/* Paleta monocroma (grafito y blanco), la misma de la demo. Para cambiar la identidad, se cambian solo estas variables.
   Contraste: texto blanco sobre --ink y --ink-2, y --text sobre blanco y sobre --paper, superan 4.5:1. */
:root {
  --ink: #1f2328;
  --ink-2: #3b424a;
  --text: #444a50;
  --muted: #5b6168;
  --paper: #f4f4f5;
  --card: #ffffff;
  --line: #d5d9dd;
  --tint: #e9ebed;
  --radius: 12px;
  --max: 68rem;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 4.5rem; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--card);
}

.wrap { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 1.25rem; }
.narrow { max-width: 46rem; }

h1, h2, h3 { color: var(--ink); line-height: 1.2; margin: 0 0 0.75rem; }
h1 { font-size: clamp(2rem, 5.5vw, 3.4rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.5rem, 3.6vw, 2.1rem); letter-spacing: -0.01em; }
h3 { font-size: 1.15rem; }
p { margin: 0 0 1rem; }
a { color: var(--ink); }
code { background: var(--tint); padding: 0.1rem 0.4rem; border-radius: 6px; font-size: 0.95em; word-break: break-all; }
.nowrap { white-space: nowrap; }

.skip { position: absolute; left: -999px; top: 0; background: var(--ink); color: #fff; padding: 0.6rem 1rem; z-index: 10; }
.skip:focus { left: 0.5rem; top: 0.5rem; }

/* Foco visible en todo lo interactivo (accesibilidad por teclado) */
a:focus-visible, summary:focus-visible { outline: 3px solid var(--ink); outline-offset: 3px; border-radius: 6px; }

/* Barra superior */
.top { position: sticky; top: 0; z-index: 5; background: #ffffff; border-bottom: 1px solid var(--line); }
.top-row { display: flex; align-items: center; justify-content: space-between; gap: 1rem; min-height: 3.5rem; }
.logo { font-weight: 700; color: var(--ink); text-decoration: none; letter-spacing: -0.01em; }
.top nav { display: flex; align-items: center; gap: 1.1rem; flex-wrap: wrap; justify-content: flex-end; }
.top nav a { text-decoration: none; font-weight: 500; }
.top nav a:hover { text-decoration: underline; }
@media (max-width: 40rem) { .top nav a:not(.btn) { display: none; } }

/* Botones */
.btn {
  display: inline-block;
  padding: 0.8rem 1.4rem;
  background: var(--ink);
  color: #fff;
  border: 2px solid var(--ink);
  border-radius: 10px;
  font-weight: 600;
  text-decoration: none;
  text-align: center;
}
.btn:hover { background: var(--ink-2); border-color: var(--ink-2); }
.btn-outline { background: transparent; color: var(--ink); }
.btn-outline:hover { background: var(--tint); color: var(--ink); border-color: var(--ink); }
.btn-small { padding: 0.4rem 0.95rem; }
.top nav .btn, .top nav .btn:hover { color: #fff; text-decoration: none; }
.cta { display: flex; flex-wrap: wrap; gap: 0.8rem; margin: 1.5rem 0 0.75rem; }

/* Secciones */
section { padding: 3.5rem 0; }
.band { background: var(--paper); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.hero { padding: 4rem 0 3.5rem; }
.eyebrow { font-size: 0.95rem; font-weight: 600; color: var(--muted); text-transform: uppercase; letter-spacing: 0.04em; margin-bottom: 0.75rem; }
.lead { font-size: 1.25rem; max-width: 42rem; }
.note { color: var(--muted); font-size: 0.95rem; }

.grid { display: grid; gap: 1.1rem; margin-top: 1.5rem; }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr)); }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.25rem 1.35rem; }
.card p:last-child { margin-bottom: 0; }
.card-strong { border: 2px solid var(--ink); }
.plain { margin: 0; padding-left: 1.15rem; }
.plain li { margin-bottom: 0.55rem; }

.two-col { display: grid; gap: 2rem; align-items: center; grid-template-columns: repeat(auto-fit, minmax(19rem, 1fr)); }

.checks { list-style: none; padding: 0; margin: 1rem 0; }
.checks li { position: relative; padding-left: 1.7rem; margin-bottom: 0.7rem; }
.checks li::before { content: "✓"; position: absolute; left: 0; font-weight: 700; color: var(--ink); }

/* Esquema ilustrativo del candado */
.mock { margin: 0; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.1rem 1.2rem; }
.mock-row { display: grid; grid-template-columns: 1fr auto auto auto; gap: 0.5rem; align-items: center; font-weight: 600; color: var(--ink); }
.cell { display: inline-block; min-width: 3.2rem; text-align: center; padding: 0.35rem 0.5rem; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
.cell.locked { background: var(--tint); border-style: dashed; border-color: var(--muted); }
.mock-note { color: var(--muted); font-size: 0.9rem; margin: 0.6rem 0 0.9rem; }
.mock-fix { display: grid; gap: 0.2rem; border-left: 4px solid var(--ink); background: var(--tint); padding: 0.7rem 0.9rem; border-radius: 6px; font-size: 0.95rem; }
.mock figcaption { color: var(--muted); font-size: 0.85rem; margin-top: 0.8rem; }

.steps { counter-reset: paso; list-style: none; padding: 0; margin: 1.5rem 0 0; display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr)); }
.steps li { counter-increment: paso; background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.1rem 1.25rem 1.1rem 3.6rem; position: relative; }
.steps li::before {
  content: counter(paso);
  position: absolute; left: 1.1rem; top: 1.05rem;
  width: 1.8rem; height: 1.8rem; display: grid; place-items: center;
  background: var(--ink); color: #fff; border-radius: 50%; font-weight: 700;
}

.creds { margin: 0 0 1rem; }
.creds dt { font-weight: 700; color: var(--ink); margin-top: 0.75rem; }
.creds dd { margin: 0.2rem 0 0; }

details { border-bottom: 1px solid var(--line); padding: 0.9rem 0; }
summary { cursor: pointer; font-weight: 600; color: var(--ink); }
details p { margin: 0.6rem 0 0; }

.contact { text-align: center; }
.contact .lead { margin-left: auto; margin-right: auto; }
.contact .cta { justify-content: center; }

.foot { padding: 2rem 0 2.5rem; border-top: 1px solid var(--line); }
.foot p { margin-bottom: 0.4rem; }

/* Alto contraste del sistema operativo */
@media (forced-colors: active) { .btn { border: 2px solid ButtonText; } }