body {
  font-family: Arial, sans-serif;
  background: linear-gradient(135deg, #06b6d4, #3b82f6);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  padding: 20px;
}

.bmi-container {
  background: #ffffff;
  padding: 25px;
  border-radius: 20px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.15);
  width: 100%;
  max-width: 500px;
  text-align: center;
  transition: transform 0.3s ease;
}

.bmi-container:hover {
  transform: scale(1.02);
}

.bmi-container h1 {
  margin-bottom: 20px;
  font-size: 1.8rem;
  color: #1e293b;
}

.form-group {
  margin-bottom: 15px;
  text-align: left;
}

label {
  font-weight: 600;
  display: block;
  margin-bottom: 5px;
  color: #374151;
  font-size: 0.95rem;
}

.bmi-input, select {
  width: 100%;
  padding: 10px;
  border: 2px solid #e5e7eb;
  border-radius: 10px;
  font-size: 1rem;
  outline: none;
  transition: border 0.3s;
  box-sizing: border-box;
}

.bmi-input:focus, select:focus {
  border-color: #3b82f6;
}

.bmi-btn {
  background: linear-gradient(135deg, #06b6d4, #3b82f6);
  color: white;
  border: none;
  padding: 12px 20px;
  margin-top: 15px;
  border-radius: 12px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: bold;
  transition: all 0.3s ease;
  width: 100%;
}

.bmi-btn:hover {
  background: linear-gradient(135deg, #2563eb, #0891b2);
  transform: translateY(-2px);
}

.bmi-result {
  margin-top: 20px;
  font-size: 1.2rem;
  font-weight: bold;
  color: #1e293b;
}

.bmi-category {
  margin-top: 8px;
  font-size: 1rem;
  font-weight: 600;
  padding: 8px;
  border-radius: 8px;
  display: inline-block;
}

.underweight { background: #fef3c7; color: #b45309; }
.normal { background: #dcfce7; color: #15803d; }
.overweight { background: #fef9c3; color: #a16207; }
.obese { background: #fee2e2; color: #b91c1c; }

.download-btn {
  margin-top: 15px;
  background: linear-gradient(135deg, #f97316, #fb923c);
  color: white;
  padding: 10px 18px;
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  cursor: pointer;
  transition: 0.3s;
  width: 100%;
}

.download-btn:hover {
  background: linear-gradient(135deg, #ea580c, #c2410c);
}

.bmi-chart {
  margin-top: 25px;
  text-align: left;
  font-size: 0.9rem;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  overflow-x: auto;
}

.bmi-chart table {
  width: 100%;
  border-collapse: collapse;
  min-width: 400px;
}

.bmi-chart th, .bmi-chart td {
  padding: 10px;
  text-align: center;
}

.bmi-chart th {
  background: #1e293b;
  color: white;
  font-size: 0.9rem;
}

.chart-underweight { background: #fef3c7; color: #92400e; }
.chart-normal { background: #dcfce7; color: #166534; }
.chart-overweight { background: #fef9c3; color: #854d0e; }
.chart-obese { background: #fee2e2; color: #991b1b; }

@media (max-width: 768px) {
  .bmi-container {
    padding: 20px;
  }

  .bmi-container h1 {
    font-size: 1.5rem;
  }

  label {
    font-size: 0.9rem;
  }

  .bmi-result {
    font-size: 1rem;
  }

  .download-btn, .bmi-btn {
    font-size: 0.95rem;
    padding: 10px;
  }
}

@media (max-width: 480px) {
  .bmi-container {
    padding: 15px;
    border-radius: 15px;
  }

  .bmi-container h1 {
    font-size: 1.3rem;
  }

  .bmi-input, select {
    font-size: 0.9rem;
    padding: 8px;
  }

  .bmi-result {
    font-size: 0.95rem;
  }

  .download-btn, .bmi-btn {
    font-size: 0.9rem;
    padding: 8px;
  }
}