/* ========================================
   EduVietnam SaaS - Design System
   ======================================== */

:root {
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --primary-light: #eef2ff;
  --secondary: #10b981;
  --accent: #f59e0b;
  --danger: #ef4444;
  --warning: #f97316;
  --info: #3b82f6;

  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;

  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

  --radius-sm: 0.375rem;
  --radius: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
}

/* Role-based theme colors */
.theme-admin { --role-color: #7c3aed; --role-bg: #ede9fe; }
.theme-school { --role-color: #2563eb; --role-bg: #dbeafe; }
.theme-teacher { --role-color: #059669; --role-bg: #d1fae5; }
.theme-student { --role-color: #ea580c; --role-bg: #ffedd5; }

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

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--gray-50);
  color: var(--gray-800);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
button { cursor: pointer; font-family: inherit; border: none; background: none; }
input, select, textarea { font-family: inherit; }

/* ===== Layout: Dashboard Shell ===== */
.app {
  display: grid;
  grid-template-columns: 260px 1fr;
  min-height: 100vh;
}

.sidebar {
  background: white;
  border-right: 1px solid var(--gray-200);
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.sidebar-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--gray-200);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--primary), #8b5cf6);
  border-radius: 10px;
  display: grid;
  place-items: center;
  color: white;
  font-weight: 800;
  font-size: 1.125rem;
}

.logo-text {
  font-weight: 800;
  font-size: 1.05rem;
  color: var(--gray-900);
}

.logo-text small {
  display: block;
  font-weight: 500;
  font-size: 0.7rem;
  color: var(--gray-500);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.role-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.375rem 0.75rem;
  background: var(--role-bg);
  color: var(--role-color);
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  margin: 1rem 1.5rem 0;
}

.nav-section {
  padding: 1rem 0.75rem;
  flex: 1;
}

.nav-label {
  padding: 0 0.75rem;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--gray-400);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
  margin-top: 1rem;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.625rem 0.75rem;
  border-radius: var(--radius);
  color: var(--gray-600);
  font-weight: 500;
  font-size: 0.9rem;
  transition: all 0.15s;
  margin-bottom: 0.125rem;
}

.nav-item:hover {
  background: var(--gray-100);
  color: var(--gray-900);
}

.nav-item.active {
  background: var(--role-bg);
  color: var(--role-color);
  font-weight: 600;
}

.nav-item i { width: 18px; height: 18px; }

.sidebar-footer {
  padding: 1rem;
  border-top: 1px solid var(--gray-200);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.avatar {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: linear-gradient(135deg, #f59e0b, #ef4444);
  display: grid;
  place-items: center;
  color: white;
  font-weight: 700;
  font-size: 0.875rem;
  flex-shrink: 0;
}

.user-info { flex: 1; min-width: 0; }
.user-name { font-weight: 600; font-size: 0.875rem; color: var(--gray-900); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.user-email { font-size: 0.75rem; color: var(--gray-500); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

/* ===== Main Content ===== */
.main { display: flex; flex-direction: column; min-height: 100vh; }

.topbar {
  background: white;
  border-bottom: 1px solid var(--gray-200);
  padding: 0.875rem 2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  position: sticky;
  top: 0;
  z-index: 10;
}

.topbar-title { flex: 1; }
.topbar-title h1 { font-size: 1.25rem; font-weight: 700; color: var(--gray-900); }
.topbar-title p { font-size: 0.8rem; color: var(--gray-500); margin-top: 0.125rem; }

.search-box {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.875rem;
  background: var(--gray-100);
  border-radius: var(--radius);
  width: 280px;
}

.search-box input {
  flex: 1;
  border: none;
  background: transparent;
  outline: none;
  font-size: 0.875rem;
}

.icon-btn {
  width: 38px;
  height: 38px;
  border-radius: var(--radius);
  display: grid;
  place-items: center;
  color: var(--gray-600);
  position: relative;
  transition: all 0.15s;
}

.icon-btn:hover { background: var(--gray-100); color: var(--gray-900); }

.icon-btn .dot {
  position: absolute;
  top: 8px;
  right: 8px;
  width: 8px;
  height: 8px;
  background: var(--danger);
  border-radius: 50%;
  border: 2px solid white;
}

.content { padding: 2rem; flex: 1; }

/* ===== Cards & Containers ===== */
.card {
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--gray-100);
}

.card-title { font-size: 1.05rem; font-weight: 700; color: var(--gray-900); }
.card-subtitle { font-size: 0.8rem; color: var(--gray-500); margin-top: 0.125rem; }

/* ===== Stat Cards ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  position: relative;
  overflow: hidden;
}

.stat-card .icon-wrapper {
  width: 44px;
  height: 44px;
  border-radius: var(--radius);
  display: grid;
  place-items: center;
  margin-bottom: 1rem;
}

.stat-card .label {
  font-size: 0.8rem;
  color: var(--gray-500);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.stat-card .value {
  font-size: 1.875rem;
  font-weight: 800;
  color: var(--gray-900);
  margin-top: 0.25rem;
  line-height: 1.1;
}

.stat-card .change {
  font-size: 0.8rem;
  margin-top: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.change.up { color: var(--secondary); }
.change.down { color: var(--danger); }

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.125rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.875rem;
  transition: all 0.15s;
  border: 1px solid transparent;
  white-space: nowrap;
}

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

.btn-secondary { background: var(--gray-100); color: var(--gray-700); }
.btn-secondary:hover { background: var(--gray-200); }

.btn-outline { background: white; color: var(--gray-700); border-color: var(--gray-300); }
.btn-outline:hover { background: var(--gray-50); border-color: var(--gray-400); }

.btn-success { background: var(--secondary); color: white; }
.btn-danger { background: var(--danger); color: white; }

.btn-sm { padding: 0.375rem 0.75rem; font-size: 0.8rem; }
.btn-lg { padding: 0.875rem 1.5rem; font-size: 1rem; }

/* ===== Tables ===== */
.table-wrapper {
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
  overflow: hidden;
}

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

.table th {
  text-align: left;
  padding: 0.875rem 1.25rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--gray-500);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--gray-50);
  border-bottom: 1px solid var(--gray-200);
}

.table td {
  padding: 1rem 1.25rem;
  font-size: 0.875rem;
  border-bottom: 1px solid var(--gray-100);
  color: var(--gray-700);
}

.table tbody tr:hover { background: var(--gray-50); }
.table tbody tr:last-child td { border-bottom: none; }

/* ===== Badges ===== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.2rem 0.625rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-success { background: #d1fae5; color: #065f46; }
.badge-warning { background: #fef3c7; color: #92400e; }
.badge-danger { background: #fee2e2; color: #991b1b; }
.badge-info { background: #dbeafe; color: #1e40af; }
.badge-gray { background: var(--gray-100); color: var(--gray-700); }
.badge-purple { background: #ede9fe; color: #6d28d9; }

/* ===== Form Controls ===== */
.form-group { margin-bottom: 1rem; }
.form-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 0.375rem;
}

.form-control {
  width: 100%;
  padding: 0.625rem 0.875rem;
  border: 1px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 0.9rem;
  transition: all 0.15s;
  background: white;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* ===== Progress Bar ===== */
.progress {
  width: 100%;
  height: 8px;
  background: var(--gray-100);
  border-radius: 999px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: var(--primary);
  border-radius: 999px;
  transition: width 0.3s;
}

.progress-bar.success { background: var(--secondary); }
.progress-bar.warning { background: var(--accent); }
.progress-bar.danger { background: var(--danger); }

/* ===== Avatar List ===== */
.avatar-list { display: flex; align-items: center; }
.avatar-list .avatar { margin-left: -10px; border: 2px solid white; width: 32px; height: 32px; font-size: 0.7rem; }
.avatar-list .avatar:first-child { margin-left: 0; }

/* ===== Utility ===== */
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: 0.25rem; }
.gap-2 { gap: 0.5rem; }
.gap-3 { gap: 0.75rem; }
.gap-4 { gap: 1rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.text-sm { font-size: 0.875rem; }
.text-xs { font-size: 0.75rem; }
.text-gray-500 { color: var(--gray-500); }
.text-gray-700 { color: var(--gray-700); }
.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.25rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.25rem; }

@media (max-width: 1024px) {
  .grid-3, .grid-4 { grid-template-columns: 1fr 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
}

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

.page-header h2 { font-size: 1.5rem; font-weight: 800; color: var(--gray-900); }
.page-header p { color: var(--gray-500); margin-top: 0.25rem; font-size: 0.9rem; }

/* ===== Tabs ===== */
.tabs {
  display: flex;
  gap: 0.5rem;
  border-bottom: 1px solid var(--gray-200);
  margin-bottom: 1.5rem;
}

.tab {
  padding: 0.75rem 1rem;
  font-weight: 500;
  color: var(--gray-500);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  font-size: 0.9rem;
}

.tab.active { color: var(--role-color); border-color: var(--role-color); font-weight: 600; }
.tab:hover { color: var(--gray-900); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .content { padding: 1rem; }
  .topbar { padding: 0.75rem 1rem; }
  .search-box { display: none; }
}