/* BTS Office website */
@font-face { font-family: Figtree; src: url(fonts/figtree-latin-400-normal.woff2) format('woff2'); font-weight: 400; font-display: swap; }
@font-face { font-family: Figtree; src: url(fonts/figtree-latin-500-normal.woff2) format('woff2'); font-weight: 500; font-display: swap; }
@font-face { font-family: Figtree; src: url(fonts/figtree-latin-600-normal.woff2) format('woff2'); font-weight: 600; font-display: swap; }
@font-face { font-family: Figtree; src: url(fonts/figtree-latin-700-normal.woff2) format('woff2'); font-weight: 700; font-display: swap; }
@font-face { font-family: Figtree; src: url(fonts/figtree-latin-800-normal.woff2) format('woff2'); font-weight: 800; font-display: swap; }

:root {
  --ink: #172033; --ink-2: #47526a; --ink-3: #6b7489;
  --paper: #f6f7f9; --white: #ffffff; --line: #dde1e8;
  --docs: #3C4FE0; --sheets: #0F8A6A; --slides: #D9661A; --pdf: #C7354A;
  --radius: 12px;
  --font: Figtree, "Segoe UI", system-ui, sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body { margin: 0; font-family: var(--font); color: var(--ink); background: var(--white); font-size: 17px; line-height: 1.6; -webkit-font-smoothing: antialiased; }
img { max-width: 100%; height: auto; display: block; }
a { color: inherit; }
:focus-visible { outline: 3px solid var(--docs); outline-offset: 2px; border-radius: 4px; }
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 28px; }
.narrow { max-width: 780px; }
.muted { color: var(--ink-3); }
.ic { width: 18px; height: 18px; flex: none; }
code { font-size: .9em; background: var(--paper); border: 1px solid var(--line); border-radius: 5px; padding: 1px 5px; }

/* buttons */
.btn { display: inline-flex; align-items: center; gap: 9px; height: 46px; padding: 0 20px; border-radius: 10px; font-weight: 600; text-decoration: none; border: 1px solid transparent; font-size: 16px; white-space: nowrap; }
.btn-primary { background: var(--ink); color: #fff; height: 56px; padding: 0 26px; font-size: 17px; }
.btn-primary:hover { background: #26324b; }
.btn-dark { background: var(--ink); color: #fff; }
.btn-dark:hover { background: #26324b; }
.btn-ghost { border-color: var(--line); background: #fff; }
.btn-ghost:hover { border-color: var(--ink-3); }
.btn-small { height: 38px; padding: 0 14px; font-size: 14.5px; background: var(--ink); color: #fff; }
.btn-small .ic { width: 16px; height: 16px; }

/* header */
.top { position: sticky; top: 0; z-index: 20; background: rgba(255,255,255,.9); backdrop-filter: saturate(1.4) blur(10px); border-bottom: 1px solid transparent; transition: border-color .2s; }
.top.scrolled { border-bottom-color: var(--line); }
.top-row { display: flex; align-items: center; gap: 28px; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 18px; text-decoration: none; letter-spacing: -.2px; }
.nav { display: flex; gap: 24px; margin-left: auto; }
.nav a { text-decoration: none; color: var(--ink-2); font-weight: 500; font-size: 15.5px; }
.nav a:hover { color: var(--ink); }

/* hero */
.hero { padding: 56px 0 84px; background: linear-gradient(180deg, #fff 0%, var(--paper) 100%); overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.08fr); gap: 56px; align-items: center; }
h1 { font-size: clamp(42px, 5.6vw, 74px); line-height: 1.02; letter-spacing: -2.2px; font-weight: 800; margin: 0 0 22px; text-wrap: balance; }
.lede { font-size: 19px; color: var(--ink-2); max-width: 34em; margin: 0 0 30px; }
.dl { display: flex; flex-direction: column; align-items: flex-start; gap: 10px; margin-bottom: 30px; }
.dl-meta { margin: 0; font-size: 14.5px; color: var(--ink-3); }
.hero-points { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 10px 22px; color: var(--ink-2); font-size: 15px; }
.hero-points li { display: flex; align-items: center; gap: 8px; }
.hero-points .ic { width: 17px; height: 17px; color: var(--ink-3); }

/* the paper stack: four real screenshots, fanned like sheets on a desk */
.stack { position: relative; aspect-ratio: 1.32; }
.sheet { position: absolute; margin: 0; width: 84%; border-radius: var(--radius); overflow: hidden; background: #fff;
  box-shadow: 0 1px 2px rgba(16,24,40,.08), 0 18px 40px -12px rgba(16,24,40,.28); border-top: 6px solid var(--c);
  transform-origin: 30% 100%; transition: transform .9s cubic-bezier(.2,.8,.2,1); }
.sheet img { width: 100%; height: auto; }
.s-pdf    { left: 14%; top: 2%;  transform: rotate(5deg); }
.s-slides { left: 9.5%; top: 7%; transform: rotate(2.5deg); }
.s-sheets { left: 5%;  top: 12%; transform: rotate(-.5deg); }
.s-docs   { left: 0;   top: 17%; transform: rotate(-3.5deg); }
.stack.closed .sheet { transform: rotate(0) translate(8%, 10%); }
@media (prefers-reduced-motion: reduce) { .sheet { transition: none; } }

/* section heads */
.section-title { font-size: clamp(30px, 3.4vw, 44px); line-height: 1.1; letter-spacing: -1px; font-weight: 800; margin: 0 0 14px; text-wrap: balance; }
.section-sub { color: var(--ink-2); font-size: 18px; max-width: 40em; margin: 0 0 40px; }

/* apps */
.apps { padding: 96px 0 40px; }
.app { display: grid; grid-template-columns: minmax(0, .82fr) minmax(0, 1.18fr); gap: 56px; align-items: center; padding: 44px 0; border-top: 1px solid var(--line); }
.app.flip { grid-template-columns: minmax(0, 1.18fr) minmax(0, .82fr); }
.app.flip .app-shot { order: 1; }
.app.flip .app-text { order: 2; }
.app-name { display: flex; align-items: center; gap: 12px; margin-bottom: 8px; }
.app-name h3 { margin: 0; font-size: 28px; letter-spacing: -.5px; }
.badge { width: 38px; height: 38px; border-radius: 10px; background: var(--c); color: #fff; display: grid; place-items: center; font-weight: 800; font-size: 17px; }
.app-lede { font-size: 19px; margin: 0 0 18px; color: var(--ink); }
.ticks { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; color: var(--ink-2); font-size: 16px; }
.ticks li { position: relative; padding-left: 26px; }
.ticks li::before { content: ""; position: absolute; left: 2px; top: .55em; width: 12px; height: 7px; border-left: 2.5px solid var(--c); border-bottom: 2.5px solid var(--c); transform: rotate(-45deg); }
.app-shot { margin: 0; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); box-shadow: 0 24px 50px -24px rgba(16,24,40,.35); }

/* updates band */
.band { background: var(--ink); color: #fff; padding: 88px 0; margin-top: 40px; }
.band .section-sub { color: #c4cbd8; margin-bottom: 0; }
.band-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: start; }
.facts { list-style: none; margin: 0; padding: 0; display: grid; gap: 22px; }
.facts li { display: flex; gap: 16px; }
.facts .ic { width: 22px; height: 22px; margin-top: 3px; color: #fff; opacity: .85; }
.facts b { display: block; font-size: 17px; }
.facts span { color: #c4cbd8; font-size: 15.5px; }

/* releases */
.whats-new { padding: 96px 0 40px; }
.releases { display: grid; gap: 0; }
.rel { display: grid; grid-template-columns: 150px 1fr; gap: 24px; padding: 22px 0; border-top: 1px solid var(--line); }
.rel h3 { margin: 0; font-size: 20px; letter-spacing: -.3px; }
.rel time { color: var(--ink-3); font-size: 14px; }
.rel ul { margin: 0; padding-left: 20px; color: var(--ink-2); }
.rel li { margin-bottom: 4px; }
.rel.latest h3::after { content: "Latest"; margin-left: 8px; font-size: 12px; font-weight: 700; background: #e7f5ef; color: var(--sheets); padding: 2px 8px; border-radius: 20px; vertical-align: 3px; }

/* open source */
.oss { padding: 72px 0 40px; }
.oss-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 56px; align-items: center; background: var(--paper); border-radius: 20px; padding: 48px; }
.oss .section-sub { margin-bottom: 26px; }
.oss-actions { display: flex; flex-wrap: wrap; gap: 12px; }
.formats { margin: 0; display: grid; gap: 0; background: #fff; border: 1px solid var(--line); border-radius: 14px; overflow: hidden; }
.formats div { display: grid; grid-template-columns: 140px 1fr; padding: 14px 18px; border-bottom: 1px solid var(--line); }
.formats div:last-child { border-bottom: 0; }
.formats dt { font-weight: 700; }
.formats dd { margin: 0; color: var(--ink-2); }

/* faq */
.faq { padding: 80px 0 96px; }
details { border-top: 1px solid var(--line); }
details:last-of-type { border-bottom: 1px solid var(--line); }
summary { cursor: pointer; list-style: none; padding: 20px 40px 20px 0; font-weight: 600; font-size: 18px; position: relative; }
summary::-webkit-details-marker { display: none; }
summary::after { content: ""; position: absolute; right: 6px; top: 26px; width: 9px; height: 9px; border-right: 2px solid var(--ink-3); border-bottom: 2px solid var(--ink-3); transform: rotate(45deg); transition: transform .15s; }
details[open] summary::after { transform: rotate(-135deg); top: 30px; }
details p { margin: 0 0 22px; color: var(--ink-2); max-width: 44em; }

/* footer */
.foot { border-top: 1px solid var(--line); padding: 34px 0 44px; color: var(--ink-3); font-size: 14.5px; }
.foot-row { display: flex; flex-wrap: wrap; align-items: center; gap: 14px 28px; }
.foot .brand { font-size: 16px; color: var(--ink); }
.foot p { margin: 0; }
.foot p:last-child { margin-left: auto; display: flex; gap: 18px; }
.foot a { color: var(--ink-2); }

/* responsive */
@media (max-width: 960px) {
  .hero-grid, .app, .band-grid, .oss-grid { grid-template-columns: 1fr; gap: 36px; }
  .app.flip { grid-template-columns: 1fr; }
  .app.flip .app-text, .app.flip .app-shot { order: 0; }
  .stack { max-width: 640px; width: 92%; }
  .oss-grid { padding: 32px 24px; }
  .nav { display: none; }
  .top-row .btn-small { margin-left: auto; }
}
@media (max-width: 560px) {
  .wrap { padding: 0 16px; }
  body { font-size: 16px; }
  .hero { padding: 32px 0 56px; }
  h1 { letter-spacing: -1.4px; }
  .btn-primary { width: 100%; justify-content: center; }
  .dl { align-items: stretch; }
  .rel { grid-template-columns: 1fr; gap: 6px; }
  .formats div { grid-template-columns: 1fr; }
  .foot p:last-child { margin-left: 0; }
}