:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --border-color: #30363d;
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --accent-purple: #8957e5;
    --accent-purple-dark: #6e40c9;
    --accent-blue: #58a6ff;
    --success: #3fb950;
    --warning: #d29922;
    --error: #f85149;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
.navbar {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.nav-brand h1 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-menu a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.2s;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--accent-purple);
}

/* Main Content */
.main-content {
    padding: 40px 20px;
    min-height: calc(100vh - 150px);
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 20px;
}

.header h2 {
    color: var(--text-primary);
    font-size: 2rem;
}

.controls {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

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

.controls input[type="number"] {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 8px 12px;
    border-radius: 6px;
    width: 80px;
    font-size: 0.9rem;
}

.controls input[type="number"]:focus {
    outline: none;
    border-color: var(--accent-purple);
}

/* Buttons */
.btn {
    background-color: var(--accent-purple);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.2s;
}

.btn:hover {
    background-color: var(--accent-purple-dark);
}

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

.btn-secondary:hover {
    background-color: var(--border-color);
}

/* Hero (main page) */
.hero {
    text-align: center;
    padding: 40px 20px 50px;
}

.hero h2 {
    font-size: 2.2rem;
    margin-bottom: 15px;
}

.hero p {
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto 25px;
    font-size: 1.05rem;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

.hero-actions .btn {
    padding: 11px 22px;
    text-decoration: none;
}

/* Sections */
section {
    margin-bottom: 40px;
}

.section-title {
    font-size: 1.4rem;
    margin-bottom: 18px;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 18px;
    flex-wrap: wrap;
    gap: 12px;
}

.section-header h2 {
    font-size: 1.4rem;
}

.link-more {
    color: var(--accent-purple);
    text-decoration: none;
    font-size: 0.9rem;
}

.link-more:hover {
    text-decoration: underline;
}

.page-lead {
    color: var(--text-secondary);
    margin-bottom: 25px;
}

.content-link {
    color: var(--accent-purple);
    text-decoration: none;
}

.content-link:hover {
    text-decoration: underline;
}

/* City cards */
.city-card {
    display: block;
    text-decoration: none;
    color: inherit;
    transition: border-color 0.2s, transform 0.2s;
}

.city-card:hover {
    border-color: var(--accent-purple);
    transform: translateY(-2px);
}

.city-card .city-country {
    color: var(--text-secondary);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 5px;
}

.city-card span {
    color: var(--accent-purple);
    font-weight: 600;
}

/* Cards */
.card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 24px;
    margin-bottom: 20px;
}

.card h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
    font-size: 1.2rem;
}

.card p {
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.card ul {
    list-style: none;
    padding-left: 0;
}

.card ul li {
    color: var(--text-secondary);
    margin-bottom: 8px;
    padding-left: 20px;
    position: relative;
}

.card ul li:before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--accent-purple);
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}

/* Metrics */
.metric-value {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--accent-purple);
    margin: 10px 0;
}

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

.metric-detail p {
    display: flex;
    justify-content: space-between;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
}

.metric-detail p:last-child {
    border-bottom: none;
}

.metric-detail span {
    color: var(--accent-purple);
    font-weight: 600;
}

.direction-text {
    color: var(--accent-blue);
    font-weight: 600;
    margin-top: 5px;
}

/* Table */
.table-container {
    overflow-x: auto;
}

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

thead {
    background-color: var(--bg-tertiary);
}

th {
    padding: 12px;
    text-align: left;
    color: var(--text-primary);
    font-weight: 600;
    border-bottom: 2px solid var(--border-color);
}

td {
    padding: 12px;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

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

/* Loading & Error States */
.loading {
    text-align: center;
    padding: 40px;
    color: var(--accent-purple);
    font-size: 1.1rem;
}

.error {
    background-color: rgba(248, 81, 73, 0.1);
    border: 1px solid var(--error);
    color: var(--error);
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 20px;
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 20px 0;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 768px) {
    .navbar .container {
        flex-direction: column;
        gap: 15px;
    }

    .nav-menu {
        gap: 15px;
        flex-wrap: wrap;
        justify-content: center;
    }

    .header {
        flex-direction: column;
        align-items: flex-start;
    }

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

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

    th, td {
        padding: 8px;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .main-content {
        padding: 25px 10px;
    }

    .hero {
        padding: 20px 5px 30px;
    }

    .hero h2 {
        font-size: 1.5rem;
    }

    .hero-actions .btn {
        flex: 1 1 auto;
    }

    .card {
        padding: 16px;
    }

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

    .controls {
        width: 100%;
    }

    .controls input[type="number"] {
        flex: 1 1 80px;
    }

    .controls .btn {
        flex: 1 1 auto;
    }

    .metric-value {
        font-size: 1.7rem;
        overflow-wrap: anywhere;
    }
}