* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 20px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  font-family: Arial, sans-serif;
}


.wrapper {
  background: rgba(255, 255, 255, 0.1);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.15);
  text-align: center;
  width: 100%;
  max-width: 450px;
}


.wrapper h1 {
  margin-bottom: 1.5rem;
  color: #fff;
  font-size: 2rem;
}


.wrapper input[type="number"] {
  width: 100%;
  padding: 1rem;
  margin: 0.75rem 0;
  border: none;
  border-radius: 5px;
  background: rgba(255, 255, 255, 0.2);
  color: black;
  font-size: 1rem;
}


#btn {
  width: 100%;
  padding: 1rem;
  border: none;
  border-radius: 5px;
  background: #ff5e62;
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.3s;
  margin-top: 1rem;
}

#btn:hover {
  background: #ff3b3f;
}


#output {
  margin-top: 1.25rem;
  font-size: 1.2rem;
  color: #fff;
}


#height_error,
#weight_error {
  color: #ff3b3f;
  font-size: 0.95rem;
  margin-top: 0.25rem;
}


.bmi-chart {
  margin-top: 2rem;
  background: white;
  padding: 1rem;
  border-radius: 12px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
  color: #222;
  width: 103%;

}


.bar {
  display: flex;
  height: 14px;
  margin-bottom: 0.75rem;
  border-radius: 5px;
  overflow: hidden;
}


.range {
  flex: 1;
}

.underweight { background: #fbc02d; }
.normal      { background: #388e3c; }
.overweight  { background: #f57c00; }
.obese       { background: #d32f2f; }


.labels {
  display: flex;
  justify-content: space-between;
  text-align: center;
  font-size: 12px;
  font-weight: 500;
  flex-wrap: wrap;
}

.labels div {
  flex: 1;
  padding: 5px 2px;
}

.labels span {
  display: block;
  font-size: 0.85rem;
  font-weight: bold;
  color: #555;
}

.labels small {
  font-size: 1.1rem;
  font-weight: bold;
  color: #111;
}


@media (max-width: 768px) {
  .wrapper {
    padding: 1.5rem;
  }

  .wrapper h1 {
    font-size: 1.75rem;
  }

  .wrapper input[type="number"],
  #btn {
    padding: 0.9rem;
    font-size: 1rem;
  }

  .labels small {
    font-size: 1rem;
  }

  .labels span {
    font-size: 0.8rem;
  }
}


@media (max-width: 480px) {
  .wrapper {
    padding: 1rem;
  }

  .wrapper h1 {
    font-size: 1.5rem;
  }

  .wrapper input[type="number"],
  #btn {
    padding: 0.8rem;
    font-size: 0.95rem;
  }

  .bar,
  .labels {
    flex-direction: row;
  }

  .labels div {
    min-width: 25%;
    padding: 4px 2px;
    font-size: 0.75rem;
  }

  .labels span {
    font-size: 0.75rem;
  }

  .labels small {
    font-size: 0.95rem;
  }

  #output {
    font-size: 1rem;
  }
}