/* ============================================================
   Friends Tour — Professional SaaS Dashboard Style
   ============================================================ */

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

:root {
  /* Surfaces */
  --bg: #f6f7f9;
  --bg-deep: #eef0f4;
  --surface: #ffffff;
  --surface-2: #fafbfc;
  --surface-3: #f3f4f7;

  /* Borders & dividers */
  --border: #e4e7ec;
  --border-strong: #d0d5dd;
  --divider: #eef0f3;

  /* Text */
  --text: #0f172a;
  --text-2: #344054;
  --text-muted: #667085;
  --text-subtle: #98a2b3;

  /* Brand — deep, sophisticated indigo */
  --primary: #4338ca;
  --primary-hover: #3730a3;
  --primary-soft: #eef2ff;
  --primary-ring: rgba(67, 56, 202, 0.18);

  /* Accents */
  --success: #047857;
  --success-soft: #ecfdf5;
  --danger: #b42318;
  --danger-soft: #fef3f2;
  --warning: #b54708;
  --warning-soft: #fffaeb;
  --info: #1570cf;
  --info-soft: #eff8ff;

  /* Shadows — subtle, premium */
  --shadow-xs: 0 1px 2px rgba(16, 24, 40, 0.05);
  --shadow-sm: 0 1px 3px rgba(16, 24, 40, 0.06), 0 1px 2px rgba(16, 24, 40, 0.04);
  --shadow-md: 0 4px 8px -2px rgba(16, 24, 40, 0.06), 0 2px 4px -2px rgba(16, 24, 40, 0.04);
  --shadow-lg: 0 12px 20px -4px rgba(16, 24, 40, 0.10), 0 4px 8px -4px rgba(16, 24, 40, 0.06);
  --shadow-xl: 0 20px 32px -8px rgba(16, 24, 40, 0.14);

  --radius: 10px;
  --radius-sm: 8px;
  --radius-lg: 14px;

  --transition: 160ms cubic-bezier(0.4, 0, 0.2, 1);
}

html { -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }

body {
  font-family: 'Inter', 'Hind Siliguri', 'Poppins', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
  font-size: 14px;
  font-feature-settings: 'cv11', 'ss01', 'ss03';
}

.container { max-width: 1280px; margin: 0 auto; padding: 0 32px; }
@media (max-width: 720px) { .container { padding: 0 16px; } }

.hidden { display: none !important; }
.muted { color: var(--text-muted); font-size: 0.875rem; }
.center { text-align: center; padding: 48px 20px; }

/* ============ HEADER ============ */
.app-header {
  background: var(--surface);
  color: var(--text);
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(180%) blur(8px);
  background: rgba(255, 255, 255, 0.92);
}

.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; flex-wrap: wrap;
}

.brand { display: flex; align-items: center; gap: 12px; }
.brand-icon {
  width: 38px; height: 38px;
  border-radius: 10px;
  background: linear-gradient(135deg, #4338ca 0%, #6366f1 100%);
  color: #fff;
  display: grid; place-items: center;
  font-weight: 700; font-size: 0.82rem;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 10px -2px rgba(67, 56, 202, 0.35);
}
.brand h1 {
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text);
}
.tagline {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.header-actions { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }

.tour-select {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 8px 32px 8px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  min-width: 200px;
  font-family: inherit;
  transition: var(--transition);
  appearance: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%23667085' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'><polyline points='6 9 12 15 18 9'/></svg>");
  background-repeat: no-repeat;
  background-position: right 10px center;
}
.tour-select:hover { border-color: var(--border-strong); }
.tour-select:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-ring); }

/* ============ BUTTONS ============ */
.btn {
  padding: 8px 14px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
  line-height: 1.2;
}
.btn:focus-visible { outline: none; box-shadow: 0 0 0 3px var(--primary-ring); }

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 1px 2px rgba(16, 24, 40, 0.05);
}
.btn-primary:hover { background: var(--primary-hover); }

.btn-ghost {
  background: var(--surface);
  color: var(--text-2);
  border-color: var(--border);
}
.btn-ghost:hover { background: var(--surface-3); border-color: var(--border-strong); color: var(--text); }

.btn-danger {
  background: var(--surface);
  color: var(--danger);
  border-color: var(--border);
}
.btn-danger:hover { background: var(--danger-soft); border-color: #fda29b; }

.modal-footer .btn-danger { background: var(--danger); color: #fff; border-color: var(--danger); }
.modal-footer .btn-danger:hover { background: #912018; }

.btn-sm { padding: 6px 10px; font-size: 0.8125rem; }
.btn-lg { padding: 11px 22px; font-size: 0.9375rem; font-weight: 600; }

/* ============ EMPTY STATE ============ */
.empty-state { display: grid; place-items: center; min-height: 70vh; padding: 40px 20px; }
.empty-card {
  background: var(--surface);
  padding: 56px 48px;
  border-radius: var(--radius-lg);
  text-align: center;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  max-width: 480px;
}
.empty-icon {
  width: 72px; height: 72px;
  margin: 0 auto 20px;
  border-radius: 50%;
  background: var(--primary-soft);
  display: grid; place-items: center;
  font-size: 2rem;
}
.empty-card h2 {
  font-size: 1.375rem;
  font-weight: 600;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}
.empty-card p { color: var(--text-muted); margin-bottom: 28px; font-size: 0.9375rem; }

/* ============ DASHBOARD ============ */
.dashboard { padding: 28px 0 48px; }

.tour-info-bar {
  display: flex; justify-content: space-between; align-items: flex-start; flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 28px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--divider);
}
.tour-info-bar h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 4px;
  letter-spacing: -0.02em;
  color: var(--text);
}
.tour-info-bar .muted { font-size: 0.875rem; }
.tour-actions { display: flex; gap: 8px; }

/* ============ STAT CARDS ============ */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}
.stat-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 20px 22px;
  border: 1px solid var(--border);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}
.stat-card:hover {
  border-color: var(--border-strong);
  box-shadow: var(--shadow-sm);
}
.stat-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--primary);
  opacity: 0;
  transition: var(--transition);
}
.stat-card:hover::before { opacity: 1; }

.stat-total::before { background: var(--primary); }
.stat-members::before { background: var(--info); }
.stat-perhead::before { background: var(--success); }
.stat-days::before { background: var(--warning); }

.stat-label {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-bottom: 8px;
  font-weight: 500;
  letter-spacing: 0.01em;
}
.stat-value {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
  line-height: 1.1;
}
.stat-sub {
  font-size: 0.75rem;
  color: var(--text-subtle);
  margin-top: 6px;
  font-weight: 500;
}

/* ============ TABS ============ */
.tabs {
  display: flex; gap: 0;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
  scrollbar-width: none;
}
.tabs::-webkit-scrollbar { display: none; }

.tab-btn {
  background: none;
  border: none;
  padding: 12px 18px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: var(--transition);
  font-family: inherit;
  white-space: nowrap;
  position: relative;
}
.tab-btn:hover { color: var(--text-2); }
.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
  font-weight: 600;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fadeIn 0.2s ease; }
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.panel-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 20px; flex-wrap: wrap; gap: 12px;
}
.panel-header h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.section-title {
  margin: 28px 0 14px;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-2);
  letter-spacing: -0.005em;
}

/* ============ FILTER BAR ============ */
.filter-bar {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 10px;
  margin-bottom: 20px;
  padding: 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
@media (max-width: 720px) { .filter-bar { grid-template-columns: 1fr 1fr; } }
.filter-bar .input { margin: 0; }

/* ============ EXPENSE LIST ============ */
.expense-list { display: grid; gap: 8px; }

.expense-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  display: grid;
  grid-template-columns: auto 1fr auto auto;
  gap: 16px;
  align-items: center;
  transition: var(--transition);
}
.expense-card:hover {
  border-color: var(--border-strong);
  box-shadow: var(--shadow-sm);
}

.expense-icon {
  width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--primary-soft);
  display: grid; place-items: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.expense-info h4 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--text);
  letter-spacing: -0.005em;
}
.expense-meta {
  font-size: 0.8125rem;
  color: var(--text-muted);
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}
.expense-meta span { display: inline-flex; align-items: center; gap: 4px; }

.expense-amount {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text);
  text-align: right;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.expense-actions { display: flex; gap: 4px; }

.icon-btn {
  background: transparent;
  border: 1px solid transparent;
  width: 32px; height: 32px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: grid; place-items: center;
  font-size: 0.875rem;
  transition: var(--transition);
  color: var(--text-muted);
}
.icon-btn:hover {
  background: var(--surface-3);
  border-color: var(--border);
  color: var(--text);
}
.icon-btn.danger:hover {
  background: var(--danger-soft);
  border-color: #fda29b;
  color: var(--danger);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 0.6875rem;
  font-weight: 600;
  background: var(--primary-soft);
  color: var(--primary);
  letter-spacing: 0.02em;
  text-transform: uppercase;
  border: 1px solid rgba(67, 56, 202, 0.12);
}

/* ============ MEMBER LIST ============ */
.member-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
}
.member-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  display: flex; align-items: center; gap: 14px;
  transition: var(--transition);
}
.member-card:hover { border-color: var(--border-strong); box-shadow: var(--shadow-sm); }

.member-avatar {
  width: 44px; height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, #4338ca, #6366f1);
  color: #fff;
  display: grid; place-items: center;
  font-weight: 600;
  font-size: 0.9375rem;
  letter-spacing: 0.02em;
  flex-shrink: 0;
  box-shadow: 0 2px 6px -1px rgba(67, 56, 202, 0.25);
}
.member-info { flex: 1; min-width: 0; }
.member-info h4 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin-bottom: 2px;
  color: var(--text);
}
.member-info p {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}
.member-stats {
  font-size: 0.75rem;
  font-weight: 600;
  margin-top: 4px;
}

/* ============ SETTLEMENT ============ */
.balance-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
  margin-bottom: 12px;
}
.balance-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  position: relative;
  overflow: hidden;
  transition: var(--transition);
}
.balance-card::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--text-subtle);
}
.balance-card.positive::before { background: var(--success); }
.balance-card.negative::before { background: var(--danger); }
.balance-card:hover { box-shadow: var(--shadow-sm); }

.balance-name {
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 6px;
  color: var(--text);
}
.balance-amount {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.2;
}
.balance-amount.positive { color: var(--success); }
.balance-amount.negative { color: var(--danger); }
.balance-amount.zero { color: var(--text-muted); }
.balance-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 2px;
  font-weight: 500;
}

.settlement-list { display: grid; gap: 8px; }
.settlement-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 16px;
  display: flex; align-items: center; gap: 12px;
  flex-wrap: wrap;
  transition: var(--transition);
  font-size: 0.9375rem;
}
.settlement-item:hover { border-color: var(--border-strong); }
.settlement-from { font-weight: 600; color: var(--danger); }
.settlement-to { font-weight: 600; color: var(--success); }
.settlement-amount {
  margin-left: auto;
  font-weight: 700;
  font-size: 1.0625rem;
  color: var(--text);
  letter-spacing: -0.01em;
}
.settlement-arrow { color: var(--text-subtle); font-size: 1.1rem; }

/* ============ REPORTS ============ */
.report-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(360px, 1fr));
  gap: 16px;
}
.report-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}
.report-card.full { grid-column: 1 / -1; }
.report-card h4 {
  margin-bottom: 18px;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.005em;
}

.bar-chart { display: grid; gap: 12px; }
.bar-row {
  display: grid;
  grid-template-columns: 130px 1fr auto;
  gap: 12px;
  align-items: center;
  font-size: 0.8125rem;
}
.bar-label {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--text-2);
  font-weight: 500;
}
.bar-track {
  background: var(--surface-3);
  height: 22px;
  border-radius: 6px;
  overflow: hidden;
  position: relative;
}
.bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary) 0%, #6366f1 100%);
  border-radius: 6px;
  transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}
.bar-value {
  font-weight: 600;
  font-size: 0.8125rem;
  min-width: 80px;
  text-align: right;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

/* ============ FORMS ============ */
.input {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-family: inherit;
  background: var(--surface);
  color: var(--text);
  transition: var(--transition);
  line-height: 1.4;
}
.input:hover { border-color: var(--border-strong); }
.input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-ring);
}
.input::placeholder { color: var(--text-subtle); }

select.input {
  appearance: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%23667085' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'><polyline points='6 9 12 15 18 9'/></svg>");
  background-repeat: no-repeat;
  background-position: right 10px center;
  padding-right: 32px;
}

textarea.input { resize: vertical; min-height: 60px; }

label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-2);
  margin: 14px 0 6px;
}

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 520px) { .grid-2 { grid-template-columns: 1fr; } }

.checkbox-group {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 4px;
  padding: 10px;
  background: var(--surface-2);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}
.checkbox-item {
  display: flex; align-items: center; gap: 8px;
  font-size: 0.8125rem;
  cursor: pointer;
  padding: 6px 10px;
  border-radius: 6px;
  transition: var(--transition);
  font-weight: 500;
  color: var(--text-2);
}
.checkbox-item:hover { background: var(--surface); }
.checkbox-item input {
  width: 16px; height: 16px;
  cursor: pointer;
  accent-color: var(--primary);
}

/* ============ MODAL ============ */
.modal {
  position: fixed; inset: 0;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(6px);
  z-index: 100;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
  animation: fadeIn 0.15s;
}
.modal.show { display: flex; }
.modal-content {
  background: var(--surface);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 520px;
  max-height: 90vh;
  overflow: hidden;
  display: flex; flex-direction: column;
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--border);
  animation: slideUp 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}
.modal-lg { max-width: 640px; }
.modal-sm { max-width: 420px; }
@keyframes slideUp {
  from { transform: translateY(16px) scale(0.98); opacity: 0; }
  to { transform: translateY(0) scale(1); opacity: 1; }
}
.modal-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--divider);
  display: flex; justify-content: space-between; align-items: center;
}
.modal-header h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.close-btn {
  background: none; border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
  width: 32px; height: 32px;
  border-radius: var(--radius-sm);
  display: grid; place-items: center;
  transition: var(--transition);
  line-height: 1;
}
.close-btn:hover { background: var(--surface-3); color: var(--text); }
.modal-body { padding: 18px 24px 22px; overflow-y: auto; flex: 1; }
.modal-body label:first-child { margin-top: 0; }
.modal-footer {
  padding: 14px 24px;
  border-top: 1px solid var(--divider);
  display: flex; justify-content: flex-end; gap: 8px;
  background: var(--surface-2);
}

/* ============ TOAST ============ */
.toast {
  position: fixed;
  bottom: 24px; left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--text);
  color: #fff;
  padding: 12px 20px;
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 500;
  box-shadow: var(--shadow-xl);
  z-index: 200;
  opacity: 0;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }

/* ============ FOOTER ============ */
.footer {
  padding: 24px 0;
  text-align: center;
  color: var(--text-subtle);
  font-size: 0.8125rem;
  margin-top: 48px;
  border-top: 1px solid var(--divider);
}

/* ============ SCROLLBAR ============ */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 8px; border: 2px solid var(--bg); }
::-webkit-scrollbar-thumb:hover { background: var(--text-subtle); }

/* ============ RESPONSIVE ============ */
@media (max-width: 640px) {
  body { font-size: 13px; }
  .brand h1 { font-size: 1rem; }
  .stat-value { font-size: 1.5rem; }
  .expense-card { grid-template-columns: auto 1fr; }
  .expense-amount { grid-column: 2; text-align: left; }
  .expense-actions { grid-column: 1 / -1; justify-content: flex-end; }
  .header-actions { width: 100%; }
  .tour-select { flex: 1; min-width: 0; }
}