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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --dark: #1f2937;
    --dark-light: #374151;
    --gray: #6b7280;
    --gray-light: #e5e7eb;
    --gray-lighter: #f9fafb;
    --white: #ffffff;
    --border-radius: 12px;
    --box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --box-shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: var(--dark);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

header {
    text-align: center;
    color: var(--white);
    margin-bottom: 30px;
    padding: 20px;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.95;
}

.calculator-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    align-items: start;
}

.config-panel,
.summary-panel {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.section,
.cost-card,
.info-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 25px;
    box-shadow: var(--box-shadow);
}

.section h2,
.cost-card h2,
.info-card h3 {
    margin-bottom: 20px;
    color: var(--dark);
    font-size: 1.3rem;
    border-bottom: 2px solid var(--gray-light);
    padding-bottom: 10px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--dark);
    font-size: 0.95rem;
}

.form-control {
    width: 100%;
    padding: 10px 12px;
    border: 2px solid var(--gray-light);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: var(--white);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.checkbox {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

.hint {
    display: block;
    margin-top: 5px;
    font-size: 0.85rem;
    color: var(--gray);
    font-style: italic;
}

.section-subtitle {
    color: var(--gray);
    font-size: 0.9rem;
    margin-bottom: 15px;
}

.checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.checkbox-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px;
    border-radius: 6px;
    transition: background 0.2s ease;
}

.checkbox-item:hover {
    background: var(--gray-lighter);
}

.checkbox-item label {
    margin: 0;
    cursor: pointer;
    font-weight: 500;
}

textarea.form-control {
    resize: vertical;
    font-family: inherit;
    min-height: 80px;
}

.info-box {
    background: var(--gray-lighter);
    border-left: 4px solid var(--primary-color);
    padding: 15px;
    border-radius: 6px;
    margin-top: 15px;
    margin-bottom: 15px;
}

.info-box h4 {
    margin-bottom: 10px;
    color: var(--dark);
    font-size: 1rem;
}

.requirements-list {
    list-style: none;
    padding: 0;
}

.requirements-list li {
    padding: 8px 0;
    padding-left: 20px;
    position: relative;
    color: var(--dark-light);
    line-height: 1.6;
}

.requirements-list li:before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

.requirements-list li strong {
    color: var(--dark);
}

.responsible-ai-box {
    background: linear-gradient(135deg, #fff5f5 0%, #ffe5e5 100%);
    border: 2px solid #fca5a5;
    border-radius: 8px;
    padding: 20px;
}

.ai-notice {
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 15px;
    font-size: 1rem;
}

.ai-warning {
    margin-top: 15px;
    padding: 10px;
    background: #fee2e2;
    border-radius: 6px;
    color: var(--danger-color);
    font-weight: 600;
    text-align: center;
}

.responsible-ai-box .checkbox-item {
    background: white;
    padding: 12px;
    margin-bottom: 10px;
    border-radius: 6px;
    border: 1px solid #fca5a5;
}

.responsible-ai-box .checkbox-item label {
    color: var(--dark);
    font-weight: 500;
}

.action-buttons {
    display: flex;
    gap: 10px;
    margin-top: 20px;
}

.btn {
    flex: 1;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn-primary {
    background: var(--primary-color);
    color: var(--white);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-lg);
}

.btn-secondary {
    background: var(--gray-light);
    color: var(--dark);
}

.btn-secondary:hover {
    background: var(--gray);
    color: var(--white);
    transform: translateY(-2px);
}

.cost-card {
    position: sticky;
    top: 20px;
}

.total-cost {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    padding: 30px;
    border-radius: var(--border-radius);
    text-align: center;
    margin-bottom: 25px;
    color: var(--white);
}

.cost-label {
    font-size: 1rem;
    margin-bottom: 10px;
    opacity: 0.95;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.cost-amount {
    font-size: 3rem;
    font-weight: 700;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.cost-details {
    border: 2px solid var(--gray-light);
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 20px;
}

.cost-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid var(--gray-light);
}

.cost-item:last-child {
    border-bottom: none;
}

.item-label {
    font-size: 0.95rem;
    color: var(--dark-light);
    font-weight: 500;
}

.item-cost {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
}

.cost-insights {
    background: var(--gray-lighter);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.cost-insights h3 {
    margin-bottom: 15px;
    color: var(--dark);
    font-size: 1.1rem;
}

.cost-insights ul,
.notes-list {
    list-style: none;
    padding: 0;
}

.cost-insights li,
.notes-list li {
    padding: 8px 0;
    padding-left: 25px;
    position: relative;
    color: var(--dark-light);
    line-height: 1.6;
}

.cost-insights li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

.notes-list li:before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
    font-size: 1.5rem;
    line-height: 1.2;
}

.info-card {
    background: var(--gray-lighter);
}

#usage-summary {
    color: var(--dark-light);
    line-height: 1.8;
}

#usage-summary p {
    margin-bottom: 10px;
}

#usage-summary strong {
    color: var(--dark);
}

@media (max-width: 1200px) {
    .calculator-layout {
        grid-template-columns: 1fr;
    }

    .cost-card {
        position: static;
    }
}

@media (max-width: 768px) {
    header h1 {
        font-size: 1.8rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .cost-amount {
        font-size: 2.5rem;
    }

    .action-buttons {
        flex-direction: column;
    }

    .section,
    .cost-card,
    .info-card {
        padding: 20px;
    }
}

.highlight {
    animation: pulse 0.5s ease;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}