:root {
  --bt-bg: #090909;
  --bt-ink: #151515;
  --bt-red: #e30013;
  --bt-red-dark: #9b000b;
  --bt-orange: #ff6a00;
  --bt-gold: #f5b31a;
  --bt-blue: #276fcf;
  --bt-paper: #ffffff;
  --bt-soft: #fff7f1;
  --bt-line: rgba(227, 0, 19, .18);
  --bt-muted: #6c6c6c;
  --bt-radius: 8px;
  --bt-shadow: 0 18px 50px rgba(30, 0, 0, .18);
  --bt-shell: 1180px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
html, body { min-width: 0; margin: 0; overflow-x: hidden; }
body.bt-page { color: var(--bt-ink); background: #fff; font-family: Inter, Arial, "Noto Sans Bengali", Helvetica, sans-serif; line-height: 1.5; letter-spacing: 0; }
.bt-page :where(a) { color: inherit; text-decoration: none; }
.bt-page img, .bt-page svg { display: block; }
.bt-page img { max-width: 100%; height: auto; }
.bt-page h1, .bt-page h2, .bt-page h3, .bt-page p { margin: 0; }
.bt-sprite { position: absolute; width: 0; height: 0; overflow: hidden; }
.bt-shell { width: min(var(--bt-shell), calc(100% - 48px)); margin: 0 auto; }
.bt-utility { background: linear-gradient(90deg, #19100b, #522209 48%, #111); color: #ffe9bf; font-size: 13px; line-height: 1; }
.bt-utility .bt-shell { min-height: 34px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.bt-help, .bt-mini, .bt-chip, .bt-nav a { display: inline-flex; align-items: center; gap: 8px; }
.bt-help { font-weight: 800; }
.bt-help svg, .bt-nav svg, .bt-mini svg, .bt-chip svg, .bt-icon svg { width: 18px; height: 18px; fill: currentColor; flex: 0 0 auto; }
.bt-top { position: sticky; top: 0; z-index: 30; background: #0d0d0f; box-shadow: 0 10px 24px rgba(0,0,0,.28); }
.bt-header { min-height: 82px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.bt-logo { display: inline-flex; align-items: baseline; gap: 2px; color: #f8f8f8; font-size: clamp(34px, 4.4vw, 54px); line-height: .9; font-weight: 1000; font-style: italic; letter-spacing: 0; text-shadow: 0 2px 12px rgba(255,255,255,.16); }
.bt-logo span { color: var(--bt-orange); }
.bt-actions { display: flex; align-items: center; gap: 14px; flex-shrink: 0; }
.bt-btn { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 0 24px; border: 1px solid transparent; border-radius: var(--bt-radius); font-size: 15px; line-height: 1; font-weight: 900; white-space: nowrap; transition: transform .2s ease, box-shadow .2s ease, background .2s ease; }
.bt-btn:hover { transform: translateY(-1px); }
.bt-btn-primary { color: #fff; background: linear-gradient(135deg, #ff7915, #ff3c00); box-shadow: 0 12px 28px rgba(255,98,0,.28); }
.bt-btn-blue { color: #fff; background: linear-gradient(135deg, #347adb, #1756b7); box-shadow: 0 12px 28px rgba(39,111,207,.28); }
.bt-btn-dark { color: #fff; border-color: rgba(255,255,255,.28); background: rgba(255,255,255,.06); }
.bt-nav-wrap { background: var(--bt-red); }
.bt-nav { min-height: 56px; display: flex; align-items: center; gap: 8px; overflow-x: auto; scrollbar-width: none; }
.bt-nav::-webkit-scrollbar { display: none; }
.bt-nav a { position: relative; min-height: 56px; padding: 0 13px; color: #fff; font-size: 14px; font-weight: 900; white-space: nowrap; }
.bt-nav a::after { content: ""; position: absolute; left: 14px; right: 14px; bottom: 0; height: 4px; border-radius: 4px 4px 0 0; background: transparent; }
.bt-nav a.active::after, .bt-nav a:hover::after { background: var(--bt-gold); }
.bt-nav a.active { color: #fff7c8; }
.bt-hero { position: relative; min-height: 585px; color: #fff; background: radial-gradient(circle at 78% 52%, rgba(255,95,0,.45), transparent 34%), linear-gradient(90deg, #090606 0%, #1b0505 52%, #090606 100%); overflow: hidden; }
.bt-hero::before { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, rgba(0,0,0,.94) 0%, rgba(0,0,0,.78) 38%, rgba(0,0,0,.18) 68%, rgba(0,0,0,.22) 100%), radial-gradient(circle at 8% 18%, rgba(227,0,19,.18), transparent 30%); z-index: 1; }
.bt-hero .bt-shell { position: relative; z-index: 2; min-height: 585px; display: grid; grid-template-columns: minmax(320px, 47%) 1fr; align-items: center; gap: 28px; }
.bt-hero-copy { position: relative; z-index: 3; padding: 48px 0 86px; }
.bt-title { max-width: 620px; color: #fff; font-size: clamp(46px, 6vw, 78px); line-height: .98; font-weight: 1000; letter-spacing: 0; }
.bt-title strong { display: block; color: var(--bt-orange); }
.bt-title span { color: var(--bt-gold); }
.bt-hero-copy p { max-width: 500px; margin-top: 24px; color: rgba(255,255,255,.88); font-size: 18px; line-height: 1.7; font-weight: 600; }
.bt-hero-actions { margin-top: 30px; display: flex; flex-wrap: wrap; gap: 14px; }
.bt-proof { margin-top: 30px; display: flex; flex-wrap: wrap; gap: 22px; color: rgba(255,255,255,.82); font-size: 14px; font-weight: 800; }
.bt-mini svg { color: var(--bt-gold); }
.bt-hero-media { align-self: stretch; position: relative; }
.bt-hero-img { position: absolute; inset: 0 -96px 0 0; width: calc(100% + 96px); height: 100%; object-fit: cover; object-position: center right; filter: saturate(1.08) contrast(1.02); }
.bt-feature-strip { position: relative; z-index: 4; margin: -58px auto 0; }
.bt-feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); background: #141414; color: #fff; border: 1px solid rgba(245,179,26,.26); border-radius: var(--bt-radius); box-shadow: var(--bt-shadow); overflow: hidden; }
.bt-feature { min-height: 128px; display: grid; grid-template-columns: 54px 1fr; align-items: center; gap: 14px; padding: 22px; border-right: 1px solid rgba(255,255,255,.08); }
.bt-feature:last-child { border-right: 0; }
.bt-icon { width: 54px; height: 54px; display: grid; place-items: center; border-radius: 8px; color: var(--bt-gold); background: linear-gradient(135deg, rgba(227,0,19,.9), rgba(255,106,0,.86)); }
.bt-feature h3 { color: #fff; font-size: 18px; line-height: 1.18; font-weight: 950; }
.bt-feature p { margin-top: 6px; color: rgba(255,255,255,.72); font-size: 14px; line-height: 1.5; }
.bt-section { padding: 70px 0; }
.bt-section-soft { background: var(--bt-soft); }
.bt-section-dark { color: #fff; background: radial-gradient(circle at 80% 24%, rgba(255,106,0,.32), transparent 30%), linear-gradient(135deg, #0a0a0b, #260004 74%, #0a0a0b); }
.bt-section-title { color: #161616; font-size: clamp(30px, 4vw, 46px); line-height: 1.14; font-weight: 1000; text-align: center; }
.bt-section-title strong, .bt-section-dark h2 span { color: var(--bt-orange); }
.bt-section-lead { max-width: 840px; margin: 16px auto 0; color: #656565; font-size: 17px; line-height: 1.75; text-align: center; }
.bt-categories, .bt-product-grid, .bt-news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.bt-categories { margin-top: 34px; }
.bt-card, .bt-product, .bt-news-card { overflow: hidden; border-radius: var(--bt-radius); background: #fff; box-shadow: 0 16px 40px rgba(120,0,8,.1); border: 1px solid var(--bt-line); }
.bt-card { min-height: 122px; display: flex; align-items: center; gap: 18px; padding: 22px; color: var(--bt-ink); }
.bt-card-icon { width: 62px; height: 62px; display: grid; place-items: center; border-radius: 8px; color: #fff; background: linear-gradient(135deg, var(--bt-red), var(--bt-orange)); }
.bt-card-icon svg { width: 28px; height: 28px; fill: currentColor; }
.bt-card h3 { font-size: 22px; font-weight: 1000; }
.bt-card-arrow { margin-left: auto; color: var(--bt-red); font-size: 28px; font-weight: 1000; }
.bt-product-grid { margin-top: 34px; }
.bt-product { background: #111; color: #fff; }
.bt-product img, .bt-news-card img, .bt-article-cover, .bt-column-image img { width: 100%; aspect-ratio: 16 / 9; object-fit: cover; }
.bt-product-body, .bt-news-body { padding: 20px; }
.bt-product h3 { color: var(--bt-gold); font-size: 25px; line-height: 1.12; font-weight: 1000; }
.bt-product p { min-height: 52px; margin: 10px 0 18px; color: rgba(255,255,255,.78); line-height: 1.6; }
.bt-mini-btn { min-height: 36px; padding: 0 18px; border-radius: 8px; color: #fff; background: linear-gradient(135deg, var(--bt-red), var(--bt-orange)); display: inline-flex; align-items: center; justify-content: center; font-weight: 950; }
.bt-app { display: grid; grid-template-columns: .9fr 1.1fr; align-items: center; gap: 34px; }
.bt-app h2 { color: #fff; font-size: clamp(34px, 4.2vw, 56px); line-height: 1.06; font-weight: 1000; }
.bt-app p { margin-top: 18px; color: rgba(255,255,255,.78); font-size: 17px; line-height: 1.75; }
.bt-chip-row { margin-top: 24px; display: grid; gap: 12px; }
.bt-chip { padding: 14px; border: 1px solid rgba(255,255,255,.16); border-radius: 8px; background: rgba(255,255,255,.06); }
.bt-chip svg { width: 24px; height: 24px; color: var(--bt-gold); }
.bt-chip strong { display: block; color: #fff; font-size: 15px; }
.bt-chip span { color: rgba(255,255,255,.72); line-height: 1.45; }
.bt-app-media { overflow: hidden; border-radius: 8px; box-shadow: var(--bt-shadow); }
.bt-app-media img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; }
.bt-steps { margin-top: 34px; display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; }
.bt-step { min-height: 180px; padding: 20px; border-radius: 8px; border: 1px solid var(--bt-line); background: #fff; text-align: center; box-shadow: 0 14px 34px rgba(80,0,8,.08); }
.bt-step-num { width: 42px; height: 42px; display: grid; place-items: center; margin: 0 auto 14px; border-radius: 50%; color: #fff; background: linear-gradient(135deg, var(--bt-red), var(--bt-orange)); font-weight: 1000; }
.bt-step .bt-icon { margin: 0 auto 12px; }
.bt-step h3 { color: #151515; font-size: 18px; font-weight: 1000; }
.bt-step p { margin-top: 8px; color: var(--bt-muted); font-size: 14px; line-height: 1.55; }
.bt-news-grid { margin-top: 34px; }
.bt-news-card { color: var(--bt-ink); }
.bt-news-body time, .bt-label { color: var(--bt-red); font-size: 13px; font-weight: 950; text-transform: uppercase; }
.bt-news-body h3 { margin-top: 9px; color: #151515; font-size: 20px; line-height: 1.28; font-weight: 1000; }
.bt-news-body p { margin: 10px 0 14px; color: #666; line-height: 1.6; }
.bt-read { color: var(--bt-red); font-weight: 950; }
.bt-faq { display: grid; grid-template-columns: .8fr 1.2fr; gap: 30px; align-items: start; }
.bt-faq-list { display: grid; gap: 12px; }
.bt-faq-list article { padding: 20px; border: 1px solid var(--bt-line); border-radius: 8px; background: #fff; }
.bt-faq-list h3 { color: #151515; font-size: 18px; font-weight: 1000; }
.bt-faq-list p { margin-top: 8px; color: #666; line-height: 1.65; }
.bt-column-hero { padding: 56px 0; background: linear-gradient(135deg, #fff7f1, #fff); border-bottom: 1px solid var(--bt-line); }
.bt-column-grid { display: grid; grid-template-columns: 1fr minmax(300px, 430px); gap: 34px; align-items: center; }
.bt-column-hero h1 { color: #151515; font-size: clamp(32px, 4vw, 48px); line-height: 1.12; font-weight: 1000; }
.bt-column-hero p { margin-top: 14px; color: #666; font-size: 17px; line-height: 1.7; font-weight: 650; }
.bt-column-image { margin: 0; overflow: hidden; border-radius: 8px; box-shadow: var(--bt-shadow); }
.bt-content-layout, .bt-article-layout { display: grid; grid-template-columns: minmax(0,1fr) 320px; gap: 24px; align-items: start; }
.bt-list { display: grid; gap: 16px; }
.bt-side-card { padding: 22px; border: 1px solid var(--bt-line); border-radius: 8px; background: #fff; box-shadow: 0 14px 34px rgba(80,0,8,.06); }
.bt-side-card h3 { color: #151515; font-size: 22px; font-weight: 1000; }
.bt-side-card ul { list-style: none; padding: 0; margin: 14px 0 0; display: grid; gap: 12px; }
.bt-side-card li { color: #666; line-height: 1.65; border-top: 1px solid rgba(227,0,19,.14); padding-top: 12px; }
.bt-side-card li:first-child { border-top: 0; padding-top: 0; }
.bt-article-layout { padding: 44px 0 70px; }
.bt-article { overflow: hidden; border: 1px solid var(--bt-line); border-radius: 8px; background: #fff; box-shadow: var(--bt-shadow); }
.bt-article-cover { max-height: 390px; }
.bt-article-body { padding: 30px; }
.bt-article h1 { color: #151515; font-size: clamp(30px,4vw,46px); line-height: 1.15; font-weight: 1000; }
.bt-meta { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px; color: #777; font-size: 13px; font-weight: 800; }
.bt-body { margin-top: 24px; color: #273443; font-size: 16px; line-height: 1.9; font-weight: 650; }
.bt-body h2 { margin: 26px 0 10px; color: var(--bt-red); font-size: 26px; line-height: 1.2; font-weight: 1000; }
.bt-prenext { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 12px; margin-top: 24px; }
.bt-prenext > div, .bt-actions-list li { border: 1px solid var(--bt-line); border-radius: 6px; padding: 12px; background: var(--bt-soft); }
.bt-actions-list { list-style: none; display: flex; flex-wrap: wrap; gap: 10px; padding: 0; margin: 20px 0 0; }
.bt-actions-list li { font-size: 13px; font-weight: 900; }
.bt-footer { color: #f8e7dc; background: #0c0504; }
.bt-footer-grid { display: grid; grid-template-columns: minmax(0, 1.3fr) repeat(3, minmax(150px, .7fr)); gap: 24px; padding: 42px 0; }
.bt-footer p, .bt-footer li { color: #d5bbb3; line-height: 1.7; }
.bt-footer h3 { color: #fff; font-size: 16px; font-weight: 1000; }
.bt-footer ul { list-style: none; padding: 0; margin: 12px 0 0; display: grid; gap: 8px; }
.bt-footer-bottom { border-top: 1px solid rgba(255,255,255,.1); }
.bt-footer-bottom .bt-shell { min-height: 48px; display: flex; align-items: center; justify-content: space-between; gap: 12px; color: #d5bbb3; font-size: 13px; }
@media (max-width: 1080px) {
  .bt-feature-grid, .bt-steps { grid-template-columns: repeat(2, 1fr); }
  .bt-feature:nth-child(2) { border-right: 0; }
  .bt-app, .bt-column-grid, .bt-content-layout, .bt-article-layout, .bt-faq { grid-template-columns: 1fr; }
  .bt-categories, .bt-product-grid, .bt-news-grid, .bt-footer-grid { grid-template-columns: repeat(2, 1fr); }
  .bt-hero .bt-shell { grid-template-columns: 1fr; min-height: auto; }
  .bt-hero-copy { padding: 48px 0 10px; }
  .bt-hero-media { min-height: 360px; }
  .bt-hero-img { position: relative; inset: auto; width: 100%; height: 360px; border-radius: 8px 8px 0 0; }
}
@media (max-width: 680px) {
  .bt-shell { width: min(100% - 28px, var(--bt-shell)); }
  .bt-utility .bt-shell { flex-direction: column; align-items: flex-start; justify-content: center; padding: 8px 0; line-height: 1.35; }
  .bt-header { min-height: auto; padding: 14px 0; flex-wrap: wrap; }
  .bt-actions { width: 100%; }
  .bt-actions .bt-btn { flex: 1 1 120px; }
  .bt-title { font-size: 40px; }
  .bt-hero { min-height: auto; }
  .bt-hero-copy p { font-size: 16px; }
  .bt-feature-grid, .bt-steps, .bt-categories, .bt-product-grid, .bt-news-grid, .bt-footer-grid, .bt-prenext { grid-template-columns: 1fr; }
  .bt-feature { border-right: 0; border-bottom: 1px solid rgba(255,255,255,.08); }
  .bt-feature:last-child { border-bottom: 0; }
  .bt-section { padding: 48px 0; }
  .bt-footer-bottom .bt-shell { flex-direction: column; align-items: flex-start; justify-content: center; padding: 10px 0; }
}