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

:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-success: #16a34a;
  --color-warning: #d97706;
  --color-danger: #dc2626;
  --color-bg: #f9f3e9;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-border: #e0d8cc;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.1);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --app-font-scale: 1;
}

/* ── Theme variants (Light is the :root default above) ── */
[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-surface: #1e293b;
  --color-text: #e2e8f0;
  --color-text-muted: #94a3b8;
  --color-border: #334155;
  --color-primary: #3b82f6;
  --color-primary-dark: #2563eb;
  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
}

[data-theme="black"] {
  --color-bg: #000000;
  --color-surface: #0a0a0a;
  --color-text: #f5f5f5;
  --color-text-muted: #a3a3a3;
  --color-border: #262626;
  --color-primary: #3b82f6;
  --color-primary-dark: #2563eb;
  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
}

/* ── Mesh Gradient / Aurora Background (from Virtual Lab Platform) ── */
.mesh-gradient-bg {
  position: relative;
  overflow: hidden;
}
.mesh-gradient-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 20% 40%, rgba(52, 232, 187, 0.12), transparent),
    radial-gradient(ellipse 60% 60% at 80% 20%, rgba(169, 90, 248, 0.1), transparent),
    radial-gradient(ellipse 50% 80% at 60% 80%, rgba(34, 197, 94, 0.08), transparent),
    radial-gradient(ellipse 70% 40% at 10% 90%, rgba(245, 158, 11, 0.06), transparent);
  animation: mesh-drift 8s ease-in-out infinite alternate;
  pointer-events: none;
  z-index: 0;
}
.mesh-gradient-bg > *:not(.glow-orb):not(.grid-overlay):not(.noise-overlay) {
  position: relative;
  z-index: 1;
}
@keyframes mesh-drift {
  0% {
    background:
      radial-gradient(ellipse 80% 50% at 20% 40%, rgba(52, 232, 187, 0.12), transparent),
      radial-gradient(ellipse 60% 60% at 80% 20%, rgba(169, 90, 248, 0.1), transparent),
      radial-gradient(ellipse 50% 80% at 60% 80%, rgba(34, 197, 94, 0.08), transparent),
      radial-gradient(ellipse 70% 40% at 10% 90%, rgba(245, 158, 11, 0.06), transparent);
  }
  50% {
    background:
      radial-gradient(ellipse 70% 60% at 40% 60%, rgba(169, 90, 248, 0.14), transparent),
      radial-gradient(ellipse 80% 40% at 70% 30%, rgba(52, 232, 187, 0.1), transparent),
      radial-gradient(ellipse 60% 70% at 30% 20%, rgba(245, 158, 11, 0.08), transparent),
      radial-gradient(ellipse 50% 50% at 80% 80%, rgba(34, 197, 94, 0.1), transparent);
  }
  100% {
    background:
      radial-gradient(ellipse 60% 70% at 70% 50%, rgba(34, 197, 94, 0.12), transparent),
      radial-gradient(ellipse 70% 50% at 20% 70%, rgba(245, 158, 11, 0.1), transparent),
      radial-gradient(ellipse 80% 60% at 50% 20%, rgba(169, 90, 248, 0.08), transparent),
      radial-gradient(ellipse 50% 60% at 90% 40%, rgba(52, 232, 187, 0.11), transparent);
  }
}
.glow-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.4;
  animation: orb-float 10s ease-in-out infinite alternate;
  pointer-events: none;
  z-index: 0;
}
.glow-orb-1 {
  width: 300px; height: 300px;
  background: rgba(52, 232, 187, 0.25);
  top: -100px; right: -50px;
}
.glow-orb-2 {
  width: 250px; height: 250px;
  background: rgba(169, 90, 248, 0.2);
  bottom: -80px; left: -30px;
  animation-delay: -3s;
}
.glow-orb-3 {
  width: 200px; height: 200px;
  background: rgba(34, 197, 94, 0.18);
  top: 50%; left: 50%;
  animation-delay: -6s;
}
@keyframes orb-float {
  0% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(30px, -20px) scale(1.1); }
  66% { transform: translate(-20px, 30px) scale(0.9); }
  100% { transform: translate(10px, -10px) scale(1.05); }
}
.grid-overlay {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: 0;
}
.noise-overlay {
  position: absolute;
  inset: 0;
  opacity: 0.03;
  pointer-events: none;
  z-index: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 256px 256px;
}

html {
  font-size: calc(16px * var(--app-font-scale, 1));
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
  min-height: 100vh;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
}

/* ── Button System ────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.5rem 1.125rem;
  border: 2px solid transparent;
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 600;
  font-family: var(--font);
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  text-decoration: none;
  white-space: nowrap;
  user-select: none;
  position: relative;
  overflow: hidden;
}
.btn:active { transform: scale(0.97); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

/* Primary */
.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), #3b82f6);
  color: #fff;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}
.btn-primary:hover:not(:disabled) {
  background: linear-gradient(135deg, var(--color-primary-dark), #2563eb);
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
  transform: translateY(-1px);
}

/* Success */
.btn-success {
  background: linear-gradient(135deg, var(--color-success), #22c55e);
  color: #fff;
  box-shadow: 0 2px 8px rgba(22, 163, 74, 0.3);
}
.btn-success:hover:not(:disabled) {
  background: linear-gradient(135deg, #15803d, #16a34a);
  box-shadow: 0 4px 14px rgba(22, 163, 74, 0.4);
  transform: translateY(-1px);
}

/* Danger */
.btn-danger {
  background: linear-gradient(135deg, var(--color-danger), #ef4444);
  color: #fff;
  box-shadow: 0 2px 8px rgba(220, 38, 38, 0.3);
}
.btn-danger:hover:not(:disabled) {
  background: linear-gradient(135deg, #b91c1c, #dc2626);
  box-shadow: 0 4px 14px rgba(220, 38, 38, 0.4);
  transform: translateY(-1px);
}

/* Warning */
.btn-warning {
  background: linear-gradient(135deg, var(--color-warning), #f59e0b);
  color: #fff;
  box-shadow: 0 2px 8px rgba(217, 119, 6, 0.3);
}
.btn-warning:hover:not(:disabled) {
  background: linear-gradient(135deg, #b45309, #d97706);
  box-shadow: 0 4px 14px rgba(217, 119, 6, 0.4);
  transform: translateY(-1px);
}

/* Ghost (transparent) */
.btn-ghost {
  background: transparent;
  color: var(--color-text);
  border: 2px solid var(--color-border);
}
.btn-ghost:hover:not(:disabled) {
  background: var(--color-bg);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* Outline variants */
.btn-outline-primary {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}
.btn-outline-primary:hover:not(:disabled) {
  background: var(--color-primary);
  color: #fff;
}
.btn-outline-danger {
  background: transparent;
  color: var(--color-danger);
  border: 2px solid var(--color-danger);
}
.btn-outline-danger:hover:not(:disabled) {
  background: var(--color-danger);
  color: #fff;
}

/* Sizes */
.btn-xs { padding: 0.35rem 0.6rem; font-size: 0.7rem; border-radius: 6px; min-height: 44px; }
.btn-sm { padding: 0.4rem 0.85rem; font-size: 0.8rem; border-radius: 6px; min-height: 44px; }
.btn-lg { padding: 0.7rem 1.5rem; font-size: 1rem; border-radius: 10px; }
.btn-block { width: 100%; }

/* Icon-only button */
.btn-icon {
  width: 44px;
  height: 44px;
  padding: 0;
  border-radius: 10px;
  font-size: 1rem;
}
.btn-icon.btn-sm {
  width: 44px;
  height: 44px;
  font-size: 0.8rem;
  border-radius: 8px;
}

/* ── Filter / Pill Buttons ────────────────────────────────────── */
.btn-filter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 0.4rem 0.85rem;
  border: 2px solid var(--color-border);
  border-radius: 999px;
  background: var(--color-surface);
  color: var(--color-text-muted);
  font-size: 0.8rem;
  font-weight: 500;
  font-family: var(--font);
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
  text-align: center;
  vertical-align: middle;
  line-height: 1.2;
}
.btn-filter:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(37, 99, 235, 0.04);
}
.btn-filter.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.25);
}
.btn-filter .filter-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 18px;
  padding: 0 4px;
  border-radius: 9px;
  background: rgba(0,0,0,0.08);
  font-size: 0.65rem;
  font-weight: 700;
  flex-shrink: 0;
}
.btn-filter.active .filter-count {
  background: rgba(255,255,255,0.25);
}

/* ── Tab Buttons ──────────────────────────────────────────────── */
.tab-bar {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--color-border);
  margin: 1rem 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.tab-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.65rem 1.125rem;
  border: none;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  background: transparent;
  color: var(--color-text-muted);
  font-size: 0.875rem;
  font-weight: 500;
  font-family: var(--font);
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}
.tab-btn:hover {
  color: var(--color-primary);
  background: rgba(37, 99, 235, 0.04);
}
.tab-btn.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
  font-weight: 700;
}

/* ── Action Button Group ──────────────────────────────────────── */
.btn-group {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  align-items: center;
}
.btn-group .btn {
  flex-shrink: 0;
}

/* ── Framed / Card Action Buttons ─────────────────────────────── */
.btn-card {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 0.85rem;
  font-weight: 500;
  font-family: var(--font);
  cursor: pointer;
  transition: all 0.2s ease;
}
.btn-card:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.1);
}

/* ── Patterned Buttons ────────────────────────────────────────── */
.btn-pattern {
  position: relative;
  background-image: repeating-linear-gradient(
    45deg,
    transparent,
    transparent 4px,
    rgba(255,255,255,0.06) 4px,
    rgba(255,255,255,0.06) 8px
  );
}
.btn-pattern.btn-primary {
  background-color: var(--color-primary);
}
.btn-pattern.btn-success {
  background-color: var(--color-success);
}
.btn-pattern.btn-danger {
  background-color: var(--color-danger);
}

/* ── Upload Zone Button ───────────────────────────────────────── */
.btn-upload {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  padding: 1rem;
  border: 2px dashed var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  font-family: var(--font);
  cursor: pointer;
  transition: all 0.2s ease;
}
.btn-upload:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(37, 99, 235, 0.04);
}
.btn-upload:dragover {
  border-color: var(--color-primary);
  background: rgba(37, 99, 235, 0.08);
}

/* ── Payment Checkout Enhancements ─────────────────────────────── */

/* Checkout card header */
.checkout-header {
  padding: 1.25rem 1.5rem;
  background: linear-gradient(135deg, #2563eb, #3b82f6);
  color: #fff;
  display: flex;
  align-items: center;
  gap: 0.625rem;
}
.checkout-header h3 {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
}
.checkout-body {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Form field labels */
.field-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  display: block;
  margin-bottom: 0.375rem;
}

/* Input with icon prefix */
.input-icon-wrap {
  position: relative;
}
.input-icon-wrap .input {
  padding-left: 2.5rem;
}
.input-icon-wrap svg {
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-text-muted);
  pointer-events: none;
}

/* Currency prefix */
.input-currency-prefix {
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  font-weight: 600;
  color: var(--color-text-muted);
  font-size: 0.8rem;
  pointer-events: none;
}
.input-currency-prefix + .input {
  padding-left: 3.5rem;
}

/* Provider card grid */
.provider-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
}

.provider-card {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 0.875rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s ease;
  font-size: 0.875rem;
  font-weight: 500;
  background: var(--color-surface);
}
.provider-card:hover {
  border-color: var(--color-primary);
  background: rgba(37, 99, 235, 0.02);
}
.provider-card:has(input:checked) {
  border-color: var(--color-primary);
  background: #eff6ff;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}
.provider-card input[type="radio"] {
  accent-color: var(--color-primary);
  margin: 0;
}
.provider-card .provider-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* Button focus ring */
.btn:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.3);
}

/* Button spinner */
.btn-spinner {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}
.btn-spinner svg {
  animation: spin 0.8s linear infinite;
}

/* Payment result toast */
.payment-result {
  animation: slideIn 0.3s ease-out;
  padding: 0.875rem 1rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}
.payment-result.success {
  background: #dcfce7;
  border-left: 3px solid #16a34a;
  color: #166534;
}
.payment-result.error {
  background: #fee2e2;
  border-left: 3px solid #dc2626;
  color: #991b1b;
}
@keyframes slideIn {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Status badges */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.6rem;
  border-radius: 9999px;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: capitalize;
}
.badge::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
}
.badge-completed {
  background: #dcfce7;
  color: #16a34a;
}
.badge-completed::before {
  background: #16a34a;
}
.badge-pending {
  background: #fef3c7;
  color: #d97706;
}
.badge-pending::before {
  background: #d97706;
}
.badge-failed {
  background: #fee2e2;
  color: #dc2626;
}
.badge-failed::before {
  background: #dc2626;
}

/* Table hover rows */
.tx-table tbody tr {
  transition: background 0.15s ease;
}
.tx-table tbody tr:hover {
  background: rgba(37, 99, 235, 0.03);
}

/* ── Responsive Buttons ───────────────────────────────────────── */
@media (max-width: 768px) {
  .btn { padding: 0.55rem 1rem; font-size: 0.85rem; min-height: 44px; }
  .btn-sm { padding: 0.45rem 0.85rem; font-size: 0.8rem; min-height: 44px; }
  .btn-lg { padding: 0.65rem 1.25rem; font-size: 0.95rem; }
  .btn-icon { width: 44px; height: 44px; }
  .btn-filter { padding: 0.4rem 0.8rem; font-size: 0.78rem; min-height: 44px; }
  .tab-btn { padding: 0.6rem 1rem; font-size: 0.85rem; min-height: 44px; }
}
@media (max-width: 480px) {
  .btn { padding: 0.5rem 0.9rem; font-size: 0.82rem; border-radius: 6px; min-height: 44px; }
  .btn-sm { padding: 0.4rem 0.75rem; font-size: 0.78rem; min-height: 44px; }
  .btn-filter { padding: 0.35rem 0.7rem; font-size: 0.75rem; min-height: 44px; }
  .tab-btn { padding: 0.55rem 0.8rem; font-size: 0.8rem; min-height: 44px; }
  .btn-group { gap: 0.4rem; }
}

.input {
  width: 100%;
  padding: 0.6rem 0.85rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-family: var(--font);
  min-height: 44px;
}

.input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

/* Login */
.login-page {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 1rem;
}

.login-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2.5rem;
  width: 100%;
  max-width: 400px;
}

.login-card h1 {
  font-size: 1.5rem;
  margin-bottom: 0.25rem;
}

.login-card p {
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
}

.login-card form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.login-card input {
  width: 100%;
  padding: 0.625rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-family: var(--font);
}

.login-card input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.login-card button {
  padding: 0.625rem;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
}

.login-card button:hover {
  background: var(--color-primary-dark);
}

.login-card .error {
  color: var(--color-danger);
  font-size: 0.85rem;
  text-align: center;
}

/* Sidebar layout */
.sidebar-layout {
  display: flex;
  height: 100vh;
  overflow: hidden;
}

.sidebar {
  width: 240px;
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  flex-shrink: 0;
}

.sidebar-header {
  padding: 1rem;
  border-bottom: 1px solid var(--color-border);
}

.sidebar-header h2 {
  margin: 0;
  font-size: 1.1rem;
}

.sidebar-header p {
  margin: 0.25rem 0 0;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.sidebar-nav {
  flex: 1;
  padding: 0.5rem 0;
}

.sidebar-nav-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1rem;
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.9rem;
  border-left: 3px solid transparent;
  cursor: pointer;
  user-select: none;
  transition: background 0.15s, border-color 0.15s;
  min-height: 44px;
}

.sidebar-nav-item:hover {
  background: var(--color-bg);
}

.sidebar-nav-item.active {
  background: var(--color-bg);
  border-left-color: var(--color-primary);
  font-weight: 600;
  color: var(--color-primary);
}

.sidebar-footer {
  padding: 0.75rem;
  border-top: 1px solid var(--color-border);
}

.sidebar-footer-row {
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.main-content {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.main-header {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.main-body {
  flex: 1;
  padding: 1rem;
  overflow-y: auto;
}

.sidebar-toggle-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  padding: 0.5rem;
  min-width: 44px;
  min-height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.icon-btn {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.85rem;
  padding: 0.5rem 0.75rem;
  min-width: 44px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.icon-btn:hover {
  background: var(--color-bg);
}

.notif-dropdown,
.profile-dropdown {
  display: none;
  position: absolute;
  width: min(280px, calc(100vw - 2rem));
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  z-index: 100;
  max-height: 300px;
  overflow-y: auto;
}

.notif-dropdown {
  bottom: 100%;
  left: 0;
  margin-bottom: 0.5rem;
}

.profile-dropdown {
  bottom: 100%;
  right: 0;
  width: 180px;
  margin-bottom: 0.5rem;
}

.dropdown-item {
  display: flex;
  align-items: center;
  width: 100%;
  padding: 0.6rem 0.75rem;
  min-height: 44px;
  text-align: left;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
}

.dropdown-item:hover {
  background: var(--color-bg);
}

@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    z-index: 200;
    left: -260px;
    transition: left 0.25s ease;
    height: 100vh;
    box-shadow: none;
  }
  .sidebar.open {
    left: 0;
    box-shadow: 4px 0 20px rgba(0,0,0,0.15);
  }
  .sidebar-toggle-btn {
    display: block !important;
  }
  .main-header {
    padding: 0.5rem 0.75rem;
  }
  .main-body {
    padding: 0.75rem;
  }
}

/* Content */
.content {
  flex: 1;
  padding: 1.5rem;
  max-width: 960px;
  width: 100%;
  margin: 0 auto;
}

/* Card grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.card h3 {
  font-size: 1rem;
  margin-bottom: 0.35rem;
}

.card p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Welcome banner */
.welcome-banner {
  background: linear-gradient(135deg, var(--color-primary), #7c3aed);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  color: #fff;
  margin-bottom: 1rem;
}

.welcome-banner small {
  display: block;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  opacity: 0.7;
  margin-bottom: 0.25rem;
}

.welcome-banner h2 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
}

.welcome-banner p {
  margin: 0.25rem 0 0;
  font-size: 0.85rem;
  opacity: 0.85;
  color: #fff;
}

/* Stat grid */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.stat-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  box-shadow: var(--shadow);
}

.stat-card .stat-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  margin-bottom: 0.5rem;
}

.stat-card .stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.2;
}

.stat-card .stat-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  font-weight: 500;
  margin-top: 0.15rem;
}

/* Progress bar */
.progress-bar {
  height: 6px;
  background: var(--color-border);
  border-radius: 3px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: var(--color-success);
  border-radius: 3px;
  transition: width 0.3s;
}

/* Loading / Spinner */
.loading-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 1rem;
  color: var(--color-text-muted);
  gap: 0.75rem;
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Section header */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.section-header h3 {
  margin: 0;
  font-size: 1rem;
}

/* Subject card with progress */
.subject-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 0.75rem;
}

.subject-card-enhanced {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem;
  cursor: pointer;
  transition: box-shadow 0.15s, transform 0.15s;
}

.subject-card-enhanced:hover {
  box-shadow: var(--shadow);
  transform: translateY(-1px);
}

.subject-card-enhanced .subject-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.subject-card-enhanced h4 {
  margin: 0 0 0.25rem;
  font-size: 0.95rem;
}

.subject-card-enhanced .subject-progress {
  margin-top: 0.5rem;
}

.subject-card-enhanced .subject-progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.7rem;
  color: var(--color-text-muted);
  margin-bottom: 0.25rem;
}

/* Recent lessons */
.recent-lesson-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  cursor: pointer;
  transition: box-shadow 0.15s;
}

.recent-lesson-card:hover {
  box-shadow: var(--shadow);
}

.recent-lesson-card h4 {
  margin: 0 0 0.15rem;
  font-size: 0.9rem;
}

.recent-lesson-card .recent-meta {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* Empty state */
.empty-state {
  text-align: center;
  padding: 4rem 1rem;
  color: var(--color-text-muted);
}

.empty-state h2 {
  color: var(--color-text);
  margin-bottom: 0.35rem;
}

.lesson-iframe { width: 100%; border: none; display: block; min-height: 400px; }

@media (max-width: 768px) {
  html { font-size: 15px; }
  .topbar { flex-wrap: wrap; gap: 0.5rem; padding: 0.5rem 0.75rem; }
  .topbar h1 { font-size: 1rem; width: 100%; }
  .topbar nav { order: 2; width: 100%; overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .nav-btn { flex-shrink: 0; font-size: 0.8rem; padding: 0.35rem 0.65rem; }
  .content { padding: 0.75rem; }
  .card { padding: 1rem; }
  .card-grid { grid-template-columns: 1fr; }
  .stat-grid { grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 0.5rem; }
  .subject-card-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); }
  .lesson-iframe { min-height: 300px; }
  #admin-content .lesson-iframe { min-height: 60vh; }
  .tab-bar { overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .tab-btn { flex-shrink: 0; }
  [style*="grid-template-columns: 1fr 1fr"] { grid-template-columns: 1fr !important; }
  [data-blackboard] { height: min(360px, 55vh) !important; min-height: 220px; border-radius: var(--radius) !important; }
}

@media (max-width: 480px) {
  html { font-size: 14px; }
  .topbar { padding: 0.4rem 0.5rem; }
  .topbar h1 { font-size: 0.9rem; }
  .content { padding: 0.5rem; }
  .card-grid { gap: 0.5rem; }
  .stat-grid { grid-template-columns: 1fr 1fr; gap: 0.5rem; }
  .stat-card { padding: 0.75rem; }
  .stat-card .stat-value { font-size: 1.25rem; }
  .subject-card-grid { grid-template-columns: 1fr; }
  .lesson-iframe { min-height: 250px; }
  #admin-content .lesson-iframe { min-height: 50vh; }
  .welcome-banner { padding: 1rem; }
  .welcome-banner h2 { font-size: 1.1rem; }
  .provider-grid { grid-template-columns: 1fr; }
}