*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{
  --azul:#1F4E79;
  --azul-desc:#3B82C4;
  --niebla:#EBF3FB;
  --tierra:#A0714F;
  --gris:#6B7280;
  --negro:#1A1A1A;
  --blanco:#FFFFFF;
  --fondo:#FDFAF7;
  --borde:rgba(0,0,0,0.08);
  --serif:'Playfair Display',Georgia,serif;
  --sans:'Jost',Arial,sans-serif;
}
html{font-size:16px;scroll-behavior:smooth}
body{font-family:var(--sans);background:var(--fondo);color:var(--negro);line-height:1.7;font-weight:300}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}

/* NAV */
.nav{position:fixed;top:0;left:0;right:0;z-index:100;background:rgba(253,250,247,0.96);backdrop-filter:blur(8px);border-bottom:.5px solid var(--borde);padding:0 48px;display:flex;align-items:center;justify-content:space-between;height:52px}
.nav-logo{display:flex;align-items:center}
.nav-logo-img{height:46px;width:auto;display:block}
.nav-links{display:flex;align-items:center;gap:28px;list-style:none}
.nav-links a{font-size:10px;font-weight:500;letter-spacing:.1em;text-transform:uppercase;color:var(--gris);transition:color .2s}
.nav-links a:hover{color:var(--azul)}
.nav-links a.active{color:var(--azul)}
.nav-cta{color:var(--azul) !important;border:.5px solid var(--azul);padding:5px 14px;border-radius:3px;transition:all .2s !important}
.nav-cta:hover{background:var(--azul);color:var(--blanco) !important}
.nav-burger{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:4px}
.nav-burger span{display:block;width:20px;height:1px;background:var(--negro)}
.progress-bar{position:fixed;top:52px;left:0;z-index:99;height:2px;background:var(--azul-desc);width:0%;transition:width .1s linear;opacity:.8}

/* HERO SPLIT */
.libro-hero{
  min-height:100vh;
  display:grid;
  grid-template-columns:1fr 480px;
  padding-top:52px;
}

/* LADO IZQUIERDO — contenido */
.libro-left{
  background:var(--tierra);
  padding:72px 72px 72px 96px;
  display:flex;flex-direction:column;justify-content:center;
  position:relative;overflow:hidden;
}
.libro-left::before{content:'';position:absolute;left:48px;top:0;bottom:0;width:1.5px;background:rgba(255,255,255,.08)}
.libro-back{display:inline-flex;align-items:center;gap:8px;font-size:10px;font-weight:500;letter-spacing:.1em;text-transform:uppercase;color:rgba(255,255,255,.3);margin-bottom:40px;transition:color .2s;align-self:flex-start}
.libro-back:hover{color:rgba(255,255,255,.7)}
.libro-back::before{content:'←';font-size:12px}
.libro-tag{font-size:9px;font-weight:500;color:rgba(255,255,255,.25);letter-spacing:.22em;text-transform:uppercase;margin-bottom:16px}
.libro-title{font-family:var(--serif);font-size:clamp(32px,3.5vw,48px);font-weight:400;color:var(--blanco);line-height:1.1;margin-bottom:12px}
.libro-title em{font-style:italic;color:rgba(255,255,255,.55)}
.libro-sep{display:flex;align-items:center;width:80px;margin-bottom:20px}
.libro-sep-line{flex:1;height:.5px;background:rgba(255,255,255,.15)}
.libro-sep-dot{width:4px;height:4px;border-radius:50%;background:var(--tierra);margin:0 8px;flex-shrink:0}
.libro-desc{font-size:14px;font-weight:300;color:rgba(255,255,255,.4);line-height:1.85;margin-bottom:36px;max-width:460px}

/* Fragmentos del libro */
.libro-fragmentos{display:flex;flex-direction:column;gap:0}
.libro-frag{
  padding:14px 0;
  border-bottom:.5px solid rgba(255,255,255,.08);
  display:flex;align-items:baseline;gap:12px;
}
.libro-frag:first-child{border-top:.5px solid rgba(255,255,255,.08)}
.libro-frag-text{
  font-family:var(--serif);font-size:15px;font-style:italic;
  color:rgba(255,255,255,.55);line-height:1.5;
}
.libro-frag-ref{font-size:10px;color:rgba(255,255,255,.2);letter-spacing:.06em;flex-shrink:0}

/* LADO DERECHO — formulario */
.libro-right{
  background:var(--fondo);
  padding:72px 64px 72px 56px;
  display:flex;flex-direction:column;justify-content:center;
  border-left:.5px solid var(--borde);
}
.form-section-label{font-size:9px;font-weight:500;color:var(--gris);letter-spacing:.14em;text-transform:uppercase;margin-bottom:24px;padding-bottom:10px;border-bottom:.5px solid var(--borde)}
.form-field{display:flex;flex-direction:column;gap:6px;margin-bottom:18px}
.form-label{font-size:10px;font-weight:500;letter-spacing:.1em;text-transform:uppercase;color:var(--gris)}
.form-input{
  background:var(--blanco);
  border:.5px solid var(--borde);
  border-radius:4px;
  padding:12px 16px;
  font-family:var(--sans);font-size:14px;font-weight:300;
  color:var(--negro);outline:none;
  transition:border-color .2s,box-shadow .2s;width:100%;
}
.form-input::placeholder{color:var(--gris);opacity:.45}
.form-input:focus{border-color:var(--azul-desc);box-shadow:0 0 0 3px rgba(59,130,196,.08)}
.form-textarea{min-height:100px;resize:vertical;line-height:1.65}

/* Cómo te enteraste */
.form-como{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-top:4px}
.como-opt{
  border:.5px solid var(--borde);border-radius:4px;
  padding:9px 12px;font-size:12px;color:var(--gris);
  background:var(--blanco);cursor:pointer;
  transition:all .2s;text-align:center;
  user-select:none;
}
.como-opt:hover{border-color:var(--azul-desc);color:var(--azul)}
.como-opt.selected{border-color:var(--azul);color:var(--azul);background:var(--niebla)}

/* Botón enviar */
.btn-enviar{
  display:flex;align-items:center;justify-content:center;gap:8px;
  background:var(--azul);color:var(--blanco);
  border:none;border-radius:4px;
  padding:14px 28px;width:100%;
  font-family:var(--sans);font-size:11px;font-weight:500;
  letter-spacing:.1em;text-transform:uppercase;
  cursor:pointer;transition:all .25s;margin-top:8px;
}
.btn-enviar::after{content:'→';display:inline-block;transition:transform .3s ease}
.btn-enviar:hover{background:#163a5e;transform:translateY(-1px);box-shadow:0 6px 20px rgba(31,78,121,.25)}
.btn-enviar:hover::after{transform:translateX(5px)}
.form-note{font-size:11px;color:var(--gris);opacity:.55;text-align:center;margin-top:10px}

/* ESTADO DE ÉXITO */
.form-success{
  display:none;
  text-align:center;
  padding:48px 24px;
}
.form-success.visible{display:block}
.form-success-icon{font-size:32px;margin-bottom:16px}
.form-success-title{font-family:var(--serif);font-size:26px;font-weight:400;color:var(--negro);margin-bottom:8px}
.form-success-sub{font-size:14px;font-weight:300;color:var(--gris);line-height:1.75}

/* RESPONSIVE */
@media(max-width:900px){
  .nav{padding:0 24px}
  .libro-hero{grid-template-columns:1fr;min-height:auto}
  .libro-left{padding:100px 48px 56px}
  .libro-left::before{left:24px}
  .libro-right{padding:48px 48px 64px;border-left:none;border-top:.5px solid var(--borde)}
}
@media(max-width:640px){
  .nav{padding:0 20px}
  .nav-links{display:none}
  .nav-links.open{display:flex;flex-direction:column;position:absolute;top:52px;left:0;right:0;background:rgba(253,250,247,.98);border-bottom:.5px solid var(--borde);padding:20px 24px;gap:16px}
  .nav-burger{display:flex}
  .libro-left{padding:80px 24px 48px;padding-left:52px}
  .libro-right{padding:40px 20px 56px}
  .form-como{grid-template-columns:1fr}
}

/* FOOTER */
.footer{background:var(--negro);padding:48px;display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:24px}
.footer-logo{display:flex;flex-direction:column;gap:6px}
.footer-logo-img{height:56px;width:auto;opacity:.9}
.footer-logo span{font-family:var(--sans);font-size:8px;letter-spacing:.18em;text-transform:uppercase;color:rgba(255,255,255,.25)}
.footer-links{display:flex;gap:24px;list-style:none;flex-wrap:wrap}
.footer-links a{font-size:10px;letter-spacing:.08em;text-transform:uppercase;color:rgba(255,255,255,.32);transition:color .2s}
.footer-links a:hover{color:rgba(255,255,255,.75)}
.footer-meta{font-size:9px;color:rgba(255,255,255,.18);letter-spacing:.06em}
@media(max-width:640px){.footer{padding:32px 24px;flex-direction:column;align-items:flex-start}}