* { margin: 0; padding: 0; box-sizing: border-box; }
html { overflow-x: hidden; }

:root {
    --primary: #2563eb;
    --secondary: #3b82f6;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --bg: #f8fafc;
    --surface: #ffffff;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --transition: all 0.3s ease;
}

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
}

.header {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 1.5rem 0;
    box-shadow: var(--shadow);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    text-decoration: none;
    color: white;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    opacity: 0.9;
}

.nav-links a:hover { opacity: 1; text-decoration: underline; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
    width: 100%;
    box-sizing: border-box;
}

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

.hero h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text);
}

.hero p {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto;
}

.calculator-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    margin-bottom: 2rem;
    justify-content: center;
}

.calculator-grid.two-columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    justify-content: stretch;
}

.card {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 2rem;
    transition: var(--transition);
    flex: 1;
    min-width: 300px;
    max-width: 600px;
}

.card:hover { box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1); }

.card h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.results-card { display: none; }
.results-card.show {
    display: block !important;
    animation: slideInUp 0.5s ease-out;
}

@keyframes slideInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

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

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text);
}

.input-wrapper { position: relative; }

.form-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--surface);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-input.with-prefix { padding-left: 3rem; }

.currency-prefix {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-weight: 500;
    pointer-events: none;
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.checkbox {
    width: 1.2rem;
    height: 1.2rem;
    accent-color: var(--primary);
}

.btn {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border: none;
    padding: 0.875rem 2rem;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.bracket-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    table-layout: fixed;
}

.bracket-table th,
.bracket-table td {
    padding: 0.875rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.bracket-table th {
    background: var(--primary);
    color: white;
    font-weight: 600;
}

.bracket-table tr:nth-child(even) { background: #f8fafc; }

.results { margin-top: 2rem; }

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    margin-bottom: 0.5rem;
    background: var(--bg);
    border-radius: var(--radius);
    border-left: 4px solid var(--primary);
}

.result-item.highlight {
    background: linear-gradient(135deg, var(--success), #059669);
    color: white;
    border-left-color: white;
    font-weight: 600;
    font-size: 1.1rem;
}

.result-label { font-weight: 500; }
.result-value { font-weight: 600; }

.chart-container {
    margin-top: 2rem;
    height: 300px;
    position: relative;
}

.loading {
    display: none;
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
}

.loading.show { display: block; }

.spinner {
    border: 3px solid var(--border);
    border-top: 3px solid var(--primary);
    border-radius: 50%;
    width: 2rem;
    height: 2rem;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.info-tooltip {
    position: relative;
    display: inline-block;
    color: var(--text-muted);
    cursor: help;
}

.info-tooltip:hover::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text);
    color: white;
    padding: 0.5rem;
    border-radius: 4px;
    font-size: 0.875rem;
    white-space: nowrap;
    z-index: 1000;
    margin-bottom: 0.5rem;
}

/* Large desktop screens */
@media (min-width: 1201px) {
    .card { min-width: 500px; }
}

/* Medium screens - tablets and small desktops */
@media (max-width: 1200px) {
    .calculator-grid.two-columns {
        display: flex !important;
        flex-direction: column;
        gap: 1.5rem;
        align-items: center;
        justify-content: center;
    }
    
    .card {
        min-width: auto;
        max-width: 800px;
        flex: none;
        width: 100%;
    }
}

/* Tablet range - 769px to 1200px */
@media (min-width: 769px) and (max-width: 1200px) {
    .calculator-grid {
        gap: 1.5rem;
        justify-content: center;
    }
    
    .calculator-grid.two-columns {
        gap: 1.5rem;
        align-items: center;
        justify-content: center;
    }
    
    .card {
        min-width: 400px;
        max-width: 700px;
        margin: 0 auto;
    }
}

/* Mobile and small tablet - 768px and below */
@media (max-width: 768px) {
    .hero h1 { font-size: 2rem; }
    .nav-links { display: none; }
    .container { padding: 1rem 0.5rem; }
    .card { padding: 1rem; margin: 0; min-width: auto; max-width: none; width: 100%; }
    .hero {margin-bottom: 1rem; }
    .calculator-grid { gap: 1rem; }
    .calculator-grid.two-columns { gap: 1rem; }
    .form-group label { font-size: 0.9rem; line-height: 1.4; }
    .form-input { padding: 0.6rem 0.8rem; font-size: 0.9rem; }
    .form-input.with-prefix { padding-left: 2.5rem; }
    .currency-prefix { left: 0.8rem; font-size: 0.9rem; }
    .checkbox-group { flex-wrap: wrap; gap: 0.3rem; }
    .checkbox-group label { font-size: 0.85rem; line-height: 1.3; }
    .btn { padding: 0.75rem 1.5rem; font-size: 0.9rem; }
    .bracket-table { font-size: 0.85rem; }
    .bracket-table th, .bracket-table td { padding: 0.5rem 0.75rem; word-break: break-word; }
}

/* Small mobile - 480px and below */
@media (max-width: 480px) {
    .hero h1 { font-size: 1.6rem; line-height: 1.2; }
    .hero p { font-size: 0.9rem; line-height: 1.4; }
    .container { padding: 0.75rem 0.25rem; }
    .card { padding: 0.75rem; margin: 0; }
    .card h2 { font-size: 1.2rem; margin-bottom: 1rem; }
    .calculator-grid { gap: 0.75rem; }
    .calculator-grid.two-columns { gap: 0.75rem; }
    .form-group { margin-bottom: 1rem; }
    .form-group label { font-size: 0.85rem; margin-bottom: 0.3rem; }
    .form-input { padding: 0.5rem 0.6rem; font-size: 0.85rem; }
    .form-input.with-prefix { padding-left: 2.2rem; }
    .currency-prefix { left: 0.6rem; font-size: 0.85rem; }
    .checkbox-group { align-items: flex-start; gap: 0.25rem; }
    .checkbox { width: 1rem; height: 1rem; margin-top: 0.1rem; flex-shrink: 0; }
    .checkbox-group label { font-size: 0.8rem; line-height: 1.2; }
    .btn { padding: 0.65rem 1rem; font-size: 0.85rem; }
    .info-tooltip { font-size: 0.8rem; }
    .bracket-table { font-size: 0.8rem; }
    .bracket-table th, .bracket-table td { padding: 0.4rem 0.5rem; }
    .bracket-table th:first-child, .bracket-table td:first-child { width: 70%; }
    .bracket-table th:last-child, .bracket-table td:last-child { width: 30%; text-align: center; }
}

/* Ultra-small screens */
@media (max-width: 320px) {
    .container { padding: 0.75rem 0.125rem; }
    .card { padding: 0.5rem; margin: 0 0.125rem; }
    .hero h1 { font-size: 1.4rem; }
    .hero p { font-size: 0.85rem; }
    .bracket-table { font-size: 0.75rem; }
    .bracket-table th, .bracket-table td { padding: 0.3rem 0.4rem; }
    .form-input { font-size: 0.8rem; padding: 0.45rem 0.5rem; }
    .form-input.with-prefix { padding-left: 2rem; }
    .currency-prefix { left: 0.5rem; font-size: 0.8rem; }
}

/* Touch targets for mobile */
@media (max-width: 768px) {
    .btn, .form-input { min-height: 44px; }

}