:root{
  --paper:#ECEBE3;
  --paper2:#F5F4EE;
  --ink:#1B1D1A;
  --chalk:#2E63B4;
  --tape:#E0A23C;
  --vermilion:#C24033;
  --rule:#C9C6B8;
  --rule-soft:#dedbcf;
  --muted:#6b6b60;
}
*{box-sizing:border-box}
html,body{margin:0}
body{
  font-family:"Hiragino Sans","Hiragino Kaku Gothic ProN","Noto Sans JP",system-ui,sans-serif;
  color:var(--ink);background:var(--paper);
  -webkit-font-smoothing:antialiased;
}

/* ---- header ---- */
.site-header{
  display:flex;align-items:baseline;gap:14px;flex-wrap:wrap;
  padding:14px 20px;border-bottom:1.5px solid var(--ink);
  background:var(--paper2);position:sticky;top:0;z-index:10;
}
.site-header .brand{
  font-size:22px;font-weight:800;letter-spacing:.22em;
  text-decoration:none;color:var(--ink);
}
.site-header .brand b{color:var(--vermilion)}
.site-header .tag{font-size:12px;color:var(--muted);letter-spacing:.04em}

/* ---- article ---- */
.article{
  max-width:680px;margin:0 auto;padding:40px 24px 80px;
}
.article-head{margin-bottom:40px}
.category{
  font-size:11px;letter-spacing:.18em;color:var(--vermilion);
  font-weight:700;margin:0 0 8px;
}
h1{font-size:26px;font-weight:800;margin:0 0 16px;line-height:1.3;letter-spacing:.02em}
.lead{font-size:14px;line-height:1.9;color:var(--muted);margin:0 0 24px}

/* ---- toc ---- */
.toc{
  background:var(--paper2);border:1.5px solid var(--rule);
  border-radius:2px;padding:14px 18px;display:inline-block;
}
.toc-h{font-size:11px;font-weight:700;letter-spacing:.14em;color:var(--muted);margin:0 0 8px}
.toc ol{margin:0;padding-left:18px}
.toc li{font-size:13px;margin-bottom:4px;line-height:1.5}
.toc a{color:var(--chalk);text-decoration:none}
.toc a:hover{text-decoration:underline}

/* ---- sections ---- */
section{margin-bottom:44px}
h2{
  font-size:17px;font-weight:800;margin:0 0 14px;padding-bottom:7px;
  border-bottom:2px solid var(--ink);letter-spacing:.03em;
}
h3{font-size:13.5px;font-weight:700;margin:18px 0 8px;color:var(--ink)}
p{font-size:13.5px;line-height:1.85;margin:0 0 10px}
ul,ol{font-size:13.5px;line-height:1.85;padding-left:20px;margin:0 0 10px}
li{margin-bottom:6px}
strong{font-weight:700}
em{font-style:normal;font-weight:700;color:var(--chalk)}
a{color:var(--chalk)}
a:hover{text-decoration:underline}

/* ---- step list ---- */
.steps{counter-reset:step;padding-left:0;list-style:none;margin:0 0 12px}
.steps li{
  position:relative;padding:10px 14px 10px 42px;
  margin-bottom:8px;background:var(--paper2);border:1px solid var(--rule);border-radius:2px;
}
.steps li::before{
  counter-increment:step;content:counter(step);
  position:absolute;left:12px;top:10px;
  width:20px;height:20px;line-height:20px;text-align:center;
  background:var(--chalk);color:#fff;font-size:11px;font-weight:700;border-radius:50%;
}

/* ---- note ---- */
.note{
  font-size:12.5px;color:var(--muted);line-height:1.7;
  border-left:3px solid var(--tape);padding:6px 10px;
  background:var(--paper2);margin:10px 0 14px;
}

/* ---- CTA ---- */
.cta-box{
  margin-top:28px;padding:20px 22px;
  background:var(--chalk);border-radius:2px;
}
.cta-box p{color:#fff;font-size:13.5px;margin:0 0 12px}
.cta-btn{
  display:inline-block;padding:10px 20px;
  background:#fff;color:var(--chalk);font-weight:700;font-size:13.5px;
  text-decoration:none;border-radius:2px;letter-spacing:.02em;
}
.cta-btn:hover{background:var(--paper)}

/* ---- footer ---- */
.site-footer{
  border-top:1px solid var(--rule);padding:10px 20px;
  display:flex;gap:16px;align-items:center;
  font-size:11px;color:var(--muted);background:var(--paper2);
}
.site-footer a{color:var(--muted);text-decoration:underline}
.site-footer a:hover{color:var(--ink)}

/* ---- affiliate material box ---- */
.material-box{
  margin:20px 0 0;padding:16px 18px;
  border:1.5px solid var(--rule);border-radius:2px;
  background:var(--paper2);
}
.material-box-head{
  font-size:11px;font-weight:700;letter-spacing:.14em;
  color:var(--muted);margin:0 0 10px;
}
.material-links{
  display:flex;flex-wrap:wrap;gap:8px;margin-bottom:10px;
}
.ml-btn{
  display:inline-flex;align-items:center;gap:5px;
  padding:6px 12px;border-radius:2px;font-size:12px;font-weight:700;
  text-decoration:none;line-height:1;white-space:nowrap;
}
.ml-btn-rakuten{
  background:#bf0000;color:#fff;
}
.ml-btn-amazon{
  background:#FF9900;color:#111;
}
.ml-btn:hover{opacity:.85}
.material-pr{
  font-size:10.5px;color:var(--muted);margin:8px 0 0;
}
@media print{.material-box{display:none}}

/* ---- term link (auto-linked glossary words) ---- */
.term-link{
  color:var(--chalk);text-decoration:underline;
  text-decoration-style:dotted;text-underline-offset:2px;
}
.term-link:hover{text-decoration-style:solid}

@media (max-width:600px){
  .article{padding:24px 16px 60px}
  h1{font-size:21px}
}