:root {
  --teal: #0d9488;
  --teal-dark: #0f766e;
  --teal-light: #ccfbf1;
  --bg: #f6f8f8;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --red: #dc2626;
  --green: #16a34a;
  --orange: #ea580c;
  --radius: 14px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08), 0 4px 12px rgba(0, 0, 0, 0.04);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans", sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

#app {
  max-width: 560px;
  margin: 0 auto;
  min-height: 100vh;
  padding-bottom: 96px;
}

/* ---------- Header ---------- */
.topbar {
  background: var(--teal);
  color: #fff;
  padding: 18px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  position: sticky;
  top: 0;
  z-index: 10;
}
.topbar h1 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  flex: 1;
}
.topbar .tagline {
  font-size: 0.75rem;
  opacity: 0.85;
  display: block;
  font-weight: 400;
}
.back-btn {
  background: rgba(255, 255, 255, 0.15);
  border: none;
  color: #fff;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  font-size: 1.1rem;
  cursor: pointer;
  flex-shrink: 0;
}
.back-btn:hover { background: rgba(255, 255, 255, 0.28); }

/* ---------- Cards & lists ---------- */
.section { padding: 16px; }
.section h3 {
  margin: 4px 4px 10px;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.group-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  cursor: pointer;
  border: none;
  background: var(--card);
  width: 100%;
  text-align: left;
  font: inherit;
  color: inherit;
  border-bottom: 1px solid var(--border);
}
.group-card:last-child { border-bottom: none; }
.group-card:hover { background: #fafcfc; }

.avatar {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--teal-light);
  color: var(--teal-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}
.avatar.round { border-radius: 50%; width: 38px; height: 38px; font-size: 0.9rem; }

.group-card .meta { flex: 1; min-width: 0; }
.group-card .meta strong { display: block; font-size: 1rem; }
.group-card .meta span { font-size: 0.8rem; color: var(--muted); }
.group-card .amt { font-weight: 700; font-size: 0.95rem; }

/* ---------- Empty state ---------- */
.empty {
  text-align: center;
  padding: 64px 24px;
  color: var(--muted);
}
.empty .big { font-size: 3rem; margin-bottom: 12px; }
.empty p { margin: 4px 0; }

/* ---------- Buttons ---------- */
.btn {
  border: none;
  border-radius: 10px;
  padding: 11px 18px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
}
.btn.primary { background: var(--teal); color: #fff; }
.btn.primary:hover { background: var(--teal-dark); }
.btn.ghost {
  background: #fff;
  color: var(--teal-dark);
  border: 1.5px solid var(--teal);
}
.btn.ghost:hover { background: var(--teal-light); }
.btn.full { width: 100%; margin-top: 8px; }
.btn.small { padding: 6px 12px; font-size: 0.8rem; border-radius: 8px; }

.fab {
  position: fixed;
  bottom: 24px;
  right: calc(50% - 280px + 24px);
  background: var(--teal);
  color: #fff;
  border: none;
  border-radius: 28px;
  padding: 15px 22px;
  font-size: 0.95rem;
  font-weight: 700;
  box-shadow: 0 6px 20px rgba(13, 148, 136, 0.4);
  cursor: pointer;
  z-index: 20;
  font-family: inherit;
}
@media (max-width: 600px) { .fab { right: 20px; } }
.fab:hover { background: var(--teal-dark); }

.action-row {
  display: flex;
  gap: 10px;
  padding: 16px 16px 0;
}
.action-row .btn { flex: 1; }

.icon-btn {
  background: none;
  border: none;
  font-size: 1.5rem;
  line-height: 1;
  cursor: pointer;
  color: var(--muted);
  padding: 4px 8px;
}

/* ---------- Tabs ---------- */
.tabs {
  display: flex;
  margin: 16px 16px 0;
  background: #e9eeee;
  border-radius: 10px;
  padding: 4px;
}
.tabs button {
  flex: 1;
  border: none;
  background: none;
  padding: 8px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--muted);
  cursor: pointer;
  font-family: inherit;
}
.tabs button.active {
  background: #fff;
  color: var(--teal-dark);
  box-shadow: var(--shadow);
}

/* ---------- Expense list ---------- */
.expense-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 13px 16px;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
}
.expense-row:last-child { border-bottom: none; }
.expense-row:hover { background: #fafcfc; }
.expense-row .date-chip {
  width: 42px;
  text-align: center;
  color: var(--muted);
  flex-shrink: 0;
}
.expense-row .date-chip .mon { font-size: 0.65rem; text-transform: uppercase; display: block; }
.expense-row .date-chip .day { font-size: 1.1rem; font-weight: 700; display: block; color: var(--text); }
.expense-row .meta { flex: 1; min-width: 0; }
.expense-row .meta strong { display: block; font-size: 0.95rem; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.expense-row .meta span { font-size: 0.78rem; color: var(--muted); }
.expense-row .amt { font-weight: 700; }
.expense-row.settle-row .meta strong { color: var(--green); }

.expense-detail {
  background: #f0fdfa;
  padding: 12px 16px 14px 70px;
  font-size: 0.85rem;
  border-bottom: 1px solid var(--border);
}
.expense-detail ul { margin: 6px 0 10px; padding-left: 18px; }
.expense-detail li { margin: 2px 0; }
.btn.danger { background: #fee2e2; color: var(--red); }
.btn.danger:hover { background: #fecaca; }

/* ---------- Balances ---------- */
.balance-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 13px 16px;
  border-bottom: 1px solid var(--border);
}
.balance-row:last-child { border-bottom: none; }
.balance-row .name { flex: 1; font-weight: 600; }
.pos { color: var(--green); font-weight: 700; }
.neg { color: var(--orange); font-weight: 700; }
.zero { color: var(--muted); font-weight: 600; }

.debt-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 13px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 0.92rem;
}
.debt-row:last-child { border-bottom: none; }
.debt-row .flow { flex: 1; }
.debt-row .flow b { font-weight: 700; }
.debt-row .flow .arrow { color: var(--muted); margin: 0 6px; }
.all-settled {
  padding: 28px 16px;
  text-align: center;
  color: var(--green);
  font-weight: 600;
}

/* ---------- Modals ---------- */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  z-index: 50;
}
@media (min-width: 600px) { .modal-backdrop { align-items: center; } }
.modal-backdrop.hidden { display: none; }
.modal {
  background: #fff;
  border-radius: 20px 20px 0 0;
  width: 100%;
  max-width: 480px;
  padding: 20px 22px 26px;
  max-height: 88vh;
  overflow-y: auto;
}
@media (min-width: 600px) { .modal { border-radius: 20px; } }
.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
}
.modal-head h2 { margin: 0; font-size: 1.15rem; }

.modal label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
  margin: 14px 0 0;
}
.modal input, .modal select, .modal textarea {
  display: block;
  width: 100%;
  margin-top: 5px;
  padding: 11px 12px;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  font-size: 1rem;
  font-family: inherit;
  background: #fff;
  color: var(--text);
}
.modal input:focus, .modal select:focus, .modal textarea:focus {
  outline: none;
  border-color: var(--teal);
}

/* split UI inside expense modal */
.split-tabs {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}
.split-tab {
  flex: 1;
  padding: 8px;
  border: 1.5px solid var(--border);
  background: #fff;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.83rem;
  color: var(--muted);
  cursor: pointer;
  font-family: inherit;
}
.split-tab.active {
  border-color: var(--teal);
  color: var(--teal-dark);
  background: var(--teal-light);
}
.split-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 2px;
}
.split-row label {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  flex: 1;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
  cursor: pointer;
}
.split-row input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin: 0;
  accent-color: var(--teal);
  display: inline-block;
}
.split-row input.share {
  width: 96px;
  margin: 0;
  padding: 7px 10px;
  text-align: right;
}
.split-hint {
  font-size: 0.8rem;
  color: var(--muted);
  margin: 6px 2px 0;
  min-height: 1em;
}
.split-hint.err { color: var(--red); font-weight: 600; }

/* member chips */
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 12px 16px 0;
}
.chip {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 12px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
  box-shadow: var(--shadow);
}
.chip.add {
  color: var(--teal-dark);
  border-color: var(--teal);
  cursor: pointer;
  background: var(--teal-light);
  font-family: inherit;
}

.summary-strip {
  background: var(--card);
  margin: 16px 16px 0;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 14px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: var(--muted);
}
.summary-strip b { display: block; font-size: 1.05rem; margin-top: 2px; }
.me-chip { font-weight: 600; color: var(--teal-dark); font-size: 0.8rem; }

/* ---------- boot / signed-out hero ---------- */
.boot { text-align: center; padding: 80px 20px; color: var(--muted); }
.hero {
  text-align: center;
  padding: 72px 28px;
  max-width: 380px;
  margin: 0 auto;
}
.hero-logo {
  width: 76px;
  height: 76px;
  border-radius: 22px;
  background: var(--teal);
  color: #fff;
  font-size: 2.4rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 18px;
  box-shadow: 0 8px 24px rgba(13, 148, 136, 0.35);
}
.hero h1 { margin: 0; font-size: 2rem; }
.hero-tag { color: var(--muted); margin: 6px 0 22px; }
.hero-points {
  list-style: none;
  padding: 0;
  margin: 0 0 28px;
  text-align: left;
  display: inline-block;
}
.hero-points li { padding: 5px 0 5px 26px; position: relative; color: var(--text); }
.hero-points li::before { content: "\2714"; position: absolute; left: 0; color: var(--teal); font-weight: 700; }
.btn.google {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: #fff;
  color: var(--text);
  border: 1.5px solid var(--border);
  box-shadow: var(--shadow);
  padding: 12px 22px;
  font-size: 1rem;
}
.btn.google:hover { border-color: var(--teal); }
.auth-error { color: var(--red); font-size: 0.85rem; margin-top: 16px; }
.gate-text { color: var(--muted); font-size: 0.92rem; margin: 0 0 24px; line-height: 1.5; }

/* ---------- home extras ---------- */
.topbar .user-pic {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.5);
  flex-shrink: 0;
}
.signout-btn {
  background: rgba(255, 255, 255, 0.15);
  border: none;
  color: #fff;
  border-radius: 8px;
  padding: 7px 12px;
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  flex-shrink: 0;
}
.signout-btn:hover { background: rgba(255, 255, 255, 0.28); }
.amt-sm { font-size: 0.82rem; font-weight: 600; text-align: right; }
.form-note { font-size: 0.78rem; color: var(--muted); margin: 12px 2px 0; }
.added-by { font-size: 0.75rem; color: var(--muted); margin-right: 10px; }
.btn.danger.full { margin-top: 10px; }