:root {
  --green: #20B759; --green-dark: #093011; --green-light: #4CD97B;
  --blue: #285CE1; --ink: #111827; --ink-2: #374151; --muted: #6B7280;
  --line: #E5E7EB; --bg: #F9FAFB; --card: #FFFFFF; --warn-bg: #FFFBEB; --warn: #B45309;
  --radius: 16px; --max: 1040px;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; color: var(--ink); background: var(--bg); line-height: 1.6; }
a { color: var(--blue); }
img { max-width: 100%; }
.container { max-width: var(--max); margin: 0 auto; padding: 0 16px; }
.site-header { background: var(--card); border-bottom: 1px solid var(--line); }
.site-header .container { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); font-weight: 700; }
.brand img { height: 32px; }
.nav a { color: var(--ink-2); text-decoration: none; margin-left: 20px; font-size: 14px; }
.nav a:hover { color: var(--green); }
.site-footer { border-top: 1px solid var(--line); margin-top: 56px; padding: 28px 0; font-size: 14px; color: var(--muted); }
.site-footer .links a { margin-right: 16px; color: var(--ink-2); text-decoration: none; }
.site-footer .links a:hover { text-decoration: underline; }

/* Trang nội dung (policy, terms, ...) */
.doc { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 32px 28px; margin-top: 32px; }
.doc h1 { font-size: 30px; line-height: 1.25; margin: 0 0 6px; }
.doc .meta { color: var(--muted); font-size: 14px; margin-bottom: 24px; }
.doc h2 { font-size: 20px; margin: 32px 0 10px; padding-top: 8px; border-top: 1px solid var(--line); }
.doc h3 { font-size: 16px; margin: 20px 0 6px; }
.doc p, .doc li { font-size: 15.5px; color: var(--ink-2); }
.doc ul, .doc ol { padding-left: 22px; }
.doc table { width: 100%; border-collapse: collapse; font-size: 14.5px; margin: 12px 0 20px; }
.doc th, .doc td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; vertical-align: top; }
.doc th { background: var(--bg); }
.doc .toc { background: var(--bg); border-radius: 12px; padding: 14px 18px 14px 34px; margin: 0 0 8px; }
.doc .toc li { margin: 2px 0; }
.lang-switch { font-size: 14px; margin-top: 16px; }
.note { background: var(--warn-bg); border-left: 4px solid var(--warn); padding: 10px 14px; border-radius: 8px; font-size: 14.5px; color: var(--warn); }

/* Trang download */
.hero { display: grid; grid-template-columns: 1.2fr 1fr; gap: 32px; align-items: center; padding: 48px 0 24px; }
.hero h1 { font-size: 40px; line-height: 1.15; margin: 12px 0; }
.hero p.lead { font-size: 18px; color: var(--ink-2); }
.badge { display: inline-block; background: #E8F8EE; color: var(--green-dark); border-radius: 999px; padding: 4px 12px; font-size: 13px; font-weight: 600; min-height: 26px; }
.app-id { display: flex; align-items: center; gap: 14px; }
.app-id img { width: 64px; height: 64px; border-radius: 16px; box-shadow: 0 4px 14px rgba(0,0,0,.12); }
.qr-card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; text-align: center; }
.qr-card #qr svg, .qr-card #qr img { width: 220px; height: 220px; }
.qr-card .hint { font-size: 14px; color: var(--muted); margin: 10px 0 0; }
.platforms { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 16px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; }
.card h2 { margin: 0 0 6px; font-size: 22px; display: flex; align-items: center; gap: 10px; }
.card .sub { color: var(--muted); font-size: 14px; margin: 0 0 16px; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 20px; border-radius: 12px; font-weight: 600; text-decoration: none; border: 0; cursor: pointer; font-size: 16px; }
.btn-primary { background: var(--green); color: #fff; }
.btn-primary:hover { background: #1AA04D; }
.btn-ghost { background: var(--bg); color: var(--ink-2); border: 1px solid var(--line); }
.btn[aria-disabled="true"] { opacity: .5; cursor: not-allowed; pointer-events: none; }
.kv { font-size: 14px; color: var(--muted); margin: 12px 0 0; }
.kv b { color: var(--ink-2); font-weight: 600; }
.kv code { font-size: 12px; word-break: break-all; }
.steps { counter-reset: s; padding-left: 0; list-style: none; margin: 12px 0 0; }
.steps li { position: relative; padding-left: 36px; margin: 10px 0; font-size: 15px; color: var(--ink-2); }
.steps li::before { counter-increment: s; content: counter(s); position: absolute; left: 0; top: 2px; width: 24px; height: 24px; border-radius: 50%; background: #E8F8EE; color: var(--green-dark); font-weight: 700; font-size: 13px; display: flex; align-items: center; justify-content: center; }
.notes-list { padding-left: 20px; font-size: 14.5px; color: var(--ink-2); }
.section-title { font-size: 22px; margin: 40px 0 8px; }
.highlight { outline: 2px solid var(--green); }
@media (max-width: 820px) {
  .hero { grid-template-columns: 1fr; padding-top: 28px; }
  .hero h1 { font-size: 30px; }
  .platforms { grid-template-columns: 1fr; }
  .nav a { margin-left: 12px; }
  .doc { padding: 22px 16px; }
}