:root {
  --primary: #0d9488;
  --primary-dark: #0f766e;
  --primary-light: #ccfbf1;
  --accent: #4f46e5;
  --bg: #f4f6f8;
  --card: #ffffff;
  --border: #e2e8f0;
  --text: #1e293b;
  --muted: #64748b;
  --success: #16a34a;
  --success-bg: #dcfce7;
  --warning: #d97706;
  --warning-bg: #fef3c7;
  --danger: #dc2626;
  --danger-bg: #fee2e2;
  --info: #2563eb;
  --info-bg: #dbeafe;
  --radius: 10px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.08), 0 1px 2px rgba(15, 23, 42, 0.06);
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
  font-family: "Segoe UI", "Noto Sans Thai", "Sarabun", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; margin: 0; padding: 0; }

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

.sidebar {
  width: 240px;
  flex-shrink: 0;
  background: #0f172a;
  color: #e2e8f0;
  display: flex;
  flex-direction: column;
  padding: 20px 14px;
}

.sidebar .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 10px 22px;
  font-size: 18px;
  font-weight: 700;
  color: #fff;
}
.sidebar .brand svg { flex-shrink: 0; }

.sidebar nav a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 14px;
  color: #cbd5e1;
  margin-bottom: 2px;
  cursor: pointer;
}
.sidebar nav a:hover { background: #1e293b; color: #fff; }
.sidebar nav a.active { background: var(--primary); color: #fff; }
.sidebar .section-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: #64748b;
  padding: 14px 12px 6px;
}

.sidebar .sidebar-footer {
  margin-top: auto;
  padding: 12px;
  font-size: 12px;
  color: #64748b;
  border-top: 1px solid #1e293b;
}

.main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.topbar {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 14px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.topbar h1 { font-size: 19px; margin: 0; }
.topbar .sub { color: var(--muted); font-size: 13px; margin-top: 2px; }

.content { padding: 24px 28px 60px; }

.view { display: none; }
.view.active { display: block; }

/* ---------- Cards ---------- */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
  margin-bottom: 20px;
}
.card h2 { margin: 0 0 4px; font-size: 16px; }
.card .card-desc { color: var(--muted); font-size: 13px; margin-bottom: 16px; }
.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}
.card-head h2 { margin: 0; }

/* ---------- Stat grid ---------- */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 16px;
  margin-bottom: 20px;
}
.stat-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  box-shadow: var(--shadow);
}
.stat-card .label { font-size: 12.5px; color: var(--muted); margin-bottom: 6px; }
.stat-card .value { font-size: 26px; font-weight: 700; }
.stat-card .delta { font-size: 12px; margin-top: 6px; }
.stat-card .delta.up { color: var(--success); }
.stat-card .delta.down { color: var(--danger); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 9px 16px;
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  transition: filter .15s ease;
}
.btn:hover { filter: brightness(0.95); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-accent { background: var(--accent); color: #fff; }
.btn-outline { background: #fff; border-color: var(--border); color: var(--text); }
.btn-ghost { background: transparent; color: var(--primary); padding: 8px 10px; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-sm { padding: 6px 10px; font-size: 12.5px; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

/* ---------- Badges ---------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}
.badge-lite { background: #e2e8f0; color: #334155; }
.badge-standard { background: var(--info-bg); color: var(--info); }
.badge-pro { background: #ede9fe; color: #6d28d9; }
.badge-success { background: var(--success-bg); color: var(--success); }
.badge-warning { background: var(--warning-bg); color: var(--warning); }
.badge-danger { background: var(--danger-bg); color: var(--danger); }
.badge-muted { background: #f1f5f9; color: var(--muted); }

/* ---------- Table ---------- */
table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
thead th {
  text-align: left;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .04em;
  color: var(--muted);
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
tbody td {
  padding: 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: #fafbfc; }
.table-actions { display: flex; gap: 6px; flex-wrap: wrap; }

/* ---------- Forms ---------- */
.form-group { margin-bottom: 14px; }
.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 6px;
}
.form-group .hint { font-size: 12px; color: var(--muted); margin-top: 4px; }
input[type=text], input[type=email], input[type=password], input[type=number], input[type=date], select, textarea {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 13.5px;
  font-family: inherit;
  background: #fff;
  color: var(--text);
}
textarea { resize: vertical; min-height: 70px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }

/* ---------- Toggle switch ---------- */
.switch { position: relative; display: inline-block; width: 40px; height: 22px; flex-shrink: 0; }
.switch input { opacity: 0; width: 0; height: 0; }
.switch .slider {
  position: absolute; cursor: pointer; inset: 0;
  background: #cbd5e1; border-radius: 999px; transition: .15s;
}
.switch .slider::before {
  content: ""; position: absolute; height: 16px; width: 16px; left: 3px; top: 3px;
  background: #fff; border-radius: 50%; transition: .15s;
}
.switch input:checked + .slider { background: var(--primary); }
.switch input:checked + .slider::before { transform: translateX(18px); }
.switch input:disabled + .slider { opacity: .5; cursor: not-allowed; }

/* ---------- Modal ---------- */
.modal-overlay {
  display: none;
  position: fixed; inset: 0;
  background: rgba(15, 23, 42, 0.45);
  align-items: center; justify-content: center;
  z-index: 100;
  padding: 20px;
}
.modal-overlay.active { display: flex; }
.modal {
  background: #fff;
  border-radius: 12px;
  width: 100%;
  max-width: 560px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 20px 50px rgba(0,0,0,.25);
}
.modal.modal-lg { max-width: 720px; }
.modal-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 22px; border-bottom: 1px solid var(--border);
}
.modal-header h3 { margin: 0; font-size: 16px; }
.modal-close { cursor: pointer; background: none; border: none; font-size: 20px; color: var(--muted); line-height: 1; }
.modal-body { padding: 20px 22px; }
.modal-footer {
  padding: 16px 22px; border-top: 1px solid var(--border);
  display: flex; justify-content: flex-end; gap: 8px;
}

/* ---------- Package select cards ---------- */
.package-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.package-card {
  border: 2px solid var(--border);
  border-radius: 10px;
  padding: 14px;
  cursor: pointer;
  text-align: center;
}
.package-card.selected { border-color: var(--primary); background: var(--primary-light); }
.package-card .pkg-name { font-weight: 700; margin-bottom: 4px; }
.package-card .pkg-price { font-size: 12px; color: var(--muted); }

/* ---------- Bill items (customer) ---------- */
.bill-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 16px; border: 1px solid var(--border); border-radius: 10px; margin-bottom: 10px;
  background: #fff;
}
.bill-item .bi-left { display: flex; align-items: center; gap: 12px; }
.bill-item .bi-icon {
  width: 38px; height: 38px; border-radius: 9px; background: var(--primary-light);
  display: flex; align-items: center; justify-content: center; color: var(--primary-dark); flex-shrink: 0;
}
.bill-item .bi-name { font-weight: 600; font-size: 14px; }
.bill-item .bi-meta { font-size: 12px; color: var(--muted); margin-top: 2px; }
.bill-item .bi-amount { font-weight: 700; font-size: 15px; text-align: right; }

/* ---------- Utility ---------- */
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-8 { gap: 8px; }
.gap-12 { gap: 12px; }
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.text-muted { color: var(--muted); }
.text-sm { font-size: 12.5px; }
.font-bold { font-weight: 700; }
.w-full { width: 100%; }
.empty-state { text-align: center; padding: 40px 20px; color: var(--muted); }
.divider { height: 1px; background: var(--border); margin: 16px 0; }
.tag-lock { font-size: 11px; color: var(--muted); background: #f1f5f9; padding: 2px 6px; border-radius: 6px; margin-left: 6px; }

/* ---------- Sub-tabs (within a view) ---------- */
.subtabs {
  display: flex; gap: 4px; margin-bottom: 18px; border-bottom: 1px solid var(--border); overflow-x: auto;
}
.subtabs button {
  background: none; border: none; padding: 9px 14px; font-size: 13px; font-weight: 600;
  color: var(--muted); cursor: pointer; border-bottom: 2px solid transparent; white-space: nowrap;
}
.subtabs button.active { color: var(--primary); border-color: var(--primary); }
.subview { display: none; }
.subview.active { display: block; }

/* ---------- Filter bar ---------- */
.filter-bar {
  display: flex; gap: 12px; flex-wrap: wrap; align-items: flex-end;
  margin-bottom: 18px; background: #f8fafc; border: 1px solid var(--border); border-radius: 10px; padding: 14px 16px;
}
.filter-bar .form-group { margin-bottom: 0; min-width: 160px; }
.filter-bar .form-group label { font-size: 11.5px; }

/* ---------- Inline editable table cells ---------- */
input.cell-input { width: 92px; padding: 6px 8px; font-size: 13px; }

/* ---------- Program picker (index.html) ---------- */
.program-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin: 32px 0 60px; }
.program-card {
  background: #fff; border: 1px solid var(--border); border-radius: 14px; padding: 26px 22px;
  display: flex; flex-direction: column;
}
.program-card .p-icon {
  width: 46px; height: 46px; border-radius: 12px; display: flex; align-items: center; justify-content: center;
  font-size: 22px; margin-bottom: 14px;
}
.program-card .p-code { font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
.program-card h3 { margin: 4px 0 8px; font-size: 17px; }
.program-card p.desc { color: var(--muted); font-size: 13px; margin: 0 0 16px; }
.program-card ul { margin: 0 0 20px; flex: 1; }
.program-card li { font-size: 13px; margin-bottom: 8px; display: flex; gap: 8px; color: #334155; }
.program-card li span { color: var(--success); flex-shrink: 0; }

.toast {
  position: fixed; bottom: 24px; right: 24px;
  background: #0f172a; color: #fff; padding: 12px 18px; border-radius: 8px;
  font-size: 13.5px; box-shadow: var(--shadow); z-index: 200;
  opacity: 0; transform: translateY(10px); transition: .2s;
  pointer-events: none;
}
.toast.show { opacity: 1; transform: translateY(0); }

@media (max-width: 900px) {
  .app-shell { flex-direction: column; }
  .sidebar { width: 100%; flex-direction: row; overflow-x: auto; }
  .sidebar nav { display: flex; }
  .form-row, .package-cards { grid-template-columns: 1fr; }
}