/* ========================================================
   GST Billing ERP - Modern SaaS Design System
   ======================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --color-primary-50: #eef2ff;
  --color-primary-100: #e0e7ff;
  --color-primary-500: #6366f1;
  --color-primary-600: #4f46e5;
  --color-primary-700: #4338ca;
  --color-slate-50: #f8fafc;
  --color-slate-100: #f1f5f9;
  --color-slate-200: #e2e8f0;
  --color-slate-300: #cbd5e1;
  --color-slate-400: #94a3b8;
  --color-slate-500: #64748b;
  --color-slate-600: #475569;
  --color-slate-700: #334155;
  --color-slate-800: #1e293b;
  --color-slate-900: #0f172a;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.07), 0 2px 4px -2px rgb(0 0 0 / 0.07);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.08), 0 4px 6px -4px rgb(0 0 0 / 0.08);
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
}

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

body {
  font-family: var(--font-sans);
  background-color: #f8fafc;
  color: var(--color-slate-800);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

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

.sidebar {
  width: 260px;
  background-color: var(--color-slate-900);
  color: #fff;
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 40;
  transition: transform 0.25s ease;
}

.sidebar-header {
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.brand-badge {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #6366f1 0%, #3b82f6 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 1.15rem;
  box-shadow: 0 4px 10px rgba(99, 102, 241, 0.35);
}

.sidebar-nav {
  padding: 1.25rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  overflow-y: auto;
  flex: 1;
}

.nav-section-title {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-slate-400);
  font-weight: 600;
  padding: 0.75rem 0.75rem 0.35rem;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius-md);
  color: var(--color-slate-300);
  font-size: 0.875rem;
  font-weight: 500;
  transition: all 0.15s ease;
}

.nav-link:hover {
  background-color: rgba(255, 255, 255, 0.06);
  color: #fff;
}

.nav-link.active {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.25) 0%, rgba(59, 130, 246, 0.15) 100%);
  color: #fff;
  border: 1px solid rgba(99, 102, 241, 0.4);
  font-weight: 600;
}

.nav-link svg {
  width: 19px;
  height: 19px;
  opacity: 0.85;
}

.main-content {
  flex: 1;
  margin-left: 260px;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

/* Header */
.topbar {
  height: 64px;
  background-color: #fff;
  border-bottom: 1px solid var(--color-slate-200);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.75rem;
  position: sticky;
  top: 0;
  z-index: 30;
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Content Area */
.content-body {
  padding: 1.75rem;
  flex: 1;
}

/* Page Header */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.75rem;
}

.page-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-slate-900);
  letter-spacing: -0.02em;
}

.page-subtitle {
  font-size: 0.875rem;
  color: var(--color-slate-500);
  margin-top: 0.15rem;
}

/* Cards */
.card {
  background: #fff;
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-slate-200);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  margin-bottom: 1.5rem;
  transition: box-shadow 0.2s ease, border-color 0.2s ease;
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--color-slate-200);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.card-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-slate-900);
}

.card-body {
  padding: 1.5rem;
}

.card-footer {
  padding: 1rem 1.5rem;
  background-color: var(--color-slate-50);
  border-top: 1px solid var(--color-slate-200);
}

/* KPI Metrics */
.kpi-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}

.kpi-card {
  background: #fff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-slate-200);
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  gap: 1rem;
  position: relative;
  overflow: hidden;
}

.kpi-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.kpi-value {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--color-slate-900);
  line-height: 1.2;
}

.kpi-label {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-slate-500);
  margin-top: 0.15rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.6rem 1.15rem;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.15s ease;
  line-height: 1.25;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--color-primary-600);
  color: #fff;
  box-shadow: 0 2px 4px rgba(79, 70, 229, 0.2);
}

.btn-primary:hover {
  background-color: var(--color-primary-700);
  box-shadow: 0 4px 8px rgba(79, 70, 229, 0.3);
}

.btn-secondary {
  background-color: #fff;
  border-color: var(--color-slate-300);
  color: var(--color-slate-700);
}

.btn-secondary:hover {
  background-color: var(--color-slate-50);
  border-color: var(--color-slate-400);
}

.btn-success {
  background-color: #10b981;
  color: #fff;
}
.btn-success:hover {
  background-color: #059669;
}

.btn-danger {
  background-color: #ef4444;
  color: #fff;
}
.btn-danger:hover {
  background-color: #dc2626;
}

.btn-sm {
  padding: 0.4rem 0.75rem;
  font-size: 0.8125rem;
}

.btn-lg {
  padding: 0.8rem 1.5rem;
  font-size: 1rem;
  border-radius: var(--radius-lg);
}

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

.form-label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-slate-700);
  margin-bottom: 0.375rem;
}

.form-label .required {
  color: #ef4444;
}

.form-control, .form-select {
  width: 100%;
  padding: 0.625rem 0.875rem;
  font-size: 0.875rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-slate-300);
  background-color: #fff;
  color: var(--color-slate-800);
  transition: border-color 0.15s, box-shadow 0.15s;
  outline: none;
}

.form-control:focus, .form-select:focus {
  border-color: var(--color-primary-500);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.form-hint {
  font-size: 0.75rem;
  color: var(--color-slate-500);
  margin-top: 0.35rem;
}

/* Tables */
.table-responsive {
  width: 100%;
  overflow-x: auto;
}

.table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.875rem;
}

.table th {
  background-color: var(--color-slate-50);
  color: var(--color-slate-600);
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-slate-200);
}

.table td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--color-slate-200);
  color: var(--color-slate-800);
  vertical-align: middle;
}

.table tbody tr:hover {
  background-color: rgba(248, 250, 252, 0.8);
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.6rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  line-height: 1;
}

.badge-success {
  background-color: #ecfdf5;
  color: #065f46;
  border: 1px solid #a7f3d0;
}

.badge-warning {
  background-color: #fffbeb;
  color: #92400e;
  border: 1px solid #fde68a;
}

.badge-info {
  background-color: #eff6ff;
  color: #1e40af;
  border: 1px solid #bfdbfe;
}

.badge-danger {
  background-color: #fef2f2;
  color: #991b1b;
  border: 1px solid #fecaca;
}

/* Alerts */
.alert {
  padding: 0.9rem 1.25rem;
  border-radius: var(--radius-md);
  margin-bottom: 1.25rem;
  font-size: 0.875rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.alert-success {
  background-color: #ecfdf5;
  border: 1px solid #a7f3d0;
  color: #065f46;
}

.alert-danger {
  background-color: #fef2f2;
  border: 1px solid #fecaca;
  color: #991b1b;
}

/* Skeleton Loading Shimmer */
.skeleton {
  background: linear-gradient(90deg, #f1f5f9 25%, #e2e8f0 50%, #f1f5f9 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-sm);
  display: inline-block;
}

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

/* Business Card Grid */
.business-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.business-card {
  background: #fff;
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-slate-200);
  box-shadow: var(--shadow-sm);
  padding: 1.5rem;
  transition: all 0.2s ease;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.business-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary-500);
}

/* Dropzone */
.dropzone {
  border: 2px dashed var(--color-slate-300);
  border-radius: var(--radius-xl);
  padding: 2.5rem 1.5rem;
  text-align: center;
  background-color: var(--color-slate-50);
  cursor: pointer;
  transition: all 0.15s ease;
}

.dropzone:hover, .dropzone.dragover {
  border-color: var(--color-primary-500);
  background-color: #eef2ff;
}

/* Responsive */
@media (max-width: 991px) {
  .sidebar {
    transform: translateX(-100%);
  }
  .sidebar.open {
    transform: translateX(0);
  }
  .main-content {
    margin-left: 0;
  }
}