:root{
  --brand:#1a73e8;        /* โทนฟ้าเทค */
  --brand-2:#0b5bd3;
  --ink:#0f172a;          /* ข้อความ */
  --muted:#475569;        /* คำอธิบาย */
  --bg:#ffffff;           /* พื้นหลัง */
  --bg-soft:#f8fafc;      /* พื้นหลังอ่อน */
  --card:#ffffff;         /* การ์ด */
  --border:#e2e8f0;       /* เส้นขอบ */
  --success:#16a34a;
  --warning:#f59e0b;
  --radius:16px;
  --shadow:0 8px 30px rgba(2,6,23,.08);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:ui-sans-serif,system-ui,"Segoe UI",Roboto,Inter,Helvetica,Arial,"Noto Sans",sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.65
}
img{max-width:100%;height:auto;display:block}
.container{width:min(1120px,92vw);margin-inline:auto}
.grid{display:grid;gap:24px}
.btn{display:inline-block;padding:12px 18px;border-radius:12px;background:var(--brand);color:#fff;text-decoration:none;font-weight:600}
.btn:hover{background:var(--brand-2)}
.badge{display:inline-flex;gap:8px;align-items:center;padding:6px 10px;border:1px solid var(--border);border-radius:999px;color:var(--muted);font-size:.9rem}
.section{padding:56px 0}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden}
.card-body{padding:20px}
.muted{color:var(--muted)}
hr{border:none;border-top:1px solid var(--border);margin:24px 0}

/* Header */
.header{
  position:static;            /* เดิม sticky → ให้ไหลไปกับเนื้อหา */
  background:#fff;
  border-bottom:1px solid var(--border);
  z-index:50;                 /* จะมีหรือไม่มีก็ได้ เมื่อไม่ sticky แล้ว */
}

.header-inner{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:12px 0}
.logo{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--ink)}
.logo .mark{width:36px;height:36px;border-radius:10px;background:linear-gradient(135deg,var(--brand),#60a5fa)}
.nav{display:flex;gap:18px}
.nav a{color:var(--ink);text-decoration:none;font-weight:600}
.nav a:hover{color:var(--brand)}

/* Mobile menu + dropdown sheet in header */
.mobile-only{display:none}
@media (max-width: 768px){
  .desktop-only{display:none}
  .mobile-only{display:block}
  .nav{display:none}
}

/* Hero */
.hero{padding:64px 0;background:linear-gradient(180deg,#f1f5ff 0%, #fff 100%)}
.hero-wrap{display:grid;grid-template-columns:1.1fr .9fr;gap:28px;align-items:center}
.hero h1{font-size:clamp(28px,4vw,42px);line-height:1.15;margin:0 0 12px}
.hero p{font-size:clamp(16px,2.2vw,18px)}
.hero .cta{display:flex;flex-wrap:wrap;gap:12px;margin-top:16px}
@media (max-width: 900px){.hero-wrap{grid-template-columns:1fr}}

/* Feature cards */
.features{grid-template-columns:repeat(3,1fr)}
@media (max-width: 900px){.features{grid-template-columns:1fr 1fr}}
@media (max-width: 640px){.features{grid-template-columns:1fr}}

/* Footer */
.footer{background:var(--bg-soft);padding:28px 0;border-top:1px solid var(--border)}
.footer a{color:var(--muted);text-decoration:none}
.footer a:hover{color:var(--brand)}

/* Cookie/info bar (simple, non-tracking, Ads-friendly) */
.notice{position:fixed;left:16px;right:16px;bottom:16px;background:#0b1020;color:#e2e8f0;border-radius:14px;padding:14px 16px;box-shadow:var(--shadow);display:flex;align-items:center;gap:12px}
.notice .btn{background:#22c55e}
.notice .btn:hover{background:#16a34a}

/* Content typography */
.prose h2{margin-top:0}
.prose h3{margin:28px 0 8px}
.prose p{margin:10px 0}
.prose ul{margin:6px 0 18px 18px}
.prose li{margin:6px 0}
.code{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;background:#f1f5f9;border:1px solid var(--border);padding:10px 12px;border-radius:10px;display:inline-block}

/* Mobile Top Stack: แสดงเฉพาะมือถือ */
.mobile-top-stack{display:none}
@media (max-width:768px){
  .mobile-top-stack{
    display:block;
    width:100vw;
    margin:0; padding:0;
  }
  .mobile-top-stack a{display:block; line-height:0}
  .mobile-top-stack img{
    display:block;
    width:100vw;
    height:auto;
    margin:0;
  }
}