/* ================================
   GOCheap • Ba Đình Landing Page
   Responsive, accessible, SEO-friendly
   Author: GOCheap Việt Nam
   ================================ */

:root {
  --bg: #0b1020;
  --card: #11172a;
  --elev: #0c1430;
  --text: #e6eaf2;
  --muted: #b8c2d9;
  --primary: #0068ff;
  --primary-600: #0b63e6;
  --accent: #15c0a6;
  --ring: 0 0 0 3px color-mix(in oklab, var(--primary) 35%, transparent);
  --radius: 14px;
  --shadow: 0 10px 30px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }
html, body { height: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: radial-gradient(1000px 600px at 85% -20%, rgba(0,104,255,.25), transparent),
              radial-gradient(800px 500px at -10% 20%, rgba(21,192,166,.15), transparent),
              var(--bg);
  line-height: 1.7;
}

.container { width: min(1120px, 92%); margin-inline: auto; }

h1, h2, h3, h4 { line-height: 1.25; margin: 0 0 .6em; }
h1 { font-size: clamp(28px, 3.2vw + 1rem, 48px); letter-spacing: -.02em; }
h2 { font-size: clamp(22px, 1.4vw + 1rem, 32px); }
h3 { font-size: clamp(18px, .9vw + 1rem, 22px); }

p { margin: 0 0 1em; color: var(--muted); }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--bg), black 10%);
  backdrop-filter: saturate(130%) blur(10px);
  border-bottom: 1px solid rgba(255,255,255,.06);
}
.header-inner { display: flex; align-items: center; gap: 16px; padding: 14px 0; }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-weight: 700; }
.logo { width: 36px; height: 36px; display: grid; place-items: center; background: linear-gradient(135deg, var(--primary), #2d7bff); border-radius: 10px; box-shadow: var(--shadow); }
.brand-text { letter-spacing: .2px; }

.nav { margin-left: auto; }
.nav-toggle { display: none; background: transparent; color: var(--text); border: 1px solid rgba(255,255,255,.16); border-radius: 10px; padding: 8px 10px; font-size: 18px; }
.menu { list-style: none; display: flex; gap: 18px; padding: 0; margin: 0; }
.menu a { color: var(--muted); text-decoration: none; padding: 10px 12px; border-radius: 10px; }
.menu a:hover { color: var(--text); background: rgba(255,255,255,.06); }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 16px; border-radius: 12px; border: 1px solid transparent; text-decoration: none; font-weight: 600; transition: .2s ease; }
.btn:focus { outline: none; box-shadow: var(--ring); }
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-600); transform: translateY(-1px); }
.btn-outline { background: transparent; color: var(--text); border-color: rgba(255,255,255,.18); }
.btn-outline:hover { background: rgba(255,255,255,.06); }
.btn-dark { background: #151a2b; color: white; border-color: #1c2236; }
.btn-call { white-space: nowrap; }

/* Hero */
.hero { padding: clamp(32px, 6vw, 80px) 0; }
.hero-grid { display: grid; grid-template-columns: 1.04fr .9fr; gap: 40px; align-items: center; }
.hero-text p { font-size: 1.05rem; }
.hl { color: var(--accent); }
.hero .cta { display: flex; flex-wrap: wrap; gap: 12px; margin: 18px 0; }
.hero .quick-points { list-style: none; padding: 0; margin: 14px 0 0; display: grid; gap: 6px; color: var(--muted); }

.hero-media { margin: 0; background: linear-gradient(180deg, rgba(0,104,255,.18), rgba(21,192,166,.12)); padding: 12px; border-radius: 18px; border: 1px solid rgba(255,255,255,.1); box-shadow: var(--shadow); }
.hero-media img { width: 100%; height: auto; display: block; border-radius: 12px; }
.hero-media figcaption { font-size: .9rem; margin-top: 8px; color: var(--muted); }

/* Sections */
.section { padding: clamp(40px, 7vw, 90px) 0; }
.section.alt { background: linear-gradient(180deg, rgba(255,255,255,.03), rgba(255,255,255,.00)); border-block: 1px solid rgba(255,255,255,.06); }
.section-header { margin-bottom: 22px; }
.section-header p { margin-top: -6px; }

.cards.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.card {
  background: linear-gradient(180deg, var(--card), color-mix(in oklab, var(--card), black 8%));
  border: 1px solid rgba(255,255,255,.08);
  border-radius: var(--radius);
  padding: clamp(16px, 2.2vw, 24px);
  box-shadow: var(--shadow);
}
.card h3 { margin-bottom: 10px; }
.list-rich { margin: 0; padding-left: 18px; }
.list-rich li + li { margin-top: 10px; }

.metro { margin-top: 16px; padding-top: 12px; border-top: 1px dashed rgba(255,255,255,.12); }

/* Pricing */
.pricing-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 10px; }
.price-card { background: linear-gradient(180deg, var(--elev), color-mix(in oklab, var(--elev), black 10%)); border: 1px solid rgba(255,255,255,.09); border-radius: var(--radius); padding: 18px; }
.price-card h3 { margin-bottom: 10px; }
.price-card ul { margin: 0; padding-left: 18px; }
.note { margin-top: 14px; color: var(--muted); }

/* Benefits */
.benefits { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.benefit { background: linear-gradient(180deg, var(--card), color-mix(in oklab, var(--card), black 8%)); border: 1px solid rgba(255,255,255,.08); border-radius: 12px; padding: 14px; text-align: center; }

/* Contact */
.contact-grid { display: grid; gap: 16px; }
.contact-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.contact-card { display: block; text-decoration: none; color: var(--text); background: linear-gradient(180deg, var(--elev), color-mix(in oklab, var(--elev), black 10%)); border: 1px solid rgba(255,255,255,.09); border-radius: 12px; padding: 16px; box-shadow: var(--shadow); }
.contact-card:hover { transform: translateY(-2px); border-color: rgba(255,255,255,.2); }
.app-links { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 6px; }
.btn.store { background: #0f1322; border-color: #1e2742; color: var(--text); }
.btn.store:hover { background: #151c33; }

/* Footer */
.site-footer { padding: 22px 0 30px; border-top: 1px solid rgba(255,255,255,.06); background: color-mix(in oklab, var(--bg), black 6%); }
.footer-inner { display: flex; gap: 16px; align-items: center; justify-content: space-between; color: var(--muted); }
.footer-inner nav a { color: var(--muted); text-decoration: none; margin-left: 10px; }
.footer-inner nav a:hover { color: var(--text); }

/* Responsive */
@media (max-width: 1024px) {
  .hero-grid { grid-template-columns: 1fr; }
}

@media (max-width: 900px) {
  .cards.two-col { grid-template-columns: 1fr; }
  .pricing-grid { grid-template-columns: 1fr 1fr; }
  .benefits { grid-template-columns: 1fr 1fr; }
  .contact-cards { grid-template-columns: 1fr; }
  .btn-call { display: none; }
}

@media (max-width: 720px) {
  .menu { display: none; position: absolute; right: 4%; top: 62px; background: color-mix(in oklab, var(--bg), black 14%); backdrop-filter: blur(8px); border: 1px solid rgba(255,255,255,.1); border-radius: 12px; padding: 10px; flex-direction: column; gap: 4px; min-width: 220px; }
  .menu.open { display: flex; }
  .nav-toggle { display: inline-flex; }
}

@media (max-width: 520px) {
  .pricing-grid { grid-template-columns: 1fr; }
}