:root {
  --bg: #f4f6f8;
  --card-bg: #ffffff;
  --primary: #2f6f4f;
  --accent: #b45309;
  --text: #1f2937;
  --border: #e2e8f0;
}

* { box-sizing: border-box; }

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

#app {
  max-width: 480px;
  margin: 0 auto;
  padding: 16px;
}

.hidden { display: none !important; }

h1 { font-size: 1.4rem; margin: 0 0 16px; }
h2 { font-size: 1.05rem; margin: 0 0 12px; }

.card {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.balance {
  text-align: center;
  padding: 24px 16px;
}
.balance-text {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 0 0 12px;
}
.balance.settled .balance-text { color: var(--primary); }
.balance.owe .balance-text { color: var(--accent); }

#settle-btn {
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 8px;
  padding: 8px 16px;
  font-size: 0.9rem;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}
header > div { display: flex; align-items: center; gap: 8px; }

label {
  display: block;
  margin-bottom: 12px;
  font-size: 0.9rem;
  color: #475569;
}

input[type="text"], input[type="number"], input[type="password"] {
  width: 100%;
  padding: 10px 12px;
  margin-top: 4px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
}

input[type="range"] { width: 100%; }

button { cursor: pointer; font-size: 0.95rem; }

button[type="submit"] {
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 8px;
  padding: 10px 16px;
  width: 100%;
}

#logout-btn {
  background: transparent;
  color: #64748b;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
}

.btn-secondary {
  background: transparent;
  color: #64748b;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 16px;
  width: 100%;
  margin-top: 8px;
}

.user-toggle {
  display: flex;
  gap: 12px;
  margin-bottom: 16px;
}
.user-btn {
  flex: 1;
  padding: 16px;
  border-radius: 10px;
  border: 2px solid var(--border);
  background: white;
  font-size: 1.05rem;
}
.user-btn.active {
  border-color: var(--primary);
  color: var(--primary);
  font-weight: 600;
}

.field-group { margin-bottom: 14px; }
.field-label {
  display: block;
  font-size: 0.9rem;
  color: #475569;
  margin-bottom: 6px;
}

.segmented {
  display: flex;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}
.segmented button {
  flex: 1;
  padding: 8px;
  border: none;
  background: white;
  border-right: 1px solid var(--border);
}
.segmented button:last-child { border-right: none; }
.segmented button.active {
  background: var(--primary);
  color: white;
}

.slider-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: #475569;
  margin-top: 4px;
}

.hint { font-size: 0.85rem; color: #475569; }
.hint.error { color: #dc2626; }
.error { color: #dc2626; font-size: 0.9rem; }

#expense-list { list-style: none; padding: 0; margin: 0; }
#expense-list li {
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
}
#expense-list li:last-child { border-bottom: none; }
.expense-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 8px;
}
.meta { font-size: 0.8rem; color: #64748b; margin-top: 2px; }
.expense-amount {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  white-space: nowrap;
}
.delete-btn {
  background: none;
  border: none;
  color: #94a3b8;
  font-size: 1.2rem;
  line-height: 1;
  padding: 0 4px;
}
.empty { color: #94a3b8; text-align: center; padding: 12px 0; }