/* 29/10: blog SEO tĩnh — trang app nằm sau đăng nhập (React), Google / ChatGPT không đọc được, nên bài viết là HTML thuần. */
:root {
  --bg: #f6f6fa; --surface: #ffffff; --ink: #17151f; --muted: #5d5a6b; --line: #e6e3ef;
  --accent: #7c3aed; --accent-2: #c026d3; --soft: #f1ebff;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #0f0e14; --surface: #18161f; --ink: #ecebf2; --muted: #a8a4b8; --line: #2a2735;
    --accent: #a78bfa; --accent-2: #e879f9; --soft: #221c33; }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.75 "Be Vietnam Pro", system-ui, -apple-system,
  "Segoe UI", Roboto, sans-serif; }
a { color: var(--accent); }
.top { border-bottom: 1px solid var(--line); background: var(--surface); }
.top .in, main, footer .in { max-width: 760px; margin: 0 auto; padding: 0 16px; }
.top .in { display: flex; align-items: center; justify-content: space-between; height: 60px; gap: 12px; }
.logo { display: flex; align-items: center; gap: 8px; font-weight: 800; color: var(--ink); text-decoration: none; }
.logo img { width: 28px; height: 28px; }
.top nav a { color: var(--muted); text-decoration: none; margin-left: 16px; font-size: 15px; }
.btn { display: inline-block; background: linear-gradient(135deg, var(--accent), var(--accent-2)); color: #fff !important;
  padding: 10px 18px; border-radius: 12px; font-weight: 700; text-decoration: none; }
.crumb { font-size: 14px; color: var(--muted); margin: 24px 0 8px; }
.crumb a { color: var(--muted); }
h1 { font-size: 32px; line-height: 1.25; margin: 8px 0 12px; letter-spacing: -0.01em; }
h2 { font-size: 24px; line-height: 1.3; margin: 40px 0 8px; }
h3 { font-size: 19px; margin: 28px 0 6px; }
.meta { color: var(--muted); font-size: 14px; margin-bottom: 24px; }
.tldr { background: var(--soft); border-left: 4px solid var(--accent); border-radius: 12px; padding: 14px 18px; }
.tldr p { margin: 6px 0; }
.tldr ul { margin: 6px 0; padding-left: 20px; }
table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 15px; display: block; overflow-x: auto; }
th, td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; vertical-align: top; }
th { background: var(--surface); }
figure { margin: 24px 0; }
figure img { width: 100%; max-width: 360px; border-radius: 14px; display: block; }
figcaption { color: var(--muted); font-size: 14px; margin-top: 6px; }
.cta { background: var(--surface); border: 1px solid var(--line); border-radius: 16px; padding: 20px; margin: 40px 0; }
.cta p { margin: 0 0 12px; }
.faq h3 { margin-top: 20px; }
.related ul { padding-left: 20px; }
.cards { list-style: none; padding: 0; display: grid; gap: 14px; }
.cards li { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 16px 18px; }
.cards a { font-weight: 700; font-size: 18px; text-decoration: none; }
.cards p { margin: 6px 0 0; color: var(--muted); font-size: 15px; }
footer { border-top: 1px solid var(--line); margin-top: 48px; padding: 24px 0 40px; color: var(--muted); font-size: 14px; }
footer a { color: var(--muted); }
@media (max-width: 560px) {
  body { font-size: 16px; }
  h1 { font-size: 26px; }
  h2 { font-size: 21px; }
  .top nav a.hide-sm { display: none; }
}