/* ─── Vidu-S design system · light / professional ─────────────────── */
:root {
  --bg: #ffffff;
  --bg-soft: #f7f8fa;
  --bg-sink: #eef1f5;
  --panel: #ffffff;
  --ink: #14151a;          /* headings, primary text */
  --ink-2: #3c3f48;
  --mut: #656975;          /* secondary text */
  --faint: #9499a3;
  --line: #e7e9ee;
  --line-2: #d6dae2;
  --accent: #2563eb;       /* professional blue — links, emphasis */
  --accent-ink: #1d4ed8;
  --accent-soft: #eff4ff;
  --cta: #16171d;          /* near-black CTA */
  --cta-hover: #000000;
  --ok: #14895f;
  --ok-soft: #e7f6ef;
  --warn: #9a6a00;
  --warn-soft: #fdf3e0;
  --err: #c0392b;
  --shadow-sm: 0 1px 2px rgba(16,18,25,.05), 0 1px 3px rgba(16,18,25,.05);
  --shadow: 0 4px 14px rgba(16,18,25,.06), 0 2px 5px rgba(16,18,25,.04);
  --shadow-lg: 0 18px 44px rgba(16,18,25,.11), 0 5px 14px rgba(16,18,25,.06);
  --r-lg: 16px;
  --r: 12px;
  --r-sm: 8px;
  --font-b: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-d: "Inter", system-ui, -apple-system, sans-serif;
  --font-m: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --nav-h: 64px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 16px); }
body {
  background: var(--bg);
  color: var(--ink-2);
  font: 400 16px/1.65 var(--font-b);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
::selection { background: rgba(37, 99, 235, .16); }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }

.wrap { max-width: 1140px; margin: 0 auto; padding: 0 28px; }
.grad-text { color: var(--accent); }

/* nav */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 100; height: var(--nav-h);
  display: flex; align-items: center;
  background: rgba(255, 255, 255, .82);
  -webkit-backdrop-filter: saturate(180%) blur(12px); backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s, box-shadow .25s;
}
.nav.scrolled { border-bottom-color: var(--line); box-shadow: 0 1px 0 rgba(16,18,25,.02); }
.nav-in { display: flex; align-items: center; gap: 34px; width: 100%; max-width: 1140px; margin: 0 auto; padding: 0 28px; }
.logo { display: flex; align-items: center; gap: 9px; font: 700 18px var(--font-d); letter-spacing: -.3px; color: var(--ink); }
.logo img, .logo svg { width: 26px; height: 26px; }
.logo .beta {
  font: 600 10px/1 var(--font-b); letter-spacing: .8px; text-transform: uppercase;
  color: var(--accent-ink); background: var(--accent-soft);
  border: 1px solid rgba(37,99,235,.2);
  padding: 4px 7px; border-radius: 6px; margin-left: 2px;
}
.nav-links { display: flex; gap: 26px; margin-left: auto; }
.nav-links a { font-size: 14.5px; font-weight: 500; color: var(--mut); transition: color .18s; white-space: nowrap; }
.nav-links a:hover { color: var(--ink); }
.nav .btn { margin-left: 6px; }
.nav-burger { display: none; margin-left: auto; width: 40px; height: 40px; border-radius: 9px; border: 1px solid var(--line); color: var(--ink-2); font-size: 17px; }

/* buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font: 600 14.5px var(--font-b); border-radius: 10px;
  padding: 10px 18px; white-space: nowrap; letter-spacing: -.1px;
  transition: transform .12s, box-shadow .2s, background .18s, border-color .18s, color .18s, opacity .18s;
}
.btn-p { background: var(--cta); color: #fff; box-shadow: var(--shadow-sm); }
.btn-p:hover { background: var(--cta-hover); box-shadow: var(--shadow); transform: translateY(-1px); }
.btn-g { border: 1px solid var(--line-2); background: #fff; color: var(--ink); }
.btn-g:hover { border-color: #b9bec9; background: var(--bg-soft); }
.btn-lg { padding: 13px 24px; font-size: 15px; border-radius: 11px; }
.btn[disabled] { opacity: .5; cursor: not-allowed; transform: none !important; box-shadow: none; }

/* sections */
section { position: relative; padding: 92px 0; }
.kicker {
  font: 600 12.5px var(--font-b); letter-spacing: .4px;
  color: var(--accent); margin-bottom: 14px;
}
.h2 { font: 700 clamp(27px, 3.6vw, 40px)/1.14 var(--font-d); letter-spacing: -1px; color: var(--ink); margin-bottom: 16px; }
.sub { color: var(--mut); font-size: 17px; max-width: 620px; }

/* cards */
.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--r-lg);
  padding: 26px; box-shadow: var(--shadow-sm);
  transition: border-color .22s, box-shadow .22s, transform .22s;
}
.card:hover { border-color: var(--line-2); box-shadow: var(--shadow); transform: translateY(-2px); }

/* code blocks — dark, as is conventional in light doc sites */
.code {
  position: relative; background: #16181f; border: 1px solid #23262f;
  border-radius: var(--r); overflow: hidden; margin: 14px 0;
}
.code-head {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 14px; border-bottom: 1px solid #23262f;
  font: 500 12px var(--font-m); color: #8b90a0;
}
.code-head .dot { width: 9px; height: 9px; border-radius: 50%; background: rgba(255,255,255,.14); }
.code pre {
  padding: 16px 18px; overflow-x: auto;
  font: 400 13px/1.7 var(--font-m); color: #d5d8e3;
  scrollbar-width: thin;
}
.code .cp {
  position: absolute; top: 7px; right: 8px;
  font: 500 11.5px var(--font-b); color: #9297a6;
  border: 1px solid #2c2f3a; border-radius: 7px; padding: 4px 10px;
  background: rgba(30,33,42,.9); transition: color .2s, border-color .2s;
}
.code .cp:hover { color: #fff; border-color: #3a3e4a; }
.tk-k { color: #9db2ff; }
.tk-s { color: #8ad6a1; }
.tk-n { color: #f0b36b; }
.tk-c { color: #6b7186; font-style: italic; }
.tk-m { color: #5cc8f5; font-weight: 600; }
.tk-h { color: #c9a6ff; }

/* tables */
.tbl-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--r); margin: 14px 0; box-shadow: var(--shadow-sm); }
table.tbl { width: 100%; border-collapse: collapse; font-size: 13.8px; min-width: 520px; background: #fff; }
.tbl th {
  text-align: left; font: 600 11.5px var(--font-b); letter-spacing: .4px; text-transform: uppercase;
  color: var(--faint); padding: 11px 16px; background: var(--bg-soft);
  border-bottom: 1px solid var(--line);
}
.tbl td { padding: 11px 16px; border-bottom: 1px solid var(--line); color: var(--mut); vertical-align: top; }
.tbl tr:last-child td { border-bottom: 0; }
.tbl td:first-child { color: var(--ink); font-weight: 500; white-space: nowrap; }
.tbl code, .ic { font: 500 12.5px var(--font-m); background: var(--accent-soft); color: var(--accent-ink); padding: 2px 6px; border-radius: 5px; }

/* chips / badges */
.chip {
  display: inline-flex; align-items: center; gap: 6px;
  font: 500 12.5px var(--font-b); color: var(--mut);
  border: 1px solid var(--line-2); border-radius: 8px; padding: 6px 13px;
  transition: all .18s; cursor: pointer; background: #fff;
}
.chip.on { color: #fff; border-color: var(--cta); background: var(--cta); }
.chip:hover:not(.on) { border-color: #b9bec9; color: var(--ink); }
.pill {
  display: inline-flex; align-items: center; gap: 7px;
  font: 600 12px var(--font-b); letter-spacing: .2px;
  border-radius: 8px; padding: 6px 12px;
}
.method {
  font: 700 11px/1 var(--font-m); letter-spacing: .4px; border-radius: 5px; padding: 4px 8px;
}
.m-post { color: #0f7a52; background: var(--ok-soft); }
.m-get { color: #1668c4; background: var(--accent-soft); }
.m-ws { color: #7c3aed; background: #f2ebfe; }

/* reveal on scroll */
.rv { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
.rv.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .rv { opacity: 1; transform: none; transition: none; }
}

/* footer */
.foot { border-top: 1px solid var(--line); background: var(--bg-soft); padding: 44px 0 54px; color: var(--faint); font-size: 13.5px; }
.foot-in { display: flex; flex-wrap: wrap; gap: 18px 40px; align-items: center; }
.foot a { color: var(--mut); font-weight: 500; }
.foot a:hover { color: var(--ink); }

@media (max-width: 880px) {
  .nav-links, .nav .btn { display: none; }
  .nav-burger { display: block; }
  .nav.open .nav-links {
    display: flex; flex-direction: column; gap: 4px;
    position: absolute; top: var(--nav-h); left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--line);
    padding: 12px 28px 20px; box-shadow: var(--shadow);
  }
  .nav.open .nav-links a { padding: 10px 0; font-size: 16px; }
  section { padding: 64px 0; }
}