body::before {
  content: "";
  position: fixed;
  top: -10%;
  left: -10%;
  width: 120%;
  height: 120%;
  background: linear-gradient(-45deg, #5d198ace, #24034b, #004d96, #025ca7);
  background-size: 400% 400%;
  animation: fondoAnimado 20s ease infinite;
  z-index: -1;

  opacity: 1;
  filter: blur(15px);
  box-shadow: inset 0 0 50px 20px #121212;
}

@keyframes fondoAnimado {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* Caja principal */
.presupuesto-box {
  max-width: 460px;
  margin: 40px auto;
  padding: 25px 30px;
  border-radius: 15px;
  background: #1e1e2f;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.6);
  color: #e0e0e0;

  animation: fadeInUp 1.2s ease both;
}

@keyframes fadeInUp {
  0% {
    opacity: 0;
    transform: translateY(30px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Título con RGB animado */
.presupuesto-title {
  text-align: center;
  margin-bottom: 20px;
  font-weight: 700;
  font-size: 24px;
  text-shadow: 0 2px 5px rgba(0,0,0,0.5);
}

.rgb-title {
  background: linear-gradient(90deg, red, orange, yellow, green, blue, indigo, violet);
  background-size: 300% 300%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: rgbAnim 6s ease infinite;
}

@keyframes rgbAnim {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* Textarea */
#descripcionProyecto {
  width: 100%;
  padding: 12px 14px;
  font-size: 15px;
  border-radius: 10px;
  border: none;
  resize: none;
  background-color: #2c2c3a;
  color: #f0f0f0;
  box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.4);
  margin-bottom: 16px;
}

/* Botón calcular presupuesto */
#calcularPresupuesto {
  width: 100%;
  padding: 14px 0;
  background-color: #303f9f;
  font-size: 17px;
  font-weight: 600;
  color: #fff;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: background-color 0.3s ease;
  box-shadow: 0 4px 10px rgba(48, 63, 159, 0.5);
}

#calcularPresupuesto:hover {
  background-color: #1a237e;
  box-shadow: 0 0 15px #3f51b5, 0 0 30px #3f51b5;
}

/* Resultado */
#resultadoPresupuesto {
  text-shadow: 0 0 4px rgba(255, 255, 255, 0.2);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

/* Botón Creative Web: negro, redondo con flecha blanca hacia atrás */
.creative-web-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background-color: #000000;
  border-radius: 50%;
  color: white;
  border: none;
  cursor: pointer;
  position: fixed;
  top: 20px;
  left: 20px;
  padding: 0;
  text-indent: -9999px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.5);
  transition: background-color 0.3s ease;
  text-decoration: none;
  z-index: 10;
}

.creative-web-btn:hover {
  background-color: #222222;
}

.creative-web-btn::before {
  content: "";
  border: solid white;
  border-width: 0 3px 3px 0;
  display: inline-block;
  padding: 6px;
  transform: rotate(135deg);
  -webkit-transform: rotate(135deg);
}