:root {
  --bg-dark: #0a0a1a;
  --bg-card: #0f0f2d;
  --bg-card2: #141430;
  --primary: #f5a623;
  --primary-glow: rgba(245,166,35,0.3);
  --accent-green: #00e676;
  --accent-pink: #ff4db8;
  --accent-blue: #00b4ff;
  --text-main: #e8eaf6;
  --text-dim: #9e9ec0;
  --border: rgba(255,255,255,0.08);
  --danger: #ff5252;
  --success: #00e676;
  --warning: #ffd740;
}

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

body {
  background: var(--bg-dark);
  color: var(--text-main);
  font-family: 'Segoe UI', 'Be Vietnam Pro', sans-serif;
  min-height: 100vh;
}

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-dark); }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 3px; }

/* ── Navbar ── */
.navbar {
  background: rgba(10,10,26,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
}
.navbar-brand {
  font-size: 1.3rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--accent-pink));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-decoration: none;
}
.navbar-right { display: flex; align-items: center; gap: 12px; }
.nav-user { font-size: 0.85rem; color: var(--text-dim); }

/* ── Buttons ── */
.btn {
  padding: 8px 18px;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.875rem;
  transition: all 0.2s;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.btn-primary { background: linear-gradient(135deg, var(--primary), #e8940f); color: #000; }
.btn-primary:hover { opacity: 0.88; transform: translateY(-1px); box-shadow: 0 4px 16px var(--primary-glow); }
.btn-outline { background: transparent; border: 1px solid var(--border); color: var(--text-main); }
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { opacity: 0.85; }
.btn-success { background: var(--success); color: #000; }
.btn-sm { padding: 5px 12px; font-size: 0.8rem; }
.btn-icon { padding: 6px; border-radius: 6px; }

/* ── Cards ── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px;
}
.card-glow { box-shadow: 0 0 30px rgba(0,180,255,0.08); }

/* ── Stats row ── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}
.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
  text-align: center;
}
.stat-value {
  font-size: 2rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--accent-pink));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.stat-label { font-size: 0.78rem; color: var(--text-dim); margin-top: 4px; }

/* ── Tables ── */
.table-wrap { overflow-x: auto; border-radius: 12px; }
table { width: 100%; border-collapse: collapse; font-size: 0.875rem; }
thead th {
  background: rgba(245,166,35,0.1);
  color: var(--primary);
  padding: 12px 14px;
  text-align: left;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  white-space: nowrap;
}
tbody tr { border-bottom: 1px solid var(--border); transition: background 0.15s; }
tbody tr:hover { background: rgba(255,255,255,0.03); }
tbody td { padding: 12px 14px; vertical-align: middle; }

/* ── Badges ── */
.badge {
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  display: inline-block;
}
.badge-success { background: rgba(0,230,118,0.18); color: var(--accent-green); border: 1px solid rgba(0,230,118,0.3); }
.badge-danger { background: rgba(255,82,82,0.18); color: var(--danger); border: 1px solid rgba(255,82,82,0.3); }
.badge-warning { background: rgba(255,215,64,0.18); color: var(--warning); border: 1px solid rgba(255,215,64,0.3); }
.badge-info { background: rgba(0,180,255,0.18); color: var(--accent-blue); border: 1px solid rgba(0,180,255,0.3); }

/* ── Checkbox toggle ── */
.toggle-check {
  width: 20px;
  height: 20px;
  cursor: pointer;
  accent-color: var(--accent-green);
}

/* ── Tabs ── */
.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--border); margin-bottom: 24px; }
.tab-btn {
  padding: 10px 20px;
  background: transparent;
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
  white-space: nowrap;
}
.tab-btn.active { color: var(--primary); border-bottom-color: var(--primary); }
.tab-btn:hover:not(.active) { color: var(--text-main); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ── Forms ── */
.form-group { margin-bottom: 16px; }
.form-label { display: block; font-size: 0.83rem; color: var(--text-dim); margin-bottom: 6px; font-weight: 600; }
.form-control {
  width: 100%;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  color: var(--text-main);
  font-size: 0.9rem;
  transition: border-color 0.2s;
  outline: none;
}
.form-control:focus { border-color: var(--primary); }
.form-control::placeholder { color: var(--text-dim); }
textarea.form-control { resize: vertical; min-height: 100px; }

/* ── Modal ── */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(4px);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.modal-overlay.open { display: flex; }
.modal {
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  width: 100%;
  max-width: 520px;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
}
.modal-title {
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: 20px;
  color: var(--primary);
}
.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-size: 1.4rem;
  cursor: pointer;
}
.modal-footer { display: flex; gap: 10px; justify-content: flex-end; margin-top: 20px; }

/* ── Alert ── */
.alert {
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 0.875rem;
  margin-bottom: 16px;
}
.alert-success { background: rgba(0,230,118,0.12); border: 1px solid rgba(0,230,118,0.3); color: var(--accent-green); }
.alert-danger { background: rgba(255,82,82,0.12); border: 1px solid rgba(255,82,82,0.3); color: var(--danger); }
.alert-info { background: rgba(0,180,255,0.12); border: 1px solid rgba(0,180,255,0.3); color: var(--accent-blue); }
.alert-warning { background: rgba(255,215,64,0.12); border: 1px solid rgba(255,215,64,0.3); color: var(--warning); }

/* ── Deposit balance card ── */
.balance-card {
  background: linear-gradient(135deg, rgba(245,166,35,0.15), rgba(255,77,184,0.1));
  border: 1px solid rgba(245,166,35,0.3);
  border-radius: 16px;
  padding: 24px;
  text-align: center;
  margin-bottom: 24px;
}
.balance-amount {
  font-size: 2.5rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--primary), #fff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.balance-label { color: var(--text-dim); font-size: 0.85rem; margin-top: 4px; }

/* ── Session cards (student) ── */
.sessions-grid { display: grid; gap: 16px; }
.session-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 16px;
}
.session-num {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary), var(--accent-pink));
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  font-size: 1.2rem;
  color: #000;
  flex-shrink: 0;
}
.session-info h3 { font-size: 1rem; margin-bottom: 6px; }
.session-links { display: flex; gap: 8px; flex-wrap: wrap; }
.session-status { display: flex; flex-direction: column; gap: 6px; align-items: flex-end; }

/* ── QR display ── */
.qr-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 20px;
}
.qr-container img { border-radius: 12px; border: 4px solid var(--primary); }
.qr-timer { font-size: 1.1rem; font-weight: 700; color: var(--warning); }

/* ── Responsive ── */
@media (max-width: 640px) {
  .session-card { grid-template-columns: 1fr; }
  .session-status { align-items: flex-start; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .navbar { padding: 10px 16px; }
}

/* ── Page layout ── */
.page-container { max-width: 1200px; margin: 0 auto; padding: 24px 20px; }
.page-header { margin-bottom: 24px; }
.page-header h1 { font-size: 1.5rem; font-weight: 800; }
.page-header p { color: var(--text-dim); font-size: 0.875rem; margin-top: 4px; }
.section-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ── Login page ── */
.login-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: radial-gradient(ellipse at 20% 50%, rgba(245,166,35,0.1) 0%, transparent 50%),
              radial-gradient(ellipse at 80% 20%, rgba(255,77,184,0.1) 0%, transparent 50%),
              var(--bg-dark);
  padding: 20px;
}
.login-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 40px;
  width: 100%;
  max-width: 420px;
  box-shadow: 0 0 60px rgba(245,166,35,0.08);
}
.login-logo { text-align: center; margin-bottom: 28px; }
.login-logo h1 {
  font-size: 2.2rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--primary), var(--accent-pink));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.login-logo p { color: var(--text-dim); font-size: 0.9rem; margin-top: 6px; }

/* ── QR info row ── */
.qr-bank-info {
  display: flex;
  align-items: center;
  gap: 16px;
  background: rgba(245,166,35,0.08);
  border: 1px solid rgba(245,166,35,0.2);
  border-radius: 12px;
  padding: 14px 18px;
  flex-wrap: wrap;
}

/* ── Loading ── */
.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 40px auto;
}
@keyframes spin { to { transform: rotate(360deg); } }

.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 20px;
  font-size: 0.875rem;
  z-index: 9999;
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.3s;
  max-width: 300px;
}
.toast.show { opacity: 1; transform: translateY(0); }
.toast.success { border-color: var(--accent-green); color: var(--accent-green); }
.toast.error { border-color: var(--danger); color: var(--danger); }