:root {
  --bg-color: #f8fafc;
  --surface-color: #ffffff;
  --primary-color: #0ea5e9;
  --primary-hover: #0284c7;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --danger-color: #ef4444;
  --radius: 12px;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* Layout */
.app-container {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 260px;
  background-color: #1e293b;
  color: white;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  transition: transform 0.3s ease;
}

.main-content {
  flex: 1;
  padding: 2rem;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

/* Typography */
h1 { font-size: 1.875rem; font-weight: 700; margin-bottom: 0.5rem; }
h2 { font-size: 1.5rem; font-weight: 600; margin-bottom: 1rem; }
h3 { font-size: 1.25rem; font-weight: 600; margin-bottom: 0.75rem; }
p { color: var(--text-muted); }

/* Components */
.card {
  background: var(--surface-color);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid var(--border-color);
  margin-bottom: 1.5rem;
}

.kpi-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.kpi-card {
  background: var(--surface-color);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
}

.kpi-title {
  color: var(--text-muted);
  font-size: 0.875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.kpi-value {
  font-size: 1.875rem;
  font-weight: 700;
  color: var(--text-main);
}

.kpi-trend {
  margin-top: 0.5rem;
  font-size: 0.875rem;
  font-weight: 500;
}

.trend-up { color: var(--success-color); }
.trend-down { color: var(--danger-color); }

/* Forms */
.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.5rem;
  color: var(--text-main);
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-family: inherit;
  font-size: 1rem;
  transition: all 0.2s;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.1);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
  font-family: inherit;
}

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

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

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

.btn-outline:hover {
  background-color: #f1f5f9;
}

/* Sidebar Menu */
.nav-menu {
  list-style: none;
  margin-top: 2rem;
}

.nav-item {
  margin-bottom: 0.5rem;
}

.nav-link {
  display: block;
  padding: 0.75rem 1rem;
  color: #94a3b8;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 500;
  transition: all 0.2s;
  cursor: pointer;
}

.nav-link:hover, .nav-link.active {
  background-color: #334155;
  color: white;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: white;
  letter-spacing: -0.025em;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* File Upload */
.file-upload-area {
  border: 2px dashed var(--border-color);
  border-radius: var(--radius);
  padding: 2rem;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
  background-color: #fafafa;
}

.file-upload-area:hover {
  border-color: var(--primary-color);
  background-color: #f0f9ff;
}

.file-upload-area input[type="file"] {
  display: none;
}

/* Tables */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}

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

.data-table th {
  font-weight: 600;
  color: var(--text-muted);
  background-color: #f8fafc;
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.data-table tr:hover {
  background-color: #f1f5f9;
}

/* Badges */
.badge {
  display: inline-flex;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
}

.badge-primary { background-color: #e0f2fe; color: #0284c7; }
.badge-secondary { background-color: #f1f5f9; color: #475569; }
.badge-success { background-color: #dcfce3; color: #166534; }
.badge-danger { background-color: #fee2e2; color: #991b1b; }

/* Alert */
.alert {
  padding: 1rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  font-weight: 500;
}

.alert-success {
  background-color: #d1fae5;
  color: #065f46;
  border: 1px solid #a7f3d0;
}

.alert-error {
  background-color: #fee2e2;
  color: #991b1b;
  border: 1px solid #fecaca;
}

/* Mobile Responsive */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
}

@media (max-width: 768px) {
  .app-container {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    padding: 1rem;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
  
  .nav-menu {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    width: 100%;
    background: #1e293b;
    margin: 0;
    padding: 1rem;
    z-index: 50;
  }
  
  .nav-menu.show {
    display: block;
  }
  
  .mobile-menu-btn {
    display: block;
    color: white;
  }
  
  .main-content {
    padding: 1rem;
  }
}