:root {
  --primary: #EF4444; /* đỏ chủ đạo */
  --accent: #F43F5E; /* hồng/đỏ nhấn */
  --text: #0F172A;
  --muted: #475569;
  --bg: #FFFFFF;
  --bg-soft: #FFF1F2;
  --radius: 16px;
  --shadow-sm: 0 4px 12px rgba(2, 6, 23, .06);
  --shadow-md: 0 10px 30px rgba(2, 6, 23, .10);
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; font-family: Inter, Roboto, system-ui, -apple-system, Segoe UI, Arial, sans-serif; color: var(--text); background:
  radial-gradient(1400px 800px at -10% -20%, rgba(239,68,68,.18) 0%, transparent 60%),
  radial-gradient(900px 600px at 120% -10%, rgba(244,63,94,.18) 0%, transparent 70%),
  linear-gradient(180deg, #FFF5F5, #FFF1F2 50%, #FFFFFF 100%);
}
.container { max-width: 1120px; margin: 0 auto; padding: 0 16px; }
body { line-height: 1.6; }

.site-header { position: sticky; top: 0; background: rgba(255,255,255,.8); backdrop-filter: blur(10px); border-bottom: 1px solid rgba(253,164,175,.6); z-index: 20; box-shadow: 0 2px 20px rgba(190, 18, 60, .06); }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand .logo { height: 32px; }
.brand-text { font-weight: 700; font-size: 18px; color: var(--primary); letter-spacing: 0.3px; }
.header-actions { display: flex; gap: 8px; }

.btn { display: inline-flex; align-items: center; justify-content: center; height: 40px; padding: 0 18px; border-radius: 999px; border: 1px solid transparent; text-decoration: none; font-weight: 600; letter-spacing: .2px; transition: transform .15s ease, box-shadow .25s ease, background .25s ease, color .25s ease; }
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn-primary { background: linear-gradient(180deg, #F05252, #DC2626); color: #fff; box-shadow: 0 10px 28px rgba(239,68,68,.35); }
.btn-primary:hover { box-shadow: 0 12px 32px rgba(239,68,68,.45); }
.btn-outline { background: #fff; color: var(--text); border-color: #FECACA; }
.btn-ghost { background: transparent; color: var(--text); border-color: transparent; }
.btn-accent { background: linear-gradient(90deg, #FB7185, #F43F5E); color: #fff; box-shadow: 0 10px 28px rgba(244,63,94,.35); }
.btn-lg { height: 48px; padding: 0 20px; }
.btn-xl { height: 56px; padding: 0 24px; font-size: 18px; }

.hero { position: relative; background:
  radial-gradient(1400px 700px at -10% 0%, rgba(239,68,68,.18) 0%, transparent 60%),
  radial-gradient(900px 500px at 120% 10%, rgba(244,63,94,.18) 0%, transparent 70%),
  linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0));
  padding: 72px 0; overflow: hidden; color: #0F172A; }
.hero::after { content: ""; position: absolute; width: 600px; height: 600px; right: -120px; top: -160px; background: radial-gradient(40% 40% at 50% 50%, rgba(37,99,235,.18), transparent 70%); filter: blur(30px); pointer-events: none; }
.hero-inner { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 32px; align-items: center; }
.hero h1 { font-size: 56px; line-height: 1.1; margin: 0 0 12px; letter-spacing: 0.2px; }
.hero .highlight { color: var(--primary); }
.hero .subtitle { color: #334155; margin: 0 0 16px; }
.typing { height: 24px; color: var(--primary); font-weight: 600; letter-spacing: .2px; margin: 6px 0 10px; }
.bullets { margin: 0 0 16px; padding-left: 18px; color: var(--text); }
.bullets li { margin: 8px 0; }
.hero-cta { display: flex; gap: 12px; margin: 16px 0 12px; }
.hero-media .media-placeholder { width: 100%; height: auto; aspect-ratio: 16/9; object-fit: cover; border: 1px solid #FECACA; border-radius: 20px; display: block; background: #fff; box-shadow: var(--shadow-md); }

.countdown { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-top: 16px; }
.cd-item { background: linear-gradient(180deg, #FFFFFF, #F6F8FC); border: 1px solid #E2E8F0; border-radius: 18px; padding: 14px; text-align: center; box-shadow: var(--shadow-sm); }
.cd-number { font-size: 28px; font-weight: 700; color: var(--primary); display: block; }
.cd-label { font-size: 12px; color: var(--muted); }
.countdown-note { font-size: 12px; color: var(--muted); margin-top: 8px; }

.section-cta { position: relative; padding: 48px 0; text-align: center; background: #fff; }
.section-cta h2 { margin: 0 0 8px; font-size: 28px; }
.section-cta p { margin: 0 0 16px; color: var(--muted); }
.section-cta .bg-glow { position: absolute; inset: 0; background: radial-gradient(60% 60% at 50% 30%, rgba(37,99,235,.12), transparent 70%); pointer-events: none; }

.site-footer { border-top: 1px solid #E2E8F0; background: #fff; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 12px; height: 72px; }
.footer-links { display: flex; gap: 12px; }
.footer-links a { color: var(--muted); text-decoration: none; }

/* Sections */
.section { position: relative; padding: 56px 0; }
.section-title { margin: 0 0 8px; font-size: 34px; text-align: center; letter-spacing: .2px; }
.section-sub { margin: 0 auto 24px; color: var(--muted); text-align: center; max-width: 720px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.card { background: #FFFFFF; border: 1px solid #FECACA; border-radius: 20px; padding: 16px; box-shadow: var(--shadow-sm), inset 0 0 0 1px rgba(239,68,68,.12); transition: transform .2s ease, box-shadow .25s ease, border-color .25s ease; }
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow-md), 0 0 0 2px rgba(239,68,68,.18); border-color: #FDA4AF; }
.reveal { opacity: 0; transform: translateY(8px); transition: opacity .5s ease, transform .5s ease; }
.reveal.in { opacity: 1; transform: translateY(0); }
.section-title { opacity: 0; transform: translateY(8px); transition: opacity .5s ease, transform .5s ease; }
.section-title.in { opacity: 1; transform: translateY(0); }
.usp { background: radial-gradient(900px 400px at -10% 20%, rgba(239,68,68,.14), transparent 70%), linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0)); }
.outcomes { background: radial-gradient(900px 400px at 110% 0%, rgba(244,63,94,.16), transparent 70%), linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0)); }
.checklist { margin: 0; padding-left: 20px; }
.checklist li { margin: 10px 0; }
.stat-card .stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-bottom: 8px; }
.stat .num { font-size: 32px; font-weight: 700; color: var(--primary); display: block; }
.stat .label { color: var(--muted); font-size: 12px; }

/* Curriculum */
.curriculum-list { max-width: 880px; margin: 0 auto; }
.module { background: #fff; border: 1px solid #E2E8F0; border-radius: var(--radius); padding: 12px 16px; margin: 10px 0; }
.module summary { cursor: pointer; font-weight: 600; }
.module summary span { color: var(--primary); margin-right: 6px; }
.module ul { margin: 10px 0 0; padding-left: 20px; color: var(--muted); }

/* Instructor */
.instructor .avatar { width: 48px; height: 48px; border-radius: 50%; background: var(--primary); color: #fff; display: inline-flex; align-items: center; justify-content: center; font-weight: 700; margin-right: 12px; }
.instructor .instructor-header { display: flex; align-items: center; margin-bottom: 10px; }
.muted { color: var(--muted); }
.stat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-top: 8px; }
 .instructor { background: radial-gradient(900px 400px at -10% 10%, rgba(239,68,68,.14), transparent 70%), linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0)); }
/* Slider ảnh giảng viên */
.instructor-slider { position: relative; overflow: hidden; border-radius: 20px; border: 1px solid #FECACA; box-shadow: var(--shadow-sm); }
.instructor-slider .track { display: flex; width: max-content; gap: 12px; animation: slide-left 18s linear infinite; padding: 6px; }
.instructor-slider .slide { flex: 0 0 auto; }
.instructor-slider img { display: block; width: 480px; height: 280px; object-fit: cover; border-radius: 16px; }
@keyframes slide-left { from { transform: translateX(0); } to { transform: translateX(-50%); } }

/* Cases */
.case-card .thumb { height: 160px; border: 2px dashed #CBD5E1; border-radius: var(--radius); margin-bottom: 10px; display: flex; align-items: center; justify-content: center; color: #64748B; }
 .cases { background: radial-gradient(900px 400px at 110% 10%, rgba(244,63,94,.16), transparent 70%), linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0)); }

/* Testimonials */
.t-card p { margin: 0 0 12px; }
.t-user { display: flex; align-items: center; gap: 10px; }
.t-user .ava { width: 36px; height: 36px; border-radius: 50%; background: var(--primary); color: #fff; display: inline-flex; align-items: center; justify-content: center; font-weight: 700; }
 .testimonials { background: radial-gradient(900px 400px at -10% 10%, rgba(239,68,68,.14), transparent 70%), linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0)); }

/* Pricing */
.pricing { background: radial-gradient(900px 400px at 110% 0%, rgba(244,63,94,.16), transparent 70%), linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0)); }
.price-card { position: relative; text-align: center; }
.price-card .price { font-size: 28px; font-weight: 700; color: var(--text); margin: 6px 0 12px; display: flex; flex-direction: column; align-items: center; gap: 4px; justify-content: center; }
.price-card .price .original { color: #94A3B8; text-decoration: line-through; font-weight: 500; line-height: 1; }
.price-card .price .sale { color: var(--primary); font-size: 32px; font-weight: 800; line-height: 1.1; }
.price-card.single { max-width: 520px; margin: 0 auto; }
/* Desktop optimization for single pricing card */
.pricing .grid-3 { display: flex; justify-content: center; }
.price-card.single { width: 640px; padding: 20px; background: linear-gradient(180deg, #FFFFFF, #FFF5F5); border: 1px solid #FECACA; border-radius: 24px; box-shadow: 0 16px 48px rgba(239,68,68,.08); }
.price-card.single .checklist { text-align: left; max-width: 520px; margin: 0 auto 8px; }
.price-card.single .btn { width: 100%; max-width: 360px; }
.price-card.single .badge { top: -14px; right: -14px; }
.price-card.single .countdown.small { max-width: 520px; margin: 12px auto; }
.price-card .badge { position: absolute; top: -12px; right: -12px; background: linear-gradient(180deg, #FB7185, #F43F5E); color: #fff; padding: 6px 10px; border-radius: 999px; font-size: 12px; box-shadow: 0 12px 30px rgba(244, 63, 94, .35); }
.price-card.featured { border: 1px solid rgba(239,68,68,.6); box-shadow: 0 14px 36px rgba(239,68,68,.20); transform: translateY(-2px); }
.countdown.small { grid-template-columns: repeat(4, 1fr); gap: 8px; margin: 12px 0; }
 .price-card.featured::before { content: none !important; }
 @keyframes spin { to { transform: rotate(360deg); } }

/* Bonuses */
.bonuses { background: radial-gradient(900px 400px at -10% 10%, rgba(244,63,94,.14), transparent 70%), linear-gradient(180deg, rgba(255,255,255,.25), rgba(255,255,255,0)); }

/* FAQ */
.faq { background: linear-gradient(180deg, rgba(255,255,255,.18), rgba(255,255,255,0)); }
.faq details { background: #fff; border: 1px solid #E2E8F0; border-radius: var(--radius); padding: 12px 16px; margin: 10px 0; }
.faq summary { cursor: pointer; font-weight: 600; }
 .usp .section-title, .outcomes .section-title, .pricing .section-title, .cases .section-title, .testimonials .section-title, .bonuses .section-title, .faq .section-title, .instructor .section-title { color: #0F172A; }
 .usp .section-sub, .outcomes .section-sub, .pricing .section-sub, .cases .section-sub, .testimonials .section-sub, .bonuses .section-sub, .faq .section-sub, .instructor .section-sub { color: #334155; }

/* Trust bar */
.trust { padding: 24px 0; }
.trust-inner { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; text-align: center; }
.trust-item { background: #fff; border: 1px solid #E2E8F0; border-radius: 999px; padding: 10px 16px; box-shadow: var(--shadow-sm); }

/* Sticky CTA (mobile-first) */
.sticky-cta { position: fixed; left: 0; right: 0; bottom: 12px; display: flex; gap: 8px; justify-content: center; z-index: 50; padding: 0 12px; }
.sticky-cta .btn { flex: 1; max-width: 240px; }
@media (min-width: 992px) {
  .sticky-cta { display: none; }
}

/* Modal */
.modal { position: fixed; inset: 0; display: none; align-items: center; justify-content: center; z-index: 100; }
.modal[aria-hidden="false"] { display: flex; }
.modal-backdrop { position: absolute; inset: 0; background: rgba(2,6,23,.6); backdrop-filter: blur(2px); }
.modal-dialog { position: relative; background: #fff; border-radius: 20px; width: min(920px, 96vw); padding: 16px; box-shadow: var(--shadow-md); z-index: 1; }
.modal-close { position: absolute; top: 8px; right: 12px; background: transparent; border: 0; font-size: 22px; line-height: 1; cursor: pointer; }
.modal-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.pay-box { border: 1px solid #FECACA; border-radius: 16px; padding: 12px; }
.qr img { width: 100%; height: auto; border-radius: 12px; }
.qr-placeholder { display: grid; place-items: center; height: 240px; border: 2px dashed #FECACA; border-radius: 12px; color: #EF4444; }
.price-line { margin-top: 8px; }
.note-line { margin-top: 4px; }
.note-line code { background: #FFF1F2; padding: 2px 6px; border-radius: 6px; }
.form-box { display: grid; gap: 10px; border: 1px solid #FECACA; border-radius: 16px; padding: 12px; }
.form-box input { width: 100%; height: 40px; border-radius: 10px; border: 1px solid #E2E8F0; padding: 0 10px; }

@media (max-width: 991px) {
  .modal-grid { grid-template-columns: 1fr; }
}

@media (max-width: 991px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero { padding: 40px 0; }
  .hero h1 { font-size: 36px; line-height: 1.15; }
  .hero-media { order: -1; }
  .countdown { grid-template-columns: repeat(4, minmax(64px, 1fr)); gap: 8px; }
  .cd-item { padding: 10px; border-radius: 14px; }
  .cd-number { font-size: 22px; }
  .grid-3 { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
  .price-card.single { width: 100%; border-radius: 20px; }
}