/* ==========================================================================
   lp.css · Design system dùng chung cho các landing khóa học AI 5 Phút
   Trích từ index.html (AI Fluency OS bản cũ) để 4 trang mới nhất quán.
   Quy tắc repo: không transition-all, không màu Tailwind mặc định,
   heading Be Vietnam Pro + body Inter, shadow nhiều lớp, không em dash trong copy.
   ========================================================================== */

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: 'Inter', system-ui, sans-serif;
  color: #1D1D1F;
  background: #fff;
  -webkit-font-smoothing: antialiased;
  line-height: 1.6;
}

/* ---------- Typography ---------- */
.heading-display { font-family: 'Be Vietnam Pro', 'Inter', system-ui, sans-serif; font-weight: 600; letter-spacing: -0.03em; }
h1, h2, h3, h4 { font-family: 'Be Vietnam Pro', 'Inter', system-ui, sans-serif; margin: 0; letter-spacing: -0.03em; }
p { margin: 0; }
a { color: inherit; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; }
.wrap-narrow { max-width: 720px; margin: 0 auto; padding: 0 24px; }

.eyebrow {
  font-size: 12px; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.12em; color: #6E6E73;
}
.lead { font-size: 19px; color: #3A3A3C; line-height: 1.7; }
.muted { color: #6E6E73; }
.tiny { font-size: 13px; color: #6E6E73; }

.section { padding: 96px 0; }
.section.tint { background: #F5F5F7; }
.section-head { max-width: 720px; margin: 0 auto 56px; text-align: center; }
.section-head h2 { font-size: clamp(30px, 4vw, 44px); font-weight: 600; line-height: 1.1; margin: 14px 0 16px; text-wrap: balance; }
.section-head p { font-size: 17px; color: #6E6E73; line-height: 1.65; }
.section-divider { border: none; border-top: 1px solid #D2D2D7; margin: 0; }

/* ---------- Shadow ---------- */
.shadow-apple { box-shadow: 0 2px 8px rgba(0,0,0,0.05), 0 8px 32px rgba(0,0,0,0.07); }
.shadow-apple-lg { box-shadow: 0 4px 16px rgba(0,0,0,0.06), 0 16px 48px rgba(0,0,0,0.10); }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(180%) blur(20px); -webkit-backdrop-filter: saturate(180%) blur(20px);
  background: rgba(255,255,255,0.85);
  border-bottom: 1px solid rgba(0,0,0,0.06);
}
.nav-inner { max-width: 1080px; margin: 0 auto; padding: 12px 24px; display: flex; align-items: center; gap: 14px; }
.nav-brand { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.nav-brand .mark {
  width: 30px; height: 30px; border-radius: 8px; background: #1D1D1F; color: #fff;
  display: inline-flex; align-items: center; justify-content: center;
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 12px; font-weight: 700; letter-spacing: -0.02em;
}
.nav-brand .name { font-family: 'Be Vietnam Pro', sans-serif; font-size: 15px; font-weight: 600; letter-spacing: -0.02em; }
.nav-spacer { flex: 1; }
.nav-link { font-size: 14px; color: #6E6E73; text-decoration: none; transition: color 0.18s ease; }
.nav-link:hover { color: #1D1D1F; }
.nav-link:focus-visible { outline: 2px solid #1D1D1F; outline-offset: 3px; border-radius: 4px; }
@media (max-width: 640px) { .nav-link.hide-sm { display: none; } }

/* ---------- Buttons ---------- */
.btn-primary, .btn-secondary {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 28px; border-radius: 980px;
  font-family: 'Inter', sans-serif;
  font-size: 15px; font-weight: 500; letter-spacing: -0.01em;
  text-decoration: none; cursor: pointer; outline: none; border: none;
}
.btn-primary { background: #1D1D1F; color: #fff; transition: background 0.18s ease, transform 0.15s ease; }
.btn-primary:hover { background: #3A3A3C; transform: scale(1.015); }
.btn-primary:active { transform: scale(0.985); background: #2A2A2C; }
.btn-primary:focus-visible { outline: 3px solid #1D1D1F; outline-offset: 3px; }
.btn-primary[disabled] { opacity: 0.5; cursor: not-allowed; transform: none; }
.btn-secondary { background: transparent; color: #1D1D1F; border: 1.5px solid #1D1D1F; transition: background 0.18s ease, color 0.18s ease, transform 0.15s ease; }
.btn-secondary:hover { background: #1D1D1F; color: #fff; }
.btn-secondary:active { transform: scale(0.985); }
.btn-secondary:focus-visible { outline: 3px solid #1D1D1F; outline-offset: 3px; }
.btn-sm { padding: 10px 20px; font-size: 14px; }
.btn-block { width: 100%; }

/* ---------- Badge / pill ---------- */
.badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: #F5F5F7; border: 1px solid #D2D2D7;
  padding: 7px 15px; border-radius: 980px;
  font-size: 13px; font-weight: 500; color: #3A3A3C;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.badge .dot { width: 7px; height: 7px; border-radius: 50%; background: #6E6E73; }
.badge.soon .dot { background: #B4650A; }
.badge.soon { color: #8A4E06; background: #FDF4E7; border-color: #F0DCC0; }
.badge.open .dot { background: #1B7F3B; }
.badge.open { color: #1B7F3B; background: #EAF6EE; border-color: #C8E6D2; }

/* ---------- Hero ---------- */
.hero { padding: 72px 0 80px; position: relative; overflow: hidden; }
.hero h1 { font-size: clamp(36px, 6vw, 64px); font-weight: 700; line-height: 1.03; letter-spacing: -0.04em; margin: 20px 0 18px; text-wrap: balance; }
.hero .tagline { font-size: clamp(19px, 2.4vw, 24px); color: #3A3A3C; font-weight: 500; line-height: 1.4; margin-bottom: 24px; letter-spacing: -0.02em; }
.hero .body-copy { max-width: 660px; }
.hero .body-copy p { font-size: 17px; color: #3A3A3C; line-height: 1.75; margin-bottom: 16px; }
.noise-overlay {
  position: absolute; inset: 0; pointer-events: none; opacity: 0.025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-size: 200px 200px;
}

/* ---------- Stats strip ---------- */
.stats { display: flex; flex-wrap: wrap; gap: 40px; padding: 26px 0 0; border-top: 1px solid #D2D2D7; margin-top: 36px; }
.stat .v { font-family: 'Be Vietnam Pro', sans-serif; font-size: 30px; font-weight: 700; letter-spacing: -0.035em; line-height: 1; }
.stat .l { font-size: 12.5px; color: #6E6E73; margin-top: 6px; }

/* ---------- Narrative ---------- */
.narrative p { font-size: 18px; line-height: 1.8; color: #3A3A3C; margin-bottom: 20px; }
.narrative p strong { color: #1D1D1F; font-weight: 600; }
.pull {
  border-left: 3px solid #1D1D1F; padding: 4px 0 4px 22px; margin: 32px 0;
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 22px; font-weight: 600;
  line-height: 1.4; letter-spacing: -0.025em; color: #1D1D1F;
}

/* ---------- Cards / grids ---------- */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
@media (max-width: 900px) { .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 620px) { .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; } }

.card {
  background: #fff; border: 1px solid #E4E4E7; border-radius: 18px; padding: 26px 24px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.tint .card { background: #fff; }
.card-hover:hover { transform: translateY(-2px); box-shadow: 0 4px 20px rgba(0,0,0,0.09), 0 16px 48px rgba(0,0,0,0.09); }
.card h4 { font-size: 17px; font-weight: 600; margin-bottom: 8px; letter-spacing: -0.02em; }
.card p { font-size: 14.5px; color: #6E6E73; line-height: 1.6; }
.card .ico {
  width: 42px; height: 42px; border-radius: 11px; background: #F5F5F7; color: #1D1D1F;
  display: inline-flex; align-items: center; justify-content: center; margin-bottom: 16px;
}

/* ---------- Module list ---------- */
.modules { display: flex; flex-direction: column; gap: 10px; }
.module {
  display: flex; gap: 20px; align-items: flex-start;
  background: #fff; border: 1px solid #E4E4E7; border-radius: 16px; padding: 22px 24px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.module:hover { transform: translateY(-2px); box-shadow: 0 4px 20px rgba(0,0,0,0.07), 0 12px 36px rgba(0,0,0,0.06); }
.module .n {
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 13px; font-weight: 700;
  letter-spacing: 0.02em; color: #6E6E73; background: #F5F5F7;
  border-radius: 8px; padding: 5px 9px; flex-shrink: 0; margin-top: 2px;
}
.module .body { flex: 1; }
.module .body .t { font-family: 'Be Vietnam Pro', sans-serif; font-size: 16.5px; font-weight: 600; letter-spacing: -0.02em; margin-bottom: 5px; }
.module .body .s { font-size: 14.5px; color: #6E6E73; line-height: 1.6; }
.module .dur { font-size: 12.5px; color: #6E6E73; flex-shrink: 0; margin-top: 3px; }

/* ---------- Value stack ---------- */
.stack { display: flex; flex-direction: column; gap: 0; }
.stack-item { display: flex; gap: 14px; align-items: flex-start; padding: 15px 0; border-bottom: 1px solid #E4E4E7; }
.stack-item:last-child { border-bottom: none; }
.stack-item .check { flex-shrink: 0; color: #1B7F3B; margin-top: 2px; }
.stack-item .t { font-size: 15px; font-weight: 600; letter-spacing: -0.015em; }
.stack-item .s { font-size: 13.5px; color: #6E6E73; margin-top: 3px; line-height: 1.55; }

/* ---------- Ladder strip ---------- */
.ladder { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
@media (max-width: 900px) { .ladder { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .ladder { grid-template-columns: 1fr; } }
.rung {
  display: block; text-decoration: none; padding: 20px 18px;
  background: #fff; border: 1px solid #E4E4E7; border-radius: 14px;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.rung:hover { transform: translateY(-2px); box-shadow: 0 4px 20px rgba(0,0,0,0.08); }
.rung.current { border-color: #1D1D1F; border-width: 1.5px; background: #1D1D1F; color: #fff; }
.rung .lv { font-size: 11px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.1em; color: #6E6E73; }
.rung.current .lv { color: #B0B0B5; }
.rung .nm { font-family: 'Be Vietnam Pro', sans-serif; font-size: 15px; font-weight: 600; letter-spacing: -0.02em; margin: 7px 0 9px; line-height: 1.25; }
.rung .pr { font-family: 'Be Vietnam Pro', sans-serif; font-size: 15px; font-weight: 700; letter-spacing: -0.02em; }
.rung.current .pr { color: #fff; }

/* ---------- FAQ ---------- */
.faq { max-width: 760px; margin: 0 auto; }
.faq-item { border-bottom: 1px solid #D2D2D7; }
.faq-q {
  width: 100%; background: none; border: none; cursor: pointer;
  display: flex; align-items: flex-start; justify-content: space-between; gap: 20px;
  padding: 22px 0; text-align: left;
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 17px; font-weight: 600;
  letter-spacing: -0.02em; color: #1D1D1F;
  transition: color 0.18s ease;
}
.faq-q:hover { color: #6E6E73; }
.faq-q:focus-visible { outline: 2px solid #1D1D1F; outline-offset: 2px; }
.faq-icon { flex-shrink: 0; margin-top: 3px; transition: transform 0.3s cubic-bezier(0.4,0,0.2,1); }
.faq-icon.rotated { transform: rotate(45deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height 0.35s cubic-bezier(0.4,0,0.2,1); }
.faq-a.open { max-height: 700px; }
.faq-a p { font-size: 15.5px; color: #3A3A3C; line-height: 1.75; padding-bottom: 22px; }

/* ---------- Forms ---------- */
.form-card {
  background: #fff; border-radius: 22px; padding: 36px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.06), 0 16px 48px rgba(0,0,0,0.10);
}
@media (max-width: 620px) { .form-card { padding: 26px 20px; } }
.form-row { display: flex; flex-direction: column; gap: 6px; margin-bottom: 14px; }
.form-row label { font-size: 13.5px; font-weight: 500; color: #3A3A3C; }
.form-input {
  width: 100%; padding: 14px 16px; border: 1.5px solid #D2D2D7; border-radius: 12px;
  font-size: 15px; font-family: 'Inter', sans-serif; color: #1D1D1F; background: #fff;
  outline: none; transition: border-color 0.18s ease, box-shadow 0.18s ease;
}
.form-input:focus { border-color: #1D1D1F; box-shadow: 0 0 0 3px rgba(29,29,31,0.08); }
.form-input::placeholder { color: #B0B0B5; }
.form-input.error { border-color: #FF3B30; }
textarea.form-input { min-height: 96px; resize: vertical; line-height: 1.55; }
.form-msg { font-size: 13.5px; margin-top: 12px; display: none; line-height: 1.5; }
.form-msg.ok { display: block; color: #1B7F3B; }
.form-msg.err { display: block; color: #C0392B; }
.price-tag {
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 40px; font-weight: 700;
  letter-spacing: -0.04em; line-height: 1;
}
.price-note { font-size: 13.5px; color: #6E6E73; margin-top: 8px; line-height: 1.55; }

/* ---------- Countdown + giá theo mốc ---------- */
.countdown {
  display: flex; gap: 10px; flex-wrap: wrap;
}
.cd-cell {
  min-width: 74px; padding: 12px 10px;
  background: #1D1D1F; color: #fff; border-radius: 14px; text-align: center;
}
.tint .cd-cell, .form-card .cd-cell { background: #1D1D1F; }
.cd-cell .n {
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 28px; font-weight: 700;
  letter-spacing: -0.04em; line-height: 1; font-variant-numeric: tabular-nums;
}
.cd-cell .u { font-size: 10.5px; color: #B0B0B5; margin-top: 5px; letter-spacing: 0.06em; text-transform: uppercase; }
.cd-note { font-size: 13px; color: #6E6E73; margin-top: 10px; line-height: 1.55; }

.deal { border: 1.5px solid #1D1D1F; border-radius: 18px; padding: 22px; background: #fff; }
.deal .row { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.price-old {
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 19px; font-weight: 500;
  color: #6E6E73; text-decoration: line-through; letter-spacing: -0.02em;
}
.save-pill {
  display: inline-flex; align-items: center; gap: 6px;
  background: #1D1D1F; color: #fff; border-radius: 980px;
  padding: 5px 12px; font-size: 12px; font-weight: 600; letter-spacing: 0.02em;
}
/* Trước mốc hiện khối .before, sau mốc hiện khối .after */
.after { display: none; }
.expired .before { display: none; }
.expired .after { display: block; }

/* ---------- Footer ---------- */
.footer { background: #F5F5F7; border-top: 1px solid #D2D2D7; padding: 44px 0; }
.footer-inner { display: flex; flex-wrap: wrap; gap: 18px; align-items: center; justify-content: space-between; }
.footer a { color: #6E6E73; text-decoration: none; font-size: 13.5px; transition: color 0.18s ease; }
.footer a:hover { color: #1D1D1F; }
.footer .links { display: flex; flex-wrap: wrap; gap: 18px; }

/* ---------- Scroll reveal ---------- */
.fade-in { opacity: 0; transform: translateY(24px); transition: opacity 0.6s ease, transform 0.6s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
  .fade-in { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #D2D2D7; border-radius: 3px; }

/* ---------- Nút quay lại (mọi landing đều phải có đường về hub) ---------- */
.nav-back {
  display: inline-flex; align-items: center; gap: 6px; flex-shrink: 0;
  padding: 7px 13px 7px 10px; border-radius: 980px;
  background: #F5F5F7; border: 1px solid #E4E4E7;
  font-size: 13.5px; color: #3A3A3C; text-decoration: none;
  transition: background 0.18s ease, color 0.18s ease;
}
.nav-back:hover { background: #1D1D1F; color: #fff; border-color: #1D1D1F; }
.nav-back:focus-visible { outline: 2px solid #1D1D1F; outline-offset: 3px; }
.nav-back svg { flex-shrink: 0; }
@media (max-width: 520px) { .nav-back .lbl { display: none; } .nav-back { padding: 7px 10px; } }

/* ---------- Chi tiết module: gạch đầu dòng nội dung + dòng đầu ra ---------- */
.mod-points { list-style: none; margin: 10px 0 0; padding: 0; }
.mod-points li {
  position: relative; padding-left: 18px; margin-bottom: 6px;
  font-size: 14.5px; color: #6E6E73; line-height: 1.6;
}
.mod-points li::before {
  content: ''; position: absolute; left: 3px; top: 9px;
  width: 5px; height: 5px; border-radius: 50%; background: #D2D2D7;
}
.mod-out {
  margin-top: 12px; padding: 10px 14px; border-radius: 10px;
  background: #F5F5F7; font-size: 13.5px; line-height: 1.55; color: #3A3A3C;
}
.mod-out b { font-weight: 600; color: #1D1D1F; }

/* ---------- Dải số liệu đứng riêng một khối ---------- */
.statbar { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.statbar .cell {
  background: #fff; border: 1px solid #E4E4E7; border-radius: 16px;
  padding: 24px 20px; text-align: center;
}
.statbar .v {
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 34px; font-weight: 700;
  letter-spacing: -0.035em; line-height: 1; margin-bottom: 8px;
}
.statbar .l { font-size: 13.5px; color: #3A3A3C; line-height: 1.5; }
.statbar .src { font-size: 11.5px; color: #6E6E73; margin-top: 6px; }
@media (max-width: 900px) { .statbar { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .statbar { grid-template-columns: 1fr; } }

/* ---------- Comment thật ---------- */
.quotes { columns: 3; column-gap: 14px; }
@media (max-width: 900px) { .quotes { columns: 2; } }
@media (max-width: 620px) { .quotes { columns: 1; } }
.quote {
  break-inside: avoid; -webkit-column-break-inside: avoid;
  background: #fff; border: 1px solid #E4E4E7; border-radius: 16px;
  padding: 20px 20px 18px; margin-bottom: 14px;
}
.quote .src {
  font-size: 11.5px; font-weight: 500; color: #6E6E73;
  letter-spacing: 0.04em; text-transform: uppercase; margin-bottom: 10px;
}
.quote .txt { font-size: 14.5px; line-height: 1.65; color: #1D1D1F; margin-bottom: 14px; }
.quote .who { display: flex; align-items: center; gap: 10px; }
.quote .av {
  width: 30px; height: 30px; border-radius: 50%; background: #F5F5F7; color: #3A3A3C;
  display: inline-flex; align-items: center; justify-content: center;
  font-family: 'Be Vietnam Pro', sans-serif; font-size: 11px; font-weight: 700; flex-shrink: 0;
}
.quote .handle { font-size: 13px; color: #6E6E73; }