/* =========================================================
   Centery / Tullaby Components - Owner Dashboard Design System
   World-class Glassmorphism, Dynamic Fluid Layouts & Responsive
   ========================================================= */

/* --- KPI / Stats Grid --- */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
  width: 100%;
}

.stat-card {
  background: var(--surface-1, #0f1523);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 14px;
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 8px;
  position: relative;
  overflow: hidden;
  box-shadow: 0 4px 16px -2px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.06);
  transition: all 0.22s cubic-bezier(0.16, 1, 0.3, 1);
}

.stat-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2.5px;
  background: transparent;
  transition: background 0.3s ease;
}

.stat-card.primary::before { background: linear-gradient(90deg, #6366f1, #818cf8); }
.stat-card.secondary::before { background: linear-gradient(90deg, #0ea5e9, #38bdf8); }
.stat-card.success::before { background: linear-gradient(90deg, #10b981, #34d399); }
.stat-card.danger::before { background: linear-gradient(90deg, #f43f5e, #fb7185); }

.stat-card:hover {
  transform: translateY(-2px);
  border-color: rgba(255, 255, 255, 0.16);
  box-shadow: 0 8px 22px -4px rgba(0, 0, 0, 0.45), inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

.stat-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.stat-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: #94a3b8;
  line-height: 1.35;
}

.stat-icon {
  width: 32px;
  height: 32px;
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: transform 0.2s ease;
}

.stat-card:hover .stat-icon {
  transform: scale(1.05);
}

.stat-card.primary .stat-icon {
  background: rgba(99, 102, 241, 0.15);
  border: 1px solid rgba(99, 102, 241, 0.3);
  color: #818cf8;
}
.stat-card.secondary .stat-icon {
  background: rgba(14, 165, 233, 0.15);
  border: 1px solid rgba(14, 165, 233, 0.3);
  color: #38bdf8;
}
.stat-card.success .stat-icon {
  background: rgba(16, 185, 129, 0.15);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: #10b981;
}
.stat-card.danger .stat-icon {
  background: rgba(244, 63, 94, 0.15);
  border: 1px solid rgba(244, 63, 94, 0.3);
  color: #f43f5e;
}

.stat-value-group {
  display: flex;
  align-items: baseline;
  gap: 6px;
  flex-wrap: wrap;
}

.stat-value {
  font-family: 'Plus Jakarta Sans', 'Alexandria', system-ui;
  font-variant-numeric: tabular-nums;
  font-size: 1.45rem;
  font-weight: 800;
  color: #ffffff;
  line-height: 1;
  letter-spacing: -0.3px;
}

.stat-unit {
  font-size: 0.74rem;
  font-weight: 600;
  color: #64748b;
}

.stat-subtext {
  font-size: 0.72rem;
  color: #94a3b8;
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

/* Progress bar inside revenue stat card */
.stat-progress {
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 999px;
  overflow: hidden;
  margin-top: 6px;
}

.stat-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #10b981, #34d399);
  border-radius: 999px;
  transition: width 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

/* =========================================================
   Official Platform WhatsApp Gateway & OTP Section
   ========================================================= */
.whatsapp-platform-card {
  background: linear-gradient(135deg, rgba(37, 211, 102, 0.1) 0%, rgba(15, 23, 42, 0.9) 60%), #0f1523;
  border: 1px solid rgba(37, 211, 102, 0.28);
  border-radius: 20px;
  padding: 20px 24px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
  position: relative;
  overflow: hidden;
  width: 100%;
}

.whatsapp-platform-card::after {
  content: '';
  position: absolute;
  top: -40px;
  left: -40px;
  width: 140px;
  height: 140px;
  background: radial-gradient(circle, rgba(37, 211, 102, 0.15) 0%, transparent 70%);
  pointer-events: none;
}

.whatsapp-platform-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  position: relative;
  z-index: 2;
}

.whatsapp-platform-info {
  display: flex;
  align-items: center;
  gap: 16px;
  flex: 1 1 360px;
}

.whatsapp-icon-badge {
  width: 52px;
  height: 52px;
  border-radius: 16px;
  background: rgba(37, 211, 102, 0.14);
  border: 1.5px solid rgba(37, 211, 102, 0.35);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  box-shadow: 0 4px 16px rgba(37, 211, 102, 0.25);
}

.whatsapp-icon-badge img {
  width: 30px;
  height: 30px;
  object-fit: contain;
}

.whatsapp-text-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.whatsapp-title-row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.whatsapp-title-row h2 {
  font-size: 1.12rem;
  font-weight: 800;
  color: #f8fafc;
  margin: 0;
}

.whatsapp-text-group p {
  margin: 0;
  font-size: 0.82rem;
  color: #94a3b8;
  line-height: 1.45;
}

.whatsapp-phone-highlight {
  color: #25d366;
  font-weight: 700;
  margin-right: 6px;
  font-family: monospace;
}

.whatsapp-platform-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.whatsapp-platform-actions .btn {
  padding: 9px 16px;
  font-size: 0.86rem;
  font-weight: 700;
}

/* =========================================================
   Controls & Filter Toolbar
   ========================================================= */
.controls-bar {
  background: var(--surface-1, #0f1523);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 18px;
  padding: 14px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
  box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.25), inset 0 1px 0 rgba(255, 255, 255, 0.05);
  width: 100%;
}

.search-box {
  position: relative;
  flex: 1 1 auto;
  min-width: 240px;
  height: auto;
}

.search-box input {
  width: 100%;
  height: 42px;
  padding: 10px 42px 10px 14px;
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  color: #ffffff;
  font-size: 0.88rem;
  font-family: inherit;
  outline: none;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.search-box input::placeholder {
  color: #64748b;
}

.search-box input:focus {
  border-color: #6366f1;
  background: var(--surface-1, #0f1523);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2), inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

.search-icon {
  position: absolute;
  top: 50%;
  right: 14px;
  transform: translateY(-50%);
  color: #64748b;
  pointer-events: none;
  display: flex;
  align-items: center;
}
.search-icon svg { width: 18px; height: 18px; }

.filters-group {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.filter-select {
  height: 42px;
  padding: 8px 14px;
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  color: #e2e8f0;
  font-size: 0.84rem;
  font-weight: 600;
  outline: none;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: inherit;
}

.filter-select:hover {
  border-color: rgba(255, 255, 255, 0.18);
  background: var(--surface-hover, #1a253c);
}

.filter-select:focus {
  border-color: #6366f1;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.view-toggle {
  display: flex;
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  padding: 3px;
  height: 42px;
  align-items: center;
}

.view-toggle-btn {
  background: transparent;
  border: none;
  color: #94a3b8;
  padding: 6px 12px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  transition: all 0.2s ease;
}

.view-toggle-btn.active {
  background: #6366f1;
  color: white;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.4);
}

/* --- Section Heading --- */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 4px;
  flex-wrap: wrap;
  gap: 8px;
}

.section-title {
  font-size: 1.18rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  gap: 10px;
  letter-spacing: -0.3px;
  color: #ffffff;
}

.section-count {
  font-size: 0.78rem;
  font-weight: 700;
  color: #818cf8;
  background: rgba(99, 102, 241, 0.14);
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid rgba(99, 102, 241, 0.25);
}

/* =========================================================
   Teachers Cards Grid - Flawless Responsive & Aesthetic
   ========================================================= */
.teachers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 20px;
  width: 100%;
}

.teacher-card {
  background: var(--surface-1, #0f1523);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 20px;
  padding: 22px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  position: relative;
  box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.07);
  box-sizing: border-box;
  overflow: hidden;
}

.teacher-card:hover {
  transform: translateY(-3px);
  border-color: rgba(99, 102, 241, 0.4);
  box-shadow: 0 12px 30px -4px rgba(0, 0, 0, 0.6), inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

.teacher-card.suspended {
  opacity: 0.75;
  border-style: dashed;
}

.teacher-card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.teacher-profile {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.teacher-avatar {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  font-weight: 800;
  color: white;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
  flex-shrink: 0;
}

.teacher-info {
  min-width: 0;
}

.teacher-info h3 {
  font-size: 1.05rem;
  font-weight: 800;
  color: #ffffff;
  line-height: 1.3;
  margin: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.teacher-subject {
  font-size: 0.8rem;
  color: #94a3b8;
  font-weight: 500;
  margin-top: 3px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* QR Code & Code Prefix Pill */
.qr-prefix-box {
  background: var(--surface-2, #151d30);
  border: 1px dashed rgba(99, 102, 241, 0.45);
  border-radius: 12px;
  padding: 10px 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  transition: all 0.2s ease;
}

.qr-prefix-box:hover {
  background: rgba(99, 102, 241, 0.12);
  border-style: solid;
  border-color: #6366f1;
}

.qr-prefix-content {
  display: flex;
  align-items: center;
  gap: 10px;
}

.qr-prefix-icon {
  color: #818cf8;
  display: flex;
}
.qr-prefix-icon svg { width: 20px; height: 20px; }

.qr-prefix-info {
  display: flex;
  flex-direction: column;
}

.qr-prefix-title {
  font-size: 0.72rem;
  color: #64748b;
  font-weight: 600;
}

.qr-prefix-code {
  font-family: 'Plus Jakarta Sans', monospace;
  font-size: 0.95rem;
  font-weight: 800;
  color: #818cf8;
  letter-spacing: 0.5px;
}

.qr-sample-tag {
  font-size: 0.72rem;
  background: rgba(99, 102, 241, 0.15);
  color: #818cf8;
  padding: 3px 8px;
  border-radius: 6px;
  font-weight: 700;
}

/* Info Badges Row */
.teacher-stats-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.teacher-stat-pill {
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 12px;
  padding: 8px 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
}

.teacher-stat-pill-label {
  font-size: 0.72rem;
  color: #64748b;
  font-weight: 600;
}

.teacher-stat-pill-value {
  font-size: 0.86rem;
  font-weight: 800;
  color: #ffffff;
  font-family: 'Plus Jakarta Sans', 'Alexandria', system-ui;
  font-variant-numeric: tabular-nums;
}

/* Subscription Row */
.subscription-status-box {
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 12px;
  padding: 10px 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.subscription-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.subscription-fee {
  font-size: 0.86rem;
  font-weight: 800;
  color: #ffffff;
}

.subscription-due {
  font-size: 0.72rem;
  color: #64748b;
}

/* Credentials Box (Username & Password) */
.credentials-box {
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 12px;
  padding: 10px 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.cred-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
}

.cred-label {
  color: #64748b;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 6px;
}

.cred-val-wrap {
  display: flex;
  align-items: center;
  gap: 6px;
  font-family: 'Plus Jakarta Sans', monospace;
  font-weight: 700;
  color: #ffffff;
}

.copy-mini-btn {
  background: transparent;
  border: none;
  color: #94a3b8;
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 4px;
  display: flex;
  align-items: center;
  transition: all 0.15s ease;
}
.copy-mini-btn:hover { color: #818cf8; }

/* =========================================================
   TWO-TIER CARD ACTION SYSTEM (NO OVERLAPS / ZERO CLIPPING)
   ========================================================= */
.teacher-actions-container {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-top: 10px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  width: 100%;
}

.teacher-actions-primary {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  width: 100%;
}

.teacher-actions-primary .btn {
  width: 100%;
  padding: 8px 6px;
  font-size: 0.8rem;
  font-weight: 700;
  justify-content: center;
  min-height: 38px;
  white-space: nowrap;
}

.btn-whatsapp-action {
  background: rgba(37, 211, 102, 0.12);
  color: #25d366;
  border: 1px solid rgba(37, 211, 102, 0.3);
}
.btn-whatsapp-action:hover {
  background: #25d366;
  color: white;
  border-color: #25d366;
}

.teacher-actions-secondary {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  width: 100%;
}

.teacher-actions-secondary .btn {
  width: 100%;
  padding: 6px 4px;
  font-size: 0.76rem;
  font-weight: 600;
  justify-content: center;
  min-height: 34px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
}
.teacher-actions-secondary .btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #ffffff;
}

/* =========================================================
   Table View - Enterprise Clean Data Grid
   ========================================================= */
.table-container {
  background: var(--surface-1, #0f1523);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 20px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  touch-action: pan-x pan-y;
  box-shadow: 0 4px 24px -2px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.06);
  width: 100%;
}

.teachers-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  text-align: right;
  font-size: 0.88rem;
  min-width: 780px;
}

.teachers-table th {
  background: rgba(21, 29, 48, 0.9);
  backdrop-filter: blur(8px);
  color: #94a3b8;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 14px 18px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  white-space: nowrap;
}

.teachers-table td {
  padding: 14px 18px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
  color: #ffffff;
  vertical-align: middle;
  transition: background 0.15s ease;
}

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

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

.table-action-group {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: nowrap;
}

/* =========================================================
   Modals System
   ========================================================= */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(5, 8, 15, 0.82);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.22s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  background: var(--surface-1, #0f1523);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 22px;
  width: 100%;
  max-width: 620px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.8), inset 0 1px 0 rgba(255, 255, 255, 0.1);
  transform: scale(0.96) translateY(12px);
  opacity: 0;
  transition: transform 0.22s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.2s ease;
  display: flex;
  flex-direction: column;
}

.modal-backdrop.open .modal-card {
  transform: scale(1) translateY(0);
  opacity: 1;
}

.modal-header {
  padding: 18px 24px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: 1.15rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  gap: 10px;
  color: #ffffff;
  margin: 0;
}

.modal-close-btn {
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: #94a3b8;
  cursor: pointer;
  width: 34px;
  height: 34px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
  font-size: 1.2rem;
}
.modal-close-btn:hover {
  background: #f43f5e;
  color: white;
  border-color: #f43f5e;
}

.modal-body {
  padding: 22px 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
  background: rgba(15, 21, 35, 0.6);
  flex-wrap: wrap;
}

/* Form Controls */
.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group.full-width {
  grid-column: 1 / -1;
}

.form-label {
  font-size: 0.82rem;
  font-weight: 700;
  color: #94a3b8;
}

.form-label span.req {
  color: #f43f5e;
  margin-right: 4px;
}

.form-input, .form-textarea, .form-select-custom {
  width: 100%;
  padding: 10px 14px;
  background: var(--surface-2, #151d30);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  color: #ffffff;
  font-size: 0.88rem;
  outline: none;
  font-family: inherit;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.form-input:focus, .form-textarea:focus, .form-select-custom:focus {
  border-color: #6366f1;
  background: var(--surface-1, #0f1523);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.input-with-action {
  display: flex;
  gap: 8px;
}

.input-action-btn {
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: 12px;
  color: #818cf8;
  padding: 0 14px;
  font-size: 0.82rem;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease;
}
.input-action-btn:hover {
  background: #6366f1;
  color: white;
}

.form-hint {
  font-size: 0.74rem;
  color: #64748b;
}

/* Credential Pass Card */
.credential-pass {
  background: linear-gradient(135deg, #151c30, #090d16);
  border: 1px solid rgba(99, 102, 241, 0.35);
  border-radius: 18px;
  padding: 22px;
  color: white;
  position: relative;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.pass-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  padding-bottom: 12px;
}

.pass-brand {
  font-size: 1.15rem;
  font-weight: 900;
}

.pass-body {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.pass-field {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.88rem;
}

.pass-label {
  color: #94a3b8;
  font-size: 0.82rem;
}

.pass-value {
  font-weight: 800;
  font-family: 'Plus Jakarta Sans', monospace;
}

/* Empty State */
.empty-state {
  padding: 60px 20px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
  background: var(--surface-1, #0f1523);
  border: 1px dashed rgba(255, 255, 255, 0.12);
  border-radius: 20px;
}

.empty-icon {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--surface-2, #151d30);
  color: #64748b;
  display: flex;
  align-items: center;
  justify-content: center;
}
.empty-icon svg { width: 30px; height: 30px; }

/* =========================================================
   COMPREHENSIVE MULTI-DEVICE RESPONSIVENESS
   ========================================================= */
@media (max-width: 1200px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 992px) {
  .teachers-grid {
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  }
}

@media (max-width: 768px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
  .stat-card {
    padding: 16px;
    border-radius: 16px;
    min-height: auto;
  }
  .stat-icon {
    width: 38px;
    height: 38px;
  }
  .stat-icon svg, .stat-icon img {
    width: 22px !important;
    height: 22px !important;
  }

  .whatsapp-platform-card {
    padding: 18px 16px;
  }
  .whatsapp-platform-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 14px;
  }
  .whatsapp-platform-info {
    flex: 1 1 auto;
  }
  .whatsapp-platform-actions {
    width: 100%;
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
  }
  .whatsapp-platform-actions .btn {
    width: 100%;
    justify-content: center;
  }

  .controls-bar {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    padding: 12px 14px;
  }
  .search-box {
    width: 100% !important;
    min-width: 100% !important;
    flex: none !important;
    height: auto !important;
    position: relative !important;
  }
  .filters-group {
    width: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
  }
  .filter-select {
    width: 100%;
    font-size: 0.8rem;
    padding: 8px 10px;
  }
  .view-toggle {
    grid-column: 1 / -1;
    width: 100%;
    justify-content: center;
  }
  .view-toggle-btn {
    flex: 1;
  }

  .teachers-grid {
    grid-template-columns: 1fr;
    gap: 14px;
  }
  .teacher-card {
    padding: 16px;
    border-radius: 16px;
  }

  .modal-backdrop {
    padding: 12px;
    align-items: flex-end;
  }
  .modal-card {
    max-height: 88vh;
    border-radius: 20px 20px 0 0;
    max-width: 100% !important;
  }
  .modal-header {
    padding: 14px 18px;
  }
  .modal-body {
    padding: 16px 18px;
  }
  .modal-footer {
    padding: 12px 18px;
  }
  .form-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }
}

@media (max-width: 480px) {
  .stats-grid {
    grid-template-columns: 1fr;
    gap: 10px;
  }
  .stat-card {
    padding: 14px 16px;
  }
  .stat-value {
    font-size: 1.7rem;
  }

  .filters-group {
    grid-template-columns: 1fr;
  }

  .teacher-actions-primary {
    grid-template-columns: 1fr;
    gap: 6px;
  }
  .teacher-actions-secondary {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .whatsapp-title-row h2 {
    font-size: 1rem;
  }
}