:root{
  --primary:#1e40af;
  --secondary:#1e3a8a;
  --accent:#84cc16;
  --bg:#ffffff;
  --surface:#eff6ff;
  --surface-alt:#dbeafe;
  --text:#1e3a8a;
  --muted:#5d6a7a;
  --border:#bfdbfe;
  --row-alt:#eff6ff;
  --radius:6px;
  --shadow:0 6px 24px rgba(30,64,175,.08);
  --shadow-strong:0 10px 40px rgba(30,58,138,.16);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:"Sarabun","IBM Plex Sans Thai","Noto Sans Thai",system-ui,sans-serif;
  font-size:17px;
  line-height:1.75;
  color:var(--text);
  background:var(--bg);
}
img,svg{max-width:100%;height:auto;display:block}
a{color:var(--primary);text-decoration:underline;text-underline-offset:3px}
a:hover{color:var(--secondary)}
p{margin:0 0 1.1em}

/* Header */
.site-header{
  position:sticky;top:0;z-index:20;
  background:linear-gradient(120deg,var(--primary) 0%,var(--secondary) 100%);
  color:#fff;
  box-shadow:var(--shadow);
}
.site-header .wrap{
  max-width:1120px;margin:0 auto;padding:12px 18px;
  display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;
}
.brand{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none;font-weight:700}
.brand img{width:36px;height:36px;background:#fff;border-radius:8px;padding:3px}
.brand span{font-size:1.05rem;letter-spacing:.2px}
nav.primary{display:flex;flex-wrap:wrap;gap:6px 14px}
nav.primary a{color:#fff;text-decoration:none;font-weight:500;padding:6px 8px;border-radius:4px;font-size:.98rem}
nav.primary a:hover{background:rgba(255,255,255,.15)}

/* Hero */
.hero{
  background:linear-gradient(140deg,var(--surface) 0%,var(--surface-alt) 100%);
  padding:44px 18px 36px;
  border-bottom:1px solid var(--border);
}
.hero .wrap{max-width:1000px;margin:0 auto}
.hero h1{
  font-size:1.9rem;line-height:1.35;margin:0 0 12px;color:var(--secondary);
  font-weight:800;
}
.byline{color:var(--muted);font-size:.95rem;margin:0 0 14px}
.byline strong{color:var(--secondary)}
.lede{font-size:1.08rem;color:var(--text);margin:0}

/* Content wrap */
main{max-width:920px;margin:0 auto;padding:36px 18px 24px}
h2{
  font-size:1.45rem;margin:36px 0 12px;padding:10px 14px;
  border-left:5px solid var(--accent);
  background:var(--surface);
  color:var(--secondary);
  border-radius:0 var(--radius) var(--radius) 0;
  font-weight:700;
  line-height:1.4;
}
h3{color:var(--secondary);font-size:1.12rem;margin:22px 0 8px}

/* Lists */
ul{list-style:none;padding-left:0;margin:0 0 1.2em}
ul li{position:relative;padding-left:1.6em;margin-bottom:.5em}
ul li::before{
  content:"▸";position:absolute;left:0;top:0;color:var(--accent);font-weight:700;
}
ol{list-style:none;counter-reset:oi;padding-left:0;margin:0 0 1.2em}
ol li{
  position:relative;padding-left:2.2em;margin-bottom:.6em;counter-increment:oi;
}
ol li::before{
  content:counter(oi);
  position:absolute;left:0;top:.15em;
  width:1.6em;height:1.6em;line-height:1.6em;text-align:center;
  border-radius:50%;background:var(--primary);color:#fff;font-size:.85em;font-weight:700;
}

/* Table */
.table-wrap{overflow-x:auto;margin:1.2em 0;border-radius:var(--radius);box-shadow:var(--shadow)}
table{width:100%;border-collapse:collapse;background:var(--bg);min-width:520px}
thead th{
  background:linear-gradient(120deg,var(--primary),var(--secondary));
  color:#fff;text-align:left;padding:10px 12px;font-weight:600;font-size:.96rem;
}
tbody td{padding:10px 12px;border-bottom:1px solid var(--border);font-size:.96rem}
tbody tr:nth-child(even){background:var(--row-alt)}

/* TOC */
nav.toc{
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius);padding:14px 18px;margin:20px 0 28px;
}
nav.toc strong{display:block;color:var(--secondary);margin-bottom:8px}
nav.toc ol{margin:0;padding-left:0}
nav.toc ol li{padding-left:2em}
nav.toc a{text-decoration:none;color:var(--primary)}
nav.toc a:hover{text-decoration:underline}

/* FAQ */
details{
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius);padding:12px 16px;margin-bottom:10px;
}
details summary{
  cursor:pointer;font-weight:600;color:var(--secondary);list-style:none;
  display:flex;justify-content:space-between;align-items:center;gap:12px;
}
details summary::-webkit-details-marker{display:none}
details summary::after{
  content:"▼";color:var(--accent);transition:transform .2s;font-size:.85em;
}
details[open] summary::after{transform:rotate(180deg)}
details p{margin:10px 0 0;color:var(--text)}

/* Callout */
.callout{
  background:var(--surface-alt);border-left:4px solid var(--primary);
  border-radius:var(--radius);padding:14px 18px;margin:20px 0;
}
.callout strong{color:var(--secondary)}

/* Author box */
.author-box{
  display:flex;gap:16px;align-items:flex-start;
  background:linear-gradient(120deg,var(--surface),var(--surface-alt));
  border:1px solid var(--border);border-radius:var(--radius);
  padding:18px;margin:36px 0 12px;
}
.author-box img{width:72px;height:72px;border-radius:50%;background:#fff;padding:4px;flex-shrink:0}
.author-box h3{margin:0 0 6px;color:var(--secondary)}
.author-box p{margin:0;color:var(--text);font-size:.96rem}
.author-box .role{color:var(--muted);font-size:.9rem;margin-bottom:6px}

/* Figures */
figure{margin:20px 0;text-align:center}
figure img,figure svg{margin:0 auto;border-radius:var(--radius)}
figcaption{font-size:.9rem;color:var(--muted);margin-top:8px}

/* Footer */
footer{
  background:var(--secondary);color:#fff;
  padding:32px 18px;margin-top:48px;
}
footer .wrap{max-width:1120px;margin:0 auto;display:grid;gap:20px;grid-template-columns:1fr;}
footer a{color:#dbeafe;text-decoration:none}
footer a:hover{text-decoration:underline}
footer h3{margin:0 0 8px;font-size:1rem;color:#fff}
footer ul li::before{color:var(--accent)}
footer p{margin:0;font-size:.92rem;color:#dbeafe}
.copyright{border-top:1px solid rgba(255,255,255,.15);padding-top:16px;margin-top:16px;text-align:center;font-size:.88rem;color:#bfdbfe}

/* CTA */
.cta-row{display:flex;flex-wrap:wrap;gap:10px;margin:18px 0}
.btn{
  display:inline-block;padding:10px 18px;border-radius:var(--radius);
  background:var(--primary);color:#fff;text-decoration:none;font-weight:600;
  transition:background .15s;
}
.btn:hover{background:var(--secondary);color:#fff}
.btn.alt{background:transparent;color:var(--primary);border:2px solid var(--primary)}
.btn.alt:hover{background:var(--primary);color:#fff}

/* Card grid */
.grid{display:grid;gap:16px;grid-template-columns:1fr;margin:16px 0}
.card{
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius);padding:16px;
}
.card h3{margin-top:0}

/* Responsive */
@media(min-width:700px){
  body{font-size:17px}
  .hero{padding:60px 24px 48px}
  .hero h1{font-size:2.35rem}
  main{padding:44px 22px 28px}
  h2{font-size:1.6rem}
  footer .wrap{grid-template-columns:1.4fr 1fr 1fr}
  .grid{grid-template-columns:repeat(2,1fr)}
}
@media(min-width:980px){
  main{padding:52px 24px 36px}
  .hero h1{font-size:2.55rem}
  h2{font-size:1.7rem}
  .grid{grid-template-columns:repeat(3,1fr)}
}

/* a11y additions */
.skip-link{position:absolute;left:-9999px;top:0;background:var(--primary);color:#fff;padding:10px 16px;border-radius:4px;z-index:1000;text-decoration:none;font-weight:700}
.skip-link:focus{left:12px;top:12px}
a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--accent);outline-offset:2px}
@media (prefers-reduced-motion: reduce){*,*::before,*::after{transition-duration:.01ms !important;animation-duration:.01ms !important}}