:root {
  --brand-bg: #f4f6f8;
  --brand-surface: #ffffff;
  --brand-ink: #15191d;
  --brand-muted: #59636e;
  --brand-border: #dce1e6;
  --brand-header: #101417;
  --brand-header-soft: #1c2228;
  --brand-primary: #f57c00;
  --brand-primary-dark: #c45f00;
  --brand-secondary: #1268d4;
  --brand-positive: #138a62;
  --brand-warning: #fff4df;
  --space-xs: 8px;
  --space-sm: 12px;
  --space-md: 18px;
  --space-lg: 28px;
  --space-xl: 44px;
  --space-2xl: 72px;
  --radius: 8px;
  --shadow: 0 10px 28px rgba(21, 25, 29, .08);
  --container: 1200px;
  --copy: 780px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--brand-bg);
  color: var(--brand-ink);
  font-family: "Noto Sans Bengali", "Hind Siliguri", system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.72;
  letter-spacing: 0;
}
a { color: var(--brand-secondary); text-decoration-thickness: .08em; text-underline-offset: .18em; }
a:hover { color: #084f9f; }
img { display: block; max-width: 100%; height: auto; }
button, input, textarea, select { font: inherit; }
.screen-reader-text { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

.tbb-topbar { background: #07090b; color: #c4cbd2; font-size: 14px; }
.tbb-topbar__inner,
.tbb-header__inner,
.tbb-footer__inner,
.tbb-main,
.tbb-hero,
.tbb-page-head {
  width: min(var(--container), calc(100% - 32px));
  margin-inline: auto;
}
.tbb-topbar__inner { min-height: 38px; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.tbb-topbar a { color: #ffffff; }

.tbb-header { position: sticky; top: 0; z-index: 40; background: rgba(16, 20, 23, .97); border-bottom: 1px solid #2b3238; }
.tbb-header__inner { min-height: 72px; display: flex; align-items: center; gap: 24px; }
.tbb-brand { flex: 0 0 auto; display: inline-flex; align-items: center; gap: 10px; color: #ffffff; text-decoration: none; font-weight: 900; font-size: 20px; }
.tbb-brand__mark { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 6px; background: var(--brand-primary); color: #17120b; font-size: 12px; }
.tbb-nav { min-width: 0; flex: 1; display: flex; align-items: center; justify-content: flex-end; gap: 20px; }
.tbb-nav__links { display: flex; align-items: center; justify-content: flex-end; gap: 15px; }
.tbb-nav a { color: #cbd2d8; text-decoration: none; font-size: 14px; font-weight: 700; white-space: nowrap; }
.tbb-nav a:hover { color: #ffffff; }
.tbb-header__actions { display: flex; gap: 8px; padding-left: 16px; border-left: 1px solid #343c43; }
.tbb-menu-toggle { display: none; width: 44px; height: 44px; border: 1px solid #3a444c; border-radius: 6px; background: transparent; color: #ffffff; cursor: pointer; }

.tbb-btn { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 10px 18px; border: 1px solid var(--brand-border); border-radius: 6px; background: var(--brand-surface); color: var(--brand-ink); font-weight: 800; text-decoration: none; }
.tbb-btn:hover { transform: translateY(-1px); color: var(--brand-ink); }
.tbb-btn--primary { border-color: var(--brand-primary); background: var(--brand-primary); color: #17120b; }
.tbb-btn--secondary { border-color: #ffffff; background: #ffffff; color: var(--brand-ink); }
.tbb-btn--quiet { border-color: #56616a; background: transparent; color: #ffffff; }

.tbb-hero { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(320px, .95fr); gap: clamp(28px, 5vw, 64px); align-items: center; padding: clamp(46px, 7vw, 84px) 0; color: #ffffff; }
.home .tbb-main { width: 100%; max-width: none; padding: 0; background: var(--brand-header); }
.home .tbb-content { background: var(--brand-bg); color: var(--brand-ink); }
.tbb-hero__label { display: inline-flex; width: fit-content; padding: 5px 9px; border-left: 3px solid var(--brand-primary); color: #ffd19f; font-size: 14px; font-weight: 800; }
h1, h2, h3 { margin-top: 0; color: var(--brand-ink); line-height: 1.18; letter-spacing: 0; }
.tbb-hero h1 { max-width: 760px; margin: 16px 0 18px; color: #ffffff; font-size: clamp(38px, 5.6vw, 68px); }
h1 { margin: 14px 0 16px; font-size: clamp(34px, 4.5vw, 56px); }
h2 { margin-bottom: 16px; font-size: clamp(26px, 3vw, 38px); }
h3 { margin-bottom: 8px; font-size: 21px; }
.tbb-lead { max-width: 700px; color: #cbd2d8; font-size: clamp(18px, 2vw, 22px); }
.tbb-hero__actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
.tbb-hero__media { margin: 0; overflow: hidden; border: 1px solid #3d464e; border-radius: var(--radius); background: var(--brand-header-soft); box-shadow: 0 20px 42px rgba(0, 0, 0, .24); }
.tbb-hero__media img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; }

.tbb-main { padding: 12px 0 var(--space-2xl); }
.tbb-page-head { display: grid; grid-template-columns: minmax(0, 1fr) minmax(260px, 410px); gap: 40px; align-items: center; padding: 48px 0 32px; }
.tbb-page-head--compact { grid-template-columns: 1fr; }
.tbb-page-head__summary { max-width: 760px; margin: 0; color: var(--brand-muted); font-size: 19px; }
.tbb-page-head__media { margin: 0; overflow: hidden; border: 1px solid var(--brand-border); border-radius: var(--radius); background: var(--brand-surface); box-shadow: var(--shadow); }
.tbb-page-head__media img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }
.tbb-breadcrumb { display: flex; flex-wrap: wrap; gap: 7px; align-items: center; color: var(--brand-muted); font-size: 14px; }
.tbb-breadcrumb a { color: var(--brand-muted); }
.tbb-content { display: grid; gap: var(--space-xl); }
.home .tbb-content > * { width: min(var(--container), calc(100% - 32px)); margin-inline: auto; }
.home .tbb-content > .alignfull { width: 100%; }

.tbb-copy { width: min(var(--copy), 100%); }
.tbb-copy--wide { width: 100%; }
.tbb-copy p, .tbb-policy p { margin: 0 0 16px; color: var(--brand-muted); }
.tbb-updated { width: fit-content; margin-top: var(--space-lg); padding: 7px 10px; border-left: 3px solid var(--brand-positive); background: #edf8f4; color: #225e4b; font-size: 14px; }

.tbb-quick-links { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); margin-top: -26px; position: relative; z-index: 2; border: 1px solid var(--brand-border); border-radius: var(--radius); background: var(--brand-surface); box-shadow: var(--shadow); }
.tbb-quick-links a { min-height: 86px; padding: 18px; border-right: 1px solid var(--brand-border); color: var(--brand-ink); text-decoration: none; font-weight: 850; }
.tbb-quick-links a:last-child { border-right: 0; }
.tbb-quick-links small { display: block; margin-top: 4px; color: var(--brand-muted); font-weight: 500; }

.tbb-feature-band { display: grid; grid-template-columns: minmax(0, .78fr) minmax(0, 1.22fr); gap: 48px; align-items: start; padding: 42px; border-radius: var(--radius); background: #e8eef5; }
.tbb-feature-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px 28px; }
.tbb-feature-list > div { padding-top: 12px; border-top: 3px solid var(--brand-primary); }
.tbb-feature-list p { margin: 0; color: var(--brand-muted); }

.tbb-category-grid { display: grid; grid-template-columns: 1.35fr repeat(2, 1fr); grid-auto-rows: minmax(152px, auto); gap: 14px; }
.tbb-category-grid a { display: flex; flex-direction: column; justify-content: flex-end; min-height: 152px; padding: 22px; border: 1px solid var(--brand-border); border-radius: var(--radius); background: var(--brand-surface); color: var(--brand-ink); text-decoration: none; }
.tbb-category-grid a:first-child { grid-row: span 2; background: var(--brand-header); color: #ffffff; }
.tbb-category-grid strong { font-size: 23px; }
.tbb-category-grid span { color: var(--brand-muted); }
.tbb-category-grid a:first-child span { color: #cbd2d8; }

.tbb-app-split { display: grid; grid-template-columns: minmax(280px, .82fr) minmax(0, 1.18fr); gap: 48px; align-items: center; padding: 44px; border-radius: var(--radius); background: var(--brand-header); color: #ffffff; }
.tbb-app-split h2 { color: #ffffff; }
.tbb-app-split p { color: #cbd2d8; }
.tbb-app-split a { color: #8fc6ff; font-weight: 750; }
.tbb-app-split figure { margin: 0; overflow: hidden; border-radius: var(--radius); }
.tbb-app-split img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }
.tbb-device-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px; }
.tbb-device-row span { padding: 7px 10px; border: 1px solid #465159; border-radius: 5px; color: #ffffff; font-size: 14px; }

.tbb-table-wrap { width: 100%; overflow-x: auto; border: 1px solid var(--brand-border); border-radius: var(--radius); background: var(--brand-surface); }
.tbb-matrix { width: 100%; min-width: 720px; border-collapse: collapse; }
.tbb-matrix th, .tbb-matrix td { padding: 14px 16px; border-bottom: 1px solid var(--brand-border); text-align: left; vertical-align: top; }
.tbb-matrix th { background: #eef1f4; color: var(--brand-ink); }
.tbb-matrix td { color: var(--brand-muted); }

.tbb-steps { display: grid; counter-reset: steps; border-top: 1px solid var(--brand-border); }
.tbb-steps > div { display: grid; grid-template-columns: 52px minmax(0, 1fr); gap: 18px; padding: 22px 0; border-bottom: 1px solid var(--brand-border); counter-increment: steps; }
.tbb-steps > div::before { grid-column: 1; grid-row: 1 / span 2; content: counter(steps, decimal-leading-zero); color: var(--brand-primary-dark); font-weight: 900; font-size: 18px; }
.tbb-steps > div > * { grid-column: 2; }
.tbb-steps p { margin: 4px 0 0; color: var(--brand-muted); }

.tbb-info-card, .tbb-notice, .tbb-support-panel, .tbb-offer-status, .tbb-policy, .tbb-related-links { border: 1px solid var(--brand-border); border-radius: var(--radius); background: var(--brand-surface); }
.tbb-info-card { padding: 22px; min-height: 154px; }
.tbb-info-card p, .tbb-notice p, .tbb-support-panel p, .tbb-offer-status p { margin: 0; color: var(--brand-muted); }
.tbb-card-grid, .tbb-card-grid--four, .tbb-stat-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.tbb-card-grid--four { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.tbb-notice { padding: 24px; border-left: 4px solid var(--brand-primary); background: var(--brand-warning); }
.tbb-status-empty { padding: 28px; border: 1px dashed #aab3bc; border-radius: var(--radius); background: #fafbfc; color: var(--brand-muted); }
.tbb-support-panel { display: grid; grid-template-columns: .9fr 1.1fr; gap: 32px; padding: 30px; }
.tbb-policy { width: min(860px, 100%); padding: 32px; }
.tbb-policy h2 { padding-top: 14px; border-top: 1px solid var(--brand-border); }
.tbb-policy ul { color: var(--brand-muted); }
.tbb-related-links { padding: 18px 20px; }
.tbb-related-links ul { display: flex; flex-wrap: wrap; gap: 10px 20px; margin: 8px 0 0; padding: 0; list-style: none; }
.tbb-feature-image { margin: 0; overflow: hidden; border: 1px solid var(--brand-border); border-radius: var(--radius); }
.tbb-feature-image img { width: 100%; max-height: 520px; object-fit: cover; }

.schema-faq-section { margin-bottom: 10px; border-bottom: 1px solid var(--brand-border); background: var(--brand-surface); }
.schema-faq-question { display: block; padding: 18px 0 8px; color: var(--brand-ink); font-size: 18px; }
.schema-faq-answer { margin: 0; padding-bottom: 18px; color: var(--brand-muted); }

.tbb-footer { border-top: 1px solid #2a3035; background: #0b0e10; color: #c6cdd3; }
.tbb-footer__inner { display: grid; grid-template-columns: 1.35fr repeat(4, 1fr); gap: 30px; padding: 48px 0; }
.tbb-footer h2, .tbb-footer h3 { color: #ffffff; font-size: 18px; }
.tbb-footer a, .tbb-footer p, .tbb-footer li { color: #aeb7bf; }
.tbb-footer ul { display: grid; gap: 8px; margin: 0; padding: 0; list-style: none; }

.tbb-search-form { display: flex; gap: 10px; max-width: 640px; }
.tbb-search-form input { flex: 1; min-height: 44px; padding: 10px 12px; border: 1px solid var(--brand-border); border-radius: 6px; background: var(--brand-surface); color: var(--brand-ink); }

@media (max-width: 1100px) {
  .tbb-nav__links { gap: 11px; }
  .tbb-nav a { font-size: 13px; }
  .tbb-header__actions { padding-left: 10px; }
}

@media (max-width: 920px) {
  body { font-size: 16px; }
  .tbb-header__inner { justify-content: space-between; }
  .tbb-menu-toggle { display: inline-grid; place-items: center; margin-left: auto; }
  .tbb-nav { display: none; position: absolute; inset: 72px 16px auto 16px; padding: 18px; border: 1px solid #343d44; border-radius: var(--radius); background: var(--brand-header); box-shadow: 0 16px 34px rgba(0,0,0,.28); }
  .tbb-nav.is-open { display: grid; gap: 18px; }
  .tbb-nav__links { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 4px 18px; }
  .tbb-nav__links a { padding: 10px 0; border-bottom: 1px solid #2d353b; font-size: 15px; }
  .tbb-header__actions { padding: 0; border: 0; }
  .tbb-hero, .tbb-page-head, .tbb-app-split, .tbb-feature-band, .tbb-support-panel { grid-template-columns: 1fr; }
  .tbb-quick-links, .tbb-card-grid--four { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .tbb-quick-links a:nth-child(2) { border-right: 0; }
  .tbb-quick-links a:nth-child(-n+2) { border-bottom: 1px solid var(--brand-border); }
  .tbb-category-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .tbb-category-grid a:first-child { grid-row: auto; }
  .tbb-card-grid, .tbb-stat-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .tbb-footer__inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 560px) {
  .tbb-topbar__inner { display: grid; gap: 2px; padding: 7px 0; }
  .tbb-hero { padding: 34px 0 52px; }
  .tbb-hero h1, h1 { font-size: 36px; overflow-wrap: anywhere; }
  .tbb-quick-links, .tbb-card-grid, .tbb-card-grid--four, .tbb-stat-grid, .tbb-category-grid, .tbb-feature-list { grid-template-columns: 1fr; }
  .tbb-quick-links a { border-right: 0; border-bottom: 1px solid var(--brand-border); }
  .tbb-quick-links a:last-child { border-bottom: 0; }
  .tbb-feature-band, .tbb-app-split, .tbb-policy { padding: 24px; }
  .tbb-footer__inner { grid-template-columns: 1fr; }
  .tbb-page-head { padding-top: 32px; }
  .tbb-nav__links { grid-template-columns: 1fr; }
}