/* ============================================================
   ByeByeDPI — design system
   Headings: Space Grotesk · Body: IBM Plex Sans · Mono: JetBrains Mono
   ============================================================ */

:root {
  /* color */
  --ink:      #0b0f17;   /* near-black navy */
  --ink-2:    #141b27;   /* raised dark surface */
  --ink-3:    #1d2738;   /* hairlines on dark */
  --paper:    #ffffff;
  --paper-2:  #f5f7fa;   /* muted section bg */
  --paper-3:  #eceff4;   /* card / border on light */
  --text:     #0b0f17;
  --text-2:   #4a5566;   /* secondary text */
  --text-3:   #8a94a6;   /* tertiary / captions */
  --line:     #e2e7ee;

  --accent:   #007FFF;   /* brand blue */
  --accent-d: #0066d6;
  --accent-ink:#ffffff;
  --cyan:     #34d8ff;
  --danger:   #ff5d5d;

  /* type */
  --f-head: 'Space Grotesk', ui-sans-serif, system-ui, sans-serif;
  --f-body: 'IBM Plex Sans', ui-sans-serif, system-ui, sans-serif;
  --f-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', monospace;

  /* layout */
  --maxw: 1180px;
  --radius: 16px;
  --radius-s: 10px;
  --shadow: 0 1px 2px rgba(11,15,23,.04), 0 8px 30px rgba(11,15,23,.06);
  --shadow-lg: 0 20px 60px rgba(11,15,23,.14);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--f-body);
  color: var(--text);
  background: var(--paper);
  font-size: 18px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }

a { color: inherit; text-decoration: none; }

h1, h2, h3, h4 {
  font-family: var(--f-head);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0 0 .5em;
  text-wrap: balance;
}

h1 { font-size: clamp(2.4rem, 6vw, 4.2rem); }
h2 { font-size: clamp(1.9rem, 4vw, 2.9rem); }
h3 { font-size: clamp(1.25rem, 2.4vw, 1.6rem); }

p { margin: 0 0 1rem; text-wrap: pretty; }

.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: clamp(20px, 5vw, 40px);
}

.mono {
  font-family: var(--f-mono);
  font-size: .8em;
  letter-spacing: .02em;
}

/* ---------- eyebrow / kicker ---------- */
.kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--f-mono);
  font-size: .78rem;
  font-weight: 500;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent-d);
  margin-bottom: 18px;
}
.kicker::before {
  content: "";
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(0,127,255,.18);
}
.kicker--light { color: var(--accent); }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-family: var(--f-head);
  font-weight: 600;
  font-size: 1.02rem;
  letter-spacing: -0.01em;
  padding: 15px 26px;
  border-radius: 12px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .15s ease, box-shadow .2s ease, background .2s ease, border-color .2s ease, color .2s ease;
  white-space: nowrap;
}
.btn svg { width: 20px; height: 20px; }
.btn--primary {
  background: var(--accent);
  color: var(--accent-ink);
  box-shadow: 0 6px 22px rgba(0,127,255,.35);
}
.btn--primary:hover { background: var(--accent-d); transform: translateY(-2px); box-shadow: 0 12px 30px rgba(0,127,255,.42); }
.btn--ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--line);
}
.btn--ghost:hover { border-color: var(--text); transform: translateY(-2px); }
.btn--on-dark.btn--ghost { color: #fff; border-color: rgba(255,255,255,.22); }
.btn--on-dark.btn--ghost:hover { border-color: #fff; background: rgba(255,255,255,.06); }
.btn--lg { padding: 18px 34px; font-size: 1.12rem; }
.btn--block { width: 100%; }

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,.82);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav {
  display: flex;
  align-items: center;
  gap: 20px;
  height: 72px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  font-family: var(--f-head);
  font-weight: 700;
  font-size: 1.18rem;
  letter-spacing: -0.02em;
  margin-right: auto;
}
.brand-mark {
  width: 40px; height: 40px;
  border-radius: 11px;
  display: grid; place-items: center;
  overflow: hidden;
  flex: none;
}
.brand-mark img { width: 100%; height: 100%; display: block; }
.brand-mark .brand-svg { width: 100%; height: 100%; display: block; }
.brand-mark svg { width: 21px; height: 21px; }
.brand b { color: var(--accent-d); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav-links a {
  padding: 9px 14px;
  border-radius: 9px;
  font-weight: 500;
  font-size: .98rem;
  color: var(--text-2);
  white-space: nowrap;
  transition: background .15s, color .15s;
}
.nav-links a:hover { background: var(--paper-2); color: var(--text); }
.nav-links a[aria-current="page"] { color: var(--text); background: var(--paper-2); }

.nav-cta { margin-left: 8px; }

.nav-toggle {
  display: none;
  background: none; border: 1px solid var(--line);
  border-radius: 10px;
  width: 44px; height: 44px;
  cursor: pointer;
  padding: 0;
  place-items: center;
  color: var(--text);
}
.nav-toggle svg { width: 22px; height: 22px; }

/* ---------- sections ---------- */
section { padding: clamp(56px, 9vw, 110px) 0; }
.section-muted { background: var(--paper-2); }
.section-dark { background: var(--ink); color: #e8edf4; }
.section-dark h1, .section-dark h2, .section-dark h3 { color: #fff; }

.section-head { max-width: 720px; margin-bottom: 52px; }
.section-head.center { margin-inline: auto; text-align: center; }
.lead { font-size: 1.18rem; color: var(--text-2); }
.section-dark .lead { color: #aab6c6; }

/* ---------- hero ---------- */
.hero {
  position: relative;
  background: var(--ink);
  color: #e8edf4;
  overflow: hidden;
  padding: clamp(70px, 11vw, 130px) 0 clamp(64px, 9vw, 110px);
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background:
    radial-gradient(680px 420px at 78% -8%, rgba(0,127,255,.16), transparent 60%),
    radial-gradient(560px 380px at 8% 108%, rgba(52,216,255,.10), transparent 60%);
  pointer-events: none;
}
.hero-grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(700px 500px at 70% 0%, #000, transparent 75%);
  pointer-events: none;
}
.hero .container { position: relative; }
.hero-layout {
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: 56px;
  align-items: center;
}
.hero h1 { color: #fff; }
.hero h1 .hl { color: var(--accent); }
.hero-sub {
  font-size: 1.22rem;
  color: #aeb9c8;
  max-width: 30ch;
  margin-bottom: 30px;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 26px; }
.hero-meta {
  display: flex; flex-wrap: wrap; gap: 22px;
  font-size: .92rem; color: #8896a8;
}
.hero-meta span { display: inline-flex; align-items: center; gap: 7px; }
.hero-meta svg { width: 17px; height: 17px; color: var(--accent); }

/* device mock in hero */
.phone {
  position: relative;
  width: 100%;
  max-width: 320px;
  margin-inline: auto;
  aspect-ratio: 9 / 18.6;
  background: #0a0d14;
  border: 2px solid #232f43;
  border-radius: 38px;
  padding: 12px;
  box-shadow: var(--shadow-lg), inset 0 0 0 1px rgba(255,255,255,.03);
}
.phone-screen {
  height: 100%;
  border-radius: 28px;
  background: linear-gradient(180deg, #0f1622, #0b1019);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  border: 1px solid #1b2536;
}
.phone-status {
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px 18px 8px;
  font-family: var(--f-mono);
  font-size: .68rem; color: #6b7892;
}
.phone-body { padding: 6px 18px 18px; display: flex; flex-direction: column; gap: 13px; }
.phone-title { font-family: var(--f-head); font-weight: 700; color: #fff; font-size: 1.05rem; }
.toggle-card {
  background: #131c2b;
  border: 1px solid #21304a;
  border-radius: 16px;
  padding: 16px;
  display: flex; align-items: center; gap: 12px;
}
.toggle-card.on { border-color: rgba(0,127,255,.5); box-shadow: 0 0 0 1px rgba(0,127,255,.25), 0 8px 24px rgba(0,127,255,.12); }
.toggle-ico { width: 38px; height: 38px; border-radius: 11px; background: rgba(0,127,255,.14); color: var(--accent); display: grid; place-items: center; flex: none; }
.toggle-ico svg { width: 20px; height: 20px; }
.toggle-meta b { display: block; color: #fff; font-size: .92rem; font-family: var(--f-head); }
.toggle-meta span { font-size: .74rem; color: #7d8aa0; }
.toggle-switch { margin-left: auto; width: 44px; height: 26px; border-radius: 20px; background: var(--accent); position: relative; flex: none; }
.toggle-switch::after { content:""; position:absolute; top:3px; right:3px; width:20px; height:20px; border-radius:50%; background:#fff; }
.phone-stat { display: grid; grid-template-columns: 1fr 1fr; gap: 9px; }
.stat-pill { background:#101826; border:1px solid #1d2a40; border-radius:12px; padding:11px 13px; }
.stat-pill b { display:block; font-family: var(--f-mono); color: var(--cyan); font-size: 1.02rem; }
.stat-pill span { font-size:.68rem; color:#6f7d94; }
.phone-log { background:#0a111c; border:1px solid #182336; border-radius:12px; padding:12px; font-family: var(--f-mono); font-size:.66rem; color:#5d7a8f; line-height:1.7; }
.phone-log .ok { color: var(--accent); }

/* ---------- feature grid ---------- */
.grid {
  display: grid;
  gap: 22px;
}
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px;
  box-shadow: var(--shadow);
  transition: transform .18s ease, box-shadow .2s ease, border-color .2s;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: #d5dde7; }
.card .ico {
  width: 52px; height: 52px;
  border-radius: 13px;
  display: grid; place-items: center;
  background: rgba(0,127,255,.1);
  color: var(--accent-d);
  margin-bottom: 18px;
}
.card .ico svg { width: 26px; height: 26px; }
.card h3 { font-size: 1.28rem; margin-bottom: 8px; }
.card p { color: var(--text-2); margin: 0; font-size: 1rem; }

/* dark variant card */
.section-dark .card {
  background: var(--ink-2);
  border-color: var(--ink-3);
  box-shadow: none;
}
.section-dark .card:hover { border-color: #2a3850; }
.section-dark .card p { color: #9fabbd; }
.section-dark .card .ico { background: rgba(0,127,255,.12); color: var(--accent); }

/* ---------- steps ---------- */
.steps { display: grid; gap: 18px; counter-reset: step; }
.step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 22px;
  align-items: start;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 28px;
  box-shadow: var(--shadow);
}
.step-num {
  counter-increment: step;
  width: 56px; height: 56px;
  border-radius: 14px;
  background: var(--ink);
  color: var(--accent);
  font-family: var(--f-head);
  font-weight: 700;
  font-size: 1.4rem;
  display: grid; place-items: center;
}
.step-num::before { content: counter(step, decimal-leading-zero); }
.step h3 { margin-bottom: 6px; font-size: 1.2rem; }
.step p { margin: 0; color: var(--text-2); font-size: 1rem; }

/* ---------- download CTA banner ---------- */
.cta-band {
  background: linear-gradient(135deg, #0f1622, var(--ink) 60%);
  border-radius: 28px;
  padding: clamp(40px, 6vw, 68px);
  text-align: center;
  position: relative;
  overflow: hidden;
  color: #fff;
  box-shadow: var(--shadow-lg);
}
.cta-band::before {
  content:""; position:absolute; inset:0;
  background: radial-gradient(500px 300px at 50% -20%, rgba(0,127,255,.22), transparent 70%);
}
.cta-band > * { position: relative; }
.cta-band h2 { color:#fff; }
.cta-band p { color:#a9b5c5; max-width: 56ch; margin-inline:auto; }
.cta-actions { display:flex; flex-wrap:wrap; gap:14px; justify-content:center; margin-top: 26px; }

/* ---------- faq ---------- */
.faq { max-width: 820px; margin-inline: auto; }
.faq details {
  border: 1px solid var(--line);
  border-radius: var(--radius-s);
  background: var(--paper);
  margin-bottom: 12px;
  overflow: hidden;
  transition: border-color .2s;
}
.faq details[open] { border-color: var(--accent); }
.faq summary {
  list-style: none;
  cursor: pointer;
  padding: 20px 24px;
  font-family: var(--f-head);
  font-weight: 600;
  font-size: 1.12rem;
  display: flex;
  align-items: center;
  gap: 14px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  margin-left: auto;
  font-size: 1.5rem;
  color: var(--accent-d);
  font-family: var(--f-mono);
  transition: transform .2s;
}
.faq details[open] summary::after { transform: rotate(45deg); }
.faq .faq-body { padding: 0 24px 22px; color: var(--text-2); }
.faq .faq-body p:last-child { margin-bottom: 0; }
.faq-cat {
  font-family: var(--f-head);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text);
  margin: 36px 0 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  gap: 10px;
}
.faq-cat:first-child { margin-top: 0; }
.faq-cat .n {
  font-family: var(--f-mono);
  font-size: .8rem;
  color: var(--accent-d);
  background: rgba(0,127,255,.1);
  border-radius: 7px;
  padding: 3px 9px;
}

/* ---------- callout ---------- */
.callout {
  display: flex;
  gap: 16px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-s);
  padding: 20px 22px;
}
.callout svg { width: 24px; height: 24px; color: var(--accent-d); flex: none; margin-top: 2px; }
.callout p { margin: 0; color: var(--text-2); font-size: 1rem; }
.callout b { color: var(--text); }
.callout--warn { border-left-color: var(--danger); }
.callout--warn svg { color: var(--danger); }

/* ---------- prose ---------- */
.prose { max-width: 760px; }
.prose h2 { margin-top: 1.6em; }
.prose h3 { margin-top: 1.4em; }
.prose p, .prose li { color: var(--text-2); }
.prose ul, .prose ol { padding-left: 1.3em; margin: 0 0 1.2em; }
.prose li { margin-bottom: .5em; }
.prose strong { color: var(--text); }
.prose code {
  font-family: var(--f-mono);
  font-size: .86em;
  background: var(--paper-3);
  padding: 2px 7px;
  border-radius: 6px;
  color: var(--accent-d);
}

/* ---------- pill row ---------- */
.pills { display: flex; flex-wrap: wrap; gap: 10px; }
.pill {
  font-family: var(--f-mono);
  font-size: .82rem;
  padding: 7px 14px;
  border-radius: 100px;
  background: var(--paper-2);
  border: 1px solid var(--line);
  color: var(--text-2);
}
.section-dark .pill { background: var(--ink-2); border-color: var(--ink-3); color: #9fabbd; }

/* ---------- spec table ---------- */
.spec {
  width: 100%;
  border-collapse: collapse;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 1rem;
}
.spec th, .spec td { padding: 16px 22px; text-align: left; border-bottom: 1px solid var(--line); }
.spec th { font-family: var(--f-head); font-weight: 600; color: var(--text); width: 42%; background: var(--paper-2); }
.spec td { color: var(--text-2); }
.spec tr:last-child th, .spec tr:last-child td { border-bottom: none; }

/* ---------- breadcrumbs ---------- */
.crumbs { font-size: .9rem; color: var(--text-3); margin-bottom: 14px; font-family: var(--f-mono); }
.crumbs a:hover { color: var(--accent-d); }
.crumbs .sep { margin: 0 8px; opacity: .5; }

.page-head { padding: clamp(48px, 7vw, 84px) 0 clamp(30px, 5vw, 48px); background: var(--paper-2); border-bottom: 1px solid var(--line); }
.page-head .lead { max-width: 60ch; }

/* ---------- footer ---------- */
.site-footer {
  background: var(--ink);
  color: #93a0b4;
  padding: 64px 0 36px;
  font-size: .96rem;
}
.footer-top { display: grid; grid-template-columns: 1.6fr 1fr 1fr; gap: 40px; padding-bottom: 40px; border-bottom: 1px solid var(--ink-3); }
.footer-brand { display:flex; align-items:center; gap:11px; font-family: var(--f-head); font-weight:700; font-size:1.18rem; color:#fff; margin-bottom: 14px; }

.footer-col h4 { font-family: var(--f-head); color: #fff; font-size: 1rem; margin-bottom: 14px; }
.footer-col a { display: block; padding: 5px 0; color: #93a0b4; transition: color .15s; }
.footer-col a:hover { color: var(--accent); }
.footer-bottom { padding-top: 26px; display: flex; flex-wrap: wrap; gap: 14px; justify-content: space-between; font-size: .85rem; color: #6b7890; }
.footer-bottom .disclaimer { max-width: 70ch; }

/* ---------- utility ---------- */
.center { text-align: center; }
.mt-s { margin-top: 14px; }
.mt-m { margin-top: 28px; }
.mb-0 { margin-bottom: 0; }
.hide-mobile { }

/* ---------- responsive ---------- */
@media (max-width: 960px) {
  .hero-layout { grid-template-columns: 1fr; gap: 44px; }
  .hero-sub { max-width: none; }
  .phone { max-width: 290px; }
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-top { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  body { font-size: 17px; }
  .nav-links, .nav-cta.hide-mobile { display: none; }
  .nav-toggle { display: grid; }
  .site-header.open .nav-links {
    display: flex;
    position: absolute;
    top: 72px; left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    padding: 12px 20px 18px;
    box-shadow: var(--shadow);
  }
  .site-header.open .nav-links a { padding: 13px 14px; font-size: 1.05rem; }
  .site-header.open .nav-links .btn { margin-top: 8px; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .footer-top { grid-template-columns: 1fr; gap: 28px; }
  .step { grid-template-columns: 44px 1fr; gap: 16px; padding: 22px; }
  .step-num { width: 44px; height: 44px; font-size: 1.15rem; }
  .spec th { width: 46%; }
  .btn--block-mobile { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; transition: none !important; animation: none !important; }
}