/* ══════════════════════════════════════════════════════════════
   BLR Tutoring — Admin Dashboard Design System
   Dark mode, sleek & professional
   ══════════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ── DESIGN TOKENS ─────────────────────────────────────────── */
:root {
  --bg-primary:    #0f1117;
  --bg-secondary:  #1a1d27;
  --bg-tertiary:   #22263a;
  --accent:        #6366f1;
  --accent-hover:  #4f46e5;
  --success:       #22c55e;
  --warning:       #f59e0b;
  --danger:        #ef4444;
  --text-primary:  #f1f5f9;
  --text-secondary:#94a3b8;
  --border:        #2e3348;
  --sidebar-w:     260px;
  --radius:        12px;
  --shadow:        0 4px 24px rgba(0,0,0,0.35);
}

/* ── RESET & BASE ──────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 14px; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.5;
}

a { color: var(--accent); text-decoration: none; }

/* ── LAYOUT ────────────────────────────────────────────────── */
.admin-layout {
  display: flex;
  min-height: 100vh;
}

.admin-main {
  flex: 1;
  margin-left: var(--sidebar-w);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

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

/* ── SIDEBAR ───────────────────────────────────────────────── */
.sidebar {
  width: var(--sidebar-w);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border);
  position: fixed;
  top: 0; left: 0; bottom: 0;
  display: flex;
  flex-direction: column;
  z-index: 200;
  overflow-y: auto;
}

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

.sidebar-brand img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  object-fit: cover;
}

.sidebar-brand-text {
  display: flex;
  flex-direction: column;
}

.sidebar-brand-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.01em;
}

.sidebar-brand-sub {
  font-size: 0.7rem;
  color: var(--text-secondary);
  font-weight: 400;
}

.sidebar-nav {
  flex: 1;
  padding: 1rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.sidebar-label {
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: 0.75rem 0.5rem 0.35rem;
}

.sidebar-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 0.85rem;
  border-radius: 8px;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: all 0.15s;
  cursor: pointer;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
}

.sidebar-link:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.sidebar-link.active {
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent);
  border-left: 3px solid var(--accent);
}

.sidebar-link i {
  width: 18px;
  text-align: center;
  font-size: 0.9rem;
}

.sidebar-footer {
  padding: 1rem 0.75rem;
  border-top: 1px solid var(--border);
}

/* ── TOPBAR ────────────────────────────────────────────────── */
.topbar {
  height: 60px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

.topbar-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.topbar-admin {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* ── CARDS ─────────────────────────────────────────────────── */
.admin-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.stat-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.stat-icon.indigo  { background: rgba(99,102,241,0.15); color: var(--accent); }
.stat-icon.green   { background: rgba(34,197,94,0.15);  color: var(--success); }
.stat-icon.amber   { background: rgba(245,158,11,0.15); color: var(--warning); }
.stat-icon.red     { background: rgba(239,68,68,0.15);  color: var(--danger); }

.stat-info { flex: 1; min-width: 0; }

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

/* ── TABLE ─────────────────────────────────────────────────── */
.table-wrapper {
  overflow-x: auto;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

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

.admin-table thead {
  position: sticky;
  top: 0;
  background: var(--bg-tertiary);
  z-index: 1;
}

.admin-table th {
  padding: 0.75rem 1rem;
  text-align: left;
  font-weight: 600;
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

.admin-table td {
  padding: 0.8rem 1rem;
  border-bottom: 1px solid var(--border);
  color: var(--text-primary);
  vertical-align: middle;
}

.admin-table tbody tr:last-child td { border-bottom: none; }

.admin-table tbody tr:nth-child(even) td {
  background: rgba(34,38,58,0.4);
}

.admin-table tbody tr:hover td {
  background: rgba(99,102,241,0.05);
}

/* ── BUTTONS ───────────────────────────────────────────────── */
.admin-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  font-family: 'Inter', sans-serif;
  font-size: 0.8rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}

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

.btn-danger {
  background: rgba(239,68,68,0.15);
  color: var(--danger);
  border: 1px solid rgba(239,68,68,0.3);
}
.btn-danger:hover { background: var(--danger); color: #fff; }

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border);
}
.btn-ghost:hover { background: var(--bg-tertiary); color: var(--text-primary); }

.btn-success {
  background: rgba(34,197,94,0.15);
  color: var(--success);
  border: 1px solid rgba(34,197,94,0.3);
}
.btn-success:hover { background: var(--success); color: #fff; }

.btn-sm { padding: 0.35rem 0.75rem; font-size: 0.75rem; }

/* ── BADGES ────────────────────────────────────────────────── */
.admin-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  font-size: 0.7rem;
  font-weight: 600;
}

.badge-green  { background: rgba(34,197,94,0.15);  color: var(--success); }
.badge-amber  { background: rgba(245,158,11,0.15); color: var(--warning); }
.badge-red    { background: rgba(239,68,68,0.15);  color: var(--danger); }
.badge-indigo { background: rgba(99,102,241,0.15); color: var(--accent); }

/* ── INPUTS ────────────────────────────────────────────────── */
.admin-input,
.admin-select,
.admin-textarea {
  width: 100%;
  padding: 0.6rem 0.85rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  font-size: 0.875rem;
  transition: border-color 0.15s;
  outline: none;
}

.admin-input:focus,
.admin-select:focus,
.admin-textarea:focus {
  border-color: var(--accent);
}

.admin-input::placeholder,
.admin-textarea::placeholder { color: var(--text-secondary); }

.admin-select { appearance: none; cursor: pointer; }

.admin-textarea { resize: vertical; min-height: 100px; }

.form-group { margin-bottom: 1rem; }

.form-label {
  display: block;
  margin-bottom: 0.4rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.char-counter {
  font-size: 0.7rem;
  color: var(--text-secondary);
  text-align: right;
  margin-top: 4px;
}

.char-counter.over { color: var(--danger); }

/* ── MODALS ────────────────────────────────────────────────── */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal-overlay.open { display: flex; }

.modal {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 16px;
  width: 100%;
  max-width: 520px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow);
  animation: modalIn 0.2s ease;
}

@keyframes modalIn {
  from { opacity: 0; transform: translateY(-12px) scale(0.98); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

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

.modal-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.modal-close {
  width: 30px;
  height: 30px;
  border-radius: 6px;
  background: var(--bg-tertiary);
  border: none;
  color: var(--text-secondary);
  font-size: 1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}
.modal-close:hover { background: var(--danger); color: #fff; }

.modal-body { padding: 1.5rem; }

.modal-footer {
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
}

/* ── TOAST ─────────────────────────────────────────────────── */
#toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toast {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.85rem 1.25rem;
  border-radius: 10px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  font-size: 0.85rem;
  color: var(--text-primary);
  min-width: 280px;
  max-width: 400px;
  animation: toastIn 0.3s ease;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateX(20px); }
  to   { opacity: 1; transform: translateX(0); }
}

@keyframes toastOut {
  from { opacity: 1; transform: translateX(0); }
  to   { opacity: 0; transform: translateX(20px); }
}

.toast.leaving { animation: toastOut 0.3s ease forwards; }

.toast-icon { font-size: 1rem; flex-shrink: 0; }
.toast.success .toast-icon { color: var(--success); }
.toast.error   .toast-icon { color: var(--danger); }
.toast.warning .toast-icon { color: var(--warning); }

/* ── PAGE HEADER ───────────────────────────────────────────── */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.page-header-left h1 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
}

.page-header-left p {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

/* ── TOOLBAR (search + filters) ────────────────────────────── */
.toolbar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.toolbar .admin-input { max-width: 260px; }
.toolbar .admin-select { max-width: 160px; }

/* ── TABS ──────────────────────────────────────────────────── */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.tab-btn {
  padding: 0.6rem 1.25rem;
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all 0.15s;
  font-family: 'Inter', sans-serif;
}

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.tab-btn:hover:not(.active) { color: var(--text-primary); }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ── EMPTY STATE ───────────────────────────────────────────── */
.empty-state {
  text-align: center;
  padding: 3rem 1.5rem;
  color: var(--text-secondary);
}

.empty-state i {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  opacity: 0.4;
}

.empty-state p { font-size: 0.875rem; }

/* ── CONFIRM DIALOG ────────────────────────────────────────── */
.confirm-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  z-index: 1100;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.confirm-overlay.open { display: flex; }

.confirm-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 2rem;
  max-width: 380px;
  width: 100%;
  text-align: center;
  box-shadow: var(--shadow);
}

.confirm-box h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.confirm-box p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

.confirm-actions {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

/* ── LOADING SPINNER ───────────────────────────────────────── */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  color: var(--text-secondary);
  gap: 0.5rem;
  font-size: 0.875rem;
}

.spinner {
  width: 18px;
  height: 18px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ── CHART WRAPPER ─────────────────────────────────────────── */
.chart-wrapper {
  position: relative;
  height: 240px;
}

/* ── RESPONSIVE ────────────────────────────────────────────── */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.25s;
  }
  .sidebar.open { transform: translateX(0); }
  .admin-main { margin-left: 0; }
  .admin-content { padding: 1rem; }
  .form-row { grid-template-columns: 1fr; }
  .stat-grid { grid-template-columns: 1fr 1fr; }
  .topbar { padding: 0 1rem; }
}

@media (max-width: 480px) {
  .stat-grid { grid-template-columns: 1fr; }
  .table-wrapper { font-size: 0.8rem; }
}