/* ============================================
   FinTrack — Design System & Styles
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
    /* Colors */
    --bg-primary: #0a0e1a;
    --bg-secondary: #111827;
    --bg-card: rgba(17, 24, 39, 0.8);
    --bg-card-hover: rgba(30, 41, 59, 0.9);
    --bg-glass: rgba(255, 255, 255, 0.03);
    --bg-input: rgba(255, 255, 255, 0.05);

    --border-color: rgba(255, 255, 255, 0.06);
    --border-active: rgba(99, 102, 241, 0.4);

    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    --accent-primary: #6366f1;
    --accent-primary-light: #818cf8;
    --accent-secondary: #06b6d4;
    --accent-green: #10b981;
    --accent-green-light: #34d399;
    --accent-red: #ef4444;
    --accent-red-light: #f87171;
    --accent-yellow: #f59e0b;
    --accent-yellow-light: #fbbf24;
    --accent-purple: #a855f7;

    --gradient-primary: linear-gradient(135deg, #6366f1, #8b5cf6);
    --gradient-green: linear-gradient(135deg, #10b981, #06b6d4);
    --gradient-red: linear-gradient(135deg, #ef4444, #f97316);
    --gradient-yellow: linear-gradient(135deg, #f59e0b, #eab308);
    --gradient-blue: linear-gradient(135deg, #3b82f6, #6366f1);

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-md: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;

    /* Layout */
    --sidebar-width: 260px;
    --sidebar-collapsed: 72px;
    --border-radius-sm: 8px;
    --border-radius-md: 12px;
    --border-radius-lg: 16px;
    --border-radius-xl: 20px;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.15);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 400ms ease;
}

/* --- Reset --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; color: inherit; }
input, select, textarea { font-family: inherit; }
ul { list-style: none; }

/* --- Sidebar --- */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 100;
    transition: transform var(--transition-normal);
}

.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-lg) var(--space-lg);
    border-bottom: 1px solid var(--border-color);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.logo-icon { font-size: 1.5rem; }

.logo-text {
    font-size: var(--font-size-xl);
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    padding: var(--space-xs);
}

.sidebar-toggle span {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--text-secondary);
    border-radius: 2px;
    transition: var(--transition-fast);
}

.nav-links {
    flex: 1;
    padding: var(--space-md) var(--space-sm);
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-glass);
}

.nav-link.active {
    color: var(--accent-primary-light);
    background: rgba(99, 102, 241, 0.1);
}

.nav-link.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 60%;
    background: var(--gradient-primary);
    border-radius: 0 3px 3px 0;
}

.nav-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.sidebar-footer {
    padding: var(--space-md) var(--space-lg);
    border-top: 1px solid var(--border-color);
}

.btn-reset {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--border-radius-sm);
    width: 100%;
    transition: all var(--transition-fast);
}

.btn-reset:hover {
    color: var(--accent-red);
    background: rgba(239, 68, 68, 0.1);
}

/* --- Mobile Header --- */
.mobile-header {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    align-items: center;
    padding: 0 var(--space-lg);
    gap: var(--space-md);
    z-index: 90;
}

.hamburger {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: var(--space-xs);
}

.hamburger span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition-fast);
}

.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    z-index: 95;
}

.sidebar-overlay.active {
    display: block;
}

/* --- Main Content --- */
.main-content {
    margin-left: var(--sidebar-width);
    flex: 1;
    padding: var(--space-2xl);
    min-height: 100vh;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

/* --- Page Header --- */
.page-header {
    margin-bottom: var(--space-2xl);
}

.page-header h1 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--space-xs);
    letter-spacing: -0.02em;
}

.page-header p {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

/* --- Cards --- */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: var(--space-xl);
    backdrop-filter: blur(12px);
    transition: all var(--transition-normal);
}

.card:hover {
    border-color: var(--border-active);
    box-shadow: var(--shadow-glow);
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-lg);
}

.card-title {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.card-value {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-bottom: var(--space-xs);
}

.card-subtitle {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

/* Stat Cards Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--space-lg);
    margin-bottom: var(--space-2xl);
}

.stat-card {
    position: relative;
    overflow: hidden;
}

.stat-card .card-icon {
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.stat-card::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    opacity: 0.05;
    transform: translate(30%, -30%);
}

.stat-card.income { --accent: var(--accent-green); }
.stat-card.income .card-icon { background: rgba(16, 185, 129, 0.15); }
.stat-card.income .card-value { color: var(--accent-green-light); }
.stat-card.income::after { background: var(--accent-green); }

.stat-card.expense { --accent: var(--accent-red); }
.stat-card.expense .card-icon { background: rgba(239, 68, 68, 0.15); }
.stat-card.expense .card-value { color: var(--accent-red-light); }
.stat-card.expense::after { background: var(--accent-red); }

.stat-card.balance { --accent: var(--accent-primary); }
.stat-card.balance .card-icon { background: rgba(99, 102, 241, 0.15); }
.stat-card.balance .card-value { color: var(--accent-primary-light); }
.stat-card.balance::after { background: var(--accent-primary); }

.stat-card.debt-stat { --accent: var(--accent-yellow); }
.stat-card.debt-stat .card-icon { background: rgba(245, 158, 11, 0.15); }
.stat-card.debt-stat .card-value { color: var(--accent-yellow-light); }
.stat-card.debt-stat::after { background: var(--accent-yellow); }

/* --- Warning / Alert Banners --- */
.alert-banner {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    border-radius: var(--border-radius-md);
    margin-bottom: var(--space-lg);
    font-size: var(--font-size-sm);
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateX(-10px); }
    to { opacity: 1; transform: translateX(0); }
}

.alert-banner.warning {
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.2);
    color: var(--accent-yellow-light);
}

.alert-banner.danger {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.2);
    color: var(--accent-red-light);
}

.alert-banner.info {
    background: rgba(6, 182, 212, 0.1);
    border: 1px solid rgba(6, 182, 212, 0.2);
    color: var(--accent-secondary);
}

.alert-icon { font-size: 1.2rem; flex-shrink: 0; }

/* --- Charts Section --- */
.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--space-lg);
    margin-bottom: var(--space-2xl);
}

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

.chart-container canvas {
    width: 100% !important;
    height: auto !important;
}

/* --- Tables --- */
.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th {
    text-align: left;
    padding: var(--space-md) var(--space-lg);
    font-size: var(--font-size-xs);
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid var(--border-color);
}

.data-table td {
    padding: var(--space-md) var(--space-lg);
    font-size: var(--font-size-sm);
    border-bottom: 1px solid var(--border-color);
    vertical-align: middle;
}

.data-table tr:last-child td {
    border-bottom: none;
}

.data-table tbody tr {
    transition: background var(--transition-fast);
}

.data-table tbody tr:hover {
    background: var(--bg-glass);
}

/* --- Forms --- */
.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--space-sm);
}

.form-input,
.form-select {
    width: 100%;
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    transition: all var(--transition-fast);
    outline: none;
}

.form-input:focus,
.form-select:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.form-input::placeholder { color: var(--text-muted); }

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}

.form-select option {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--space-md);
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    border-radius: var(--border-radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 600;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.btn-secondary:hover {
    background: var(--bg-glass);
    color: var(--text-primary);
}

.btn-danger {
    background: rgba(239, 68, 68, 0.15);
    color: var(--accent-red-light);
}

.btn-danger:hover {
    background: rgba(239, 68, 68, 0.25);
}

.btn-sm {
    padding: var(--space-sm) var(--space-md);
    font-size: var(--font-size-xs);
}

.btn-icon {
    padding: var(--space-sm);
    border-radius: var(--border-radius-sm);
}

.btn-icon:hover {
    background: var(--bg-glass);
}

/* --- Badges --- */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 2px 10px;
    border-radius: 100px;
    font-size: var(--font-size-xs);
    font-weight: 600;
}

.badge.primary { background: rgba(99, 102, 241, 0.15); color: var(--accent-primary-light); }
.badge.secondary { background: rgba(6, 182, 212, 0.15); color: var(--accent-secondary); }
.badge.debt-badge { background: rgba(245, 158, 11, 0.15); color: var(--accent-yellow-light); }
.badge.full { background: rgba(168, 85, 247, 0.15); color: var(--accent-purple); }
.badge.simple { background: rgba(16, 185, 129, 0.15); color: var(--accent-green-light); }

/* --- Progress Bar --- */
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--bg-input);
    border-radius: 100px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    border-radius: 100px;
    transition: width 0.8s ease;
    background: var(--gradient-primary);
}

.progress-fill.green { background: var(--gradient-green); }
.progress-fill.red { background: var(--gradient-red); }
.progress-fill.yellow { background: var(--gradient-yellow); }

/* --- Modal --- */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(6px);
    z-index: 200;
    justify-content: center;
    align-items: center;
    padding: var(--space-lg);
}

.modal-overlay.active {
    display: flex;
    animation: fadeIn 0.2s ease;
}

.modal {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    animation: modalSlide 0.3s ease;
}

@keyframes modalSlide {
    from { opacity: 0; transform: translateY(20px) scale(0.95); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-xl);
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: var(--font-size-lg);
    font-weight: 600;
}

.modal-close {
    font-size: 1.5rem;
    color: var(--text-muted);
    padding: var(--space-xs);
    line-height: 1;
}

.modal-close:hover { color: var(--text-primary); }

.modal-body {
    padding: var(--space-xl);
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: var(--space-md);
    padding: var(--space-lg) var(--space-xl);
    border-top: 1px solid var(--border-color);
}

/* --- Recommendation Card --- */
.recommendation-card {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.08), rgba(139, 92, 246, 0.08));
    border: 1px solid rgba(99, 102, 241, 0.15);
}

.recommendation-item {
    display: flex;
    align-items: flex-start;
    gap: var(--space-md);
    padding: var(--space-md) 0;
    font-size: var(--font-size-sm);
}

.recommendation-item + .recommendation-item {
    border-top: 1px solid var(--border-color);
}

.recommendation-icon {
    font-size: 1.1rem;
    flex-shrink: 0;
    margin-top: 2px;
}

/* --- Slider --- */
.slider-group {
    margin-bottom: var(--space-lg);
}

.slider-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--space-sm);
}

.slider-label {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.slider-value {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--accent-primary-light);
}

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

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent-primary);
    cursor: pointer;
    box-shadow: 0 0 8px rgba(99, 102, 241, 0.4);
    transition: transform var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* --- Empty State --- */
.empty-state {
    text-align: center;
    padding: var(--space-2xl) var(--space-xl);
    color: var(--text-muted);
}

.empty-state-icon {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    opacity: 0.5;
}

.empty-state h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--space-sm);
    color: var(--text-secondary);
}

.empty-state p {
    font-size: var(--font-size-sm);
    margin-bottom: var(--space-lg);
}

/* --- Toast Notification --- */
.toast-container {
    position: fixed;
    bottom: var(--space-xl);
    right: var(--space-xl);
    z-index: 300;
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.toast {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    font-size: var(--font-size-sm);
    box-shadow: var(--shadow-lg);
    animation: toastIn 0.3s ease;
    min-width: 280px;
}

.toast.success { border-left: 3px solid var(--accent-green); }
.toast.error { border-left: 3px solid var(--accent-red); }
.toast.info { border-left: 3px solid var(--accent-primary); }

@keyframes toastIn {
    from { opacity: 0; transform: translateX(20px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes toastOut {
    from { opacity: 1; transform: translateX(0); }
    to { opacity: 0; transform: translateX(20px); }
}

/* --- Two Column Layout --- */
.two-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
}

/* --- Debt Progress Item --- */
.debt-item {
    padding: var(--space-lg) 0;
}

.debt-item + .debt-item {
    border-top: 1px solid var(--border-color);
}

.debt-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-sm);
}

.debt-item-name {
    font-weight: 600;
    font-size: var(--font-size-md);
}

.debt-item-details {
    display: flex;
    gap: var(--space-lg);
    margin-bottom: var(--space-md);
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

.debt-item-actions {
    display: flex;
    gap: var(--space-sm);
    margin-top: var(--space-sm);
}

/* --- Responsive --- */
@media (max-width: 1024px) {
    .two-col {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .mobile-header {
        display: flex;
    }

    .sidebar-overlay.active {
        display: block;
    }

    .main-content {
        margin-left: 0;
        padding: var(--space-lg);
        padding-top: calc(60px + var(--space-lg));
    }

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

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

    .page-header h1 {
        font-size: var(--font-size-2xl);
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .modal {
        margin: var(--space-md);
    }

    .toast-container {
        left: var(--space-md);
        right: var(--space-md);
        bottom: var(--space-md);
    }

    .toast {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .main-content {
        padding: var(--space-md);
        padding-top: calc(60px + var(--space-md));
    }
}

/* --- Utility Classes --- */
.text-green { color: var(--accent-green-light); }
.text-red { color: var(--accent-red-light); }
.text-yellow { color: var(--accent-yellow-light); }
.text-blue { color: var(--accent-primary-light); }
.text-muted { color: var(--text-muted); }
.text-center { text-align: center; }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.hidden { display: none !important; }