/* ============================================================
   Shared stylesheet — local-first, AI-ready tools for the Mac
   ------------------------------------------------------------
   Reused across: ai.cygnusyang.top (home), kaido.cygnusyang.top
   and bitcoffer.cygnusyang.top. Product accent colors live here
   so the sites read as one family.
   ============================================================ */

:root{
  color-scheme: light;
  --ink:#1c1c1e;
  --muted:#686a73;
  --faint:#9a9ca6;
  --line:#e5e6eb;
  --line-strong:#d6d8df;
  --paper:#ffffff;
  --soft:#f5f6fa;
  --night:#0e1420;        /* deep ink-blue */
  --night-2:#16223a;      /* hero gradient end */
  --star:#e8b84b;         /* gold accent */
  --star-dim:#c79a2f;
  --accent-kaido:#5f6cf8; /* product accent — Kaido */
  --accent-bitcoffer:#0f7b6c; /* product accent — Bitcoffer */
  --max:1160px;
  --radius:14px;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Helvetica Neue",sans-serif;
  color:var(--ink);
  background:var(--paper);
  font-synthesis:none;
  text-rendering:optimizeLegibility;
  -webkit-font-smoothing:antialiased;
}

@media (prefers-color-scheme: dark){
  :root{
    color-scheme: dark;
    --ink:#ececee;
    --muted:#a6a8b2;
    --faint:#7b7d87;
    --line:#2a2d36;
    --line-strong:#3a3e48;
    --paper:#14161c;
    --soft:#1c1f27;
    --night:#0b0f18;
    --night-2:#101828;
  }
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;line-height:1.6}
a{color:inherit}
img{max-width:100%;display:block}
h1,h2,h3{margin:0;line-height:1.15;letter-spacing:-.02em;font-weight:650}
p{margin:0}
.wrap{max-width:var(--max);margin:0 auto;padding-left:24px;padding-right:24px}
.skip{position:absolute;left:-9999px;top:0}
.skip:focus{left:12px;top:12px;background:var(--ink);color:var(--paper);padding:8px 14px;border-radius:8px;z-index:100}

/* ---------- top navigation (shared across the three sites) ---------- */
.nav{display:flex;align-items:center;justify-content:space-between;height:64px}
.nav .brand{display:flex;align-items:center;gap:9px;font-weight:700;font-size:18px;letter-spacing:-.01em;text-decoration:none}
.nav .brand .mark{width:22px;height:22px;flex:0 0 auto}
.navlinks{display:flex;align-items:center;gap:22px;font-size:14px}
.navlinks a{text-decoration:none;color:var(--muted)}
.navlinks a:hover{color:var(--ink)}
.navlinks a.active{color:var(--ink);font-weight:600}
.nav .lang{color:var(--muted);text-decoration:none;font-size:14px}
.nav .lang:hover{color:var(--ink)}
@media (max-width:720px){
  .navlinks .optional{display:none}
  .navlinks{gap:14px}
}

/* ---------- hero (studio, dark) ---------- */
.hero{background:linear-gradient(160deg,var(--night) 0%,var(--night-2) 100%);color:#fff;overflow:hidden;position:relative}
.hero .wrap{position:relative;padding-top:88px;padding-bottom:96px}
.hero .eyebrow{font-size:13px;letter-spacing:.14em;text-transform:uppercase;color:var(--star);margin-bottom:20px}
.hero h1{font-size:52px;line-height:1.05;letter-spacing:-.03em;max-width:16ch}
.hero h1 .accent{color:var(--star)}
.hero .lede{margin-top:22px;font-size:19px;line-height:1.55;color:rgba(255,255,255,.72);max-width:56ch}
.hero .actions{margin-top:36px;display:flex;gap:14px;flex-wrap:wrap}
.button{display:inline-flex;align-items:center;gap:8px;padding:13px 22px;border-radius:11px;font-weight:650;font-size:15px;text-decoration:none;border:1px solid transparent;cursor:pointer}
.button.primary{background:var(--star);color:#1a1508}
.button.primary:hover{background:#f2c96a}
.button.ghost{background:rgba(255,255,255,.06);color:#fff;border-color:rgba(255,255,255,.18)}
.button.ghost:hover{background:rgba(255,255,255,.12)}
.hero .stars{position:absolute;inset:0;pointer-events:none}
.hero .stars .dot{position:absolute;width:3px;height:3px;border-radius:50%;background:rgba(255,255,255,.5)}
@media (max-width:720px){
  .hero h1{font-size:36px}
  .hero .wrap{padding-top:56px;padding-bottom:64px}
}

/* ---------- section scaffolding ---------- */
.section{padding:88px 0}
.section.tight{padding:64px 0}
.section-head{margin-bottom:44px}
.section-head .eyebrow{font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin-bottom:14px}
.section-head h2{font-size:34px;letter-spacing:-.025em}
.section-head p{color:var(--muted);margin-top:14px;max-width:62ch}

/* ---------- product cards ---------- */
.products{display:grid;grid-template-columns:1fr 1fr;gap:26px}
.product{position:relative;border:1px solid var(--line);border-radius:var(--radius);padding:34px;background:var(--paper);text-decoration:none;color:inherit;transition:transform .12s ease,border-color .12s ease,box-shadow .12s ease;overflow:hidden}
.product:hover{transform:translateY(-3px);border-color:var(--line-strong);box-shadow:0 18px 44px rgba(0,0,0,.09)}
.product .bar{position:absolute;top:0;left:0;right:0;height:4px}
.product.kaido .bar{background:var(--accent-kaido)}
.product.bitcoffer .bar{background:var(--accent-bitcoffer)}
.product .tag{font-size:11px;letter-spacing:.12em;text-transform:uppercase;font-weight:650;margin-bottom:16px}
.product.kaido .tag{color:var(--accent-kaido)}
.product.bitcoffer .tag{color:var(--accent-bitcoffer)}
.product h3{font-size:26px;margin-bottom:12px}
.product p{color:var(--muted);margin-bottom:22px}
.product .go{font-weight:650;font-size:15px;display:inline-flex;align-items:center;gap:6px}
.product.kaido .go{color:var(--accent-kaido)}
.product.bitcoffer .go{color:var(--accent-bitcoffer)}
.product .go .arr{transition:transform .12s ease}
.product:hover .go .arr{transform:translateX(3px)}
.product .price{font-size:34px;font-weight:700;letter-spacing:-.02em;margin-bottom:16px}
.product .price .per{font-size:15px;font-weight:600;color:var(--muted)}
.product ul.feats{list-style:none;padding:0;margin:0 0 22px;color:var(--muted)}
.product ul.feats li{position:relative;padding-left:22px;margin-bottom:8px;font-size:15px}
.product ul.feats li::before{content:"✓";position:absolute;left:0;color:var(--star);font-weight:700}
@media (max-width:760px){.products{grid-template-columns:1fr}}

/* ---------- pricing note ---------- */
.pricing-note{margin-top:48px;max-width:720px}
.pricing-note h2{font-size:20px;margin-bottom:14px}
.pricing-note .note{color:var(--muted);font-size:14px;margin-top:14px}

/* ---------- principles ---------- */
.principles{display:grid;grid-template-columns:repeat(3,1fr);gap:26px}
.principle h3{font-size:18px;margin-bottom:10px}
.principle p{color:var(--muted);font-size:15px}
@media (max-width:760px){.principles{grid-template-columns:1fr}}

/* ---------- about strip ---------- */
.about-strip{background:var(--soft);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.about-strip .wrap{display:flex;align-items:center;justify-content:space-between;gap:28px;padding-top:56px;padding-bottom:56px}
.about-strip h2{font-size:26px}
.about-strip p{color:var(--muted);margin-top:10px;max-width:64ch}
@media (max-width:720px){.about-strip .wrap{flex-direction:column;align-items:flex-start}}

/* ---------- footer (shared) ---------- */
.footer{border-top:1px solid var(--line);padding:36px 0 48px;color:var(--muted);font-size:13px}
.footer-inner{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}
.footer a{text-decoration:none;color:var(--muted)}
.footer a:hover{color:var(--ink)}
.footer .cols{display:flex;gap:20px;flex-wrap:wrap}

/* ---------- legal / prose pages ---------- */
.prose{max-width:720px;margin:0 auto;padding:64px 24px 96px}
.prose h1{font-size:30px;margin-bottom:6px}
.prose h2{font-size:20px;margin-top:40px}
.prose .meta{color:var(--faint);font-size:14px;margin-bottom:28px}
.prose p,.prose li{color:var(--ink);font-size:16px}
.prose ul,.prose ol{padding-left:22px}
.prose a{color:var(--accent-kaido)}
.prose .box{border-left:3px solid var(--star);padding:12px 16px;margin:24px 0;background:var(--soft);border-radius:0 8px 8px 0}
.prose table{border-collapse:collapse;width:100%;margin:18px 0}
.prose th,.prose td{border:1px solid var(--line);padding:9px 12px;text-align:left;font-size:15px}
.prose hr{border:0;border-top:1px solid var(--line);margin:44px 0}

/* ---------- brand mark ---------- */
.nav .brand{color:var(--ink)}
.nav .brand .mark{width:22px;height:22px;flex:0 0 auto}

/* ---------- products dropdown ---------- */
.dropdown{position:relative}
.dropbtn{display:inline-flex;align-items:center;gap:6px;padding:0;background:none;border:none;font:inherit;font-size:14px;color:var(--muted);cursor:pointer}
.dropbtn:hover{color:var(--ink)}
.caret{font-size:9px;line-height:1;transition:transform .14s ease}
.dropdown-menu{position:absolute;top:calc(100% + 12px);left:-16px;min-width:224px;background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:6px;box-shadow:0 18px 48px rgba(0,0,0,.16);opacity:0;visibility:hidden;transform:translateY(-6px);transition:opacity .16s ease,transform .16s ease,visibility .16s;z-index:60}
.dropdown-menu a{display:flex;flex-direction:column;gap:2px;padding:10px 12px;border-radius:8px;text-decoration:none;color:var(--ink)}
.dropdown-menu a:hover{background:var(--soft)}
.dropdown-menu .d-title{font-weight:600;font-size:14px}
.dropdown-menu .d-sub{font-size:12px;color:var(--muted)}
.dropdown:hover .dropdown-menu,.dropdown:focus-within .dropdown-menu{opacity:1;visibility:visible;transform:translateY(0)}
.dropdown:hover .caret,.dropdown:focus-within .caret{transform:rotate(180deg)}