/* Duosub — marketing site. Vanilla CSS, light/dark aware. */
:root {
  --bg: #ffffff;
  --bg-soft: #f7f7fb;
  --panel: #ffffff;
  --fg: #0f172a;
  --muted: #64748b;
  --line: #e8e8f0;
  --brand1: #6366f1;
  --brand2: #a855f7;
  --brand3: #ec4899;
  --shadow: 0 24px 60px rgba(79, 70, 229, .18);
  --radius: 18px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0a12; --bg-soft: #101019; --panel: #14141f; --fg: #e8eaf2;
    --muted: #98a0b3; --line: #242435; --shadow: 0 24px 60px rgba(0, 0, 0, .55);
  }
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg); color: var(--fg); line-height: 1.6; -webkit-font-smoothing: antialiased;
}
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; }
a { color: inherit; }
h1, h2, h3 { line-height: 1.14; letter-spacing: -.02em; }
.grad {
  background: linear-gradient(120deg, var(--brand1), var(--brand2) 55%, var(--brand3));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}

/* buttons */
.btn {
  display: inline-flex; align-items: center; gap: 8px; font-weight: 700; font-size: 15px;
  padding: 12px 22px; border-radius: 999px; text-decoration: none; cursor: pointer;
  border: 1px solid transparent; transition: transform .12s ease, box-shadow .12s ease;
}
.btn.big { font-size: 16px; padding: 15px 28px; }
.btn-primary {
  color: #fff; background: linear-gradient(120deg, var(--brand1), var(--brand2) 55%, var(--brand3));
  box-shadow: 0 10px 26px rgba(124, 58, 237, .35);
}
.btn-primary:hover { transform: translateY(-2px); }
.btn-ghost { border-color: var(--line); background: var(--panel); color: var(--fg); }
.btn-ghost:hover { transform: translateY(-2px); }

/* header */
.site-header {
  position: sticky; top: 0; z-index: 50; backdrop-filter: blur(12px);
  background: color-mix(in srgb, var(--bg) 82%, transparent); border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; text-decoration: none; font-size: 18px; }
.brand img { width: 30px; height: 30px; border-radius: 8px; }
.nav-links { display: flex; align-items: center; gap: 22px; }
.nav-links a { text-decoration: none; color: var(--muted); font-weight: 600; font-size: 15px; }
.nav-links a:hover { color: var(--fg); }
.nav-links .btn-primary { color: #fff; }

/* hero */
.hero { padding: 70px 0 40px; }
.hero-grid { display: grid; grid-template-columns: 1.05fr 1fr; gap: 48px; align-items: center; }
.eyebrow {
  display: inline-block; font-size: 13px; font-weight: 700; color: var(--brand1);
  background: color-mix(in srgb, var(--brand1) 12%, transparent); padding: 6px 12px;
  border-radius: 999px; margin-bottom: 18px;
}
.hero h1 { font-size: clamp(34px, 5vw, 56px); margin-bottom: 18px; }
.lede { font-size: 19px; color: var(--muted); max-width: 30ch; margin-bottom: 26px; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: 22px; }
.hero-note { display: flex; flex-wrap: wrap; gap: 8px 18px; color: var(--muted); font-size: 13.5px; font-weight: 600; }

/* mock player */
.player {
  background: #0f0f16; border-radius: 16px; overflow: hidden; box-shadow: var(--shadow);
  border: 1px solid #22222f;
}
.player-top { display: flex; align-items: center; gap: 7px; padding: 11px 14px; background: #16161f; }
.player-top .d { width: 11px; height: 11px; border-radius: 50%; }
.d.r { background: #ff5f57; } .d.y { background: #febc2e; } .d.g { background: #28c840; }
.player-top .url { margin-left: 10px; color: #7d8598; font-size: 12px; font-family: ui-monospace, monospace; }
.screen {
  position: relative; aspect-ratio: 16 / 9;
  background: radial-gradient(120% 100% at 50% 20%, #2a2350, #0c0c14 70%);
  display: flex; align-items: flex-end; justify-content: center;
}
.frame {
  position: absolute; inset: 0;
  background:
    radial-gradient(40% 45% at 30% 40%, rgba(168,85,247,.35), transparent 70%),
    radial-gradient(45% 50% at 72% 55%, rgba(99,102,241,.35), transparent 70%);
}
.subs {
  position: relative; z-index: 2; width: 92%; text-align: center;
  margin-bottom: 12%; display: flex; flex-direction: column; gap: 6px;
}
.sub { display: inline-block; align-self: center; max-width: 100%; padding: 3px 10px; border-radius: 6px; background: rgba(8,8,8,.8); }
.sub.orig { color: #fff; font-weight: 600; font-size: clamp(15px, 2.6vw, 24px); }
.sub.trans { color: #ffe08a; font-weight: 500; font-size: clamp(13px, 2.1vw, 20px); }
.word { cursor: pointer; border-radius: 3px; transition: background .1s; }
.word:hover, .word.lit { background: #6d5cff; color: #fff; }
.tip {
  position: absolute; z-index: 3; top: 12px; left: 50%; transform: translateX(-50%);
  background: rgba(0,0,0,.55); color: #cbd5e1; font-size: 12px; padding: 5px 10px; border-radius: 999px;
  transition: opacity .3s;
}
.controls { display: flex; align-items: center; gap: 12px; padding: 12px 14px; background: #16161f; }
.play {
  width: 30px; height: 30px; flex: none; border: none; border-radius: 7px; cursor: pointer;
  background: linear-gradient(120deg, var(--brand1), var(--brand3)); color: #fff; font-size: 11px;
}
.bar { flex: 1; height: 5px; background: #2a2a38; border-radius: 999px; overflow: hidden; }
.fill { height: 100%; width: 0; background: linear-gradient(90deg, var(--brand1), var(--brand3)); }
.pair { color: #8a92a6; font-size: 12px; font-weight: 700; font-family: ui-monospace, monospace; }

/* popover on the demo */
.demo-pop {
  position: absolute; z-index: 5; transform: translateX(-50%);
  background: #14141f; border: 1px solid #2a2a3a; border-radius: 10px; padding: 8px 10px;
  box-shadow: 0 12px 30px rgba(0,0,0,.5); text-align: center; min-width: 110px;
}
.demo-pop b { color: #fff; font-size: 14px; }
.demo-pop small { display: block; color: #ffe08a; font-size: 12px; margin-top: 2px; }

/* blocks */
.block { padding: 76px 0; }
.block.soft { background: var(--bg-soft); }
.section-head { text-align: center; max-width: 640px; margin: 0 auto 44px; }
.section-head h2 { font-size: clamp(26px, 4vw, 38px); margin-bottom: 12px; }
.section-head p { color: var(--muted); font-size: 17px; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.step { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.step .n {
  width: 34px; height: 34px; border-radius: 10px; display: grid; place-items: center; font-weight: 800; color: #fff;
  background: linear-gradient(135deg, var(--brand1), var(--brand3)); margin-bottom: 14px;
}
.step h3 { font-size: 18px; margin-bottom: 6px; }
.step p { color: var(--muted); font-size: 15px; }

.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.feature .ic { font-size: 26px; margin-bottom: 12px; }
.feature h3 { font-size: 18px; margin-bottom: 6px; }
.feature p { color: var(--muted); font-size: 15px; }
code { font-family: ui-monospace, monospace; font-size: .9em; background: var(--bg-soft); padding: 1px 5px; border-radius: 5px; }

.privacy-card { max-width: 760px; margin: 0 auto; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 40px; }
.privacy-card h2 { font-size: 28px; margin-bottom: 14px; }
.privacy-card p { color: var(--muted); margin-bottom: 16px; }
.privacy-card ul { list-style: none; display: flex; flex-direction: column; gap: 10px; margin-bottom: 18px; }
.privacy-card li { padding-left: 26px; position: relative; color: var(--muted); }
.privacy-card li::before { content: "✓"; position: absolute; left: 0; color: var(--brand1); font-weight: 800; }
.link { color: var(--brand1); font-weight: 700; text-decoration: none; }
.link:hover { text-decoration: underline; }

.install { text-align: center; max-width: 620px; margin: 0 auto; }
.install h2 { font-size: clamp(26px, 4vw, 38px); margin-bottom: 12px; }
.install p { color: var(--muted); font-size: 17px; margin-bottom: 24px; }
.install-cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-bottom: 14px; }
.install .small { font-size: 13px; }

/* footer */
.site-footer { border-top: 1px solid var(--line); padding: 32px 0; }
.foot { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.foot .brand img { width: 26px; height: 26px; }
.foot-links { display: flex; gap: 20px; }
.foot-links a { text-decoration: none; color: var(--muted); font-weight: 600; font-size: 14px; }
.foot-links a:hover { color: var(--fg); }
.copy { color: var(--muted); font-size: 13px; }

@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; gap: 34px; }
  .steps, .features { grid-template-columns: 1fr; }
  .hide-sm { display: none; }
}