:root,
[data-theme="clean"] {
  --bg: #ffffff;
  --surface: #f5f7f9;
  --surface-2: #eceff3;
  --text: #1c2230;
  --muted: #55607a;
  --primary: #0f6b5c;
  --primary-hover: #0b5145;
  --primary-active: #083c33;
  --on-primary: #ffffff;
  --secondary: #eceff3;
  --on-secondary: #1c2230;
  --border: #d7dde5;
  --focus: #0f6b5c;
  --font-heading: 'Noto Serif Thai', serif;
  --font-body: 'IBM Plex Sans Thai', sans-serif;
  --radius: 10px;
  --btn-radius: 999px;
  --btn-border-width: 1px;
  --btn-shadow: none;
  --btn-shadow-active: none;
  --btn-translate-active: 0;
}

[data-theme="nature"] {
  --bg: #f2f5f0;
  --surface: #e7ede3;
  --surface-2: #dbe4d5;
  --text: #1f2a22;
  --muted: #4c5a4f;
  --primary: #3d6b35;
  --primary-hover: #325829;
  --primary-active: #274520;
  --on-primary: #ffffff;
  --secondary: #dbe4d5;
  --on-secondary: #1f2a22;
  --border: #c2cfba;
  --focus: #3d6b35;
  --font-heading: 'Mitr', sans-serif;
  --font-body: 'Sarabun', sans-serif;
  --radius: 14px;
  --btn-radius: 14px;
  --btn-border-width: 1px;
  --btn-shadow: inset 0 -4px 0 rgba(0,0,0,.28);
  --btn-shadow-active: inset 0 -1px 0 rgba(0,0,0,.28);
  --btn-translate-active: 3px;
}

[data-theme="midnight"] {
  --bg: #121a2b;
  --surface: #1a2439;
  --surface-2: #223049;
  --text: #e8ecf4;
  --muted: #a9b5cc;
  --primary: #e3b35b;
  --primary-hover: #f0c477;
  --primary-active: #c99741;
  --on-primary: #1a1406;
  --secondary: #223049;
  --on-secondary: #e8ecf4;
  --border: #2e3d59;
  --focus: #e3b35b;
  --font-heading: 'Prompt', sans-serif;
  --font-body: 'Anuphan', sans-serif;
  --radius: 8px;
  --btn-radius: 8px;
  --btn-border-width: 1px;
  --btn-shadow: none;
  --btn-shadow-active: none;
  --btn-translate-active: 0;
}

[data-theme="pop"] {
  --bg: #f4f1ff;
  --surface: #ffffff;
  --surface-2: #e9e3ff;
  --text: #1a1633;
  --muted: #4a4470;
  --primary: #5b3df5;
  --primary-hover: #4a2fd6;
  --primary-active: #3b24ad;
  --on-primary: #ffffff;
  --secondary: #ffd23f;
  --on-secondary: #1a1633;
  --border: #1a1633;
  --focus: #5b3df5;
  --font-heading: 'Kanit', sans-serif;
  --font-body: 'K2D', sans-serif;
  --radius: 12px;
  --btn-radius: 12px;
  --btn-border-width: 2px;
  --btn-shadow: 4px 4px 0 #1a1633;
  --btn-shadow-active: 0 0 0 #1a1633;
  --btn-translate-active: 4px;
}

[data-theme="formal"] {
  --bg: #fafaf8;
  --surface: #f1f1ed;
  --surface-2: #e6e6e0;
  --text: #1f1f1f;
  --muted: #585856;
  --primary: #7a1f2b;
  --primary-hover: #611821;
  --primary-active: #4a1219;
  --on-primary: #ffffff;
  --secondary: #e6e6e0;
  --on-secondary: #1f1f1f;
  --border: #cfcfc7;
  --focus: #7a1f2b;
  --font-heading: 'Trirong', serif;
  --font-body: 'Sarabun', sans-serif;
  --radius: 2px;
  --btn-radius: 2px;
  --btn-border-width: 1px;
  --btn-shadow: none;
  --btn-shadow-active: none;
  --btn-translate-active: 0;
}

*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 18px;
  line-height: 1.8;
  word-break: break-word;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  line-height: 1.35;
  margin: 0 0 .6em;
  font-weight: 600;
}
h1 { font-size: clamp(1.75rem, 1.25rem + 2.2vw, 2.6rem); }
h2 { font-size: clamp(1.4rem, 1.15rem + 1.2vw, 1.9rem); margin-top: 1.6em; }
h3 { font-size: clamp(1.15rem, 1.05rem + .55vw, 1.4rem); margin-top: 1.4em; }

p { margin: 0 0 1.1em; }
ul, ol { margin: 0 0 1.1em; padding-inline-start: 1.5em; }
li { margin-bottom: .45em; }
strong { font-weight: 600; }

a { color: var(--primary); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible,
button:focus-visible,
summary:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}

img { max-width: 100%; height: auto; display: block; }

.wrap { width: min(100% - 2.5rem, 820px); margin-inline: auto; }
.wrap-wide { width: min(100% - 2.5rem, 1100px); margin-inline: auto; }

.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--primary); color: var(--on-primary);
  padding: .8rem 1.2rem; z-index: 100;
}
.skip-link:focus { left: 0; }

/* ---------- header ---------- */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  position: sticky; top: 0; z-index: 30;
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: .75rem; padding: .6rem 0;
}
.brand {
  display: inline-flex; align-items: center; gap: .6rem;
  font-family: var(--font-heading); font-weight: 600;
  font-size: 1.15rem; color: var(--text); text-decoration: none;
  min-height: 48px; flex-shrink: 1; min-width: 0;
}
.brand-logo { height: 36px; width: auto; flex-shrink: 0; }
.brand span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ปุ่มมุมขวาบน — ห้ามหด ต้องเห็นเสมอแม้จอแคบ */
.header-cta { display: flex; gap: .5rem; flex-shrink: 0; align-items: center; }
.btn-compact { padding: .55rem 1.05rem; font-size: .95rem; min-height: 48px; }

.header-nav-row { border-top: 1px solid var(--border); background: var(--surface); }
.site-nav ul {
  display: flex; gap: .2rem 1.4rem;
  list-style: none; margin: 0; padding: 0;
  overflow-x: auto; scrollbar-width: none; -ms-overflow-style: none;
}
.site-nav ul::-webkit-scrollbar { display: none; }
.site-nav a {
  display: inline-flex; align-items: center; min-height: 48px;
  color: var(--muted); text-decoration: none; font-weight: 500;
  white-space: nowrap; font-size: .96rem;
  border-bottom: 3px solid transparent;
}
.site-nav a:hover { color: var(--primary); }
.site-nav a[aria-current="page"] {
  color: var(--primary); border-bottom-color: var(--primary);
}

/* ---------- hero (เฉพาะหน้าแรก) ---------- */
.hero {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 2.8rem 0 3rem;
  margin-bottom: 2.5rem;
}
.hero-inner {
  display: grid; gap: 2.2rem;
  grid-template-columns: 1.05fr .95fr;
  align-items: center;
}
.hero-text h1 { margin-bottom: .5em; }
.hero-text .intro { font-size: 1.16rem; margin-bottom: 1.5rem; }
.hero-text .byline { border-block: 0; padding: 0; margin: 1.4rem 0 0; }
.hero-cta { margin: 0; }
.hero-media .cover { margin: 0; }
.hero-media .cover img {
  border-radius: var(--radius);
  box-shadow: 0 18px 40px rgba(0, 0, 0, .18);
}
.hero-media figcaption { display: none; }

/* ---------- breadcrumb ---------- */
.breadcrumb { padding: 1rem 0 .25rem; font-size: .92rem; color: var(--muted); }
.breadcrumb ol { display: flex; flex-wrap: wrap; gap: .45rem; list-style: none; margin: 0; padding: 0; }
.breadcrumb li + li::before { content: "/"; margin-inline-end: .45rem; opacity: .6; }
.breadcrumb a { color: var(--muted); }

/* ---------- article ---------- */
main { padding-bottom: 3.5rem; }
.intro { font-size: 1.12rem; color: var(--muted); margin-bottom: 1.4rem; }
.byline {
  display: flex; flex-wrap: wrap; gap: .4rem 1.1rem;
  font-size: .93rem; color: var(--muted);
  padding: .8rem 0; border-block: 1px solid var(--border);
  margin-bottom: 1.6rem;
}
.cover { margin: 0 0 2rem; }
.cover img { width: 100%; border-radius: var(--radius); }
figure { margin: 0 0 1.5rem; }
figcaption { font-size: .9rem; color: var(--muted); margin-top: .5rem; }

/* ---------- สารบัญ ---------- */
.toc {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.1rem 1.3rem; margin-bottom: 2.2rem;
}
.toc h2 { margin: 0 0 .6rem; font-size: 1.05rem; }
.toc ol { margin: 0; padding-inline-start: 1.3rem; }
.toc li { margin-bottom: .3rem; }
.toc a { display: inline-block; padding: .25rem 0; min-height: 32px; }

.section { margin-bottom: 2.6rem; }
.section img { border-radius: var(--radius); margin-bottom: 1rem; }

/* ---------- FAQ ---------- */
.faq { margin: 2.8rem 0; }
.faq-item {
  border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--surface); margin-bottom: .8rem; overflow: hidden;
}
.faq-item summary {
  cursor: pointer; list-style: none; padding: 1rem 1.2rem;
  font-weight: 600; font-family: var(--font-heading);
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
  min-height: 48px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 1.4rem; line-height: 1; color: var(--primary); }
.faq-item[open] summary::after { content: "\2212"; }
.faq-answer { padding: 0 1.2rem 1rem; color: var(--muted); }

/* ---------- ปุ่ม ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 48px; padding: .75rem 1.6rem;
  font-family: var(--font-heading); font-size: 1rem; font-weight: 600;
  text-decoration: none; cursor: pointer;
  border: var(--btn-border-width) solid transparent;
  border-radius: var(--btn-radius);
  background: var(--primary); color: var(--on-primary);
  box-shadow: var(--btn-shadow);
  transition: background-color .15s ease, box-shadow .15s ease, transform .15s ease;
}
.btn:hover { background: var(--primary-hover); }
.btn:active {
  background: var(--primary-active);
  box-shadow: var(--btn-shadow-active);
  transform: translateY(var(--btn-translate-active));
}
.btn:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; }
.btn[disabled], .btn[aria-disabled="true"] {
  opacity: .5; cursor: not-allowed; pointer-events: none;
  box-shadow: none; transform: none;
}
.btn-secondary {
  background: var(--secondary); color: var(--on-secondary);
  border-color: var(--border);
}
.btn-secondary:hover { filter: brightness(.94); background: var(--secondary); }
.btn-secondary:active { background: var(--secondary); filter: brightness(.88); }

.cta-group { display: flex; flex-wrap: wrap; gap: .9rem; margin: 2.2rem 0; }
.cta-group.center { justify-content: center; }

/* ---------- บทความที่เกี่ยวข้อง ---------- */
.related { margin: 3rem 0 0; }
.related-grid {
  display: grid; gap: 1rem;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  list-style: none; margin: 0; padding: 0;
}
.related-card {
  display: block; padding: 1.1rem 1.2rem; text-decoration: none;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); color: var(--text);
  transition: border-color .15s ease, transform .15s ease;
  min-height: 48px;
}
.related-card:hover { border-color: var(--primary); transform: translateY(-2px); }
.related-card strong { display: block; font-family: var(--font-heading); margin-bottom: .35rem; }
.related-card span { font-size: .92rem; color: var(--muted); }

/* ---------- footer ---------- */
.site-footer {
  border-top: 1px solid var(--border); background: var(--surface);
  padding: 2rem 0; margin-top: 3rem; color: var(--muted); font-size: .95rem;
}
.footer-inner { display: flex; flex-wrap: wrap; gap: 1rem 2rem; justify-content: space-between; }
.site-footer ul { display: flex; flex-wrap: wrap; gap: .3rem 1.3rem; list-style: none; margin: 0; padding: 0; }
.site-footer a { color: var(--muted); min-height: 48px; display: inline-flex; align-items: center; }
.site-footer a:hover { color: var(--primary); }

/* ---------- 404 ---------- */
.notfound { text-align: center; padding: 4rem 0; }
.notfound .code { font-size: 4rem; font-family: var(--font-heading); color: var(--primary); margin: 0; }

/* ---------- มือถือ ---------- */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: 1.6rem; }
  .hero { padding: 2rem 0 2.2rem; margin-bottom: 2rem; }
  /* บนมือถือให้รูปปกอยู่ใต้ข้อความและปุ่ม เพื่อให้ปุ่มขึ้นมาอยู่ช่วงบนของจอ */
  .hero-media { order: 2; }
  .hero-text { order: 1; }
}

@media (max-width: 640px) {
  body { font-size: 17px; }
  .wrap, .wrap-wide { width: min(100% - 2rem, 820px); }

  /* หัวเว็บบนมือถือ: โลโก้ย่อลง ปุ่มยังเต็มขนาดและเห็นชัด */
  .brand { font-size: 1rem; gap: .45rem; }
  .brand-logo { height: 30px; }
  .header-cta { gap: .4rem; }
  .btn-compact { padding: .5rem .85rem; font-size: .9rem; }

  .hero-text .intro { font-size: 1.05rem; }
  .hero-cta { flex-direction: column; align-items: stretch; }
  .hero-cta .btn { width: 100%; }
  .cta-group .btn { width: 100%; }
}

/* จอแคบมาก: ซ่อนชื่อเว็บที่เป็นตัวอักษร เหลือโลโก้ เพื่อให้ปุ่มมีที่พอ */
@media (max-width: 400px) {
  .brand span { display: none; }
  .btn-compact { padding: .5rem .7rem; font-size: .86rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  .btn:active, .related-card:hover { transform: none; }
}