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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #ffffff;
}

.bmi-container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
}

.bmi-header {
    text-align: center;
    margin-bottom: 30px;
}

.bmi-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #1a1a1a;
    margin-bottom: 15px;
}

.info-card {
    background: #f8f9fa;
    border: 1px solid #e9ecef;
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
}

.info-card p {
    color: #6c757d;
    font-size: 1rem;
    line-height: 1.6;
}

.bmi-calculator {
    background: #ffffff;
    border: 1px solid #e9ecef;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.unit-tabs {
    display: flex;
    margin-bottom: 30px;
    border-bottom: 1px solid #e9ecef;
}

.tab-btn {
    flex: 1;
    padding: 12px 20px;
    border: none;
    background: transparent;
    color: #6c757d;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: all 0.3s ease;
}

.tab-btn.active {
    color: #007bff;
    border-bottom-color: #007bff;
}

.tab-btn:hover {
    color: #007bff;
}

.input-group {
    margin-bottom: 25px;
}

.input-label {
    display: block;
    font-weight: 600;
    color: #1a1a1a;
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.height-option {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
}

.height-option input[type="radio"] {
    margin-right: 8px;
}

.height-option label {
    color: #495057;
    font-weight: 500;
    cursor: pointer;
}

.height-inputs {
    margin-top: 15px;
}

.cm-input, .feet-input, .feet-input-us, .inches-input, .weight-input {
    display: flex;
    align-items: center;
    gap: 10px;
}

.cm-input input, .feet-input input, .feet-input-us input, .inches-input input, .weight-input input {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.cm-input input:focus, .feet-input input:focus, .feet-input-us input:focus, .inches-input input:focus, .weight-input input:focus {
    outline: none;
    border-color: #007bff;
}

.unit {
    color: #6c757d;
    font-weight: 500;
    min-width: 30px;
}

.calculate-btn {
    width: 100%;
    padding: 15px;
    background: #007bff;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.calculate-btn:hover {
    background: #0056b3;
}

.results-section {
    margin-top: 30px;
    padding-top: 30px;
    border-top: 1px solid #e9ecef;
}

.bmi-result {
    text-align: center;
    margin-bottom: 30px;
}

.bmi-result h3 {
    color: #1a1a1a;
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.bmi-value {
    font-size: 3rem;
    font-weight: 700;
    color: #007bff;
    margin-bottom: 10px;
}

.bmi-category {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.bmi-description {
    color: #6c757d;
    font-size: 1rem;
}

.bmi-chart h4 {
    color: #1a1a1a;
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.chart-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    border-radius: 6px;
    margin-bottom: 8px;
}

.chart-item.underweight {
    background: #e3f2fd;
    border-left: 4px solid #2196f3;
}

.chart-item.normal {
    background: #e8f5e8;
    border-left: 4px solid #4caf50;
}

.chart-item.overweight {
    background: #fff3e0;
    border-left: 4px solid #ff9800;
}

.chart-item.obese {
    background: #ffebee;
    border-left: 4px solid #f44336;
}

.chart-item.active {
    transform: scale(1.02);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.range {
    font-weight: 600;
}

.category {
    color: #6c757d;
}

/* Category colors */
.bmi-category.underweight {
    color: #2196f3;
}

.bmi-category.normal {
    color: #4caf50;
}

.bmi-category.overweight {
    color: #ff9800;
}

.bmi-category.obese {
    color: #f44336;
}

/* Responsive design */
@media (max-width: 768px) {
    .bmi-container {
        padding: 15px;
    }
    
    .bmi-header h1 {
        font-size: 2rem;
    }
    
    .bmi-calculator {
        padding: 20px;
    }
    
    .bmi-value {
        font-size: 2.5rem;
    }
}