/* ==========================================================================
   CalculaTodo — Hoja de estilos principal
   Un único archivo para minimizar peticiones HTTP (Core Web Vitals).
   Organizado por secciones. Sin frameworks, sin dependencias externas.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. TOKENS DE DISEÑO
   Dirección: "instrumento de precisión". Tipografía técnica (Space Grotesk)
   para titulares, humanista (Inter) para lectura, monoespaciada (JetBrains
   Mono) para todo resultado numérico — como el visor de una calculadora.
   -------------------------------------------------------------------------- */
:root {
  /* Color */
  --color-bg: #FAFAF9;
  --color-surface: #FFFFFF;
  --color-surface-alt: #F3F4F6;
  --color-ink: #12151A;
  --color-ink-soft: #565D6B;
  --color-ink-faint: #8A93A3;
  --color-primary: #2954E5;
  --color-primary-dark: #1E3FB8;
  --color-primary-soft: #EAEFFE;
  --color-accent: #00A87E;
  --color-accent-dark: #00805F;
  --color-accent-soft: #E3F7F1;
  --color-line: #E4E7EC;
  --color-line-soft: #EFF1F4;
  --color-danger: #E0483E;
  --color-danger-soft: #FCEAE9;

  /* Tipografía */
  --font-display: 'Space Grotesk', 'Arial Narrow', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;

  /* Escala tipográfica */
  --fs-xs: 0.8125rem;
  --fs-sm: 0.9375rem;
  --fs-base: 1rem;
  --fs-md: 1.125rem;
  --fs-lg: 1.375rem;
  --fs-xl: 1.75rem;
  --fs-2xl: 2.25rem;
  --fs-3xl: 3rem;
  --fs-4xl: 3.75rem;

  /* Espaciado */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --space-9: 96px;
  --space-10: 128px;

  /* Radios y sombras */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-full: 999px;
  --shadow-sm: 0 1px 2px rgba(18, 21, 26, 0.04), 0 1px 1px rgba(18, 21, 26, 0.03);
  --shadow-md: 0 8px 24px rgba(18, 21, 26, 0.06), 0 2px 6px rgba(18, 21, 26, 0.04);
  --shadow-lg: 0 20px 48px rgba(18, 21, 26, 0.10), 0 4px 12px rgba(18, 21, 26, 0.05);

  /* Layout */
  --container-max: 1180px;
  --container-narrow: 760px;
  --header-height: 72px;
  --transition-base: 180ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 320ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* --------------------------------------------------------------------------
   2. RESET
   -------------------------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { min-height: 100vh; line-height: 1.5; -webkit-font-smoothing: antialiased; }
img, picture, svg { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; color: inherit; }
button { cursor: pointer; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; padding: 0; }
table { border-collapse: collapse; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* --------------------------------------------------------------------------
   3. BASE
   -------------------------------------------------------------------------- */
body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-ink);
  font-size: var(--fs-base);
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.12;
  letter-spacing: -0.015em;
  color: var(--color-ink);
}

h1 { font-size: var(--fs-4xl); }
h2 { font-size: var(--fs-2xl); }
h3 { font-size: var(--fs-lg); }
h4 { font-size: var(--fs-md); }

p { color: var(--color-ink-soft); }

.container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.container--narrow {
  max-width: var(--container-narrow);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

section { padding-block: var(--space-9); }

/* Foco visible accesible en toda la app */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-ink);
  color: #fff;
  padding: var(--space-3) var(--space-4);
  z-index: 200;
  border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus {
  left: 0;
}

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

/* --------------------------------------------------------------------------
   4. BOTONES
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--fs-sm);
  padding: 0.85em 1.5em;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  transition: transform var(--transition-base), box-shadow var(--transition-base), background var(--transition-base), border-color var(--transition-base);
  white-space: nowrap;
}
.btn:active { transform: scale(0.98); }

.btn--primary {
  background: var(--color-ink);
  color: #fff;
}
.btn--primary:hover { background: var(--color-primary-dark); box-shadow: var(--shadow-md); }

.btn--accent {
  background: var(--color-accent);
  color: #fff;
}
.btn--accent:hover { background: var(--color-accent-dark); box-shadow: var(--shadow-md); }

.btn--outline {
  background: transparent;
  color: var(--color-ink);
  border-color: var(--color-line);
}
.btn--outline:hover { border-color: var(--color-ink); }

.btn--ghost {
  background: var(--color-surface-alt);
  color: var(--color-ink);
}
.btn--ghost:hover { background: var(--color-line-soft); }

.btn--sm { padding: 0.55em 1em; font-size: var(--fs-xs); }
.btn--full { width: 100%; }
.btn--icon { padding: 0.7em; }
.btn[disabled] { opacity: 0.5; cursor: not-allowed; }

/* --------------------------------------------------------------------------
   5. HEADER / NAVBAR
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
  background: rgba(250, 250, 249, 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-line);
}

.site-header__inner {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-md);
  color: var(--color-ink);
}

.brand__mark {
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  background: var(--color-ink);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  flex-shrink: 0;
}

.navbar {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.navbar__links {
  display: flex;
  align-items: center;
  gap: var(--space-5);
}

.navbar__links a {
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--color-ink-soft);
  transition: color var(--transition-base);
  position: relative;
}
.navbar__links a:hover { color: var(--color-ink); }

.navbar__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.nav-toggle {
  display: none;
  background: transparent;
  border: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
}
.nav-toggle:hover { background: var(--color-surface-alt); }
.nav-toggle svg { width: 22px; height: 22px; }

.mobile-menu {
  display: none;
  position: fixed;
  inset: var(--header-height) 0 0 0;
  background: var(--color-bg);
  z-index: 99;
  padding: var(--space-6) var(--space-5);
  overflow-y: auto;
}
.mobile-menu.is-open { display: block; }
.mobile-menu a {
  display: block;
  font-family: var(--font-display);
  font-size: var(--fs-xl);
  font-weight: 600;
  padding-block: var(--space-3);
  border-bottom: 1px solid var(--color-line);
}

@media (max-width: 860px) {
  .navbar__links { display: none; }
  .nav-toggle { display: flex; }
}

/* --------------------------------------------------------------------------
   6. HERO
   -------------------------------------------------------------------------- */
.hero {
  padding-block: var(--space-8) var(--space-9);
  overflow: hidden;
}

.hero__grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: var(--space-8);
  align-items: center;
}

.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--color-accent-dark);
  background: var(--color-accent-soft);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-5);
}
.hero__eyebrow::before {
  content: '';
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
}

.hero h1 {
  font-size: clamp(2.25rem, 4.5vw, var(--fs-4xl));
  margin-bottom: var(--space-5);
}

.hero h1 .highlight {
  color: var(--color-primary);
}

.hero__subtitle {
  font-size: var(--fs-md);
  max-width: 46ch;
  margin-bottom: var(--space-6);
}

.hero__actions {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-7);
  flex-wrap: wrap;
}

.hero__stats {
  display: flex;
  gap: var(--space-7);
}

.hero__stat-value {
  font-family: var(--font-mono);
  font-size: var(--fs-xl);
  font-weight: 700;
  color: var(--color-ink);
  font-variant-numeric: tabular-nums;
}

.hero__stat-label {
  font-size: var(--fs-xs);
  color: var(--color-ink-faint);
}

/* Panel "visor" — el elemento firma del sitio: una calculadora real y
   funcional incrustada en el hero, con estética de instrumento. */
.hero-panel {
  background: var(--color-ink);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-lg);
  position: relative;
}

.hero-panel::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  padding: 1px;
  background: linear-gradient(135deg, rgba(0,168,126,0.5), rgba(255,255,255,0));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

.hero-panel__label {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: rgba(255,255,255,0.5);
  margin-bottom: var(--space-4);
  display: flex;
  justify-content: space-between;
}

.hero-panel__display {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  margin-bottom: var(--space-4);
}

.hero-panel__display-label {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: rgba(255,255,255,0.45);
  margin-bottom: var(--space-2);
}

.hero-panel__display-value {
  font-family: var(--font-mono);
  font-size: var(--fs-2xl);
  font-weight: 700;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
  word-break: break-all;
}

.hero-panel__row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3);
}

.hero-panel__field label {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: rgba(255,255,255,0.5);
  margin-bottom: var(--space-2);
}

.hero-panel__field input {
  width: 100%;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  color: #fff;
  border-radius: var(--radius-sm);
  padding: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
}
.hero-panel__field input:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 1px;
}

.hero-panel__footer {
  margin-top: var(--space-4);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.hero-panel__footer a {
  font-size: var(--fs-xs);
  color: rgba(255,255,255,0.55);
}
.hero-panel__footer a:hover { color: #fff; }

@media (max-width: 940px) {
  .hero__grid { grid-template-columns: 1fr; }
}

/* --------------------------------------------------------------------------
   7. SECCIONES / ENCABEZADOS DE SECCIÓN
   -------------------------------------------------------------------------- */
.section-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: var(--space-5);
  margin-bottom: var(--space-6);
}

.section-head__eyebrow {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--color-ink-faint);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-2);
  display: block;
}

.section-head p { max-width: 56ch; }

/* --------------------------------------------------------------------------
   8. TARJETAS — categorías y calculadoras
   -------------------------------------------------------------------------- */
.grid {
  display: grid;
  gap: var(--space-5);
}
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }

@media (max-width: 940px) {
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .grid--4, .grid--3, .grid--2 { grid-template-columns: 1fr; }
}

.category-card {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}
.category-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-line);
}

.category-card__icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--color-primary-soft);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-4);
}
.category-card__icon svg { width: 22px; height: 22px; }

.category-card h3 { margin-bottom: var(--space-1); font-size: var(--fs-md); }
.category-card__count {
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  color: var(--color-ink-faint);
}

.calc-card {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}
.calc-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }

.calc-card__icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--color-accent-soft);
  color: var(--color-accent-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-5);
}
.calc-card__icon svg { width: 24px; height: 24px; }

.calc-card h3 { margin-bottom: var(--space-2); }
.calc-card p { font-size: var(--fs-sm); margin-bottom: var(--space-5); flex-grow: 1; }

/* --------------------------------------------------------------------------
   9. BUSCADOR
   -------------------------------------------------------------------------- */
.search-box {
  position: relative;
  max-width: 520px;
}
.search-box input {
  width: 100%;
  padding: var(--space-4) var(--space-5) var(--space-4) 3rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-line);
  background: var(--color-surface);
  font-size: var(--fs-sm);
  box-shadow: var(--shadow-sm);
}
.search-box svg {
  position: absolute;
  left: var(--space-4);
  top: 50%;
  transform: translateY(-50%);
  width: 18px; height: 18px;
  color: var(--color-ink-faint);
}
.search-box__results {
  position: absolute;
  top: calc(100% + var(--space-2));
  left: 0; right: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  z-index: 50;
  display: none;
}
.search-box__results.is-open { display: block; }
.search-box__results a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4);
  font-size: var(--fs-sm);
  border-bottom: 1px solid var(--color-line-soft);
}
.search-box__results a:last-child { border-bottom: none; }
.search-box__results a:hover { background: var(--color-surface-alt); }
.search-box__empty {
  padding: var(--space-4);
  font-size: var(--fs-sm);
  color: var(--color-ink-faint);
}

/* --------------------------------------------------------------------------
   10. WHY US / LISTA CON ICONOS
   -------------------------------------------------------------------------- */
.feature-list {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: var(--space-5);
}
@media (max-width: 940px) { .feature-list { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .feature-list { grid-template-columns: 1fr; } }

.feature-item__icon {
  width: 40px; height: 40px;
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-accent-dark);
  margin-bottom: var(--space-3);
}
.feature-item__icon svg { width: 20px; height: 20px; }
.feature-item h4 { margin-bottom: var(--space-1); font-size: var(--fs-sm); }
.feature-item p { font-size: var(--fs-xs); }

.section--tinted {
  background: var(--color-surface-alt);
  border-block: 1px solid var(--color-line);
}

/* --------------------------------------------------------------------------
   11. FOOTER
   -------------------------------------------------------------------------- */
.site-footer {
  background: var(--color-ink);
  color: rgba(255,255,255,0.65);
  padding-block: var(--space-8) var(--space-6);
}
.footer__grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(4, 1fr);
  gap: var(--space-6);
  margin-bottom: var(--space-7);
}
@media (max-width: 860px) {
  .footer__grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .footer__grid { grid-template-columns: 1fr; }
}
.footer__brand { display: flex; align-items: center; gap: var(--space-2); color: #fff; font-family: var(--font-display); font-weight: 700; margin-bottom: var(--space-3); }
.footer__desc { font-size: var(--fs-sm); max-width: 32ch; }
.footer h5 {
  font-family: var(--font-mono);
  text-transform: uppercase;
  font-size: var(--fs-xs);
  letter-spacing: 0.08em;
  color: rgba(255,255,255,0.4);
  margin-bottom: var(--space-4);
}
.footer__col a {
  display: block;
  font-size: var(--fs-sm);
  padding-block: var(--space-2);
  color: rgba(255,255,255,0.7);
  transition: color var(--transition-base);
}
.footer__col a:hover { color: var(--color-accent); }
.footer__bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: var(--space-5);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-3);
  font-size: var(--fs-xs);
  color: rgba(255,255,255,0.4);
}

/* --------------------------------------------------------------------------
   12. BREADCRUMBS
   -------------------------------------------------------------------------- */
.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-size: var(--fs-xs);
  color: var(--color-ink-faint);
  padding-block: var(--space-5);
}
.breadcrumbs a { color: var(--color-ink-faint); }
.breadcrumbs a:hover { color: var(--color-primary); }
.breadcrumbs span[aria-hidden] { color: var(--color-line); }
.breadcrumbs li:last-child { color: var(--color-ink-soft); }
.breadcrumbs ol { display: flex; align-items: center; gap: var(--space-2); flex-wrap: wrap; }

/* --------------------------------------------------------------------------
   13. PÁGINA DE CALCULADORA
   -------------------------------------------------------------------------- */
.calc-page-head {
  padding-block: var(--space-6) var(--space-7);
}
.calc-page-head__icon {
  width: 56px; height: 56px;
  border-radius: var(--radius-md);
  background: var(--color-accent-soft);
  color: var(--color-accent-dark);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: var(--space-5);
}
.calc-page-head__icon svg { width: 28px; height: 28px; }
.calc-page-head h1 { font-size: clamp(1.75rem, 3.5vw, var(--fs-3xl)); margin-bottom: var(--space-3); }
.calc-page-head p { font-size: var(--fs-md); max-width: 60ch; }

.calc-layout {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: var(--space-7);
  align-items: start;
  padding-block: var(--space-7);
}
@media (max-width: 940px) {
  .calc-layout { grid-template-columns: 1fr; }
}

.calc-tool {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: calc(var(--header-height) + var(--space-5));
}

.calc-tool__tabs {
  display: flex;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
  border-bottom: 1px solid var(--color-line);
}
.calc-tool__tab {
  background: transparent;
  border: none;
  padding: var(--space-3) var(--space-2);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--fs-sm);
  color: var(--color-ink-faint);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}
.calc-tool__tab.is-active {
  color: var(--color-ink);
  border-color: var(--color-primary);
}
.calc-tool__panel { display: none; }
.calc-tool__panel.is-active { display: block; }

.field {
  margin-bottom: var(--space-5);
}
.field label {
  display: block;
  font-size: var(--fs-sm);
  font-weight: 600;
  margin-bottom: var(--space-2);
}
.field__hint {
  font-size: var(--fs-xs);
  color: var(--color-ink-faint);
  margin-top: var(--space-2);
  display: block;
}
.field__input-wrap {
  position: relative;
  display: flex;
  align-items: stretch;
}
.field input[type="number"],
.field input[type="text"],
.field select {
  width: 100%;
  padding: var(--space-4);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: var(--fs-md);
  background: var(--color-bg);
  transition: border-color var(--transition-base);
}
.field input:focus, .field select:focus { border-color: var(--color-primary); }
.field__affix {
  display: flex;
  align-items: center;
  padding-inline: var(--space-4);
  background: var(--color-surface-alt);
  border: 1px solid var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  color: var(--color-ink-soft);
}
.field__input-wrap .field__affix:first-child { border-right: none; border-radius: var(--radius-sm) 0 0 var(--radius-sm); }
.field__input-wrap .field__affix:last-child { border-left: none; border-radius: 0 var(--radius-sm) var(--radius-sm) 0; }
.field__input-wrap input { border-radius: var(--radius-sm); }
.field__input-wrap .field__affix:first-child + input { border-radius: 0 var(--radius-sm) var(--radius-sm) 0; }
.field__input-wrap input:has(+ .field__affix) { border-radius: var(--radius-sm) 0 0 var(--radius-sm); }

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
}
@media (max-width: 480px) { .field-row { grid-template-columns: 1fr; } }

.field-error {
  color: var(--color-danger);
  font-size: var(--fs-xs);
  margin-top: var(--space-2);
  display: none;
}
.field.has-error input { border-color: var(--color-danger); }
.field.has-error .field-error { display: block; }

.calc-tool__actions {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

.result-panel {
  margin-top: var(--space-6);
  background: var(--color-ink);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  display: none;
}
.result-panel.is-visible { display: block; }
.result-panel__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding-block: var(--space-2);
}
.result-panel__row + .result-panel__row {
  border-top: 1px solid rgba(255,255,255,0.08);
}
.result-panel__label {
  font-size: var(--fs-sm);
  color: rgba(255,255,255,0.6);
}
.result-panel__value {
  font-family: var(--font-mono);
  font-size: var(--fs-lg);
  font-weight: 700;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}
.result-panel__value--main {
  font-size: var(--fs-2xl);
}
.result-panel__copy {
  margin-top: var(--space-5);
  display: flex;
  justify-content: flex-end;
}
.result-panel__copy button {
  background: rgba(255,255,255,0.08);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.14);
}
.result-panel__copy button:hover { background: rgba(255,255,255,0.14); }

.calc-chart {
  margin-top: var(--space-6);
}
.calc-chart canvas {
  width: 100%;
  height: 220px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-line);
  background: var(--color-surface);
}
.calc-chart__legend {
  display: flex;
  gap: var(--space-5);
  margin-top: var(--space-3);
  font-size: var(--fs-xs);
  color: var(--color-ink-soft);
}
.calc-chart__legend span { display: inline-flex; align-items: center; gap: var(--space-2); }
.calc-chart__dot { width: 8px; height: 8px; border-radius: 50%; }

/* Sidebar de anuncios / info dentro de la página de calculadora */
.calc-side { display: flex; flex-direction: column; gap: var(--space-6); }
.info-card {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
}
.info-card h4 { margin-bottom: var(--space-3); }
.info-card ul { display: flex; flex-direction: column; gap: var(--space-2); }
.info-card li { font-size: var(--fs-sm); color: var(--color-ink-soft); padding-left: var(--space-4); position: relative; }
.info-card li::before {
  content: '';
  position: absolute; left: 0; top: 0.55em;
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--color-accent);
}

/* --------------------------------------------------------------------------
   14. CONTENIDO EDITORIAL SEO (artículo bajo la calculadora)
   -------------------------------------------------------------------------- */
.article {
  padding-block: var(--space-8);
  border-top: 1px solid var(--color-line);
}
.article__inner {
  max-width: var(--container-narrow);
  margin-inline: auto;
}
.article h2 { margin-top: var(--space-8); margin-bottom: var(--space-4); }
.article h2:first-child { margin-top: 0; }
.article h3 { margin-top: var(--space-6); margin-bottom: var(--space-3); }
.article p { margin-bottom: var(--space-4); font-size: var(--fs-md); line-height: 1.7; }
.article ul, .article ol { margin-bottom: var(--space-4); padding-left: var(--space-5); }
.article li { color: var(--color-ink-soft); font-size: var(--fs-md); line-height: 1.7; margin-bottom: var(--space-2); list-style: disc; }
.article ol li { list-style: decimal; }

.formula-box {
  background: var(--color-ink);
  color: #fff;
  border-radius: var(--radius-md);
  padding: var(--space-5);
  font-family: var(--font-mono);
  font-size: var(--fs-md);
  text-align: center;
  margin-block: var(--space-5);
  overflow-x: auto;
}
.formula-box small {
  display: block;
  font-family: var(--font-body);
  color: rgba(255,255,255,0.5);
  margin-top: var(--space-3);
  font-size: var(--fs-xs);
}

.faq-item {
  border-bottom: 1px solid var(--color-line);
  padding-block: var(--space-4);
}
.faq-item summary {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--fs-md);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-size: var(--fs-lg);
  color: var(--color-ink-faint);
  transition: transform var(--transition-base);
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item p { margin-top: var(--space-3); }

.example-table {
  width: 100%;
  margin-block: var(--space-5);
  font-size: var(--fs-sm);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.example-table th, .example-table td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--color-line);
}
.example-table th {
  background: var(--color-surface-alt);
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-ink-soft);
}
.example-table td { font-family: var(--font-mono); color: var(--color-ink); }
.example-table tr:last-child td { border-bottom: none; }

/* --------------------------------------------------------------------------
   15. ESPACIOS PUBLICITARIOS (Google AdSense)
   Contenedores reservados y comentados. No incluyen código de anuncios.
   -------------------------------------------------------------------------- */
.ad-slot {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface-alt);
  border: 1px dashed var(--color-line);
  border-radius: var(--radius-md);
  color: var(--color-ink-faint);
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  min-height: 90px;
}
.ad-slot--top { margin-block: var(--space-5); }
.ad-slot--in-content { margin-block: var(--space-6); }
.ad-slot--bottom { margin-block: var(--space-6); }
.ad-slot--sidebar { min-height: 250px; }
@media (max-width: 940px) {
  .ad-slot--sidebar { display: none; } /* solo escritorio, según especificación */
}

/* --------------------------------------------------------------------------
   16. PÁGINAS ESTÁTICAS (legales, contacto, acerca de)
   -------------------------------------------------------------------------- */
.static-page { padding-block: var(--space-7) var(--space-9); }
.static-page h1 { margin-bottom: var(--space-3); font-size: var(--fs-3xl); }
.static-page__updated { font-family: var(--font-mono); font-size: var(--fs-xs); color: var(--color-ink-faint); margin-bottom: var(--space-7); }
.static-page h2 { margin-top: var(--space-7); margin-bottom: var(--space-3); }
.static-page p { font-size: var(--fs-md); line-height: 1.75; margin-bottom: var(--space-4); }
.static-page ul { padding-left: var(--space-5); margin-bottom: var(--space-4); }
.static-page li { color: var(--color-ink-soft); font-size: var(--fs-md); line-height: 1.75; list-style: disc; margin-bottom: var(--space-2); }

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-7);
}
@media (max-width: 760px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-form .field { margin-bottom: var(--space-5); }
.contact-form textarea {
  width: 100%;
  padding: var(--space-4);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: var(--fs-sm);
  min-height: 140px;
  resize: vertical;
  background: var(--color-bg);
}
.contact-form textarea:focus { border-color: var(--color-primary); }

/* --------------------------------------------------------------------------
   17. UTILIDADES
   -------------------------------------------------------------------------- */
.mt-0 { margin-top: 0; }
.text-center { text-align: center; }
.flex { display: flex; }
.gap-2 { gap: var(--space-2); }
.toast {
  position: fixed;
  bottom: var(--space-6);
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--color-ink);
  color: #fff;
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base);
  z-index: 300;
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.toast.is-visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
  pointer-events: auto;
}
.toast svg { width: 16px; height: 16px; color: var(--color-accent); }

/* --------------------------------------------------------------------------
   18. CALCULADORA ESTÁNDAR (teclado numérico tipo Windows/móvil)
   -------------------------------------------------------------------------- */
.keypad-calc {
  background: var(--color-ink);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  box-shadow: var(--shadow-lg);
}

.keypad-calc__display {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  text-align: right;
  margin-bottom: var(--space-4);
  overflow: hidden;
}

.keypad-calc__expression {
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  color: rgba(255,255,255,0.45);
  min-height: 1.4em;
  white-space: nowrap;
  overflow-x: auto;
}

.keypad-calc__value {
  font-family: var(--font-mono);
  font-size: clamp(1.75rem, 6vw, var(--fs-3xl));
  font-weight: 700;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  overflow-x: auto;
}

.keypad-calc__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-3);
}

.keypad-btn {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255,255,255,0.08);
  background: rgba(255,255,255,0.06);
  color: #fff;
  font-family: var(--font-mono);
  font-size: var(--fs-lg);
  font-weight: 600;
  transition: background var(--transition-base), transform var(--transition-base);
}
.keypad-btn:hover { background: rgba(255,255,255,0.12); }
.keypad-btn:active { transform: scale(0.94); }

.keypad-btn--function {
  background: rgba(255,255,255,0.10);
  color: rgba(255,255,255,0.8);
  font-family: var(--font-display);
  font-size: var(--fs-md);
}
.keypad-btn--op {
  background: rgba(0,168,126,0.16);
  color: var(--color-accent);
}
.keypad-btn--op:hover { background: rgba(0,168,126,0.26); }
.keypad-btn--equals {
  background: var(--color-accent);
  color: #fff;
}
.keypad-btn--equals:hover { background: var(--color-accent-dark); }
.keypad-btn--span2 { grid-column: span 2; aspect-ratio: auto; }

@media (max-width: 420px) {
  .keypad-btn { font-size: var(--fs-md); }
}