/* Trang giới thiệu "/" (058): cùng bảng màu tối cam của app.css, rộng tay hơn. */
:root {
  --nen: #0d0b0a; --nen2: #171412; --the: #1d1916; --vien: #2c2622;
  --chu: #f4ede7; --mo: #a89c92; --mo2: #6f655d; --cam: #ff6a3d; --cam2: #ffb347; --xanh: #4fd1a5;
  --font: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", sans-serif;
  --le: clamp(16px, 4vw, 48px);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
html, body { margin: 0; background: var(--nen); color: var(--chu); font-family: var(--font); line-height: 1.55; -webkit-font-smoothing: antialiased; }
body { overflow-x: hidden; }
a { color: inherit; text-decoration: none; }
img, video { display: block; max-width: 100%; }
h1, h2, h3 { line-height: 1.2; margin: 0; text-wrap: balance; }
p { margin: 0; }
main { max-width: 1240px; margin: 0 auto; padding: 0 var(--le); }

/* ---------- nút ---------- */
.nut { display: inline-flex; align-items: center; justify-content: center; gap: 8px; height: 52px; padding: 0 26px; border-radius: 14px; font-weight: 700; font-size: 16px; white-space: nowrap; transition: transform .15s, filter .15s, background .15s; }
.nut-chinh { background: linear-gradient(90deg, var(--cam), #ff8a45); color: #1a0d07; box-shadow: 0 12px 34px -14px var(--cam); }
.nut-chinh:hover { filter: brightness(1.08); transform: translateY(-1px); }
.nut-phu { background: #26201c; color: var(--chu); box-shadow: inset 0 0 0 1px var(--vien); }
.nut-phu:hover { background: #2e2723; }
.nut.nho { height: 40px; padding: 0 18px; font-size: 14px; border-radius: 11px; box-shadow: none; }
.nut:focus-visible, a:focus-visible, summary:focus-visible { outline: 2px solid var(--cam2); outline-offset: 3px; }

/* ---------- thanh trên ---------- */
.ld-top { position: sticky; top: 0; z-index: 20; display: flex; align-items: center; gap: 16px; padding: 12px var(--le);
  background: rgba(13, 11, 10, .84); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); border-bottom: 1px solid var(--vien); }
.ld-brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 19px; letter-spacing: -.01em; flex: none; }
.ld-brand b { font-weight: 800; margin-left: 3px; background: linear-gradient(90deg, var(--cam), var(--cam2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.ld-nav { display: flex; gap: 4px; margin-left: 20px; margin-right: auto; }
.ld-nav a { padding: 7px 14px; border-radius: 999px; font-size: 14px; font-weight: 600; color: var(--mo); }
.ld-nav a:hover { color: var(--chu); background: var(--nen2); }
.ld-tk { display: flex; align-items: center; gap: 14px; }
.ld-tk .lk { font-size: 14px; font-weight: 600; color: var(--mo); }
.ld-tk .lk:hover { color: var(--chu); }

/* ---------- hero ---------- */
.ld-hero { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr); gap: clamp(28px, 4vw, 56px); align-items: center; padding: clamp(36px, 6vw, 84px) 0 clamp(32px, 4vw, 56px); }
.nhan-nho { display: inline-block; margin-bottom: 18px; padding: 6px 12px; border-radius: 999px; background: #2a1a12; color: var(--cam2); font-size: 13px; font-weight: 700; box-shadow: inset 0 0 0 1px #4a2a1a; }
.ld-hero h1 { font-size: clamp(32px, 4.4vw, 56px); font-weight: 800; letter-spacing: -.025em; line-height: 1.16; }
.ld-hero h1 span { background: linear-gradient(90deg, var(--cam), var(--cam2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-phu { margin-top: 20px; font-size: clamp(16px, 1.5vw, 19px); color: var(--mo); max-width: 34em; }
.hero-phu b { color: var(--chu); }
.hero-nut { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.hero-ghi { margin-top: 14px; font-size: 13px; color: var(--mo2); }
.hero-luoi { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.o-hero { margin: 0; }
.o-hero:nth-child(2n) { transform: translateY(26px); }
.o-hero figcaption { margin-top: 8px; font-size: 13px; color: var(--mo); line-height: 1.4; }

/* khung video 16:9: ảnh poster nằm dưới, video phủ lên khi đã phát */
.vd { position: relative; aspect-ratio: 16 / 9; border-radius: 14px; overflow: hidden; background: var(--nen2); box-shadow: inset 0 0 0 1px var(--vien); }
.vd img, .vd video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.vd video { opacity: 0; transition: opacity .3s; }
.vd.phat video { opacity: 1; }
.vd .nut-phat { position: absolute; right: 10px; bottom: 10px; z-index: 2; width: 38px; height: 38px; border: 0; border-radius: 50%; background: rgba(13, 11, 10, .78); color: var(--chu); cursor: pointer; display: grid; place-items: center; }

/* ---------- dải số ---------- */
.ld-so { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 1px; margin: clamp(20px, 3vw, 40px) 0 0; border-radius: 18px; overflow: hidden; background: var(--vien); box-shadow: inset 0 0 0 1px var(--vien); }
.ld-so div { background: var(--nen2); padding: 22px 22px 20px; display: flex; flex-direction: column; gap: 4px; }
.ld-so b { font-size: clamp(24px, 2.6vw, 32px); font-weight: 800; letter-spacing: -.02em; font-variant-numeric: tabular-nums; color: var(--cam2); line-height: 1.2; }
.ld-so span { font-size: 14px; color: var(--mo); line-height: 1.4; }

/* ---------- khối chung ---------- */
.ld-khoi { padding: clamp(56px, 8vw, 104px) 0 0; }
.khoi-dau { max-width: 720px; margin-bottom: clamp(24px, 3vw, 36px); }
.khoi-dau h2, .ld-cuoi h2, .aff-chu h2 { font-size: clamp(26px, 3vw, 38px); font-weight: 800; letter-spacing: -.02em; }
.khoi-dau p { margin-top: 12px; color: var(--mo); font-size: 16px; }

/* ---------- thẻ nhóm ---------- */
.luoi-nhom { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.the-nhom { display: flex; flex-direction: column; border-radius: 18px; background: var(--the); box-shadow: inset 0 0 0 1px var(--vien); overflow: hidden; transition: transform .15s, box-shadow .15s; }
.the-nhom:hover { transform: translateY(-2px); box-shadow: inset 0 0 0 1px #4a3a30; }
.the-nhom .vd { border-radius: 0; box-shadow: none; }
.tn-than { padding: 18px 20px 18px; display: flex; flex-direction: column; gap: 8px; flex: 1; }
.tn-than h3 { font-size: 18px; font-weight: 700; }
.tn-than p { font-size: 14px; color: var(--mo); line-height: 1.5; }
.tn-chan { margin-top: auto; padding-top: 8px; display: flex; align-items: center; gap: 14px; font-size: 13px; color: var(--mo); }
.tn-chan b { color: var(--chu); }
.tn-chan i { margin-left: auto; font-style: normal; color: var(--cam2); font-size: 18px; }
.the-nhom.chi-chu { background: linear-gradient(160deg, #241a14, var(--the) 60%); }

/* ---------- ba bước ---------- */
.buoc { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; counter-reset: b; }
.buoc li { padding: 24px; border-radius: 18px; background: var(--nen2); box-shadow: inset 0 0 0 1px var(--vien); }
.buoc li > b { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 12px; margin-bottom: 16px; background: linear-gradient(135deg, var(--cam), var(--cam2)); color: #1a0d07; font-weight: 800; font-size: 18px; }
.buoc h3 { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.buoc p { color: var(--mo); font-size: 15px; }

/* ---------- ai dùng ---------- */
.ai-dung { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 18px; }
.ai-dung li { padding: 22px; border-radius: 18px; background: var(--nen2); box-shadow: inset 0 0 0 1px var(--vien); }
.ai-dung svg { color: var(--cam2); margin-bottom: 14px; }
.ai-dung h3 { font-size: 17px; font-weight: 700; margin-bottom: 8px; }
.ai-dung p { color: var(--mo); font-size: 14px; }

/* ---------- bảng giá ---------- */
.gia-hai { display: grid; grid-template-columns: 1.25fr 1fr; gap: 18px; }
.o-gia { padding: clamp(20px, 2.4vw, 28px); border-radius: 18px; background: var(--nen2); box-shadow: inset 0 0 0 1px var(--vien); display: flex; flex-direction: column; }
.o-gia h3 { font-size: 18px; font-weight: 700; margin-bottom: 16px; }
.vi-du { list-style: none; margin: 0; padding: 0; }
.vi-du li { display: grid; grid-template-columns: 72px minmax(0, 1fr) auto; align-items: center; gap: 14px; padding: 10px 0; border-top: 1px solid var(--vien); }
.vi-du li:first-child { border-top: 0; padding-top: 0; }
.vd-nho { width: 72px; height: 40px; object-fit: cover; border-radius: 8px; background: var(--the); }
.vd-ten { font-size: 14px; line-height: 1.4; }
.vi-du b { font-size: 15px; font-weight: 700; white-space: nowrap; font-variant-numeric: tabular-nums; }
.goi { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.goi li { padding: 14px 16px; border-radius: 14px; background: var(--the); box-shadow: inset 0 0 0 1px var(--vien); display: flex; flex-direction: column; gap: 2px; }
.goi b { font-size: 20px; font-weight: 800; font-variant-numeric: tabular-nums; }
.goi span { font-size: 13px; color: var(--mo); }
.goi small { font-size: 12px; color: var(--mo2); }
.goi li.co-tang { box-shadow: inset 0 0 0 1px #5a3420; background: #22170f; }
.goi li.co-tang span { color: var(--cam2); font-weight: 700; }
.ghi { margin-top: auto; padding-top: 16px; font-size: 13px; color: var(--mo); }
.ghi a, .hoi a { color: var(--cam2); text-decoration: underline; text-underline-offset: 2px; }

/* ---------- affiliate ---------- */
.ld-aff { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: clamp(20px, 4vw, 48px); align-items: center; }
.ld-aff { margin-top: clamp(56px, 8vw, 104px); padding: clamp(24px, 4vw, 44px); border-radius: 22px; background: linear-gradient(135deg, #2a1810, #1a1411 70%); box-shadow: inset 0 0 0 1px #4a2a1a; }
.aff-so { display: flex; flex-direction: column; align-items: center; justify-content: center; width: clamp(120px, 14vw, 168px); aspect-ratio: 1; border-radius: 50%; background: radial-gradient(circle at 30% 30%, #ff8a45, var(--cam)); color: #1a0d07; }
.aff-so b { font-size: clamp(38px, 4.6vw, 54px); font-weight: 800; line-height: 1.16; letter-spacing: -.03em; }
.aff-so span { font-size: 13px; font-weight: 700; }
.aff-chu p { margin: 12px 0 22px; color: var(--mo); max-width: 44em; }

/* ---------- hỏi đáp ---------- */
.hoi { max-width: 860px; display: flex; flex-direction: column; gap: 10px; }
.hoi details { border-radius: 14px; background: var(--nen2); box-shadow: inset 0 0 0 1px var(--vien); }
.hoi summary { cursor: pointer; list-style: none; padding: 18px 52px 18px 20px; font-weight: 600; font-size: 16px; position: relative; line-height: 1.4; }
.hoi summary::-webkit-details-marker { display: none; }
.hoi summary::after { content: "+"; position: absolute; right: 20px; top: 50%; transform: translateY(-50%); font-size: 22px; font-weight: 400; color: var(--cam2); }
.hoi details[open] summary::after { content: "−"; }
.hoi details p { padding: 0 20px 18px; color: var(--mo); font-size: 15px; }

/* ---------- CTA cuối, chân trang ---------- */
.ld-cuoi { margin: clamp(56px, 8vw, 104px) 0 clamp(40px, 6vw, 72px); padding: clamp(32px, 5vw, 60px) var(--le); text-align: center; border-radius: 22px; background: radial-gradient(ellipse at 50% 0%, #3a1e12, var(--nen2) 70%); box-shadow: inset 0 0 0 1px var(--vien); }
.ld-cuoi p { margin: 12px auto 0; color: var(--mo); max-width: 34em; }
.ld-cuoi .hero-nut { justify-content: center; }
.ld-chan { text-align: center; color: var(--mo2); font-size: 12px; padding: 28px 16px 40px; border-top: 1px solid var(--vien); }
.ld-chan nav { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 20px; margin-bottom: 10px; font-size: 13px; }
.ld-chan nav a { color: var(--mo); }
.ld-chan nav a:hover { color: var(--chu); }

/* ---------- màn hình vừa và nhỏ ---------- */
@media (max-width: 1060px) {
  .ai-dung { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .luoi-nhom { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 900px) {
  .ld-hero { grid-template-columns: minmax(0, 1fr); }
  .ld-so { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .gia-hai { grid-template-columns: minmax(0, 1fr); }
  .buoc { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 640px) {
  .ld-nav { display: none; }
  .ld-tk { margin-left: auto; }
  .luoi-nhom, .ai-dung { grid-template-columns: minmax(0, 1fr); }
  .hero-luoi { gap: 10px; }
  .o-hero:nth-child(2n) { transform: none; }
  .o-hero figcaption { font-size: 12px; }
  .ld-so div { padding: 16px; }
  .ld-aff { grid-template-columns: minmax(0, 1fr); justify-items: start; }
  .aff-chu { justify-self: stretch; }
  .hero-nut .nut { flex: 1 1 100%; }
  .vi-du li { grid-template-columns: 56px minmax(0, 1fr); }
  .vi-du li .vd-nho { width: 56px; height: 32px; grid-row: span 2; }
  .vi-du li b { grid-column: 2; }
}
@media (max-width: 400px) {
  .ld-top { gap: 10px; }
  .ld-tk { gap: 10px; }
  .ld-tk .lk { font-size: 13px; }
  .ld-tk .nut.nho { padding: 0 14px; font-size: 13px; }
  .ld-brand { gap: 8px; font-size: 16px; }
  .ld-brand img { width: 26px; height: 26px; }
  .goi { grid-template-columns: minmax(0, 1fr); }
}