body {
  font-family: Arial, sans-serif;
  background-color: #1e1e2f;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: start;
  min-height: 100vh;
}

.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  background-color: #2e2e3e;
  padding: 30px 20px 20px 20px;
  border-radius: 10px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
  margin-top: 30px;
  max-width: 400px;
  width: 100%;
  color: #fff;
}

h2 {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-top: 10px;
  font-weight: bold;
  color: #ddd;
}

select {
  width: 100%;
  padding: 8px;
  margin-top: 5px;
  margin-bottom: 10px;
  border: 1px solid #555;
  border-radius: 4px;
  background-color: #3e3e4e;
  color: #fff;
}

button {
  padding: 10px 20px;
  background-color: #8255bd;
  color: #fff;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  margin-top: 15px;
  width: 100%;
}

button:hover {
  background-color: #6a3dad;
}

.result,
.tolerance {
  margin-top: 20px;
  font-size: 16px;
  color: #bbb;
}

.banda {
  width: 100%;
  margin-bottom: 10px;
}

#bandasSelection {
  width: 100%;
  margin-bottom: 20px;
}

/* Imagen visual al fondo */
.resistencia-visual {
  display: flex;
  justify-content: center;
  margin-top: 250px;
  margin-bottom: 10px;
  width: 100%;
}

.resistencia-cuerpo {
  width: 300px;
  height: 60px;
  background: linear-gradient(to right, #f5f5f5, #dcdcdc);
  border-radius: 30px;
  position: relative;
  border: 2px solid #aaa;
  box-shadow: inset 0 0 5px #999, 0 4px 10px rgba(0, 0, 0, 0.2);
  transition: all 0.3s ease;
}

.banda-visual {
  position: absolute;
  width: 12px;
  height: 60px;
  top: 0;
  display: none;
  border-radius: 2px;
  box-shadow: 0 0 4px rgba(0, 0, 0, 0.2);
  transition: background-color 0.4s ease, transform 0.3s ease;
}

/* Posiciones de las bandas en la resistencia */
#banda-vis-1 { left: 40px; }
#banda-vis-2 { left: 75px; }
#banda-vis-3 { left: 110px; }
#banda-vis-4 { left: 160px; }
#banda-vis-5 { left: 195px; }
#banda-vis-6 { left: 230px; }