:root {
    --brand-green: #10b981;
    --brand-green-dark: #059669;
    --brand-yellow: #fbbf24;
    --brand-red: #ef4444;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    --radius: 12px;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

header h1 {
    color: var(--brand-green-dark);
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.calculator-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
}

@media (min-width: 900px) {
    .calculator-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
    box-shadow: var(--shadow-lg);
}

h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-main);
    border-bottom: 2px solid var(--brand-green);
    display: inline-block;
    padding-bottom: 0.5rem;
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: 0.95rem;
}

small {
    display: block;
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 0.25rem;
}

input[type="number"],
input[type="date"],
select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input:focus,
select:focus {
    outline: none;
    border-color: var(--brand-green);
    box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.2);
}

.advanced-section {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px dashed var(--border-color);
}

.advanced-section h3 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text-muted);
}

.result-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.result-item {
    display: flex;
    flex-direction: column;
}

.result-item span {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0.25rem;
}

.result-item strong {
    font-size: 1.25rem;
}

.divider {
    height: 1px;
    background-color: var(--border-color);
    margin: 1.5rem 0;
}

.highlight {
    color: var(--brand-green-dark);
}

.tax-color {
    color: var(--brand-red);
}

.highlight-box {
    grid-column: span 2;
    background: linear-gradient(135deg, var(--brand-green-dark) 0%, var(--brand-green) 100%);
    padding: 1rem;
    border-radius: 8px;
    color: white;
}

.highlight-box span {
    color: rgba(255, 255, 255, 0.9);
}

.highlight-box strong {
    font-size: 1.5rem;
}

.text-green { color: var(--brand-green-dark) !important; }
.text-red { color: var(--brand-red) !important; }

.chart-card {
    margin-top: 2rem;
}

.chart-container {
    position: relative;
    height: 300px;
    width: 100%;
}

footer {
    margin-top: 3rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--radius);
    border: 1px solid var(--brand-yellow);
}

.tax-rules-banner {
    background-color: #ecfdf5;
    border-left: 4px solid var(--brand-green);
    padding: 1.25rem 1.5rem;
    border-radius: var(--radius);
    margin-bottom: 2rem;
    color: var(--brand-green-dark);
    box-shadow: var(--shadow-sm);
}

.tax-rules-banner ul {
    margin-top: 0.75rem;
    margin-left: 1.5rem;
}

.tax-rules-banner li {
    margin-bottom: 0.25rem;
}