:root{
  --purple-950:#170F2E; --purple-800:#2C2153; --purple-700:#4A34B8; --purple-600:#5B3DF6;
  --purple-400:#9C86FA; --purple-200:#D9CFFC; --lavender-50:#F7F5FE;
  --amber-500:#F5A84B; --amber-600:#E8923A;
  --ink-800:#241C3D; --ink-600:#544C72; --ink-400:#8A81A6;
  --white:#FFFFFF; --line:#E7E1FA;
  --shadow: 0 20px 50px -20px rgba(44,33,83,0.25);
  --radius-lg: 28px; --radius-md: 18px; --radius-sm: 12px;
  --font-display:'Prompt', 'IBM Plex Sans Thai', sans-serif;
  --font-body:'IBM Plex Sans Thai', 'Prompt', sans-serif;
  --ease: cubic-bezier(.16,.8,.3,1);
}
*{box-sizing:border-box; margin:0; padding:0;}
html{scroll-behavior:smooth;}
body{font-family:var(--font-body); color:var(--ink-800); background:var(--lavender-50); -webkit-font-smoothing:antialiased;}
img{max-width:100%; display:block;}
a{color:var(--purple-700); text-decoration:underline; text-decoration-color:var(--purple-200); text-underline-offset:3px;}
a:hover{color:var(--purple-600);}
ul{list-style:none;}
h1,h2,h3{font-family:var(--font-display); font-weight:700; color:var(--purple-950);}
.container{width:100%; max-width:820px; margin:0 auto; padding:0 28px;}
.wide{max-width:1180px;}

header.nav{position:sticky; top:0; z-index:100; background:rgba(247,245,254,0.92); backdrop-filter:blur(14px); border-bottom:1px solid var(--line);}
.nav-inner{display:flex; align-items:center; justify-content:space-between; height:76px; max-width:1180px; margin:0 auto; padding:0 28px;}
.brand{display:flex; align-items:center; gap:10px; font-family:var(--font-display); font-weight:700; font-size:21px; color:var(--purple-950); text-decoration:none;}
.brand img{width:36px; height:36px; border-radius:9px; object-fit:cover;}
nav.links{display:flex; align-items:center; gap:34px;}
nav.links a{font-size:14.5px; font-weight:500; color:var(--ink-600); text-decoration:none; transition:color .2s;}
nav.links a:hover{color:var(--purple-700);}
.btn{display:inline-flex; align-items:center; justify-content:center; gap:8px; padding:12px 24px; border-radius:100px; font-weight:600; font-size:14.5px; border:none; text-decoration:none; transition:all .25s var(--ease);}
.btn-primary{background:var(--purple-600); color:var(--white) !important; box-shadow:0 12px 24px -10px rgba(91,61,246,0.55);}
.btn-primary:hover{transform:translateY(-2px); background:var(--purple-700);}

.crumb{padding:28px 0 0; font-size:13.5px; color:var(--ink-400);}
.crumb a{color:var(--ink-400); text-decoration:none;}
.crumb a:hover{color:var(--purple-700);}

.art-header{padding:20px 0 36px;}
.cat{display:inline-flex; background:#FFF1DE; color:var(--amber-600); font-weight:700; font-size:12.5px; padding:7px 16px; border-radius:100px; margin-bottom:20px;}
.art-header h1{font-size:clamp(28px,4vw,42px); line-height:1.28; margin-bottom:18px;}
.art-header .lead{font-size:17px; color:var(--ink-600); line-height:1.75;}

article.body{padding-bottom:30px; font-size:16px; line-height:1.9; color:var(--ink-800);}
article.body h2{font-size:24px; margin:44px 0 16px; line-height:1.4;}
article.body h3{font-size:19px; margin:30px 0 12px; color:var(--purple-800);}
article.body p{margin-bottom:18px; color:var(--ink-800);}
article.body strong{color:var(--purple-950); font-weight:700;}
article.body ul, article.body ol{margin:0 0 18px 22px;}
article.body li{margin-bottom:8px; line-height:1.8;}
article.body ul{list-style:disc;}
article.body ol{list-style:decimal;}

.callout{background:var(--white); border:1px solid var(--line); border-left:4px solid var(--amber-500); border-radius:var(--radius-sm); padding:20px 24px; margin:26px 0; font-size:15px; color:var(--ink-600); line-height:1.8;}
.callout strong{color:var(--purple-950);}

table.data{width:100%; border-collapse:collapse; margin:24px 0; background:var(--white); border-radius:var(--radius-sm); overflow:hidden; box-shadow:0 4px 16px -8px rgba(44,33,83,0.15); font-size:14.5px;}
table.data th{background:var(--purple-950); color:var(--white); text-align:left; padding:14px 18px; font-family:var(--font-display); font-weight:600; font-size:13.5px;}
table.data td{padding:13px 18px; border-bottom:1px solid var(--line); color:var(--ink-800);}
table.data tr:last-child td{border-bottom:none;}
table.data tr:nth-child(even) td{background:var(--lavender-50);}

.calc-box{background:var(--purple-950); border-radius:var(--radius-lg); padding:32px; margin:28px 0; color:var(--white);}
.calc-box h4{font-family:var(--font-display); font-weight:600; font-size:14px; text-transform:uppercase; letter-spacing:.05em; color:var(--purple-400); margin-bottom:18px;}
.calc-row{display:flex; justify-content:space-between; padding:10px 0; border-bottom:1px solid rgba(255,255,255,0.12); font-size:15px;}
.calc-row:last-child{border-bottom:none; padding-top:16px; margin-top:6px; border-top:1px solid rgba(255,255,255,0.25);}
.calc-row .val{font-family:var(--font-display); font-weight:700;}
.calc-row.result .val{color:var(--amber-500); font-size:19px;}
.calc-row.result span:first-child{font-family:var(--font-display); font-weight:600;}

.cta-box{background:linear-gradient(155deg, var(--purple-700), var(--purple-950)); border-radius:var(--radius-lg); padding:38px; margin:40px 0; text-align:center; color:var(--white);}
.cta-box h3{color:var(--white); font-size:22px; margin-bottom:10px;}
.cta-box p{color:var(--purple-200); font-size:15px; margin-bottom:22px; max-width:480px; margin-left:auto; margin-right:auto;}
.cta-box .btn-amber{background:var(--amber-500); color:var(--purple-950) !important; text-decoration:none;}
.cta-box .btn-amber:hover{background:var(--amber-600); transform:translateY(-2px);}

.faq{margin-top:36px;}
.faq-item{border-top:1px solid var(--line); padding:20px 0;}
.faq-item h4{font-family:var(--font-display); font-weight:600; font-size:16px; color:var(--purple-950); margin-bottom:8px;}
.faq-item p{font-size:14.5px; color:var(--ink-600); line-height:1.75; margin:0;}

.disclaimer{font-size:13px; color:var(--ink-400); line-height:1.8; margin-top:40px; padding-top:24px; border-top:1px solid var(--line);}

.related{background:var(--white); border-top:1px solid var(--line); padding:60px 0 70px; margin-top:20px;}
.related h3{font-size:20px; margin-bottom:24px;}
.related-grid{display:grid; grid-template-columns:repeat(2,1fr); gap:18px;}
.related-card{display:block; background:var(--lavender-50); border:1px solid var(--line); border-radius:var(--radius-md); padding:22px; text-decoration:none; transition:transform .25s var(--ease);}
.related-card:hover{transform:translateY(-3px);}
.related-card span.cat2{display:inline-block; font-size:11.5px; font-weight:700; color:var(--amber-600); margin-bottom:8px;}
.related-card h4{font-family:var(--font-display); font-weight:600; font-size:15px; color:var(--purple-950); line-height:1.5;}

footer{background:var(--purple-950); color:var(--purple-200); padding:50px 0 30px;}
.footer-inner{display:flex; justify-content:space-between; align-items:center; flex-wrap:wrap; gap:16px; max-width:1180px; margin:0 auto; padding:0 28px;}
.footer-brand{display:flex; align-items:center; gap:10px; font-family:var(--font-display); font-weight:700; font-size:18px; color:var(--white); text-decoration:none;}
.footer-brand img{width:30px; height:30px; border-radius:8px;}
.footer-links{display:flex; gap:24px; flex-wrap:wrap;}
footer a{font-size:14px; color:var(--purple-200); text-decoration:none;}
footer a:hover{color:var(--white);}

@media (max-width:820px){
  nav.links{display:none;}
  .related-grid{grid-template-columns:1fr;}
  table.data{font-size:13px;}
  table.data th, table.data td{padding:10px 12px;}
}