:root {
    /* Color Palette */
    --primary: hsl(220, 90%, 56%);
    --primary-dark: hsl(220, 90%, 46%);
    --primary-light: hsl(220, 90%, 96%);

    --success: hsl(142, 71%, 45%);
    --success-light: hsl(142, 71%, 95%);

    --warning: hsl(38, 92%, 50%);
    --warning-light: hsl(38, 92%, 95%);

    --danger: hsl(0, 84%, 60%);
    --danger-light: hsl(0, 84%, 95%);

    --neutral-50: hsl(220, 20%, 98%);
    --neutral-100: hsl(220, 18%, 95%);
    --neutral-200: hsl(220, 16%, 90%);
    --neutral-300: hsl(220, 14%, 80%);
    --neutral-400: hsl(220, 12%, 65%);
    --neutral-500: hsl(220, 10%, 50%);
    --neutral-600: hsl(220, 12%, 40%);
    --neutral-700: hsl(220, 14%, 30%);
    --neutral-800: hsl(220, 16%, 20%);
    --neutral-900: hsl(220, 18%, 12%);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

body {
    font-family: var(--font-family);
    background: linear-gradient(135deg, var(--neutral-50) 0%, var(--primary-light) 100%);
    color: var(--neutral-800);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    padding: var(--spacing-lg) 0;
    box-shadow: var(--shadow-lg);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-xl);
    flex-wrap: wrap;
}

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

.logo-icon {
    width: 40px;
    height: 40px;
    color: white;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

.logo h1 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.header-stats {
    display: flex;
    gap: var(--spacing-xl);
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
}

.stat-label {
    font-size: 0.75rem;
    opacity: 0.9;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 500;
}

.stat-value {
    font-size: 1.25rem;
    font-weight: 700;
}

/* Hero */
.hero {
    padding: var(--spacing-3xl) 0 var(--spacing-2xl);
    text-align: center;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--neutral-900);
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.03em;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--neutral-600);
    font-weight: 400;
}

/* Filters */
.filters {
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    margin-bottom: var(--spacing-2xl);
}

.filters .container {
    display: flex;
    gap: var(--spacing-lg);
    align-items: flex-end;
    flex-wrap: wrap;
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    flex: 1;
    min-width: 150px;
}

.filter-group label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--neutral-700);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.filter-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--neutral-200);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: var(--font-family);
    background: white;
    color: var(--neutral-800);
    cursor: pointer;
    transition: all 0.2s ease;
}

.filter-select:hover {
    border-color: var(--primary);
}

.filter-select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-light);
}

.btn-refresh {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-md);
}

.btn-refresh:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-refresh:active {
    transform: translateY(0);
}

.btn-refresh svg {
    width: 20px;
    height: 20px;
}

/* Loading State */
.loading-state {
    text-align: center;
    padding: var(--spacing-3xl);
}

.spinner {
    width: 60px;
    height: 60px;
    border: 4px solid var(--neutral-200);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--spacing-lg);
}

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

.loading-state p {
    font-size: 1.125rem;
    color: var(--neutral-600);
}

/* Error State */
.error-state {
    text-align: center;
    padding: var(--spacing-3xl);
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
}

.error-state svg {
    width: 80px;
    height: 80px;
    color: var(--danger);
    margin-bottom: var(--spacing-lg);
}

.error-state h3 {
    font-size: 1.5rem;
    color: var(--neutral-900);
    margin-bottom: var(--spacing-sm);
}

.error-state p {
    color: var(--neutral-600);
    margin-bottom: var(--spacing-lg);
}

.btn-retry {
    padding: var(--spacing-sm) var(--spacing-xl);
    background: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-retry:hover {
    background: var(--primary-dark);
}

/* Rankings */
.rankings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    gap: var(--spacing-lg);
}

.rankings-header h2 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--neutral-900);
}

.legend {
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--neutral-600);
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: var(--radius-sm);
}

.legend-color.excellent {
    background: var(--success);
}

.legend-color.good {
    background: hsl(142, 71%, 65%);
}

.legend-color.average {
    background: var(--warning);
}

.legend-color.poor {
    background: var(--danger);
}

/* Table */
.table-container {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    margin-bottom: var(--spacing-2xl);
}

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

.rankings-table thead {
    background: linear-gradient(135deg, var(--neutral-900) 0%, var(--neutral-800) 100%);
    color: white;
}

.rankings-table th {
    padding: var(--spacing-md) var(--spacing-lg);
    text-align: left;
    font-weight: 600;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.rankings-table th.rank-col {
    width: 80px;
    text-align: center;
}

.rankings-table th.score-col,
.rankings-table th.ontime-col,
.rankings-table th.delay-col {
    text-align: center;
}

.rankings-table th.flights-col {
    text-align: center;
    width: 100px;
}

.rankings-table th.trend-col {
    text-align: center;
    width: 100px;
}

/* Sortable Headers */
.rankings-table th[data-sort] {
    cursor: pointer;
    user-select: none;
    transition: background-color 0.2s;
}

.rankings-table th[data-sort]:hover {
    background: var(--neutral-700);
}

.sort-icon {
    display: inline-block;
    margin-left: 4px;
    font-size: 0.8em;
    opacity: 0.3;
}

.rankings-table tbody tr {
    border-bottom: 1px solid var(--neutral-100);
    transition: all 0.2s ease;
}

.rankings-table tbody tr:hover {
    background: var(--neutral-50);
    transform: scale(1.01);
    box-shadow: var(--shadow-md);
}

.rankings-table tbody tr:last-child {
    border-bottom: none;
}

.rankings-table td {
    padding: var(--spacing-md) var(--spacing-lg);
}

.rank-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    font-weight: 700;
    font-size: 1.125rem;
}

.rank-badge.top-1 {
    background: linear-gradient(135deg, hsl(45, 100%, 51%) 0%, hsl(45, 100%, 41%) 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(255, 193, 7, 0.4);
}

.rank-badge.top-2 {
    background: linear-gradient(135deg, hsl(0, 0%, 75%) 0%, hsl(0, 0%, 65%) 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(158, 158, 158, 0.4);
}

.rank-badge.top-3 {
    background: linear-gradient(135deg, hsl(30, 80%, 55%) 0%, hsl(30, 80%, 45%) 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(205, 127, 50, 0.4);
}

.rank-badge.other {
    background: var(--neutral-100);
    color: var(--neutral-700);
}

.airline-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.airline-code {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    border-radius: var(--radius-md);
    font-weight: 700;
    font-size: 0.875rem;
    box-shadow: var(--shadow-md);
}

.airline-name {
    font-weight: 600;
    color: var(--neutral-900);
    font-size: 1rem;
}

.score-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-weight: 700;
    font-size: 1.125rem;
    min-width: 80px;
}

.score-badge.excellent {
    background: var(--success-light);
    color: var(--success);
}

.score-badge.good {
    background: hsl(142, 71%, 95%);
    color: hsl(142, 71%, 35%);
}

.score-badge.average {
    background: var(--warning-light);
    color: hsl(38, 92%, 35%);
}

.score-badge.poor {
    background: var(--danger-light);
    color: var(--danger);
}

.percentage {
    font-weight: 600;
    font-size: 1rem;
}

.delay-value {
    font-weight: 600;
    font-size: 1rem;
}

.delay-value.positive {
    color: var(--success);
}

.delay-value.negative {
    color: var(--danger);
}

.flights-count {
    font-weight: 600;
    color: var(--neutral-700);
}

.trend {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 12px;
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 600;
}

.trend.up {
    background: var(--success-light);
    color: var(--success);
}

.trend.down {
    background: var(--danger-light);
    color: var(--danger);
}

.trend.stable {
    background: var(--neutral-100);
    color: var(--neutral-600);
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.stat-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
    transition: all 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.stat-card-icon {
    width: 64px;
    height: 64px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.stat-card-icon svg {
    width: 32px;
    height: 32px;
    color: white;
}

.stat-card-icon.best {
    background: linear-gradient(135deg, hsl(45, 100%, 51%) 0%, hsl(45, 100%, 41%) 100%);
}

.stat-card-icon.ontime {
    background: linear-gradient(135deg, var(--success) 0%, hsl(142, 71%, 35%) 100%);
}

.stat-card-icon.delay {
    background: linear-gradient(135deg, var(--warning) 0%, hsl(38, 92%, 40%) 100%);
}

.stat-card-icon.airlines {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
}

.stat-card-content h3 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--neutral-600);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

.stat-card-value {
    font-size: 2rem;
    font-weight: 800;
    color: var(--neutral-900);
    line-height: 1;
    margin-bottom: var(--spacing-xs);
}

.stat-card-detail {
    font-size: 0.875rem;
    color: var(--neutral-500);
}

/* Footer */
.footer {
    background: var(--neutral-900);
    color: white;
    padding: var(--spacing-xl) 0;
    margin-top: var(--spacing-3xl);
    text-align: center;
}

.footer p {
    margin-bottom: var(--spacing-xs);
    opacity: 0.9;
}

.footer-note {
    font-size: 0.875rem;
    opacity: 0.7;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 1.75rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .header-stats {
        width: 100%;
        justify-content: space-between;
    }

    .filters .container {
        flex-direction: column;
        align-items: stretch;
    }

    .filter-group {
        min-width: 100%;
    }

    .rankings-table {
        font-size: 0.875rem;
    }

    .rankings-table th,
    .rankings-table td {
        padding: var(--spacing-sm);
    }

    .airline-code {
        width: 40px;
        height: 40px;
        font-size: 0.75rem;
    }

    .legend {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.rankings-table tbody tr {
    animation: fadeIn 0.3s ease forwards;
}

.rankings-table tbody tr:nth-child(1) {
    animation-delay: 0.05s;
}

.rankings-table tbody tr:nth-child(2) {
    animation-delay: 0.1s;
}

.rankings-table tbody tr:nth-child(3) {
    animation-delay: 0.15s;
}

.rankings-table tbody tr:nth-child(4) {
    animation-delay: 0.2s;
}

.rankings-table tbody tr:nth-child(5) {
    animation-delay: 0.25s;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    background-color: #fefefe;
    margin: 5% auto;
    padding: 0;
    border: 1px solid #888;
    width: 90%;
    max-width: 1000px;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-2xl);
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        transform: translateY(-50px);
        opacity: 0;
    }

    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-header {
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    border-top-left-radius: var(--radius-xl);
    border-top-right-radius: var(--radius-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    margin: 0;
    font-size: 1.5rem;
}

.close {
    color: white;
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    transition: 0.2s;
}

.close:hover,
.close:focus {
    color: #ddd;
    text-decoration: none;
    cursor: pointer;
}

.modal-body {
    padding: var(--spacing-lg);
    max-height: 70vh;
    overflow-y: auto;
}

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

.flights-table th {
    text-align: left;
    padding: var(--spacing-sm);
    background: var(--neutral-100);
    position: sticky;
    top: 0;
    font-size: 0.85rem;
    color: var(--neutral-600);
}

.flights-table td {
    padding: var(--spacing-sm);
    border-bottom: 1px solid var(--neutral-100);
    font-size: 0.9rem;
}

.status-badge {
    padding: 2px 8px;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
}

.status-badge.ontime {
    background: var(--success-light);
    color: var(--success);
}

.status-badge.delayed {
    background: var(--warning-light);
    color: hsl(38, 92%, 35%);
}

.status-badge.cancelled {
    background: var(--danger-light);
    color: var(--danger);
}

.clickable-row {
    cursor: pointer;
}

/* Explanation Section */
.explanation-section {
    margin-top: 40px;
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.explanation-section h3 {
    color: #1e293b;
    margin-bottom: 15px;
    font-weight: 600;
}

.explanation-section p {
    color: #64748b;
    margin-bottom: 15px;
    line-height: 1.6;
}

.formula-box {
    background: #f8fafc;
    padding: 15px;
    border-radius: 8px;
    border-left: 4px solid #0ea5e9;
}

.formula-box strong {
    color: #0f172a;
    display: block;
    margin-bottom: 5px;
}

.formula {
    font-family: monospace;
    color: #0ea5e9;
    font-size: 1.1em;
}

.explanation-list {
    margin-top: 15px;
    padding-left: 20px;
    color: #64748b;
    line-height: 1.6;
}

.explanation-list li {
    margin-bottom: 5px;
}

/* Flight Link */
.flight-link {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

.flight-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}
#destinationFilterGroup {
    flex-grow: 2;
    min-width: 300px;
    display: none;
}

.destination-selects {
    display: flex;
    gap: 5px;
}

.destination-selects .filter-select {
    flex: 1;
    min-width: 0;
}