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

:root {
  --sidebar-w: 240px;
  --sidebar-bg: #1e293b;
  --sidebar-hover: #334155;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --danger: #ef4444;
  --success: #10b981;
  --warning: #f59e0b;
  --bg: #f1f5f9;
  --card-bg: #ffffff;
  --border: #e2e8f0;
  --text: #1e293b;
  --muted: #64748b;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
}

/* ── LAYOUT ── */
#app {
  display: flex;
  min-height: 100vh;
}

/* ── SIDEBAR ── */
.sidebar {
  width: var(--sidebar-w);
  background: var(--sidebar-bg);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0; left: 0; bottom: 0;
  z-index: 100;
}

.sidebar-header {
  padding: 24px 20px 20px;
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid #334155;
}
.sidebar-logo { font-size: 1.5rem; }
.sidebar-title { color: #f8fafc; font-size: 1.1rem; font-weight: 700; }

.sidebar-nav {
  flex: 1;
  padding: 12px 0;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 20px;
  color: #94a3b8;
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.15s, color 0.15s;
  border-left: 3px solid transparent;
}
.nav-link:hover { background: var(--sidebar-hover); color: #f1f5f9; }
.nav-link.active { background: var(--sidebar-hover); color: #fff; border-left-color: var(--primary); }
.nav-icon { font-size: 1rem; width: 20px; text-align: center; }

.sidebar-footer {
  padding: 12px 0;
  border-top: 1px solid #334155;
}

.btn-logout {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 20px;
  width: 100%;
  background: none;
  border: none;
  color: #94a3b8;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: color 0.15s, background 0.15s;
}
.btn-logout:hover { background: var(--sidebar-hover); color: #f87171; }

/* ── MAIN CONTENT ── */
.main-content {
  margin-left: var(--sidebar-w);
  flex: 1;
  padding: 32px;
  min-height: 100vh;
}

/* ── PAGE HEADER ── */
.page-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 24px;
  gap: 16px;
}
.page-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
}
.page-subtitle {
  color: var(--muted);
  font-size: 0.85rem;
  margin-top: 2px;
}
.header-actions { display: flex; gap: 10px; align-items: center; }

/* ── SEARCH BAR ── */
.search-bar { margin-bottom: 20px; }
.search-bar input {
  width: 100%;
  max-width: 360px;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.9rem;
  outline: none;
  background: var(--card-bg);
  color: var(--text);
  transition: border-color 0.2s;
}
.search-bar input:focus { border-color: var(--primary); }

/* ── BUTTONS ── */
.btn {
  padding: 9px 18px;
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: background 0.15s, opacity 0.15s;
  white-space: nowrap;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline {
  background: var(--card-bg);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-outline:hover { background: var(--bg); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #dc2626; }
.btn-sm { padding: 5px 12px; font-size: 0.8rem; }

/* ── TEACHERS GRID ── */
.teachers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
}

.teacher-card {
  background: var(--card-bg);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  border: 1px solid var(--border);
  transition: box-shadow 0.2s, transform 0.2s;
}
.teacher-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.12);
  transform: translateY(-2px);
}

.teacher-card-bg {
  height: 90px;
  background-size: cover;
  background-position: center;
  background-color: #e2e8f0;
  position: relative;
}
.teacher-card-color-bar {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 4px;
}

.teacher-card-body {
  padding: 14px;
}
.teacher-name {
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.color-dot {
  width: 12px; height: 12px;
  border-radius: 50%;
  flex-shrink: 0;
}
.teacher-classes {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 12px;
  min-height: 24px;
}
.class-tag {
  background: #eff6ff;
  color: #2563eb;
  border-radius: 4px;
  padding: 2px 7px;
  font-size: 0.75rem;
  font-weight: 600;
}
.class-tag-empty {
  color: var(--muted);
  font-size: 0.8rem;
  font-style: italic;
}
.teacher-card-actions {
  display: flex;
  gap: 6px;
}

/* ── TABLES ── */
.table-wrapper {
  background: var(--card-bg);
  border-radius: 12px;
  border: 1px solid var(--border);
  overflow: hidden;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
}
.data-table th {
  padding: 12px 16px;
  text-align: left;
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  background: #f8fafc;
  border-bottom: 1px solid var(--border);
}
.data-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 0.875rem;
}
.data-table tr:last-child td { border-bottom: none; }
.data-table tr:hover td { background: #f8fafc; }
.td-actions { text-align: right; white-space: nowrap; }
.td-actions .btn + .btn { margin-left: 6px; }

/* ── MODAL ── */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15,23,42,0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 500;
  padding: 20px;
}
.modal {
  background: var(--card-bg);
  border-radius: 14px;
  width: 100%;
  max-width: 600px;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  box-shadow: 0 25px 60px rgba(0,0,0,0.25);
}
.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px 16px;
  border-bottom: 1px solid var(--border);
}
.modal-header h3 { font-size: 1.05rem; font-weight: 700; }
.modal-close {
  background: none;
  border: none;
  font-size: 1.1rem;
  cursor: pointer;
  color: var(--muted);
  padding: 4px;
  line-height: 1;
  transition: color 0.15s;
}
.modal-close:hover { color: var(--text); }
.modal-body {
  padding: 20px 24px;
  overflow-y: auto;
  flex: 1;
}
.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

/* ── FORM ── */
.form-group { margin-bottom: 16px; }
.form-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.form-group input[type="text"],
.form-group input[type="password"],
.form-group select {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.875rem;
  color: var(--text);
  outline: none;
  background: #fff;
  transition: border-color 0.2s;
}
.form-group input:focus,
.form-group select:focus { border-color: var(--primary); }

.form-row { display: flex; gap: 12px; }
.form-row .form-group { flex: 1; }

/* Color picker */
.color-picker-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.color-picker-row input[type="color"] {
  width: 44px;
  height: 38px;
  padding: 2px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  background: #fff;
}
.color-presets {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.color-preset {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform 0.1s, border-color 0.1s;
}
.color-preset:hover,
.color-preset.selected { transform: scale(1.2); border-color: #fff; box-shadow: 0 0 0 2px var(--text); }

/* Background selector */
.bg-selector {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 6px;
  max-height: 180px;
  overflow-y: auto;
  padding: 4px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #f8fafc;
}
.bg-thumb {
  aspect-ratio: 1;
  border-radius: 6px;
  overflow: hidden;
  cursor: pointer;
  border: 2px solid transparent;
  transition: border-color 0.15s, transform 0.15s;
}
.bg-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.bg-thumb:hover { border-color: var(--primary); transform: scale(1.05); }
.bg-thumb.selected { border-color: var(--primary); box-shadow: 0 0 0 2px #bfdbfe; }

/* Class multi-select */
.class-checkboxes {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  max-height: 160px;
  overflow-y: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px;
  background: #f8fafc;
}
.class-check-item {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 0.8rem;
  cursor: pointer;
}
.class-check-item input { cursor: pointer; }

/* ── SETTINGS ── */
.settings-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
  max-width: 440px;
}
.settings-card h3 { margin-bottom: 4px; font-size: 1rem; }
.settings-desc { color: var(--muted); font-size: 0.85rem; margin-bottom: 20px; }

/* ── TOAST ── */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: #1e293b;
  color: #fff;
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 0.875rem;
  font-weight: 500;
  box-shadow: 0 8px 24px rgba(0,0,0,0.2);
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.25s, transform 0.25s;
  pointer-events: none;
  z-index: 1000;
}
.toast.show { opacity: 1; transform: translateY(0); }
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }

/* ── MSG ── */
.msg { font-size: 0.85rem; padding: 8px 12px; border-radius: 6px; }
.msg.success { background: #d1fae5; color: #065f46; }
.msg.error { background: #fee2e2; color: #991b1b; }

/* ── PRINT ── */
.print-area { display: none; }

@media print {
  body * { visibility: hidden; }
  .print-area, .print-area * { visibility: visible; display: block !important; }
  .print-area {
    position: fixed;
    inset: 0;
    background: #fff;
    padding: 20px;
    display: flex !important;
    flex-wrap: wrap;
    gap: 16px;
    align-content: flex-start;
  }
  .print-card {
    width: 200px;
    border-radius: 10px;
    overflow: hidden;
    break-inside: avoid;
    border: 2px solid #e2e8f0;
    background: #fff;
  }
  .print-card-bg {
    height: 80px;
    background-size: cover;
    background-position: center;
    position: relative;
  }
  .print-card-bar { position: absolute; bottom: 0; left: 0; right: 0; height: 4px; }
  .print-card-body { padding: 10px; }
  .print-card-name { font-weight: 700; font-size: 0.85rem; margin-bottom: 6px; }
  .print-card-classes { font-size: 0.72rem; color: #334155; }
}

/* ── EMPTY STATE ── */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--muted);
}
.empty-state .empty-icon { font-size: 2.5rem; margin-bottom: 12px; }
.empty-state p { font-size: 0.9rem; }