a.is-active{background:var(--accent-soft);color:var(--accent2);font-weight:700}

/* ===== sitemap ===== */
.sitemap-head{max-width:var(--maxw);margin:0 auto;padding:60px 26px 20px}
.sitemap-head .tag{display:inline-block;font-family:var(--ff-head);font-size:11px;letter-spacing:.22em;color:var(--accent2);
  padding:5px 12px;border-radius:20px;background:var(--accent-soft);margin-bottom:16px}
.sitemap-head h1{font-family:var(--ff-head);font-weight:700;font-size:clamp(26px,4.6vw,40px)}
.sitemap-head p{margin-top:14px;color:var(--muted);max-width:60ch}
.sitemap-wrap{max-width:var(--maxw);margin:0 auto;padding:20px 26px 90px}
.sm-list{border-top:1px solid var(--line)}
.sm-list li{border-bottom:1px solid var(--line)}
.sm-list a{display:grid;grid-template-columns:44px 1fr;gap:18px;align-items:start;padding:24px 8px;transition:.2s}
.sm-list a:hover{background:var(--card)}
.sm-list a:hover .sm-ttl{color:var(--accent2)}
.sm-no{font-family:var(--ff-head);font-size:14px;color:var(--accent2);padding-top:2px}
.sm-ttl{display:block;font-family:var(--ff-head);font-weight:700;font-size:17px;transition:.2s}
.sm-desc{display:block;color:var(--muted);font-size:14px;margin-top:5px;line-height:1.8}

/* ===== footer ===== */
.foot{background:var(--panel);border-top:1px solid var(--line);margin-top:40px}
.foot-in{max-width:var(--maxw);margin:0 auto;padding:44px 26px 20px;display:flex;flex-wrap:wrap;gap:28px;justify-content:space-between;align-items:flex-start}
.foot-brand{max-width:340px}
.foot-brand .brand{margin-bottom:12px}
.foot-brand p{color:var(--muted);font-size:13.5px;line-height:1.8}
.foot-nav ul{display:grid;grid-template-columns:1fr 1fr;gap:9px 30px}
.foot-nav a{font-size:13.5px;color:var(--muted);transition:.2s}
.foot-nav a:hover{color:var(--accent2)}
.foot-copy{border-top:1px solid var(--line);text-align:center;padding:16px;color:var(--muted);font-size:12px}
@media(max-width:600px){.foot-nav ul{grid-template-columns:1fr}}

/* to top */
.to-top{position:fixed;right:20px;bottom:20px;width:46px;height:46px;border-radius:13px;
  background:linear-gradient(135deg,var(--accent),var(--accent2));color:#06101f;display:flex;align-items:center;justify-content:center;
  font-size:20px;opacity:0;pointer-events:none;transform:translateY(12px);transition:.3s;z-index:60;
  box-shadow:0 12px 26px -10px rgba(61,139,255,.7)}
.to-top.show{opacity:1;pointer-events:auto;transform:none}

/* reveal */
.reveal{opacity:0;transform:translateY(24px);transition:opacity .7s ease,transform .7s ease}
.reveal.in{opacity:1;transform:none}

/* mobile nav */
@media(max-width:860px){
  .nav-main{display:none}
  .nav-toggle{display:flex}
  .nav-mobile.open{display:block;position:fixed;top:66px;left:0;right:0;background:var(--panel);
    border-bottom:1px solid var(--line);z-index:79;padding:10px 16px 18px}
  .nav-mobile ul{display:flex;flex-direction:column;gap:2px}
  .nav-mobile a{display:block;padding:13px 14px;border-radius:10px;font-size:15px;color:var(--muted)}
  .nav-mobile a.is-active{color:var(--accent2);background:var(--accent-soft)}
}