:root {
    /* Light Mode Colors */
    --primary-blue: #1e3a8a;
    --primary-teal: #06b6d4;
    --secondary-purple: #8b5cf6;
    --secondary-pink: #ec4899;
    --accent-orange: #f59e0b;
    --success-green: #10b981;
    
    /* Light Mode Backgrounds & Text */
    --bg-primary: #fdfdfd;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #ffffff;
    --text-primary: #1f2937;
    --text-secondary: #64748b;
    --text-muted: #9ca3af;
    
    /* Light Mode Glass Effects */
    --glass-bg: rgba(255, 255, 255, 0.8);
    --glass-border: rgba(255, 255, 255, 0.3);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
    
    /* Common Colors */
    --border-color: rgba(100, 116, 139, 0.2);
    --hover-bg: rgba(6, 182, 212, 0.05);
    
    /* Fonts */
    --font-headings: 'Poppins', sans-serif;
    --font-body: 'Inter', sans-serif;
    
    /* Spacing */
    --container-max-width: 1200px;
    --border-radius: 1rem;
    --border-radius-lg: 1.5rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-glass: var(--glass-shadow);
}

/* Dark Mode Colors */
[data-theme="dark"] {
    /* Dark Mode Backgrounds & Text */
    --bg-primary: #111827;
    --bg-secondary: #1f2937;
    --bg-tertiary: #374151;
    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --text-muted: #9ca3af;
    
    /* Dark Mode Glass Effects */
    --glass-bg: rgba(55, 65, 81, 0.8);
    --glass-border: rgba(75, 85, 99, 0.3);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.5);
    
    /* Dark Mode Specific */
    --border-color: rgba(75, 85, 99, 0.3);
    --hover-bg: rgba(6, 182, 212, 0.1);
}

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

body {
    font-family: var(--font-body);
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    min-height: 100vh;
    transition: all 0.3s ease;
}

.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
    border-bottom: 1px solid var(--glass-border);
    margin-bottom: 2rem;
}

/* Dark mode specific header styling */
[data-theme="dark"] .header {
    background: rgba(17, 24, 39, 0.95);
    border-bottom: 1px solid rgba(75, 85, 99, 0.3);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo {
    font-family: var(--font-headings);
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-blue), var(--primary-teal));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
}

.breadcrumb {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.breadcrumb a {
    color: var(--primary-teal);
    text-decoration: none;
}

.back-btn {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
}

.back-btn:hover {
    background: var(--bg-tertiary);
    transform: translateY(-1px);
}

/* Main Content */
.main-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 3rem;
}

.calculator-section {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-glass);
    height: fit-content;
}

.results-section {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-glass);
}

.section-title {
    font-family: var(--font-headings);
    font-size: 1.75rem;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.section-icon {
    font-size: 2rem;
}

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

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

.input-wrapper {
    position: relative;
}

.form-group input {
    width: 100%;
    padding: 0.875rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-family: var(--font-body);
    font-size: 1rem;
    transition: all 0.3s ease;
    background: var(--glass-bg);
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-teal);
    box-shadow: 0 0 0 4px rgba(6, 182, 212, 0.1);
}

.input-suffix {
    position: absolute;
    right: 0.875rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    font-weight: 500;
}

.range-slider {
    margin-top: 0.75rem;
}

.range-slider input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--bg-secondary);
    outline: none;
    -webkit-appearance: none;
}

.range-slider input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-blue), var(--primary-teal));
    cursor: pointer;
    box-shadow: var(--shadow-md);
}

.range-slider input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-blue), var(--primary-teal));
    cursor: pointer;
    border: none;
    box-shadow: var(--shadow-md);
}

.range-labels {
    display: flex;
    justify-content: space-between;
    margin-top: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.calculate-btn {
    width: 100%;
    padding: 1rem 2rem;
    background: linear-gradient(135deg, var(--primary-blue), var(--primary-teal));
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 1rem;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    background: linear-gradient(135deg, var(--primary-teal), var(--secondary-purple));
}

.result-card {
    background: linear-gradient(135deg, var(--primary-blue), var(--primary-teal));
    color: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    text-align: center;
    margin-bottom: 2rem;
}

.result-value {
    font-family: var(--font-headings);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.result-label {
    font-size: 1.1rem;
    opacity: 0.9;
}

.breakdown-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 2rem;
}

.breakdown-item {
    background: var(--bg-tertiary);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    text-align: center;
    border: 1px solid var(--glass-border);
}

.breakdown-value {
    font-family: var(--font-headings);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.breakdown-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

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

.info-section {
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-top: 2rem;
    border-left: 4px solid var(--accent-orange);
}

.info-section h3 {
    font-family: var(--font-headings);
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.info-section p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.year-by-year {
    margin-top: 2rem;
}

.year-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-tertiary);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.year-table th,
.year-table td {
    padding: 0.75rem;
    text-align: right;
    border-bottom: 1px solid var(--border-color);
}

.year-table th {
    background: linear-gradient(135deg, var(--primary-blue), var(--primary-teal));
    color: white;
    font-weight: 600;
}

.year-table th:first-child,
.year-table td:first-child {
    text-align: center;
}

.year-table tr:hover {
    background: var(--hover-bg);
}

@media (max-width: 768px) {
    .main-content {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .calculator-section,
    .results-section {
        padding: 1.5rem;
    }

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

    .nav {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }

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

.hidden {
    display: none;
}

.fade-in {
    animation: fadeIn 0.5s ease-in;
}

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

/* Dark Mode Toggle */
.dark-mode-toggle {
    position: fixed;
    top: 50%;
    right: 2rem;
    transform: translateY(-50%);
    z-index: 1000;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: 50px;
    padding: 0.5rem;
    box-shadow: var(--shadow-glass);
    transition: all 0.3s ease;
}

.dark-mode-toggle:hover {
    transform: translateY(-50%) scale(1.05);
    box-shadow: var(--shadow-lg);
}

.toggle-btn {
    background: none;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    transition: all 0.3s ease;
    background: linear-gradient(135deg, var(--primary-blue), var(--primary-teal));
    color: white;
    box-shadow: var(--shadow-md);
}

.toggle-btn:hover {
    transform: rotate(180deg);
    box-shadow: var(--shadow-lg);
}

@media (max-width: 768px) {
    .dark-mode-toggle {
        position: fixed;
        top: auto;
        bottom: 2rem;
        right: 1rem;
        transform: none;
    }
    
    .dark-mode-toggle:hover {
        transform: scale(1.05);
    }
}