:root {
  --bg: #f6f8fc;
  --surface: #ffffff;
  --surface-soft: #f1f4fb;
  --text: #1f2a44;
  --muted: #64748b;
  --border: #dbe3f1;
  --primary: #2859d6;
  --primary-soft: #e7efff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, sans-serif;
  color: var(--text);
  background: var(--bg);
}

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 260px 1fr;
}

.global-sidebar {
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 18px 14px;
  position: sticky;
  top: 0;
  height: 100vh;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 16px;
  margin: 2px 8px 16px;
}

.brand i[data-lucide] {
  color: var(--primary);
}

.nav-section-title {
  margin: 14px 10px 8px;
  color: var(--muted);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 10px 10px;
  font-size: 14px;
  transition: all .15s ease;
}

.nav-item:hover {
  background: var(--surface-soft);
  border-color: var(--border);
}

.nav-item.active {
  background: var(--primary-soft);
  border-color: #c9d9ff;
  color: #123279;
  font-weight: 600;
}

.main-content {
  padding: 24px;
}

.page-header {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 20px;
  margin-bottom: 16px;
}

.page-header h1 {
  margin: 0;
  font-size: 22px;
}

.page-header p {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 980px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .global-sidebar {
    height: auto;
    position: relative;
    border-right: 0;
    border-bottom: 1px solid var(--border);
  }
}