:root {
  --primary-bg: #0b0f17;
  --secondary-bg: rgba(255, 255, 255, .03);
  --message-bg: rgba(255, 255, 255, .04);
  --my-message-bg: rgba(120, 160, 255, .12);
  --text-color: #e7eefc;
  --border-color: rgba(255, 255, 255, .12);
  --border-light: rgba(255, 255, 255, .10);
  --input-bg: rgba(255, 255, 255, .06);
  --form-bg: rgba(0, 0, 0, .15);
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-full: 999px;
  --accent: #4dabf7;
  --accent-green: #51cf66;
  --accent-red: #ff6b6b;
  --accent-yellow: #ffd43b;
}

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

body {
  font-family: system-ui, -apple-system, sans-serif;
  background: var(--primary-bg);
  color: var(--text-color);
  min-height: 100vh;
}

.wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 12px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 8px 0;
}

.top h2 { 
  margin: 0; 
  font-size: 1.2rem; 
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.auth-section {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
  justify-content: flex-end;
}

button {
  border-radius: var(--radius-md);
  border: 1px solid var(--border-light);
  background: var(--input-bg);
  color: var(--text-color);
  cursor: pointer;
  padding: 10px 14px;
  font-size: 0.9rem;
  white-space: nowrap;
  transition: all 0.2s ease;
  font-weight: 500;
}

button:hover:not(:disabled) { 
  background: rgba(255,255,255,.09); 
  transform: translateY(-1px);
}

button:active:not(:disabled) { transform: translateY(0); }
button:disabled { 
  opacity: .5; 
  cursor: not-allowed; 
}

button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}

button.success {
  background: var(--accent-green);
  border-color: var(--accent-green);
  color: white;
}

button.danger {
  background: var(--accent-red);
  border-color: var(--accent-red);
  color: white;
}

.pill {
  padding: 6px 10px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  opacity: .9;
  max-width: 220px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: rgba(255,255,255,.08);
  font-size: 0.85rem;
  border: 1px solid transparent;
}

.chip.user { border-color: var(--accent); }
.chip.manual { border-color: var(--accent-green); }
.chip.payer { border-color: var(--accent-yellow); }

/* CHAT */
.chat {
  flex: 1;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--secondary-bg);
  min-height: 0;
}

.msgs {
  flex: 1;
  overflow: auto;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.msg {
  max-width: 85%;
  padding: 10px 12px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-light);
  background: var(--message-bg);
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.me { 
  align-self: flex-end; 
  background: var(--my-message-bg); 
  border-color: rgba(120, 160, 255, .2); 
}

.meta {
  font-size: 0.8rem;
  opacity: .7;
  margin-bottom: 6px;
  display: flex;
  justify-content: space-between;
  gap: 10px;
}

.time { 
  font-size: 0.75rem; 
  opacity: 0.65; 
  white-space: nowrap;
}

.msg-content { 
  line-height: 1.35; 
  word-break: break-word;
}

form.chatbar {
  display: flex;
  gap: 10px;
  padding: 12px;
  border-top: 1px solid var(--border-light);
  background: var(--form-bg);
  flex-shrink: 0;
}

input, select, textarea {
  border-radius: var(--radius-md);
  border: 1px solid var(--border-light);
  background: var(--input-bg);
  color: var(--text-color);
  padding: 12px;
  outline: none;
  font-size: 1rem;
  font-family: inherit;
}

input, textarea {
  flex: 1;
  min-width: 0;
}

input::placeholder, textarea::placeholder { 
  color: rgba(231,238,252,0.6); 
}

select {
  cursor: pointer;
  background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='white'%3e%3cpath d='M7 10l5 5 5-5z'/%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 10px center;
  background-size: 20px;
  padding-right: 40px;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
}

/* SETTLEMENT IMPROVED */
.settlement-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.panel {
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--secondary-bg);
}

.panel-header {
  padding: 14px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  background: rgba(0,0,0,.1);
}

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

.panel-subtitle {
  font-size: 0.85rem;
  opacity: 0.8;
  margin-top: 2px;
}

.panel-body { 
  padding: 14px; 
  display: flex; 
  flex-direction: column; 
  gap: 14px; 
}

.grid-responsive {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 14px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.field label {
  font-size: 0.85rem;
  opacity: .8;
  font-weight: 500;
}

textarea { 
  min-height: 100px; 
  resize: vertical; 
  line-height: 1.4;
}

.hint { 
  opacity: .75; 
  font-size: 0.85rem; 
  line-height: 1.35; 
  font-style: italic;
}

.flex-row {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.flex-row button { flex-shrink: 0; }

/* Participants Selection */
.participants-section {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.participants-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 10px;
}

.participant-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  background: rgba(255,255,255,.03);
  cursor: pointer;
  transition: all 0.2s;
}

.participant-item:hover {
  background: rgba(255,255,255,.06);
  border-color: var(--accent);
}

.participant-item.selected {
  background: rgba(77, 171, 247, 0.15);
  border-color: var(--accent);
}

.participant-item.payer {
  background: rgba(255, 212, 59, 0.15);
  border-color: var(--accent-yellow);
}

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

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

.participant-item.payer .checkbox {
  background: var(--accent-yellow);
  border-color: var(--accent-yellow);
}

.checkbox::after {
  content: "✓";
  color: white;
  font-size: 12px;
  font-weight: bold;
}

.participant-name {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.role-badge {
  font-size: 0.7rem;
  padding: 2px 6px;
  border-radius: 4px;
  background: rgba(255,255,255,.1);
  white-space: nowrap;
}

/* Expenses List */
.expenses-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 12px;
}

.expense-card {
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 14px;
  background: rgba(255,255,255,.03);
  transition: all 0.2s;
}

.expense-card:hover {
  background: rgba(255,255,255,.05);
  border-color: rgba(255,255,255,.15);
}

.expense-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}

.expense-title {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text-color);
}

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

.expense-details {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 8px;
}

.expense-meta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  font-size: 0.85rem;
  opacity: 0.8;
}

.expense-note {
  margin-top: 8px;
  padding: 8px;
  background: rgba(0,0,0,.2);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  line-height: 1.4;
}

.expense-participants {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}

.settlement-stats {
  margin-top: 16px;
  padding: 16px;
  background: rgba(0,0,0,.15);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
  margin-top: 12px;
}

.stat-item {
  padding: 12px;
  border-radius: var(--radius-md);
  background: rgba(255,255,255,.04);
  border: 1px solid var(--border-light);
}

.stat-label {
  font-size: 0.85rem;
  opacity: 0.7;
  margin-bottom: 4px;
}

.stat-value {
  font-size: 1.2rem;
  font-weight: 700;
}

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

.balance-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 12px;
}

.balance-table th,
.balance-table td {
  padding: 10px;
  text-align: left;
  border-bottom: 1px solid var(--border-light);
}

.balance-table th {
  font-weight: 600;
  opacity: 0.8;
  font-size: 0.9rem;
}

.balance-table tr:last-child td {
  border-bottom: none;
}

.amount-cell {
  font-weight: 600;
  font-family: monospace;
}

.amount-cell.positive { color: var(--accent-green); }
.amount-cell.negative { color: var(--accent-red); }
.amount-cell.neutral { opacity: 0.7; }

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 20px;
}

.modal {
  background: var(--primary-bg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
  from { opacity: 0; transform: translateY(-20px); }
  to { opacity: 1; transform: translateY(0); }
}

.modal-header {
  padding: 16px;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-body {
  padding: 16px;
}

.modal-footer {
  padding: 16px;
  border-top: 1px solid var(--border-light);
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

/* Responsive */
@media (max-width: 768px) {
  .wrap {
    padding: 8px;
    gap: 8px;
  }
  .top h2 {
    font-size: 1rem;
  }
  button {
    padding: 8px 12px;
    font-size: 0.85rem;
  }
  .panel-header, .panel-body {
    padding: 12px;
  }
  .participants-grid {
    grid-template-columns: 1fr;
  }
  .expense-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
  .expense-meta {
    flex-direction: column;
    gap: 6px;
  }
  .stats-grid {
    grid-template-columns: 1fr;
  }
  .grid-responsive {
    grid-template-columns: 1fr;
  }
  form.chatbar {
    padding: 10px;
  }
  .modal {
    max-height: 95vh;
  }
}

@media (max-width: 480px) {
  .top {
    flex-direction: column;
    align-items: flex-start;
  }
  .auth-section {
    width: 100%;
    justify-content: space-between;
  }
  .panel-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  .modal-overlay {
    padding: 10px;
  }
}

/* Utility */
.hidden { display: none !important; }
.text-center { text-align: center; }
.mt-2 { margin-top: 8px; }
.mb-2 { margin-bottom: 8px; }
.gap-2 { gap: 8px; }
.full-width { width: 100%; }
.cursor-pointer { cursor: pointer; }
.loading {
  opacity: 0.6;
  pointer-events: none;
  position: relative;
}
.loading::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-light);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}

:root { color-scheme: dark; }

select {
  color-scheme: dark;
}

select option {
  background: #0b0f17;
  color: #e7eefc;
}