/* Pantalla Negra — diseño premium minimalista */
:root {
  --bg: #0a0a0b;
  --bg-elev: #121214;
  --bg-card: #161618;
  --line: #26262a;
  --txt: #f4f4f5;
  --txt-2: #a1a1aa;
  --txt-3: #63636b;
  --accent: #fafafa;
  --radius: 12px;
  --shadow-1: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.35);
  --shadow-2: 0 2px 6px rgba(0,0,0,.5), 0 24px 64px rgba(0,0,0,.55);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

[hidden] { display: none !important; }

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, "Segoe UI", Roboto, Inter, sans-serif;
  background:
    radial-gradient(1200px 600px at 50% -10%, rgba(255,255,255,.06), transparent 60%),
    var(--bg);
  color: var(--txt);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.visually-hidden {
  position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;
}

kbd {
  font: 600 .85em/1 inherit; padding: .15em .45em;
  border: 1px solid var(--line); border-bottom-width: 2px;
  border-radius: 5px; background: var(--bg-elev); color: var(--txt);
}

:focus-visible { outline: 2px solid #fff; outline-offset: 3px; border-radius: 4px; }

/* ---------- Topbar ---------- */
.topbar {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  max-width: 1040px; margin: 0 auto; padding: 20px 24px 0;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--txt); text-decoration: none;
  font-weight: 700; letter-spacing: -.02em; font-size: 1.05rem;
}
.brand__icon { width: 22px; height: 22px; color: var(--txt-2); }
.brand span { color: var(--txt-3); font-weight: 500; }
.topnav { display: flex; gap: 4px; list-style: none; }
.topnav a {
  color: var(--txt-2); text-decoration: none; font-size: .9rem;
  padding: 8px 14px; border-radius: 8px; transition: color .2s, background .2s;
}
.topnav a:hover { color: var(--txt); background: rgba(255,255,255,.06); }
@media (max-width: 480px) { .topnav li:nth-child(2) { display: none; } }

@media (max-width: 520px) {
  .hero { margin-top: 30px; }
  .hero__eyebrow { margin-bottom: 12px; }
  .hero h1 { font-size: clamp(1.9rem, 8vw, 2.3rem); }
  .hero__sub { margin-top: 14px; font-size: .93rem; }
  .tool { margin-top: 26px; }
  .tool__card { padding: 18px; }
  .swatches { gap: 8px; margin-top: 16px; }
  .swatch { min-height: 40px; padding: 9px 2px 7px; }
  .swatch__dot { width: 22px; height: 22px; }
  .tool__options { gap: 10px; margin-top: 18px; }
  .toggle { font-size: .87rem; }
  .tool__aviso { margin-top: 14px; font-size: .8rem; }
  .btn-activar { min-height: 52px; margin-top: 12px; font-size: .96rem; }
}

/* ---------- Hero ---------- */
.hero { max-width: 760px; margin: clamp(48px, 9vh, 96px) auto 0; padding: 0 24px; text-align: center; }
.hero__eyebrow {
  font-size: .75rem; font-weight: 600; letter-spacing: .18em; text-transform: uppercase;
  color: var(--txt-3); margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  font-weight: 800; letter-spacing: -.04em; line-height: 1.05;
  background: linear-gradient(180deg, #fff 30%, #777);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero__sub {
  margin: 22px auto 0; max-width: 56ch;
  color: var(--txt-2); font-size: clamp(.98rem, 2vw, 1.12rem);
}

/* ---------- Tool ---------- */
.tool { max-width: 640px; margin: clamp(36px, 6vh, 60px) auto 0; padding: 0 24px; }
.tool__card {
  background: linear-gradient(180deg, var(--bg-card), var(--bg-elev));
  border: 1px solid var(--line); border-radius: calc(var(--radius) + 6px);
  box-shadow: var(--shadow-2); padding: clamp(22px, 4vw, 34px);
}
.tool__head { display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between; gap: 6px; }
.tool__head h2 { font-size: 1.15rem; font-weight: 700; letter-spacing: -.01em; }
.tool__hint { font-size: .82rem; color: var(--txt-3); }

.swatches { border: 0; display: grid; grid-template-columns: repeat(6, 1fr); gap: 10px; margin-top: 20px; }
@media (max-width: 420px) { .swatches { grid-template-columns: repeat(3, 1fr); } }
.swatch {
  appearance: none; cursor: pointer; min-height: 44px;
  display: flex; flex-direction: column; align-items: center; gap: 7px;
  padding: 11px 4px 9px; border-radius: 10px;
  background: var(--bg-elev); border: 1px solid var(--line);
  transition: transform .15s ease, border-color .2s, background .2s;
}
.swatch:hover { background: #1c1c20; transform: translateY(-2px); }
.swatch.is-selected { border-color: #fff; background: #1e1e23; }
.swatch__dot {
  width: 26px; height: 26px; border-radius: 50%;
  background: var(--sw); border: 1px solid var(--sw-border);
  box-shadow: inset 0 0 0 2px rgba(255,255,255,.08), 0 2px 6px rgba(0,0,0,.5);
}
.swatch__label { font-size: .72rem; font-weight: 600; letter-spacing: .04em; color: var(--txt-2); }
.swatch.is-selected .swatch__label { color: var(--txt); }

.tool__options { display: flex; flex-direction: column; gap: 12px; margin-top: 22px; }
.toggle {
  display: flex; align-items: center; gap: 12px;
  font-size: .92rem; color: var(--txt-2); cursor: pointer; user-select: none;
}
.toggle input { position: absolute; opacity: 0; width: 44px; height: 26px; cursor: pointer; }
.toggle__track {
  flex: none; width: 44px; height: 26px; border-radius: 999px;
  background: var(--bg-card); border: 1px solid var(--line);
  position: relative; transition: background .25s, border-color .25s;
}
.toggle__track::after {
  content: ""; position: absolute; top: 50%; left: 3px;
  width: 18px; height: 18px; border-radius: 50%;
  transform: translateY(-50%); background: var(--txt-3);
  transition: left .25s cubic-bezier(.4,0,.2,1), background .25s;
}
.toggle input:checked + .toggle__track { background: #fff; border-color: #fff; }
.toggle input:checked + .toggle__track::after { left: 21px; background: #000; }
.toggle input:checked ~ * { color: var(--txt); }
.toggle--velocidad select {
  margin-left: auto; background: var(--bg-elev); color: var(--txt);
  border: 1px solid var(--line); border-radius: 8px;
  padding: 8px 10px; font: inherit; font-size: .88rem; min-height: 44px;
}

.tool__aviso { margin-top: 20px; font-size: .84rem; color: var(--txt-3); text-align: center; }
.btn-activar {
  width: 100%; margin-top: 16px; min-height: 56px;
  display: inline-flex; align-items: center; justify-content: center; gap: 12px;
  font: 700 1.02rem/1 inherit; letter-spacing: .01em; cursor: pointer;
  color: #000; background: #fafafa; border: 0; border-radius: var(--radius);
  box-shadow: 0 1px 0 rgba(255,255,255,.6) inset, var(--shadow-1);
  transition: transform .15s ease, box-shadow .2s, background .2s;
}
.btn-activar svg { width: 19px; height: 19px; fill: currentColor; }
.btn-activar:hover { background: #fff; transform: translateY(-2px); box-shadow: 0 1px 0 rgba(255,255,255,.6) inset, var(--shadow-2); }
.btn-activar:active { transform: translateY(0); }
.btn-activar--sec { width: auto; margin-top: 22px; padding: 0 34px; }
.tool__nota { margin-top: 14px; font-size: .84rem; color: #d9b06a; text-align: center; }

/* ---------- Contenido ---------- */
.content { max-width: 800px; margin: clamp(64px, 10vh, 110px) auto 0; padding: 0 24px; }
.block { margin-bottom: clamp(48px, 8vh, 80px); }
.block h2 { font-size: clamp(1.4rem, 3vw, 1.75rem); font-weight: 750; letter-spacing: -.02em; margin-bottom: 14px; }
.block p { color: var(--txt-2); max-width: 68ch; }

.steps { list-style: none; counter-reset: paso; display: grid; gap: 14px; margin-top: 20px; }
.steps li {
  counter-increment: paso; display: flex; gap: 16px; align-items: flex-start;
  color: var(--txt-2); padding: 16px 18px;
  background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius);
}
.steps li::before {
  content: counter(paso); flex: none;
  width: 28px; height: 28px; border-radius: 50%;
  display: grid; place-items: center;
  font-size: .8rem; font-weight: 700; color: #000;
  background: #fafafa;
}
.steps strong { color: var(--txt); }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; margin-top: 22px; }
.card {
  background: var(--bg-elev); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 22px;
  transition: transform .2s ease, border-color .2s;
}
.card:hover { transform: translateY(-3px); border-color: #3a3a41; }
.card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }
.card p { font-size: .92rem; }

details {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--bg-elev); margin-bottom: 12px; overflow: hidden;
}
summary {
  cursor: pointer; padding: 16px 20px; font-weight: 600; font-size: .97rem;
  list-style: none; position: relative; padding-right: 52px;
  transition: background .2s;
}
summary::-webkit-details-marker { display: none; }
summary:hover { background: #1a1a1e; }
summary::after {
  content: "+"; position: absolute; right: 20px; top: 50%;
  transform: translateY(-50%); font-size: 1.2rem; font-weight: 400; color: var(--txt-3);
  transition: transform .2s;
}
details[open] summary::after { content: "−"; }
details > p { padding: 0 20px 18px; color: var(--txt-2); font-size: .93rem; }

.cta-final { text-align: center; padding: 0 24px clamp(72px, 10vh, 120px); }
.cta-final h2 { font-size: clamp(1.5rem, 4vw, 2.1rem); font-weight: 750; letter-spacing: -.03em; }

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--line); padding: 36px 24px 48px; text-align: center;
}
.footer__brand { font-weight: 700; letter-spacing: -.02em; }
.footer__brand span { color: var(--txt-3); font-weight: 500; }
.footer__links { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 22px; list-style: none; margin: 16px 0 14px; }
.footer__links a { color: var(--txt-2); text-decoration: none; font-size: .88rem; transition: color .2s; }
.footer__links a:hover { color: var(--txt); }
.footer__copy { font-size: .8rem; color: var(--txt-3); }

/* ---------- Overlay fullscreen ---------- */
.overlay {
  position: fixed; inset: 0; z-index: 9999;
  background: #000; cursor: none;
  display: flex; align-items: center; justify-content: center;
}
.overlay[hidden] { display: none; }
.overlay__clock {
  font-size: clamp(3rem, 12vw, 8rem); font-weight: 200; letter-spacing: .06em;
  color: rgba(255,255,255,.55); opacity: 0; transition: opacity .4s ease;
  font-variant-numeric: tabular-nums; user-select: none;
}
.overlay__clock.is-visible { opacity: 1; }