:root {
  --bg: #f5f5f7; --card: #fff; --text: #1d1d1f; --muted: #6e6e73; --line: rgba(0,0,0,.08);
  --accent: #0071e3; --orange: #f48c22;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", "Helvetica Neue", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; font-family: var(--font); background: var(--bg); color: var(--text); -webkit-font-smoothing: antialiased; letter-spacing: -.011em; }
a { color: inherit; }
button { font: inherit; }
html[lang="en"] [data-lang="vi"]:not(button), html[lang="vi"] [data-lang="en"]:not(button) { display: none !important; }
.wrap { width: min(1040px, calc(100% - 40px)); margin: 0 auto; }
.nav { position: sticky; top: 0; z-index: 10; background: rgba(255,255,255,.8); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); border-bottom: 1px solid var(--line); }
.nav-inner { height: 52px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 600; text-decoration: none; }
.nav-links { display: flex; align-items: center; gap: 20px; font-size: 14px; }
.nav-links > a { text-decoration: none; color: var(--muted); }
.nav-links > a:hover { color: var(--text); }
.lang-switch { display: flex; background: #e8e8ed; border-radius: 999px; padding: 2px; }
.lang-switch button { border: 0; background: none; padding: 4px 10px; border-radius: 999px; font-size: 12px; cursor: pointer; color: var(--muted); }
.lang-switch button[aria-pressed="true"] { background: #fff; color: var(--text); box-shadow: 0 1px 2px rgba(0,0,0,.1); }
.hero { padding: 96px 0 72px; text-align: center; }
.hero h1 { font-size: clamp(36px, 6vw, 60px); line-height: 1.05; margin: 0 auto 20px; max-width: 760px; letter-spacing: -.03em; }
.hero p { font-size: clamp(17px, 2.2vw, 21px); color: var(--muted); max-width: 640px; margin: 0 auto; line-height: 1.45; }
.hero-actions { display: flex; justify-content: center; gap: 12px; margin-top: 32px; flex-wrap: wrap; }
.btn { display: inline-flex; align-items: center; padding: 11px 22px; border-radius: 999px; text-decoration: none; font-size: 16px; border: 1px solid var(--line); background: #fff; }
.btn.primary { background: var(--accent); color: #fff; border-color: transparent; }
.btn:hover { filter: brightness(1.05); }
.section { padding: 24px 0 48px; }
.section-title { font-size: 24px; margin: 32px 0 16px; letter-spacing: -.02em; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 16px; }
.card { display: flex; gap: 16px; align-items: flex-start; background: var(--card); border-radius: 20px; padding: 22px; border: 1px solid var(--line); }
.card .icon { border-radius: 15px; flex: none; }
.card h3 { margin: 2px 0 6px; font-size: 19px; }
.card p { margin: 0; color: var(--muted); line-height: 1.45; font-size: 15px; }
.links { display: flex; gap: 16px; margin-top: 12px; font-size: 14px; }
.links a { color: var(--accent); text-decoration: none; }
.links a:hover { text-decoration: underline; }
.contact { text-align: center; background: var(--card); border-radius: 24px; padding: 48px 24px; margin-bottom: 64px; border: 1px solid var(--line); }
.contact h2 { margin: 0 0 10px; font-size: 28px; letter-spacing: -.02em; }
.contact p { color: var(--muted); margin: 0 0 24px; }
.footer { border-top: 1px solid var(--line); padding: 24px 0 40px; font-size: 13px; color: var(--muted); }
.footer-inner { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.footer nav { display: flex; gap: 20px; }
.footer a { text-decoration: none; }
.footer a:hover { color: var(--text); }
@media (max-width: 560px) { .nav-links > a { display: none; } .hero { padding: 64px 0 48px; } }