:root {
  --bg: #0f172a;
  --card: #1e293b;
  --text: #f1f5f9;
  --muted: #94a3b8;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --border: #334155;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

header {
  text-align: center;
  padding: 2.5rem 1rem;
  border-bottom: 1px solid var(--border);
}

header h1 {
  font-size: 1.75rem;
  margin-bottom: 0.25rem;
}

.subtitle {
  color: var(--muted);
  font-size: 1rem;
}

.header-nav {
  margin-top: 1rem;
}

.nav-link {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 500;
  transition: background 0.2s;
}

.nav-link:hover {
  background: var(--accent-hover);
}

main {
  max-width: 1000px;
  margin: 0 auto;
  padding: 2rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

/* KPI Cards */
.kpi-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.kpi-card {
  text-align: center;
  padding: 1.5rem;
}

.kpi-card h3 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  margin-bottom: 0.5rem;
  font-weight: 500;
}

.kpi-value {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.2;
}

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

.chart-card {
  min-height: 350px;
}

.chart-card h2 {
  font-size: 1rem;
  margin-bottom: 1rem;
  color: var(--text);
}

.chart-full {
  grid-column: 1 / -1;
}

.chart-card canvas {
  max-height: 300px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
}

.card h2 {
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.stat {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 0.5rem;
  font-size: 0.9rem;
}

th, td {
  text-align: left;
  padding: 0.6rem 0.75rem;
  border-bottom: 1px solid var(--border);
}

th {
  color: var(--muted);
  font-weight: 600;
}

tr:hover td {
  background: rgba(59, 130, 246, 0.08);
}

.table-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-top: 1rem;
}

button {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 0.4rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.875rem;
  transition: background 0.2s;
}

button:hover:not(:disabled) {
  background: var(--accent-hover);
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

#page-info {
  color: var(--muted);
  font-size: 0.875rem;
}

footer {
  text-align: center;
  padding: 2rem;
  color: var(--muted);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
}