/* =========================================================
   COST SPLITTER — Premium Dark Design System
   ========================================================= */

/* ---------- CSS Variables / Design Tokens ---------- */
:root {
  /* Colors */
  --bg-primary: #0a0e1a;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.7);
  --bg-card-hover: rgba(31, 41, 55, 0.8);
  --bg-glass: rgba(255, 255, 255, 0.04);
  --bg-glass-hover: rgba(255, 255, 255, 0.08);
  --bg-input: rgba(255, 255, 255, 0.06);
  --bg-input-focus: rgba(255, 255, 255, 0.1);

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-accent: #818cf8;

  --accent-primary: #6366f1;
  --accent-primary-hover: #818cf8;
  --accent-secondary: #ec4899;
  --accent-green: #34d399;
  --accent-red: #f87171;
  --accent-orange: #fb923c;
  --accent-cyan: #22d3ee;

  --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #ec4899 100%);
  --gradient-card: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.05) 100%);
  --gradient-success: linear-gradient(135deg, #34d399 0%, #06b6d4 100%);
  --gradient-danger: linear-gradient(135deg, #f87171 0%, #ec4899 100%);

  --border-color: rgba(255, 255, 255, 0.08);
  --border-color-hover: rgba(255, 255, 255, 0.15);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.15);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s ease;
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Animated background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(139, 92, 246, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(236, 72, 153, 0.05) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}

#app {
  position: relative;
  z-index: 1;
  min-height: 100vh;
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-primary-hover);
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* ---------- Typography ---------- */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1rem; }

/* ---------- Loading Screen ---------- */
.loading-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  gap: 1rem;
  color: var(--text-secondary);
}

.loader {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-color);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* ---------- Navbar ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  height: 64px;
  background: rgba(10, 14, 26, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
  cursor: pointer;
  transition: opacity var(--transition-fast);
}

.navbar-brand:hover {
  opacity: 0.9;
}

.navbar-brand .brand-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

.navbar-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.navbar-link {
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: none;
  background: none;
}

.navbar-link:hover {
  color: var(--text-primary);
  background: var(--bg-glass-hover);
}

.navbar-link.active {
  color: var(--accent-primary);
  background: rgba(99, 102, 241, 0.1);
}

.navbar-user {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.navbar-avatar {
  width: 34px;
  height: 34px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8rem;
  color: white;
  text-transform: uppercase;
}

.navbar-username {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
}

.btn-logout {
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-family);
}

.btn-logout:hover {
  border-color: var(--accent-red);
  color: var(--accent-red);
  background: rgba(248, 113, 113, 0.1);
}

/* ---------- Page Container ---------- */
.page-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- Page Header ---------- */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.page-header h1 {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.page-subtitle {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 0.25rem;
}

/* ---------- Cards ---------- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: all var(--transition-normal);
}

.card:hover {
  border-color: var(--border-color-hover);
  box-shadow: var(--shadow-md);
}

.card-clickable {
  cursor: pointer;
}

.card-clickable:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
  border-color: rgba(99, 102, 241, 0.3);
}

/* ---------- Stat Cards ---------- */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  backdrop-filter: blur(10px);
}

.stat-card .stat-label {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.stat-card .stat-value {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text-primary);
}

.stat-card .stat-value.positive {
  color: var(--accent-green);
}

.stat-card .stat-value.negative {
  color: var(--accent-red);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.25rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
  font-family: var(--font-family);
  cursor: pointer;
  border: none;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: 0 2px 12px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.5);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--bg-glass);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-glass-hover);
  border-color: var(--border-color-hover);
}

.btn-success {
  background: var(--gradient-success);
  color: white;
  box-shadow: 0 2px 12px rgba(52, 211, 153, 0.3);
}

.btn-success:hover {
  box-shadow: 0 4px 20px rgba(52, 211, 153, 0.5);
  transform: translateY(-1px);
}

.btn-danger {
  background: var(--gradient-danger);
  color: white;
}

.btn-danger:hover {
  box-shadow: 0 4px 20px rgba(248, 113, 113, 0.4);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  padding: 0.5rem 0.75rem;
}

.btn-ghost:hover {
  color: var(--text-primary);
  background: var(--bg-glass-hover);
}

.btn-sm {
  padding: 0.4rem 0.85rem;
  font-size: 0.8rem;
}

.btn-lg {
  padding: 0.85rem 1.75rem;
  font-size: 1rem;
}

.btn-icon {
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: var(--radius-sm);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* ---------- Form Elements ---------- */
.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 0.7rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 0.9rem;
  font-family: var(--font-family);
  transition: all var(--transition-fast);
  outline: none;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--accent-primary);
  background: var(--bg-input-focus);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.form-input::placeholder {
  color: var(--text-muted);
}

.form-select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2394a3b8' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: calc(100% - 12px) center;
  padding-right: 2.5rem;
}

.form-select option {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.form-textarea {
  resize: vertical;
  min-height: 80px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-error {
  color: var(--accent-red);
  font-size: 0.8rem;
  margin-top: 0.35rem;
}

/* Checkbox / Radio styled */
.checkbox-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.checkbox-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.85rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: 0.875rem;
  user-select: none;
}

.checkbox-item:hover {
  border-color: var(--border-color-hover);
  background: var(--bg-glass-hover);
}

.checkbox-item.selected {
  border-color: var(--accent-primary);
  background: rgba(99, 102, 241, 0.1);
  color: var(--accent-primary-hover);
}

.checkbox-item input[type="checkbox"] {
  display: none;
}

.checkbox-dot {
  width: 18px;
  height: 18px;
  border-radius: 4px;
  border: 2px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.checkbox-item.selected .checkbox-dot {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
}

.checkbox-item.selected .checkbox-dot::after {
  content: '✓';
  color: white;
  font-size: 0.7rem;
  font-weight: 700;
}

/* Radio buttons for split type */
.radio-group {
  display: flex;
  gap: 0.5rem;
}

.radio-btn {
  flex: 1;
  padding: 0.6rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: var(--bg-glass);
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-family);
}

.radio-btn:hover {
  border-color: var(--border-color-hover);
}

.radio-btn.active {
  border-color: var(--accent-primary);
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-primary-hover);
}

/* ---------- Groups Grid ---------- */
.groups-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
}

.group-card {
  position: relative;
  overflow: hidden;
}

.group-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.group-card:hover::before {
  opacity: 1;
}

.group-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.group-card-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
}

.group-card-name {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.group-card-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.group-card-meta {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.group-card-meta span {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

/* ---------- Expense List ---------- */
.expense-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.expense-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.expense-item:hover {
  border-color: var(--border-color-hover);
  background: var(--bg-card-hover);
}

.expense-avatar {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  color: white;
  flex-shrink: 0;
}

.expense-info {
  flex: 1;
  min-width: 0;
}

.expense-desc {
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 0.15rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.expense-meta {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.expense-amount {
  text-align: right;
  flex-shrink: 0;
}

.expense-amount .amount {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.expense-amount .split-info {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.expense-delete {
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.expense-item:hover .expense-delete {
  opacity: 1;
}

/* ---------- Balance Cards ---------- */
.balance-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.balance-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.85rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.balance-arrow {
  font-size: 1.2rem;
  color: var(--text-muted);
}

.balance-amount {
  font-weight: 700;
  font-size: 1rem;
  margin-left: auto;
  color: var(--accent-orange);
}

.debt-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  gap: 1rem;
}

.debt-from-to {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex: 1;
}

.debt-arrow {
  color: var(--accent-orange);
  font-weight: 700;
  font-size: 1.1rem;
}

.debt-amount {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent-orange);
}

/* ---------- Tabs ---------- */
.tabs {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0;
}

.tab-btn {
  padding: 0.75rem 1.25rem;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  font-family: var(--font-family);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}

.tab-btn:hover {
  color: var(--text-primary);
}

.tab-btn.active {
  color: var(--accent-primary);
  border-bottom-color: var(--accent-primary);
}

/* ---------- Section headers ---------- */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
}

/* ---------- Empty state ---------- */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 3rem 2rem;
  text-align: center;
}

.empty-state-icon {
  font-size: 3.5rem;
  margin-bottom: 1rem;
  opacity: 0.6;
}

.empty-state-title {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.empty-state-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  max-width: 320px;
}

/* ---------- Auth Pages ---------- */
.auth-page {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 2rem;
}

.auth-card {
  width: 100%;
  max-width: 420px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 2.5rem;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: var(--shadow-lg);
  animation: slideUp 0.4s ease;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

.auth-logo {
  text-align: center;
  margin-bottom: 2rem;
}

.auth-logo .logo-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-lg);
  background: var(--gradient-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.auth-logo h1 {
  font-size: 1.5rem;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.auth-logo p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 0.35rem;
}

.auth-footer {
  text-align: center;
  margin-top: 1.5rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.auth-footer a {
  color: var(--accent-primary);
  font-weight: 600;
  cursor: pointer;
}

.auth-footer a:hover {
  color: var(--accent-primary-hover);
}

.auth-btn {
  width: 100%;
  padding: 0.8rem;
  margin-top: 0.5rem;
}

/* ---------- Modal ---------- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 2rem;
  opacity: 1;
  transition: opacity var(--transition-normal);
}

.modal-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.modal-container {
  width: 100%;
  max-width: 500px;
  max-height: 85vh;
  overflow-y: auto;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  animation: modalIn 0.25s ease;
}

@keyframes modalIn {
  from { opacity: 0; transform: scale(0.95) translateY(8px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-title {
  font-size: 1.1rem;
  font-weight: 700;
}

.modal-close {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  border: none;
  background: var(--bg-glass);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: var(--bg-glass-hover);
  color: var(--text-primary);
}

.modal-body {
  padding: 1.5rem;
}

.modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.75rem;
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border-color);
}

/* ---------- Toast ---------- */
#toast-container {
  position: fixed;
  top: 80px;
  right: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  z-index: 9999;
}

.toast {
  padding: 0.85rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  color: white;
  min-width: 280px;
  max-width: 400px;
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  animation: toastIn 0.3s ease;
  cursor: pointer;
}

.toast.toast-exit {
  animation: toastOut 0.3s ease forwards;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateX(50px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes toastOut {
  from { opacity: 1; transform: translateX(0); }
  to { opacity: 0; transform: translateX(50px); }
}

.toast-success {
  background: linear-gradient(135deg, #059669, #0d9488);
}

.toast-error {
  background: linear-gradient(135deg, #dc2626, #e11d48);
}

.toast-info {
  background: linear-gradient(135deg, #4f46e5, #7c3aed);
}

/* ---------- Avatar ---------- */
.avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8rem;
  color: white;
  flex-shrink: 0;
  text-transform: uppercase;
}

.avatar-sm { width: 28px; height: 28px; font-size: 0.65rem; }
.avatar-lg { width: 48px; height: 48px; font-size: 1rem; }

.avatar-stack {
  display: flex;
}

.avatar-stack .avatar {
  margin-left: -8px;
  border: 2px solid var(--bg-primary);
}

.avatar-stack .avatar:first-child {
  margin-left: 0;
}

/* ---------- Member Pill ---------- */
.member-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.3rem 0.65rem 0.3rem 0.3rem;
  border-radius: var(--radius-full);
  background: var(--bg-glass);
  border: 1px solid var(--border-color);
  font-size: 0.8rem;
  font-weight: 500;
}

/* ---------- Split input area ---------- */
.split-inputs {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.split-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  background: var(--bg-glass);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

.split-row .member-name {
  flex: 1;
  font-size: 0.875rem;
  font-weight: 500;
}

.split-row .split-input {
  width: 100px;
  padding: 0.4rem 0.6rem;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 0.85rem;
  text-align: right;
  font-family: var(--font-family);
  outline: none;
}

.split-row .split-input:focus {
  border-color: var(--accent-primary);
}

/* ---------- Two Column Layout ---------- */
.two-col {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 1.5rem;
  align-items: start;
}

/* ---------- Badge ---------- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.badge-equal {
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-primary-hover);
}

.badge-percentage {
  background: rgba(251, 146, 60, 0.15);
  color: var(--accent-orange);
}

.badge-exact {
  background: rgba(34, 211, 238, 0.15);
  color: var(--accent-cyan);
}

/* ---------- Divider ---------- */
.divider {
  height: 1px;
  background: var(--border-color);
  margin: 1.5rem 0;
}

/* ---------- Back button ---------- */
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  margin-bottom: 1rem;
  transition: color var(--transition-fast);
  background: none;
  border: none;
  font-family: var(--font-family);
}

.back-btn:hover {
  color: var(--text-primary);
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  .navbar {
    padding: 0 1rem;
  }

  .page-container {
    padding: 1.25rem;
  }

  .two-col {
    grid-template-columns: 1fr;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .groups-grid {
    grid-template-columns: 1fr;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .auth-card {
    padding: 1.75rem;
  }

  .navbar-username {
    display: none;
  }

  h1 { font-size: 1.5rem; }
}

@media (max-width: 480px) {
  .stats-grid {
    grid-template-columns: 1fr;
  }

  .radio-group {
    flex-direction: column;
  }
}