/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 2rem 0;
    margin-bottom: 2rem;
}

header h1 {
    color: #1a202c;
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 0.5rem;
}

header .subtitle {
    text-align: center;
    color: #4a5568;
    font-size: 1.1rem;
}

/* Main Content */
main {
    padding-bottom: 2rem;
}

/* Calculator Section */
.calculator-section {
    margin-bottom: 3rem;
}

.calculator-card {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
}

.calculator-card h2 {
    color: #2d3748;
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

/* Form Styles */
form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.form-group input,
.form-group select {
    padding: 0.75rem 1rem;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-group .help-text {
    color: #718096;
    font-size: 0.85rem;
    margin-top: 0.25rem;
}

/* Button Styles */
.btn-calculate {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn-calculate:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.btn-calculate:active {
    transform: translateY(0);
}

.btn-reset {
    background: #edf2f7;
    color: #2d3748;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease;
    width: 100%;
    margin-top: 1rem;
}

.btn-reset:hover {
    background: #e2e8f0;
}

/* Results Section */
.results {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 2px solid #e2e8f0;
}

.results h3 {
    color: #2d3748;
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.result-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 8px;
    padding: 1.5rem;
    text-align: center;
    color: white;
}

.result-value {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.result-label {
    font-size: 0.9rem;
    opacity: 0.9;
    font-weight: 500;
}

.result-details {
    background: #f7fafc;
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
    color: #2d3748;
    line-height: 1.8;
    animation: fadeIn 0.5s ease-in;
}

.result-details strong {
    color: #667eea;
}

.result-details .important {
    background: #eef2ff;
    padding: 0.75rem;
    border-radius: 6px;
    margin-top: 0.5rem;
    border-left: 3px solid #667eea;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Info Section */
.info-section {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
}

.info-content h2 {
    color: #2d3748;
    font-size: 2rem;
    margin-bottom: 1.5rem;
    border-bottom: 3px solid #667eea;
    padding-bottom: 0.5rem;
}

.info-content h3 {
    color: #4a5568;
    font-size: 1.3rem;
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.info-content p {
    color: #4a5568;
    margin-bottom: 1rem;
    line-height: 1.8;
}

.info-content ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
    color: #4a5568;
}

.info-content li {
    margin-bottom: 0.5rem;
    line-height: 1.7;
}

/* Footer */
footer {
    background: rgba(0, 0, 0, 0.8);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

footer p {
    margin-bottom: 0.5rem;
}

footer a {
    color: #667eea;
    text-decoration: none;
    transition: color 0.3s ease;
}

footer a:hover {
    color: #764ba2;
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    header .subtitle {
        font-size: 1rem;
    }

    .calculator-card {
        padding: 1.5rem;
    }

    .calculator-card h2 {
        font-size: 1.5rem;
    }

    .result-grid {
        grid-template-columns: 1fr;
    }

    .result-value {
        font-size: 2rem;
    }

    .info-content h2 {
        font-size: 1.5rem;
    }

    .info-content h3 {
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    header h1 {
        font-size: 1.75rem;
    }

    .calculator-card,
    .info-section {
        padding: 1rem;
    }

    .btn-calculate {
        font-size: 1rem;
        padding: 0.875rem 1.5rem;
    }
}