/* ==========================================================================
   Alarcón Fierros y Metales — styles.css · v3 (interfaz "industrial editorial")
   Paleta y tipografías según Manual de Marca v1 (no cambiar identidad).
   Mobile-first. Breakpoints:
     móvil        base (320–640px)
     tablet       @media (min-width: 641px)
     laptop       @media (min-width: 1025px)
     monitor XL   @media (min-width: 1441px+)
   ========================================================================== */

:root {
  /* ----- Paleta de marca (Manual v1) ----- */
  --naranja: #E85A1B;
  --naranja-oscuro: #C64812;   /* variante AA para texto pequeño sobre blanco */
  --acero: #3A4048;
  --plomo: #23282E;
  --tinta: #1A1D21;
  --blanco: #FFFFFF;
  --gris-suave: #F4F3F0;
  --gris-borde: #DDDFE3;
  --gris-texto: #565B62;       /* secundario sobre blanco (AA) */
  --gris-texto-claro: #C7CCD2; /* secundario sobre plomo (AA) */
  --acero-panel: #2A3038;      /* paneles sobre plomo */
  --wa-verde: #1FAF57;

  /* ----- Tipografías de marca ----- */
  --font-titular: 'Archivo', system-ui, sans-serif;
  --font-texto: 'Barlow', system-ui, sans-serif;

  /* ----- Métricas ----- */
  --radio: 6px;
  --radio-btn: 4px;
  --alto-header: 3.75rem;
  --ancho-max: 77.5rem;        /* 1240px a 16px de base; crece con la letra en XL */
  --tap-min: 3rem;             /* 48px táctiles */
  --pad-seccion: clamp(3.5rem, 5vw + 1.5rem, 6.5rem);
}

/* ----- Reset mínimo ----- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--alto-header) + .75rem); }
img, svg { display: block; max-width: 100%; }
ul[role="list"], ol[role="list"] { list-style: none; }
html, body { overflow-x: clip; }

body {
  font-family: var(--font-texto);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--tinta);
  background: var(--blanco);
  -webkit-font-smoothing: antialiased;
}

/* Escalado proporcional en monitores grandes (todo está en rem) */
@media (min-width: 1441px) { html { font-size: 112.5%; } }
@media (min-width: 1921px) { html { font-size: 131.25%; } }
@media (min-width: 2561px) { html { font-size: 162.5%; } }

/* ----- Accesibilidad ----- */
:focus-visible { outline: 3px solid var(--naranja); outline-offset: 2px; border-radius: 4px; }
.skip-link {
  position: absolute; top: -100px; left: 12px; z-index: 100;
  padding: .6rem 1rem; background: var(--tinta); color: var(--blanco);
  font-weight: 600; text-decoration: none; border-radius: 0 0 8px 8px;
}
.skip-link:focus { top: 0; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}

.container { width: min(100% - 2.5rem, var(--ancho-max)); margin-inline: auto; }
@media (min-width: 1025px) { .container { width: min(100% - 4rem, var(--ancho-max)); } }

/* ==========================================================================
   Botones
   ========================================================================== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .6rem;
  min-height: var(--tap-min);
  font-family: var(--font-titular); font-weight: 800;
  text-transform: uppercase; letter-spacing: .04em; text-decoration: none;
  border: 0; border-radius: var(--radio-btn); cursor: pointer;
  transition: transform .15s ease, box-shadow .15s ease, background-color .15s ease,
              border-color .15s ease, color .15s ease;
}
/* Texto tinta sobre naranja: contraste ≈ 4.9:1 (AA) */
.btn--wa { background: var(--naranja); color: var(--tinta); padding: .65rem 1.5rem; font-size: .95rem; }
.btn--wa:hover { background: #F0692C; transform: translateY(-2px); box-shadow: 0 8px 22px rgba(232, 90, 27, .35); }
.btn--wa:active { transform: translateY(0); }
.btn--ghost {
  background: transparent; color: var(--blanco);
  border: 1.5px solid rgba(255, 255, 255, .35);
  padding: .65rem 1.5rem; font-size: .95rem;
}
.btn--ghost:hover { border-color: var(--naranja); color: var(--naranja); }
.btn--sm { min-height: 2.75rem; padding: .4rem 1rem; font-size: .8rem; }
.btn--lg { padding: .8rem 1.9rem; font-size: clamp(.95rem, .9rem + .3vw, 1.05rem); width: 100%; }
.ico-wa { width: 1.25em; height: 1.25em; flex: none; }
@media (min-width: 641px) { .btn--lg { width: auto; } }

/* ==========================================================================
   Barra superior (solo laptop+)
   ========================================================================== */
.topbar { display: none; background: var(--tinta); color: var(--gris-texto-claro); }
@media (min-width: 1025px) {
  .topbar { display: block; }
  .topbar__inner {
    display: flex; justify-content: space-between; gap: 2rem;
    padding: .45rem 0;
    font-size: .78rem; font-weight: 600; letter-spacing: .08em; text-transform: uppercase;
  }
}

/* ==========================================================================
   Header pegajoso
   ========================================================================== */
.header {
  position: sticky; top: 0; z-index: 50;
  height: var(--alto-header);
  background: rgba(255, 255, 255, .97);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--gris-borde);
  transition: box-shadow .2s ease;
}
.header--scrolled { box-shadow: 0 8px 24px rgba(26, 29, 33, .1); }
.header__inner { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: .75rem; }
.header__brand { display: flex; align-items: center; gap: .6rem; text-decoration: none; color: var(--tinta); min-width: 0; }
.header__brand img { width: 2.375rem; height: 2.375rem; flex: none; }
.header__name {
  font-family: var(--font-titular); font-weight: 900;
  font-size: clamp(1rem, .9rem + .5vw, 1.15rem); line-height: 1;
  text-transform: uppercase; letter-spacing: -.01em; white-space: nowrap;
}
.header__sub {
  display: block; font-family: var(--font-texto); font-weight: 600;
  font-size: .58em; letter-spacing: .22em; color: var(--gris-texto); margin-top: .2rem;
}
.header__actions { display: flex; align-items: center; gap: .5rem; flex: none; }

@media (max-width: 480px) {
  .header__sub { display: none; }
  .header__name { line-height: 1.1; }
}
@media (max-width: 360px) {
  .header__actions .btn--sm { padding: .4rem .7rem; font-size: 0; gap: 0; }
  .header__actions .btn--sm .ico-wa { width: 1.35rem; height: 1.35rem; }
}

/* --- Hamburguesa (móvil/tablet) --- */
.nav-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 2.75rem; height: 2.75rem;
  background: transparent; border: 1.5px solid var(--gris-borde);
  border-radius: var(--radio-btn); cursor: pointer;
}
.nav-toggle__box { display: grid; gap: 5px; width: 1.15rem; }
.nav-toggle__box span { height: 2px; background: var(--tinta); border-radius: 2px; transition: transform .2s ease, opacity .2s ease; }
.nav-toggle[aria-expanded="true"] .nav-toggle__box span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__box span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__box span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.header__nav {
  position: absolute; top: 100%; left: 0; right: 0;
  display: grid; padding: .4rem 0 .6rem;
  background: var(--blanco); border-bottom: 1px solid var(--gris-borde);
  box-shadow: 0 14px 28px rgba(26, 29, 33, .12);
  visibility: hidden; opacity: 0; transform: translateY(-.5rem); pointer-events: none;
  transition: opacity .18s ease, transform .18s ease, visibility .18s;
}
.header__nav.is-open { visibility: visible; opacity: 1; transform: none; pointer-events: auto; }
.header__nav a {
  display: flex; align-items: center; min-height: var(--tap-min);
  padding: .4rem 1.25rem; font-weight: 600; font-size: 1.05rem;
  text-decoration: none; color: var(--acero);
}
.header__nav a:hover { color: var(--naranja-oscuro); background: var(--gris-suave); }

@media (min-width: 1025px) {
  .nav-toggle { display: none; }
  .header__nav {
    position: static; display: flex; gap: clamp(1.1rem, 2vw, 1.8rem); padding: 0;
    background: none; border: 0; box-shadow: none;
    visibility: visible; opacity: 1; transform: none; pointer-events: auto; transition: none;
  }
  .header__nav a {
    min-height: 0; padding: .3rem 0;
    font-weight: 600; font-size: .92rem; color: var(--acero);
    border-bottom: 2px solid transparent;
  }
  .header__nav a:hover { background: none; color: var(--tinta); border-bottom-color: var(--naranja); }
}

/* ==========================================================================
   Hero — asimétrico: mensaje a la izquierda, cifras a la derecha
   ========================================================================== */
.hero {
  position: relative;
  display: grid; align-items: center;
  min-height: min(78svh, 44rem);
  padding: clamp(3rem, 7vh, 5rem) 0 clamp(3.5rem, 8vh, 5.5rem);
  background:
    radial-gradient(56rem 30rem at 8% -10%, rgba(232, 90, 27, .22), transparent 60%),
    repeating-linear-gradient(-45deg, rgba(255, 255, 255, .022) 0 2px, transparent 2px 16px),
    var(--plomo);
  color: var(--blanco);
}
.hero__inner { display: grid; gap: 2.5rem; }
.hero__content { max-width: 44rem; }
.hero__eyebrow {
  display: flex; align-items: center; gap: .8rem;
  font-weight: 600; font-size: clamp(.72rem, .68rem + .25vw, .82rem);
  letter-spacing: .24em; text-transform: uppercase; color: var(--gris-texto-claro);
}
.hero__eyebrow .rule { width: 2.25rem; height: 2px; background: var(--naranja); flex: none; }
.hero__title {
  font-family: var(--font-titular); font-weight: 900;
  font-size: clamp(2.1rem, 1rem + 5vw, 4.3rem);
  line-height: .98; text-transform: uppercase; letter-spacing: -.02em;
  margin: 1rem 0 1.1rem;
}
.hero__title em { font-style: normal; color: var(--naranja); }
.hero__text { max-width: 34rem; color: var(--gris-texto-claro); font-size: clamp(1rem, .95rem + .3vw, 1.1rem); margin-bottom: 1.8rem; }
.hero__cta { display: flex; flex-wrap: wrap; gap: .75rem; }

.hero__stats { display: grid; gap: 1.1rem; }
.hero__stat {
  border-left: 2px solid rgba(255, 255, 255, .14);
  padding-left: 1.1rem;
}
.hero__stat strong {
  display: block;
  font-family: var(--font-titular); font-weight: 900;
  font-size: clamp(1.7rem, 1.4rem + 1.2vw, 2.5rem); line-height: 1.05;
  color: var(--naranja);
}
.hero__stat span { color: var(--gris-texto-claro); font-size: .9rem; line-height: 1.4; display: block; max-width: 15rem; }

@media (min-width: 641px) {
  .hero__stats { grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
}
@media (min-width: 1025px) {
  .hero__inner { grid-template-columns: 1.5fr .75fr; align-items: center; gap: 4rem; }
  .hero__stats { grid-template-columns: 1fr; align-content: center; gap: 1.6rem; }
}

/* Franja industrial al pie del hero */
.hero__hazard {
  position: absolute; left: 0; right: 0; bottom: 0; height: .55rem;
  background: repeating-linear-gradient(-45deg, var(--naranja) 0 1rem, var(--tinta) 1rem 2rem);
}

/* ==========================================================================
   Marquee de materiales
   ========================================================================== */
.marquee {
  overflow: hidden;
  background: var(--tinta);
  border-bottom: 1px solid rgba(255, 255, 255, .08);
  padding: .85rem 0;
}
.marquee__track {
  display: flex; width: max-content; white-space: nowrap;
  animation: marquee 38s linear infinite;
}
.marquee__track span {
  font-family: var(--font-titular); font-weight: 800;
  font-size: 1.05rem; letter-spacing: .14em; text-transform: uppercase;
  color: #79818B;
}
@supports (-webkit-text-stroke: 1px black) {
  .marquee__track span { color: transparent; -webkit-text-stroke: 1px #79818B; }
}
@keyframes marquee { to { transform: translateX(-50%); } }

/* ==========================================================================
   Cabecera de sección numerada (estilo del manual de marca: «01 · …»)
   ========================================================================== */
.shead { margin-bottom: clamp(2rem, 4vw, 3.25rem); }
.shead__kicker {
  display: flex; align-items: center; gap: .7rem;
  font-weight: 700; font-size: .78rem; letter-spacing: .22em; text-transform: uppercase;
  color: var(--gris-texto);
}
.shead__kicker::after { content: ""; flex: 1; height: 1px; background: var(--gris-borde); }
.shead__kicker--dark { color: var(--gris-texto-claro); }
.shead__kicker--dark::after { background: rgba(255, 255, 255, .14); }
.shead__num { font-family: var(--font-titular); font-weight: 900; color: var(--naranja-oscuro); font-size: .9rem; }
.section--dark .shead__num { color: var(--naranja); }
.shead__row { display: grid; gap: 1rem; margin-top: 1.4rem; }
.shead__title {
  font-family: var(--font-titular); font-weight: 900;
  font-size: clamp(1.8rem, 1.2rem + 2.8vw, 3.1rem);
  line-height: .98; text-transform: uppercase; letter-spacing: -.015em;
}
.shead__lead { color: var(--gris-texto); max-width: 36rem; align-self: end; }
.section--dark .shead__lead { color: var(--gris-texto-claro); }
.section--dark .shead__title { margin-top: 1.4rem; margin-bottom: .9rem; }

@media (min-width: 1025px) {
  .shead__row { grid-template-columns: 1fr 1fr; gap: 3rem; }
}

/* ==========================================================================
   Secciones
   ========================================================================== */
.section { padding: var(--pad-seccion) 0; }
.section--gray { background: var(--gris-suave); }
.section--dark { background: var(--plomo); color: var(--blanco); }

/* ==========================================================================
   Qué compramos — tarjetas numeradas: 2 col móvil · auto tablet · 5 col laptop
   ========================================================================== */
.materials {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 9.5rem), 1fr));
  gap: clamp(.7rem, 1.2vw, 1rem);
}
.material {
  position: relative;
  background: var(--blanco);
  border: 1px solid var(--gris-borde);
  border-radius: var(--radio);
  padding: 1.15rem 1rem 1.05rem;
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}
.material:hover {
  transform: translateY(-4px);
  border-color: var(--naranja);
  box-shadow: 0 14px 28px rgba(26, 29, 33, .1);
}
.material__num {
  position: absolute; top: .7rem; right: .85rem;
  font-family: var(--font-titular); font-weight: 900; font-size: 1.05rem;
  color: var(--gris-borde);
  transition: color .18s ease;
}
.material:hover .material__num { color: var(--naranja); }
.material__ico {
  width: 2.5rem; height: 2.5rem; padding: .45rem;
  color: var(--acero);
  border: 1px solid var(--gris-borde); border-radius: var(--radio-btn);
  margin-bottom: .8rem;
}
.material h3 {
  font-family: var(--font-titular); font-weight: 800;
  font-size: .95rem; line-height: 1.15;
  text-transform: uppercase; letter-spacing: .01em;
}
.material p { font-size: .82rem; color: var(--gris-texto); line-height: 1.4; margin-top: .25rem; }

@media (min-width: 1025px) {
  .materials { grid-template-columns: repeat(5, 1fr); }
}

/* ==========================================================================
   Servicios — lista editorial numerada, sin cajas
   ========================================================================== */
.services { display: grid; gap: 0; counter-reset: srv; }
.service {
  display: grid; grid-template-columns: auto 1fr; gap: 1.2rem;
  border-top: 1px solid #D8DADD;
  padding: 1.5rem 0;
}
.service__num {
  font-family: var(--font-titular); font-weight: 900;
  font-size: 1.4rem; line-height: 1.1; color: var(--naranja-oscuro);
  min-width: 2.4rem;
}
.service h3 { font-family: var(--font-titular); font-weight: 800; font-size: 1.15rem; text-transform: uppercase; letter-spacing: .01em; }
.service p { color: var(--gris-texto); margin-top: .3rem; max-width: 34rem; }

@media (min-width: 641px) {
  .services { grid-template-columns: 1fr 1fr; column-gap: 3.5rem; }
}

/* ==========================================================================
   Para empresas — texto + panel de proceso
   ========================================================================== */
.empresas { display: grid; gap: 2.5rem; }
.empresas__txt strong { color: var(--blanco); }
.checklist { display: grid; gap: .65rem; margin-top: 1.6rem; }
.checklist li { display: flex; gap: .7rem; align-items: baseline; font-weight: 500; }
.checklist li::before { content: "+"; flex: none; font-family: var(--font-titular); font-weight: 900; color: var(--naranja); }

.empresas__panel {
  background: var(--acero-panel);
  border: 1px solid rgba(255, 255, 255, .1);
  border-top: 3px solid var(--naranja);
  border-radius: var(--radio);
  padding: clamp(1.5rem, 3vw, 2.2rem);
  display: grid; gap: 1.4rem; align-content: start;
}
.empresas__panel h3 {
  font-family: var(--font-titular); font-weight: 800;
  font-size: 1.1rem; text-transform: uppercase; letter-spacing: .02em;
}
.pasos { display: grid; gap: 1rem; }
.pasos li { display: flex; gap: .9rem; align-items: flex-start; color: var(--gris-texto-claro); }
.pasos li span {
  flex: none;
  width: 1.75rem; height: 1.75rem;
  display: inline-flex; align-items: center; justify-content: center;
  font-family: var(--font-titular); font-weight: 900; font-size: .9rem;
  color: var(--tinta); background: var(--naranja); border-radius: var(--radio-btn);
  margin-top: .15rem;
}
.empresas__panel .btn { width: 100%; }

@media (min-width: 1025px) {
  .empresas { grid-template-columns: 1.15fr .85fr; gap: 4rem; align-items: start; }
}

/* ==========================================================================
   Sedes — columnas editoriales con regla superior
   ========================================================================== */
.sedes {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 15rem), 1fr));
  gap: clamp(1.5rem, 3vw, 2.5rem);
}
.sede {
  border-top: 2px solid var(--gris-borde);
  padding-top: 1.2rem;
  display: flex; flex-direction: column; gap: .5rem;
}
.sede--principal { border-top: 3px solid var(--naranja); }
.sede__badge {
  align-self: flex-start;
  font-weight: 700; font-size: .68rem; letter-spacing: .16em; text-transform: uppercase;
  color: var(--gris-texto);
}
.sede--principal .sede__badge { color: var(--naranja-oscuro); }
.sede h3 { font-family: var(--font-titular); font-weight: 800; font-size: 1.3rem; text-transform: uppercase; letter-spacing: -.01em; }
.sede__dir { color: var(--gris-texto); font-style: normal; }
.sede__hor { font-size: .9rem; color: var(--gris-texto); }
.sede__hor strong { color: var(--tinta); }
.sede__map {
  display: inline-flex; align-items: center; gap: .4rem;
  min-height: 2.75rem; margin-top: .2rem;
  font-family: var(--font-titular); font-weight: 800; font-size: .82rem;
  letter-spacing: .08em; text-transform: uppercase;
  color: var(--naranja-oscuro); text-decoration: none;
}
.sede__map:hover { text-decoration: underline; text-underline-offset: 3px; }

/* ==========================================================================
   Contacto — canales + formulario en panel oscuro
   ========================================================================== */
.contacto { display: grid; gap: 2.5rem; }
.contact-list { display: grid; margin-top: 1.6rem; }
.contact-list li {
  display: grid; gap: .05rem;
  padding: .9rem 0;
  border-bottom: 1px solid #D8DADD;
}
.contact-list li:first-child { border-top: 1px solid #D8DADD; }
.contact-list__label {
  font-weight: 700; font-size: .7rem; letter-spacing: .18em;
  text-transform: uppercase; color: var(--gris-texto);
}
.contact-list a {
  display: inline-flex; align-items: center;
  font-family: var(--font-titular); font-weight: 800;
  font-size: clamp(1.15rem, 1rem + .6vw, 1.45rem);
  color: var(--tinta); text-decoration: none; overflow-wrap: anywhere;
}
.contact-list a:hover { color: var(--naranja-oscuro); }

.form {
  background: var(--plomo);
  color: var(--blanco);
  border-radius: var(--radio);
  border-top: 3px solid var(--naranja);
  padding: clamp(1.5rem, 3vw, 2.2rem);
  display: grid; gap: 1.1rem;
}
.form__title { font-family: var(--font-titular); font-weight: 800; font-size: 1.1rem; text-transform: uppercase; letter-spacing: .02em; }
.form__field { display: grid; gap: .4rem; }
.form__field label {
  font-weight: 700; font-size: .72rem; letter-spacing: .16em;
  text-transform: uppercase; color: var(--gris-texto-claro);
}
.form__field input,
.form__field select,
.form__field textarea {
  font: inherit; color: var(--tinta); background: var(--blanco);
  border: 1.5px solid transparent; border-radius: var(--radio-btn);
  min-height: var(--tap-min); padding: .65rem .85rem; width: 100%;
}
.form__field input:focus-visible,
.form__field select:focus-visible,
.form__field textarea:focus-visible { outline: 3px solid var(--naranja); outline-offset: 0; }
.form__field textarea { resize: vertical; min-height: 6rem; }
.form__error { color: #FFB4AB; font-weight: 600; font-size: .9rem; }
.form__submit { width: 100%; }
.form__note { font-size: .8rem; color: var(--gris-texto-claro); text-align: center; }

@media (min-width: 1025px) {
  .contacto { grid-template-columns: .9fr 1.1fr; align-items: start; gap: 4rem; }
}

/* ==========================================================================
   Footer corporativo
   ========================================================================== */
.footer {
  background: var(--tinta);
  color: var(--gris-texto-claro);
  padding: clamp(2.5rem, 5vw, 4rem) 0 calc(1.5rem + 4.5rem); /* espacio para el FAB en móvil */
  font-size: .92rem;
}
.footer__grid { display: grid; gap: 2rem; }
.footer__brand img { width: 2.5rem; height: 2.5rem; margin-bottom: .8rem; }
.footer__lockup {
  font-family: var(--font-titular); font-weight: 900; font-size: 1.2rem;
  line-height: 1; text-transform: uppercase; color: var(--blanco);
}
.footer__lockup span {
  display: block; font-family: var(--font-texto); font-weight: 600;
  font-size: .55em; letter-spacing: .22em; color: var(--gris-texto-claro); margin-top: .3rem;
}
.footer__desc { margin-top: .9rem; max-width: 20rem; font-size: .88rem; }
.footer__col h4 {
  font-family: var(--font-titular); font-weight: 800;
  font-size: .75rem; letter-spacing: .2em; text-transform: uppercase;
  color: var(--naranja); margin-bottom: .8rem;
}
.footer__col li { margin: .4rem 0; }
.footer__col em { font-style: normal; color: #8A929C; }
.footer__col a {
  display: inline-flex; align-items: center; min-height: 1.9rem;
  color: var(--blanco); font-weight: 600; text-decoration: none;
}
.footer__col a:hover { color: var(--naranja); }
.footer__bottom {
  margin-top: 2.2rem; padding-top: 1.3rem;
  border-top: 1px solid rgba(255, 255, 255, .1);
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: .5rem 2rem;
  font-size: .85rem;
}

@media (min-width: 641px) {
  .footer { padding-bottom: 1.5rem; }
  .footer__grid { grid-template-columns: 1fr 1fr; }
}
@media (min-width: 1025px) {
  .footer__grid { grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 3rem; }
}

/* ==========================================================================
   FAB WhatsApp
   ========================================================================== */
.fab {
  position: fixed;
  right: max(.9rem, env(safe-area-inset-right));
  bottom: max(.9rem, env(safe-area-inset-bottom));
  z-index: 60;
  width: 3.25rem; height: 3.25rem;
  display: flex; align-items: center; justify-content: center;
  background: var(--wa-verde); color: var(--blanco);
  border-radius: 50%;
  box-shadow: 0 6px 20px rgba(0, 0, 0, .3);
  transition: transform .15s ease;
}
.fab:hover { transform: scale(1.07); }
.fab svg { width: 60%; height: 60%; }
@media (min-width: 641px) { .fab { width: 3.625rem; height: 3.625rem; right: 1.25rem; bottom: 1.25rem; } }

/* ==========================================================================
   Aparición al hacer scroll (solo si hay JS; ver script.js)
   ========================================================================== */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .55s ease, transform .55s ease; }
.reveal.is-visible { opacity: 1; transform: none; }