:root {
    /* Light theme variables */
    --primary-color: #007c89;
    --primary-hover: #005f68;
    --secondary-color: #6c757d;
    --background-color: #ffffff;
    --surface-color: #f8f9fa;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-muted: #868e96;
    --border-color: #dee2e6;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --info-color: #17a2b8;

    /* Card shadows */
    --card-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --card-shadow-hover: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);

    /* Border radius */
    --border-radius: 8px;
    --border-radius-sm: 4px;
    --border-radius-lg: 12px;
}

[data-theme="dark"] {
    --primary-color: #20b2aa;
    --primary-hover: #1a9d96;
    --secondary-color: #adb5bd;
    --background-color: #121212;
    --surface-color: #1e1e1e;
    --text-primary: #ffffff;
    --text-secondary: #adb5bd;
    --text-muted: #6c757d;
    --border-color: #343a40;
    --success-color: #20c997;
    --warning-color: #ffc107;
    --danger-color: #e74c3c;
    --info-color: #17a2b8;

    --card-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.3);
    --card-shadow-hover: 0 0.5rem 1rem rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.5;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header */
header {
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.header-left {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.back-btn {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.back-btn:hover {
    color: var(--primary-color);
}

h1 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Theme Toggle */
.theme-toggle {
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

.theme-toggle:hover {
    background: var(--surface-color);
    transform: scale(1.05);
}

/* Navigation Dropdown */
.app-nav-dropdown {
    position: relative;
    display: inline-block;
}

.nav-dropdown-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-dropdown-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.nav-dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow-hover);
    min-width: 250px;
    z-index: 1000;
    display: none;
    overflow: hidden;
}

.nav-dropdown-menu.show {
    display: block;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    text-decoration: none;
    color: var(--text-primary);
    transition: background-color 0.2s ease;
    border-bottom: 1px solid var(--border-color);
}

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

.nav-item:hover {
    background: var(--primary-color);
    color: white;
}

.nav-item.active {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.nav-icon {
    font-size: 1.1rem;
    width: 20px;
    text-align: center;
}

/* Main Content */
.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
    min-height: calc(100vh - 120px);
}

/* Authentication Section */
.auth-section {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
}

.auth-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    max-width: 400px;
    width: 100%;
    box-shadow: var(--card-shadow);
}

.auth-card h2 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.auth-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

/* Form Elements */
.form-group {
    margin-bottom: 1rem;
}

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

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--background-color);
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-group small {
    display: block;
    margin-top: 0.25rem;
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* Buttons */
.btn-primary, .btn-secondary {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

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

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

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

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

/* Controls Section */
.controls-section {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    gap: 1rem;
    flex-wrap: wrap;
}

.date-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.date-controls label {
    font-weight: 500;
    color: var(--text-primary);
}

.date-controls select {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--background-color);
    color: var(--text-primary);
}

.custom-date-range {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.custom-date-range input {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--background-color);
    color: var(--text-primary);
}

.action-controls {
    display: flex;
    gap: 0.5rem;
}

/* Statistics Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    box-shadow: var(--card-shadow);
    transition: box-shadow 0.3s ease;
}

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

.stat-card {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    font-size: 2rem;
    opacity: 0.8;
}

.stat-content h3 {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.stat-change {
    font-size: 0.875rem;
    font-weight: 500;
}

.stat-change.positive {
    color: var(--success-color);
}

.stat-change.negative {
    color: var(--danger-color);
}

/* Charts Section */
.charts-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.chart-container {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    box-shadow: var(--card-shadow);
}

.chart-container h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 600;
}

.chart-container canvas {
    width: 100% !important;
    height: 300px !important;
}

/* Tables Section */
.tables-section {
    display: grid;
    gap: 2rem;
}

.table-container {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

.table-container h3 {
    padding: 1.5rem 1.5rem 0;
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 600;
}

.table-wrapper {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

table th,
table td {
    padding: 0.75rem 1.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

table th {
    background: var(--background-color);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

table td {
    color: var(--text-secondary);
}

table tbody tr:hover {
    background: var(--background-color);
}

/* Loading Indicator */
.loading-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    gap: 1rem;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-left-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* Footer */
footer {
    background: var(--surface-color);
    border-top: 1px solid var(--border-color);
    padding: 1.5rem 0;
    margin-top: auto;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    text-align: center;
}

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

.footer-content a {
    color: var(--primary-color);
    text-decoration: none;
}

.footer-content a:hover {
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header-content {
        padding: 0 1rem;
    }

    .header-left h1 {
        font-size: 1.25rem;
    }

    .main-content {
        padding: 1rem;
    }

    .controls-section {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }

    .date-controls {
        justify-content: center;
    }

    .action-controls {
        justify-content: center;
    }

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

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

    .auth-card {
        margin: 0 1rem;
    }
}

@media (max-width: 480px) {
    .header-left {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .date-controls {
        flex-direction: column;
        align-items: stretch;
    }

    .custom-date-range {
        flex-direction: column;
    }

    table th,
    table td {
        padding: 0.5rem;
        font-size: 0.875rem;
    }
}