/* ========== CSS Variables ========== */
:root {
  --bg-dark: #1a1a2e;
  --bg-card: #16213e;
  --accent: #0f3460;
  --highlight: #e94560;
  --success: #00b894;
  --warning: #fdcb6e;
  --danger: #e94560;
  --text-primary: #eee;
  --text-secondary: #a0a0b8;
  --border: #2a2a4a;
  --sidebar-width: 250px;
  --topbar-height: 56px;
  --radius: 10px;
  --shadow: 0 2px 12px rgba(0,0,0,.35);
}

/* ========== Reset ========== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 14px; }
body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg-dark);
  color: var(--text-primary);
  min-height: 100vh;
}
a { color: var(--highlight); text-decoration: none; }
input, select, textarea, button { font-family: inherit; font-size: inherit; }

/* ========== Utility ========== */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 10px 20px; border: none; border-radius: 6px;
  cursor: pointer; font-weight: 600; transition: .2s;
}
.btn-primary { background: var(--highlight); color: #fff; }
.btn-primary:hover { filter: brightness(1.15); }
.btn-secondary { background: var(--accent); color: #fff; }
.btn-secondary:hover { filter: brightness(1.2); }
.btn-success { background: var(--success); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-sm { padding: 6px 12px; font-size: .85rem; }
.btn-block { width: 100%; justify-content: center; }
.btn-link { background: none; color: var(--text-secondary); border: none; cursor: pointer; padding: 8px 0; }
.btn-link:hover { color: var(--text-primary); }
.btn-icon { background: none; border: none; color: var(--text-secondary); cursor: pointer; font-size: 1.2rem; padding: 6px; }
.btn-icon:hover { color: var(--text-primary); }

/* ========== Login ========== */
.login-screen {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, var(--bg-dark), var(--accent));
}
.login-card {
  background: var(--bg-card); padding: 40px; border-radius: var(--radius);
  box-shadow: var(--shadow); width: 100%; max-width: 400px;
}
.login-logo { text-align: center; margin-bottom: 32px; }
.login-logo i { font-size: 3rem; color: var(--highlight); }
.login-logo h1 { margin-top: 12px; }
.login-logo p { color: var(--text-secondary); }
.login-step label { display: block; margin-bottom: 6px; color: var(--text-secondary); font-size: .9rem; }
.login-step input {
  width: 100%; padding: 12px; border: 1px solid var(--border);
  border-radius: 6px; background: var(--bg-dark); color: var(--text-primary);
  margin-bottom: 16px; font-size: 1rem;
}
.login-step input:focus { outline: none; border-color: var(--highlight); }
.phone-input-group { display: flex; align-items: center; gap: 0; margin-bottom: 16px; }
.phone-input-group .phone-prefix {
  padding: 12px; background: var(--accent); border: 1px solid var(--border);
  border-right: none; border-radius: 6px 0 0 6px; color: var(--text-secondary);
}
.phone-input-group input { margin-bottom: 0; border-radius: 0 6px 6px 0; }
.otp-info { color: var(--text-secondary); margin-bottom: 16px; font-size: .9rem; }
.login-error { margin-top: 12px; padding: 10px; background: rgba(233,69,96,.15); color: var(--highlight); border-radius: 6px; text-align: center; }

/* ========== App Shell ========== */
.app-shell { display: flex; min-height: 100vh; }

/* ========== Sidebar ========== */
.sidebar {
  position: fixed; left: 0; top: 0; bottom: 0;
  width: var(--sidebar-width); background: var(--bg-card);
  display: flex; flex-direction: column; z-index: 100;
  border-right: 1px solid var(--border);
  transition: transform .3s;
}
.sidebar-header {
  display: flex; align-items: center; gap: 10px;
  padding: 20px; font-size: 1.3rem; font-weight: 700;
  border-bottom: 1px solid var(--border);
}
.sidebar-header i { color: var(--highlight); font-size: 1.5rem; }
.sidebar-nav { flex: 1; overflow-y: auto; padding: 8px 0; }
.nav-item {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 20px; color: var(--text-secondary);
  transition: .15s; font-size: .95rem;
}
.nav-item:hover { background: rgba(255,255,255,.05); color: var(--text-primary); }
.nav-item.active { color: var(--highlight); background: rgba(233,69,96,.08); border-right: 3px solid var(--highlight); }
.nav-item i { width: 20px; text-align: center; }
.sidebar-footer { padding: 16px 20px; border-top: 1px solid var(--border); }

/* ========== Main Wrapper ========== */
.main-wrapper { flex: 1; margin-left: var(--sidebar-width); display: flex; flex-direction: column; }

/* ========== Topbar ========== */
.topbar {
  height: var(--topbar-height); display: flex; align-items: center;
  padding: 0 24px; background: var(--bg-card);
  border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 50;
}
.topbar-spacer { flex: 1; }
.topbar-user { display: flex; align-items: center; gap: 8px; color: var(--text-secondary); }
.topbar-user i { font-size: 1.5rem; }
#btn-toggle-sidebar { display: none; }

/* ========== Content ========== */
.content { padding: 24px; flex: 1; }

/* ========== Cards ========== */
.card {
  background: var(--bg-card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 20px;
  border: 1px solid var(--border);
}
.card-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
.card-header h3 { font-size: 1rem; }

/* ========== KPI Cards ========== */
.kpi-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin-bottom: 24px; }
.kpi-card {
  background: var(--bg-card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 20px;
  border: 1px solid var(--border); border-left: 4px solid var(--highlight);
}
.kpi-card .kpi-label { color: var(--text-secondary); font-size: .85rem; margin-bottom: 4px; }
.kpi-card .kpi-value { font-size: 1.5rem; font-weight: 700; }
.kpi-card.success { border-left-color: var(--success); }
.kpi-card.warning { border-left-color: var(--warning); }
.kpi-card.danger { border-left-color: var(--danger); }
.kpi-card.accent { border-left-color: var(--accent); }

/* ========== Charts ========== */
.chart-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(400px, 1fr)); gap: 16px; margin-bottom: 24px; }
.chart-container { position: relative; height: 300px; }

/* ========== Tables ========== */
.table-wrapper { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; }
thead th {
  text-align: left; padding: 12px; color: var(--text-secondary);
  border-bottom: 2px solid var(--border); font-size: .85rem;
  text-transform: uppercase; letter-spacing: .5px;
}
tbody td { padding: 12px; border-bottom: 1px solid var(--border); }
tbody tr:nth-child(even) { background: rgba(255,255,255,.02); }
tbody tr:hover { background: rgba(255,255,255,.04); }

/* ========== Badges ========== */
.badge {
  display: inline-block; padding: 3px 10px; border-radius: 20px;
  font-size: .75rem; font-weight: 600; text-transform: uppercase;
}
.badge-approved, .badge-paid { background: rgba(0,184,148,.15); color: var(--success); }
.badge-pending { background: rgba(253,203,110,.15); color: var(--warning); }
.badge-refunded, .badge-cancelled { background: rgba(233,69,96,.15); color: var(--danger); }
.badge-info { background: rgba(15,52,96,.4); color: #74b9ff; }

/* ========== Forms ========== */
.form-group { margin-bottom: 16px; }
.form-group label { display: block; margin-bottom: 6px; color: var(--text-secondary); font-size: .9rem; }
.form-control {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border);
  border-radius: 6px; background: var(--bg-dark); color: var(--text-primary);
}
.form-control:focus { outline: none; border-color: var(--highlight); }
select.form-control { cursor: pointer; }
.form-row { display: flex; gap: 16px; }
.form-row .form-group { flex: 1; }

/* ========== Filters ========== */
.filters { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 20px; align-items: flex-end; }
.filters .form-group { margin-bottom: 0; min-width: 160px; }

/* ========== Modal ========== */
.modal-overlay {
  position: fixed; inset: 0; background: rgba(0,0,0,.6);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000;
}
.modal-box {
  background: var(--bg-card); border-radius: var(--radius);
  box-shadow: 0 8px 32px rgba(0,0,0,.5);
  width: 90%; max-width: 600px; max-height: 85vh;
  display: flex; flex-direction: column;
}
.modal-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 20px; border-bottom: 1px solid var(--border);
}
.modal-body { padding: 20px; overflow-y: auto; flex: 1; }

/* ========== Drag & Drop Zone ========== */
.drop-zone {
  border: 2px dashed var(--border); border-radius: var(--radius);
  padding: 48px; text-align: center; cursor: pointer;
  transition: .2s; color: var(--text-secondary);
}
.drop-zone:hover, .drop-zone.dragover {
  border-color: var(--highlight); background: rgba(233,69,96,.05);
}
.drop-zone i { font-size: 2.5rem; margin-bottom: 12px; display: block; }

/* ========== Loading ========== */
.loading-overlay {
  position: fixed; inset: 0; background: rgba(26,26,46,.7);
  display: flex; align-items: center; justify-content: center;
  z-index: 2000;
}
.spinner {
  width: 48px; height: 48px; border: 4px solid var(--border);
  border-top-color: var(--highlight); border-radius: 50%;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Inline spinner */
.spinner-sm {
  display: inline-block; width: 18px; height: 18px;
  border: 2px solid var(--border); border-top-color: var(--highlight);
  border-radius: 50%; animation: spin .8s linear infinite; vertical-align: middle;
}

/* ========== Page Header ========== */
.page-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 24px; flex-wrap: wrap; gap: 12px; }
.page-header h2 { font-size: 1.4rem; }

/* ========== Calendar View ========== */
.calendar-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 4px; }
.calendar-day {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 6px;
  padding: 8px; min-height: 80px; font-size: .8rem;
}
.calendar-day .day-number { font-weight: 700; margin-bottom: 4px; }
.calendar-day.today { border-color: var(--highlight); }
.calendar-day .receivable-item {
  background: rgba(0,184,148,.1); padding: 2px 6px; border-radius: 4px;
  margin-top: 2px; font-size: .75rem; color: var(--success); cursor: pointer;
}
.calendar-day .receivable-item.overdue { background: rgba(233,69,96,.1); color: var(--danger); }

/* ========== Nested Fee Rules ========== */
.fee-rules-list { display: flex; flex-direction: column; gap: 8px; margin-top: 8px; }
.fee-rule-row {
  display: flex; gap: 8px; align-items: center; background: var(--bg-dark);
  padding: 8px 12px; border-radius: 6px;
}
.fee-rule-row .form-control { width: auto; flex: 1; }
.fee-rule-row .btn-icon { flex-shrink: 0; }

/* ========== Tabs ========== */
.tabs { display: flex; gap: 0; margin-bottom: 20px; border-bottom: 2px solid var(--border); }
.tab-btn {
  padding: 10px 20px; background: none; border: none; color: var(--text-secondary);
  cursor: pointer; border-bottom: 2px solid transparent; margin-bottom: -2px; font-weight: 600;
}
.tab-btn.active { color: var(--highlight); border-bottom-color: var(--highlight); }

/* ========== Empty State ========== */
.empty-state { text-align: center; padding: 48px; color: var(--text-secondary); }
.empty-state i { font-size: 3rem; margin-bottom: 12px; display: block; opacity: .5; }

/* ========== Mobile ========== */
@media (max-width: 768px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .main-wrapper { margin-left: 0; }
  #btn-toggle-sidebar { display: block; }
  .kpi-grid { grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }
  .chart-grid { grid-template-columns: 1fr; }
  .form-row { flex-direction: column; }
  .filters { flex-direction: column; }
  .modal-box { width: 95%; max-width: none; }
  .calendar-grid { grid-template-columns: repeat(3, 1fr); }
}