/* =============================================================================
   StudentTools — hoja de estilos única
   Identidad: papel cuadriculado de cuaderno + tinta azul + subrayador amarillo.
   Mobile-first. Sin frameworks ni fuentes externas (0 peticiones extra).
   ========================================================================== */

/* ---------- 1. Tokens ---------- */
:root {
  --paper: #f5f7fc;
  --surface: #ffffff;
  --surface-2: #f0f3fa;
  --line: #e0e5f1;
  --line-strong: #c9d1e4;

  --ink: #131c33;
  --ink-soft: #46506d;
  --ink-mute: #6b7593;

  --brand: #2547d0;
  --brand-dark: #1a339c;
  --brand-soft: #e7ecfe;
  --marker: #ffd84d;

  --ok: #0f7d54;
  --ok-soft: #e3f6ed;
  --warn: #9a5b00;
  --warn-soft: #fdf1dc;
  --danger: #c32c20;
  --danger-soft: #fdecea;

  --cat-estudio: #2547d0;
  --cat-matematicas: #0f8f5c;
  --cat-informatica: #6d3bd1;
  --cat-fechas: #b97500;
  --cat-conversores: #0d7286;
  --cat-generadores: #b52a68;

  --radius: 14px;
  --radius-sm: 9px;
  --radius-lg: 22px;
  --shadow-sm: 0 1px 2px rgba(19, 28, 51, .06);
  --shadow: 0 10px 30px -18px rgba(19, 28, 51, .45);

  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --font-num: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    "Liberation Mono", monospace;

  --wrap: 1140px;
  --gap: 1.25rem;
}

[data-theme="dark"] {
  --paper: #0d1322;
  --surface: #151d31;
  --surface-2: #1b2440;
  --line: #27314c;
  --line-strong: #364261;

  --ink: #eef1f9;
  --ink-soft: #c3cbe0;
  --ink-mute: #94a0bf;

  --brand: #7f96ff;
  --brand-dark: #a7b7ff;
  --brand-soft: #1d2747;

  --ok: #4ad295;
  --ok-soft: #12321f;
  --warn: #f0b356;
  --warn-soft: #34260f;
  --danger: #ff8579;
  --danger-soft: #3a1714;

  --cat-estudio: #7f96ff;
  --cat-matematicas: #3fc78d;
  --cat-informatica: #b18bff;
  --cat-fechas: #f0b356;
  --cat-conversores: #45c3d8;
  --cat-generadores: #ff7fb2;

  --shadow: 0 10px 30px -18px rgba(0, 0, 0, .8);
  color-scheme: dark;
}

/* ---------- 2. Base ---------- */
*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    transition-duration: .001ms !important;
  }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

@media (min-width: 900px) { body { font-size: 1.0625rem; } }

img, svg, video { max-width: 100%; height: auto; }

h1, h2, h3, h4 {
  line-height: 1.18;
  letter-spacing: -.017em;
  margin: 0 0 .5em;
  font-weight: 700;
  text-wrap: balance;
}

h1 { font-size: clamp(1.9rem, 1.35rem + 2.4vw, 2.75rem); }
h2 { font-size: clamp(1.35rem, 1.15rem + .9vw, 1.8rem); }
h3 { font-size: 1.125rem; }

p { margin: 0 0 1em; }

a { color: var(--brand); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--brand-dark); }

:focus-visible {
  outline: 3px solid var(--brand);
  outline-offset: 2px;
  border-radius: 4px;
}

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

.skip-link {
  position: absolute; left: .5rem; top: -4rem; z-index: 100;
  background: var(--brand); color: #fff; padding: .65rem 1rem;
  border-radius: var(--radius-sm); font-weight: 600; transition: top .15s;
}
.skip-link:focus { top: .5rem; color: #fff; }

.container { width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 0 1.1rem; }
.container-narrow { max-width: 760px; }

/* ---------- 3. Cabecera ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex; align-items: center; gap: .75rem;
  min-height: 60px; flex-wrap: wrap;
}

.brand {
  display: inline-flex; align-items: center; gap: .55rem;
  font-weight: 700; font-size: 1.12rem; letter-spacing: -.02em;
  color: var(--ink); text-decoration: none; margin-right: auto;
}
.brand-mark { color: var(--brand); display: inline-flex; }
.brand-text-accent { color: var(--brand); }

.nav-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 42px; height: 38px; border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm); background: var(--surface); cursor: pointer;
  color: var(--ink);
}
.nav-toggle-bars, .nav-toggle-bars::before, .nav-toggle-bars::after {
  display: block; width: 18px; height: 2px; background: currentColor;
  border-radius: 2px; position: relative;
}
.nav-toggle-bars::before, .nav-toggle-bars::after { content: ""; position: absolute; }
.nav-toggle-bars::before { top: -6px; }
.nav-toggle-bars::after { top: 6px; }

.site-nav { display: none; width: 100%; order: 3; }
.site-nav.is-open { display: block; }
.nav-list {
  list-style: none; margin: 0; padding: .4rem 0 .9rem;
  display: flex; flex-direction: column; gap: .1rem;
}
.nav-link {
  display: flex; align-items: center; gap: .55rem;
  padding: .55rem .5rem; border-radius: var(--radius-sm);
  color: var(--ink-soft); text-decoration: none; font-weight: 550; font-size: .95rem;
}
.nav-link:hover { background: var(--surface-2); color: var(--ink); }
.nav-link.is-active { color: var(--ink); background: var(--surface-2); }
.nav-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--brand); flex: none; }

.header-tools { display: flex; align-items: center; gap: .5rem; order: 2; }

.theme-toggle {
  width: 40px; height: 38px; display: inline-flex; align-items: center;
  justify-content: center; border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm); background: var(--surface); cursor: pointer;
  font-size: .95rem;
}
.theme-icon-moon { display: none; }
[data-theme="dark"] .theme-icon-sun { display: none; }
[data-theme="dark"] .theme-icon-moon { display: inline; }

@media (min-width: 980px) {
  .header-inner { flex-wrap: nowrap; min-height: 68px; gap: 1rem; }
  .nav-toggle { display: none; }
  .site-nav { display: block; width: auto; order: 0; margin-right: auto; }
  .brand { margin-right: .5rem; }
  .nav-list { flex-direction: row; padding: 0; gap: .1rem; }
  .nav-link { padding: .45rem .6rem; font-size: .9rem; }
  .nav-link span.nav-dot { width: 7px; height: 7px; }
}

/* ---------- 4. Buscador ---------- */
.search { position: relative; }
.search-field { position: relative; display: flex; align-items: center; }
.search-icon {
  position: absolute; left: .7rem; color: var(--ink-mute); pointer-events: none;
}
.search-input {
  width: 100%; font: inherit; color: var(--ink);
  background: var(--surface); border: 1px solid var(--line-strong);
  border-radius: 999px; padding: .6rem .9rem .6rem 2.3rem;
  transition: border-color .15s, box-shadow .15s;
}
.search-input::placeholder { color: var(--ink-mute); }
.search-input:focus {
  border-color: var(--brand);
  box-shadow: 0 0 0 4px var(--brand-soft);
  outline: none;
}
.search-compact .search-input { width: 40px; padding-right: .5rem; cursor: pointer; }
.search-compact .search-input:focus,
.search-compact.is-open .search-input { width: min(58vw, 260px); cursor: text; }
@media (min-width: 640px) { .search-compact .search-input { width: 190px; cursor: text; } }

.search-hero .search-input {
  padding: .95rem 1.1rem .95rem 2.8rem; font-size: 1.05rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}
.search-hero .search-icon { left: 1rem; }

.search-results {
  position: absolute; z-index: 60; top: calc(100% + .4rem); left: 0; right: 0;
  margin: 0; padding: .35rem; list-style: none; max-height: min(60vh, 420px);
  overflow-y: auto; background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: 0 20px 45px -25px rgba(19, 28, 51, .55);
}
.search-results li a {
  display: flex; gap: .6rem; align-items: center; padding: .55rem .6rem;
  border-radius: var(--radius-sm); color: var(--ink); text-decoration: none;
  font-size: .95rem;
}
.search-results li a:hover,
.search-results li.is-active a { background: var(--brand-soft); }
.search-results .sr-cat { margin-left: auto; font-size: .75rem; color: var(--ink-mute); }
.search-empty { padding: .8rem; color: var(--ink-mute); font-size: .92rem; }

/* ---------- 5. Portada ---------- */
.hero {
  position: relative; overflow: hidden;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}
/* Papel cuadriculado: el fondo es literalmente una hoja de cuaderno. */
.hero::before {
  content: ""; position: absolute; inset: 0;
  background-image:
    linear-gradient(to right, var(--line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line) 1px, transparent 1px);
  background-size: 28px 28px;
  -webkit-mask-image: radial-gradient(120% 90% at 18% 0%, #000 0%, transparent 72%);
  mask-image: radial-gradient(120% 90% at 18% 0%, #000 0%, transparent 72%);
  opacity: .9;
}
.hero-inner { position: relative; padding: 2.6rem 0 2.2rem; }
@media (min-width: 900px) { .hero-inner { padding: 4rem 0 3.2rem; max-width: 42rem; } }

.hero h1 { margin-bottom: .55rem; }
.marker {
  background-image: linear-gradient(transparent 58%, var(--marker) 58%, var(--marker) 94%, transparent 94%);
  padding: 0 .12em;
}
[data-theme="dark"] .marker { background-image: none !important; color: var(--ink) !important; }

.hero-lead {
  font-size: 1.08rem; color: var(--ink-soft); max-width: 56ch; margin-bottom: 1.4rem;
}
.hero-stats {
  display: flex; flex-wrap: wrap; gap: .5rem; margin: 1.2rem 0 0; padding: 0;
  list-style: none; font-size: .88rem; color: var(--ink-soft);
}
.hero-stats li {
  background: var(--surface-2); border: 1px solid var(--line);
  border-radius: 999px; padding: .3rem .75rem;
}

.section { padding: 2.4rem 0; }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.section-head p { color: var(--ink-soft); margin: -.2em 0 1.2em; max-width: 60ch; }
.section-link { font-weight: 600; font-size: .92rem; }

/* ---------- 6. Rejillas y tarjetas ---------- */
.grid { display: grid; gap: var(--gap); }
.grid-tools { grid-template-columns: 1fr; }
@media (min-width: 560px) { .grid-tools { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 900px) { .grid-tools { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 1100px) { .grid-tools { grid-template-columns: repeat(4, 1fr); } }

.grid-cats { grid-template-columns: 1fr; }
@media (min-width: 620px) { .grid-cats { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1000px) { .grid-cats { grid-template-columns: repeat(3, 1fr); } }

.tool-card {
  position: relative; background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow-sm);
  transition: border-color .15s, transform .15s, box-shadow .15s;
}
.tool-card::before {
  content: ""; position: absolute; left: 0; top: 14px; bottom: 14px; width: 3px;
  border-radius: 0 3px 3px 0; background: var(--cat-color, var(--brand));
}
.tool-card:hover { transform: translateY(-2px); border-color: var(--line-strong); box-shadow: var(--shadow); }
.tool-card-link {
  display: block; padding: 1.05rem 2.2rem 1.1rem 1.15rem; color: inherit; text-decoration: none;
  min-height: 100%;
}
.tool-card-icon { font-size: 1.35rem; display: block; margin-bottom: .35rem; }
.tool-card-title { font-size: 1rem; margin: 0 0 .25rem; }
.tool-card-text { font-size: .875rem; color: var(--ink-soft); margin: 0; line-height: 1.5; }
.tool-card-cat { display: inline-block; margin-top: .6rem; font-size: .75rem; color: var(--ink-mute); }

.fav-btn {
  position: absolute; top: .55rem; right: .5rem; width: 30px; height: 30px;
  border: 0; background: none; color: var(--line-strong); cursor: pointer;
  font-size: 1.05rem; line-height: 1; border-radius: 50%;
}
.fav-btn:hover { color: var(--marker); background: var(--surface-2); }
.fav-btn[aria-pressed="true"] { color: #e9a400; }
[data-theme="dark"] .fav-btn[aria-pressed="true"] { color: var(--marker); }
.fav-btn-lg { position: static; width: 38px; height: 38px; font-size: 1.3rem; margin-left: auto; flex: none; }

.cat-card {
  display: block; padding: 1.3rem 1.2rem; background: var(--surface);
  border: 1px solid var(--line); border-left: 4px solid var(--cat-color, var(--brand));
  border-radius: var(--radius); color: inherit; text-decoration: none;
  box-shadow: var(--shadow-sm); transition: transform .15s, box-shadow .15s;
}
.cat-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); color: inherit; }
.cat-card-icon { font-size: 1.6rem; }
.cat-card-title { margin: .4rem 0 .3rem; font-size: 1.1rem; }
.cat-card-text { color: var(--ink-soft); font-size: .92rem; margin: 0 0 .7rem; }
.cat-card-count { font-size: .8rem; color: var(--ink-mute); font-variant-numeric: tabular-nums; }

/* Colores por categoría (la pestaña de color identifica la categoría) */
[data-cat="estudio"] { --cat-color: var(--cat-estudio); }
[data-cat="matematicas"] { --cat-color: var(--cat-matematicas); }
[data-cat="informatica"] { --cat-color: var(--cat-informatica); }
[data-cat="fechas"] { --cat-color: var(--cat-fechas); }
[data-cat="conversores"] { --cat-color: var(--cat-conversores); }
[data-cat="generadores"] { --cat-color: var(--cat-generadores); }
.nav-dot[data-cat] { background: var(--cat-color); }

/* ---------- 7. "¿Qué necesitas hacer?" ---------- */
.needs { display: grid; gap: .6rem; grid-template-columns: 1fr; }
@media (min-width: 700px) { .needs { grid-template-columns: repeat(2, 1fr); } }
.need {
  display: flex; gap: .7rem; align-items: center; padding: .85rem 1rem;
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius-sm); text-decoration: none; color: inherit;
}
.need:hover { border-color: var(--brand); color: inherit; }
.need-q { font-weight: 600; }
.need-a { display: block; font-size: .85rem; color: var(--ink-mute); }

/* ---------- 8. Página de herramienta ---------- */
.breadcrumbs { padding: 1rem 0 .3rem; font-size: .85rem; color: var(--ink-mute); }
.breadcrumbs ol { list-style: none; display: flex; flex-wrap: wrap; gap: .35rem; margin: 0; padding: 0; }
.breadcrumbs li + li::before { content: "/"; margin-right: .35rem; color: var(--line-strong); }
.breadcrumbs a { color: var(--ink-mute); text-decoration: none; }
.breadcrumbs a:hover { color: var(--brand); text-decoration: underline; }

.tool-layout { display: block; padding-bottom: 3rem; }
@media (min-width: 1060px) {
  .tool-layout { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 2.5rem; align-items: start; }
  .tool-side { position: sticky; top: 88px; }
}
.tool-side { margin-top: 2rem; }
@media (min-width: 1060px) { .tool-side { margin-top: 1.2rem; } }

.tool-head { display: flex; gap: .85rem; align-items: flex-start; margin: .6rem 0 1.2rem; }
.tool-head-icon {
  font-size: 1.5rem; width: 46px; height: 46px; flex: none; display: grid; place-items: center;
  background: var(--surface); border: 1px solid var(--line);
  border-bottom: 3px solid var(--cat-color, var(--brand)); border-radius: var(--radius-sm);
}
.tool-head h1 { margin-bottom: .25rem; }
.lead { font-size: 1.06rem; color: var(--ink-soft); margin: 0; }

.tool-panel {
  background: var(--surface); border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg); padding: 1.1rem; box-shadow: var(--shadow);
  margin-bottom: 1.8rem;
}
@media (min-width: 720px) { .tool-panel { padding: 1.5rem; } }

/* ---------- 9. Formularios de herramienta ---------- */
.tw-grid { display: grid; gap: .85rem; grid-template-columns: 1fr; }
@media (min-width: 560px) { .tw-2 { grid-template-columns: repeat(2, 1fr); } .tw-3 { grid-template-columns: repeat(3, 1fr); } }

.field { display: flex; flex-direction: column; gap: .3rem; font-size: .9rem; font-weight: 600; color: var(--ink-soft); }
.field-hint { font-weight: 400; font-size: .8rem; color: var(--ink-mute); }

.input, .select, .textarea {
  font: inherit; color: var(--ink); background: var(--surface);
  border: 1px solid var(--line-strong); border-radius: var(--radius-sm);
  padding: .6rem .7rem; width: 100%; font-weight: 400;
}
.input:focus, .select:focus, .textarea:focus {
  outline: none; border-color: var(--brand); box-shadow: 0 0 0 4px var(--brand-soft);
}
.textarea { min-height: 150px; resize: vertical; line-height: 1.55; }
.input-num { font-family: var(--font-num); font-variant-numeric: tabular-nums; }
.input[aria-invalid="true"] { border-color: var(--danger); }

.check { display: flex; gap: .5rem; align-items: center; font-size: .92rem; font-weight: 500; color: var(--ink-soft); }
.check input { width: 1.05rem; height: 1.05rem; accent-color: var(--brand); flex: none; }

.tw-actions { display: flex; flex-wrap: wrap; gap: .55rem; margin-top: 1rem; }

.btn {
  font: inherit; font-weight: 600; cursor: pointer; border-radius: var(--radius-sm);
  padding: .6rem 1.05rem; border: 1px solid transparent; display: inline-flex;
  align-items: center; gap: .4rem; text-decoration: none; line-height: 1.3;
  transition: background-color .15s, border-color .15s, color .15s;
}
.btn-primary { background: var(--brand); color: #fff; }
.btn-primary:hover { background: var(--brand-dark); color: #fff; }
[data-theme="dark"] .btn-primary { color: #0d1322; }
.btn-ghost { background: var(--surface); border-color: var(--line-strong); color: var(--ink-soft); }
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); }
.btn-sm { padding: .35rem .7rem; font-size: .85rem; }
.linklike {
  background: none; border: 0; padding: 0; font: inherit; color: var(--brand);
  cursor: pointer; text-decoration: underline; text-underline-offset: 3px;
}

/* Resultados */
.result {
  display: block; margin-top: 1.1rem; padding: 1rem 1.1rem;
  background: var(--surface-2); border: 1px solid var(--line);
  border-left: 4px solid var(--ok); border-radius: var(--radius-sm);
}
.result[hidden] { display: none; }
.result-main {
  font-size: clamp(1.5rem, 1.2rem + 1.6vw, 2.1rem); font-weight: 700;
  font-family: var(--font-num); letter-spacing: -.02em; line-height: 1.2;
  margin: 0 0 .2rem; word-break: break-word;
}
.result-label { font-size: .82rem; color: var(--ink-mute); margin: 0 0 .15rem; font-weight: 600; }
.result-detail { font-size: .92rem; color: var(--ink-soft); margin: .5rem 0 0; }
.result-detail p { margin: 0 0 .3em; }
.result-error { border-left-color: var(--danger); background: var(--danger-soft); }
.result-warn { border-left-color: var(--warn); background: var(--warn-soft); }

.result-list { list-style: none; margin: .6rem 0 0; padding: 0; display: grid; gap: .3rem; font-size: .92rem; }
.result-list li { display: flex; justify-content: space-between; gap: 1rem; border-bottom: 1px dashed var(--line); padding-bottom: .25rem; }
.result-list b { font-family: var(--font-num); font-weight: 600; }

.steps-box {
  margin-top: .8rem; font-family: var(--font-num); font-size: .88rem;
  background: var(--surface); border: 1px dashed var(--line-strong);
  border-radius: var(--radius-sm); padding: .7rem .8rem; color: var(--ink-soft);
  overflow-x: auto;
}
.steps-box div { white-space: nowrap; }

.chips { display: flex; flex-wrap: wrap; gap: .4rem; margin-top: .8rem; }
.chip {
  font-size: .82rem; padding: .3rem .7rem; border-radius: 999px;
  border: 1px solid var(--line-strong); background: var(--surface);
  color: var(--ink-soft); cursor: pointer; font-family: inherit;
}
.chip:hover { border-color: var(--brand); color: var(--brand); }
.chip.is-on { background: var(--brand); border-color: var(--brand); color: #fff; }
[data-theme="dark"] .chip.is-on { color: #0d1322; }

.tabs { display: flex; gap: .25rem; border-bottom: 1px solid var(--line); margin-bottom: 1.1rem; flex-wrap: wrap; }
.tab {
  font: inherit; font-weight: 600; font-size: .92rem; background: none; border: 0;
  border-bottom: 3px solid transparent; padding: .5rem .7rem; cursor: pointer;
  color: var(--ink-mute); border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}
.tab:hover { color: var(--ink); }
.tab[aria-selected="true"] { color: var(--brand); border-bottom-color: var(--brand); }
.tabpanel[hidden] { display: none; }

/* Campos de entrada monoespaciados (binario, hexadecimal, Base64). */
.mono-in {
  font-family: var(--font-mono, ui-monospace, SFMono-Regular, Menlo, Consolas, monospace);
  letter-spacing: .03em;
}

.mono-out {
  font-family: var(--font-num); font-size: .95rem; word-break: break-all;
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: .7rem; min-height: 3rem;
}

/* ---------- 10. Prosa ---------- */
.prose { max-width: 68ch; margin: 0 0 2.2rem; }
.prose h2 { margin-top: 1.8rem; }
.prose h3 { margin-top: 1.4rem; font-size: 1.05rem; }
.prose ul, .prose ol { padding-left: 1.2rem; margin: 0 0 1em; }
.prose li { margin-bottom: .4em; }
.prose code {
  font-family: var(--font-num); font-size: .9em; background: var(--surface-2);
  padding: .1em .35em; border-radius: 4px; border: 1px solid var(--line);
}
.prose .note {
  font-size: .9rem; color: var(--ink-mute); border-left: 3px solid var(--line-strong);
  padding-left: .8rem; margin-top: 1rem;
}
.callout {
  background: var(--brand-soft); border: 1px solid transparent;
  border-radius: var(--radius-sm); padding: .85rem 1rem; margin: 0 0 1.2em;
  font-size: .95rem;
}
.callout p:last-child { margin-bottom: 0; }

.steps { counter-reset: step; list-style: none; padding: 0; }
.steps li {
  position: relative; padding-left: 2.1rem; margin-bottom: .8rem;
}
.steps li::before {
  counter-increment: step; content: counter(step);
  position: absolute; left: 0; top: .05rem; width: 1.5rem; height: 1.5rem;
  display: grid; place-items: center; border-radius: 50%;
  background: var(--brand-soft); color: var(--brand-dark);
  font-size: .8rem; font-weight: 700; font-family: var(--font-num);
}
[data-theme="dark"] .steps li::before { color: var(--brand); }

.table-wrap { overflow-x: auto; margin: 0 0 1.2em; }
.ref-table { width: 100%; border-collapse: collapse; font-size: .92rem; }
.ref-table th, .ref-table td {
  text-align: left; padding: .5rem .7rem; border-bottom: 1px solid var(--line);
  white-space: nowrap;
}
.ref-table thead th { font-size: .82rem; color: var(--ink-mute); border-bottom: 2px solid var(--line-strong); }
.ref-table tbody th { font-weight: 600; font-family: var(--font-num); }
.ref-table td { color: var(--ink-soft); font-family: var(--font-num); }

.example {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: .9rem 1.05rem; margin: 0 0 1rem;
}
.example h3 { margin-top: 0; font-size: 1rem; }
.example p:last-child { margin-bottom: 0; }

/* ---------- 11. FAQ, relacionadas ---------- */
.faq { max-width: 68ch; margin-bottom: 2.2rem; }
.faq-list { display: grid; gap: .5rem; }
.faq-item {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: .2rem .9rem;
}
.faq-item summary {
  cursor: pointer; font-weight: 600; padding: .7rem 0; list-style: none;
  display: flex; justify-content: space-between; gap: 1rem; align-items: baseline;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; color: var(--brand); font-size: 1.2rem; line-height: 1; }
.faq-item[open] summary::after { content: "−"; }
.faq-answer { padding-bottom: .8rem; color: var(--ink-soft); font-size: .95rem; }
.faq-answer p:last-child { margin-bottom: 0; }

.related-grid { margin-bottom: 2rem; }
.related-items { display: grid; gap: .6rem; grid-template-columns: 1fr; }
@media (min-width: 640px) { .related-items { grid-template-columns: repeat(2, 1fr); } }
.related-item {
  display: flex; gap: .7rem; align-items: flex-start; padding: .8rem .9rem;
  background: var(--surface); border: 1px solid var(--line);
  border-left: 3px solid var(--cat-color, var(--brand));
  border-radius: var(--radius-sm); text-decoration: none; color: inherit;
}
.related-item:hover { border-color: var(--brand); color: inherit; }
.related-item-body strong { display: block; font-size: .95rem; }
.related-item-body span { font-size: .85rem; color: var(--ink-mute); }

.related-list ul { list-style: none; margin: 0; padding: 0; display: grid; gap: .1rem; }
.related-list li a {
  display: flex; gap: .5rem; padding: .5rem .55rem; border-radius: var(--radius-sm);
  color: var(--ink-soft); text-decoration: none; font-size: .92rem;
}
.related-list li a:hover { background: var(--surface-2); color: var(--ink); }
.side-title { font-size: .82rem; color: var(--ink-mute); margin-bottom: .4rem; font-weight: 700; }

.back-cat { font-size: .92rem; color: var(--ink-soft); }

/* ---------- 12. Publicidad ---------- */
.ad { display: block; margin: 0 0 2rem; text-align: center; }
.ad-label { display: block; font-size: .7rem; color: var(--ink-mute); margin-bottom: .2rem; }
.ad-empty {
  border: 1px dashed var(--line-strong); border-radius: var(--radius-sm);
  color: var(--ink-mute); font-size: .78rem; display: grid; place-items: center;
  background: repeating-linear-gradient(45deg, transparent, transparent 9px, var(--surface-2) 9px, var(--surface-2) 18px);
}
.ad-top.ad-empty { min-height: 96px; }
.ad-inline.ad-empty { min-height: 250px; }
.ad-footer.ad-empty { min-height: 200px; }
.ad-sidebar.ad-empty { min-height: 500px; }
.ad-top { min-height: 96px; }
.ad-inline { min-height: 250px; }
.ad-sidebar { min-height: 500px; margin-top: 1.5rem; }
@media (max-width: 1059px) { .ad-sidebar { display: none; } }

/* ---------- 13. Historial y favoritos ---------- */
.strip { display: flex; gap: .5rem; flex-wrap: wrap; }
.strip a {
  display: inline-flex; align-items: center; gap: .4rem; font-size: .88rem;
  padding: .4rem .8rem; border-radius: 999px; background: var(--surface);
  border: 1px solid var(--line); color: var(--ink-soft); text-decoration: none;
}
.strip a:hover { border-color: var(--brand); color: var(--brand); }
.panel-empty { color: var(--ink-mute); font-size: .92rem; }
[data-panel][hidden] { display: none; }

/* ---------- 14. Pie ---------- */
.site-footer {
  background: var(--surface); border-top: 1px solid var(--line);
  padding: 2.4rem 0 1.2rem; margin-top: 2rem;
}
.footer-grid { display: grid; gap: 1.8rem; grid-template-columns: 1fr; }
@media (min-width: 760px) { .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 2rem; } }
.footer-brand p { font-size: .9rem; color: var(--ink-mute); max-width: 42ch; margin-top: .6rem; }
.brand-footer { margin: 0; }
.footer-col h2 { font-size: .82rem; color: var(--ink-mute); margin-bottom: .6rem; }
.footer-col ul { list-style: none; margin: 0; padding: 0; display: grid; gap: .35rem; }
.footer-col a, .footer-col .linklike {
  font-size: .9rem; color: var(--ink-soft); text-decoration: none;
}
.footer-col a:hover, .footer-col .linklike:hover { color: var(--brand); text-decoration: underline; }
.footer-bottom {
  margin-top: 1.8rem; padding-top: 1rem; border-top: 1px solid var(--line);
  font-size: .82rem; color: var(--ink-mute);
}

/* ---------- 15. Cookies ---------- */
.cookie-banner {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 90;
  background: var(--surface); border-top: 2px solid var(--brand);
  box-shadow: 0 -12px 30px -22px rgba(0, 0, 0, .6); padding: 1rem 0;
}
.cookie-banner[hidden] { display: none; }
.cookie-inner {
  width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 0 1.1rem;
  display: grid; gap: .9rem;
}
@media (min-width: 820px) { .cookie-inner { grid-template-columns: 1fr auto; align-items: center; } }
.cookie-inner h2 { font-size: 1rem; margin-bottom: .2rem; }
.cookie-inner p { font-size: .87rem; color: var(--ink-soft); margin: 0; max-width: 72ch; }
.cookie-actions { display: flex; gap: .5rem; flex-wrap: wrap; }

/* ---------- 16. Utilidades ---------- */
.stack > * + * { margin-top: 1rem; }
.mt-0 { margin-top: 0; }
.text-mute { color: var(--ink-mute); }
.hide { display: none !important; }
.form-msg { padding: .7rem .9rem; border-radius: var(--radius-sm); font-size: .92rem; border: 1px solid transparent; }
.form-msg-error { background: var(--danger-soft); color: var(--danger); border-color: var(--danger); }
.form-msg-ok { background: var(--ok-soft); color: var(--ok); border-color: var(--ok); }
.flip-card { perspective: 900px; }
.flip-inner {
  position: relative; transform-style: preserve-3d; transition: transform .45s;
  min-height: 170px;
}
.flip-card.is-flipped .flip-inner { transform: rotateY(180deg); }
.flip-face {
  position: absolute; inset: 0; backface-visibility: hidden;
  display: grid; place-items: center; text-align: center; padding: 1.2rem;
  background: var(--surface); border: 1px solid var(--line-strong);
  border-radius: var(--radius); font-size: 1.05rem;
}
.flip-back { transform: rotateY(180deg); background: var(--brand-soft); }


/* ============================================================
   FIX HEADER DESKTOP
   Evita que las categorías del menú se corten o salten de línea.
   No modifica el hero ni las herramientas.
   ============================================================ */

@media (min-width: 980px) {
  .site-header .header-inner {
    max-width: 1450px;
    flex-wrap: nowrap;
    align-items: center;
    gap: .65rem;
  }

  .site-header .brand {
    flex: 0 0 auto;
    white-space: nowrap;
    margin-right: .25rem;
  }

  .site-header .site-nav {
    flex: 1 1 auto;
    min-width: 0;
    margin-right: 0;
  }

  .site-header .nav-list {
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    flex-wrap: nowrap;
    gap: 0;
    padding: 0;
  }

  .site-header .nav-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex: 0 0 auto;
    white-space: nowrap;
    word-break: normal;
    overflow-wrap: normal;
    padding: .45rem .45rem;
    font-size: .86rem;
  }

  .site-header .nav-dot {
    flex: 0 0 7px;
  }

  .site-header .header-tools {
    flex: 0 0 auto;
    white-space: nowrap;
  }

  .site-header .search-compact .search-input {
    width: 190px;
  }

  .site-header .theme-toggle {
    flex: 0 0 40px;
  }
}

/* Pantallas especialmente anchas */
@media (min-width: 1300px) {
  .site-header .header-inner {
    max-width: 1450px;
  }

  .site-header .nav-link {
    padding-left: .5rem;
    padding-right: .5rem;
    font-size: .88rem;
  }

  .site-header .search-compact .search-input {
    width: 200px;
  }
}