:root {
  --bg: #f5f6fa;
  --card: #ffffff;
  --accent: #2e7d32;
  --accent-dark: #1b5e20;
  --text: #222;
  --muted: #666;
  --owe: #c62828;
  --owed: #2e7d32;
  --border: #e0e0e0;
}

[data-theme="dark"] {
  --bg: #14161a;
  --card: #1e2126;
  --accent: #4caf50;
  --accent-dark: #66bb6a;
  --text: #e8e8e8;
  --muted: #9aa0a6;
  --owe: #ef5350;
  --owed: #66bb6a;
  --border: #33373d;
}

body {
  transition: background-color 0.15s ease, color 0.15s ease;
}

* { box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  margin: 0;
  padding: 24px 16px 60px;
}

.container {
  max-width: 720px;
  margin: 0 auto;
}

h1 {
  margin-bottom: 0;
}

.subtitle {
  color: var(--muted);
  margin-top: 4px;
}

.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
}

.theme-toggle {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 8px 14px;
  font-size: 0.9rem;
  cursor: pointer;
}

.theme-toggle:hover {
  background: var(--border);
}

.card {
  background: var(--card);
  border-radius: 12px;
  padding: 20px 24px;
  margin-top: 20px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  transition: background-color 0.15s ease;
}

[data-theme="dark"] .card {
  box-shadow: 0 1px 3px rgba(0,0,0,0.4);
}

.card h2 {
  margin-top: 0;
  font-size: 1.1rem;
}

form label {
  display: block;
  margin-bottom: 12px;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--muted);
}

form input, form select {
  display: block;
  width: 100%;
  margin-top: 4px;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  background: var(--card);
  color: var(--text);
}

fieldset {
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 16px;
}

#participants-checkboxes label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: normal;
  margin-right: 16px;
  color: var(--text);
}

#participants-checkboxes input {
  width: auto;
}

button {
  background: var(--accent);
  color: white;
  border: none;
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
}

button:hover {
  background: var(--accent-dark);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

th, td {
  text-align: left;
  padding: 8px 6px;
  border-bottom: 1px solid var(--border);
}

th {
  color: var(--muted);
  font-weight: 600;
}

.delete-btn {
  background: transparent;
  color: var(--owe);
  padding: 2px 8px;
  font-size: 0.85rem;
}

.delete-btn:hover {
  background: #ffebee;
}

#balances-list, #settlements-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

#balances-list li, #settlements-list li {
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
}

#balances-list li:last-child, #settlements-list li:last-child {
  border-bottom: none;
}

.balance-positive { color: var(--owed); font-weight: 700; }
.balance-negative { color: var(--owe); font-weight: 700; }
.balance-zero { color: var(--muted); }

.original-amount {
  color: var(--muted);
  font-size: 0.85em;
}

#whoami-bar {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 20px 4px 0;
}

.link-btn {
  background: none;
  border: none;
  color: var(--accent-dark);
  padding: 0;
  font-size: 0.9rem;
  text-decoration: underline;
  cursor: pointer;
}

.link-btn:hover {
  background: none;
  color: var(--owe);
}

#login-message.error { color: var(--owe); }
#login-message.success { color: var(--owed); }
#login-message {
  min-height: 1.2em;
  font-size: 0.9rem;
}

.empty {
  color: var(--muted);
  font-style: italic;
}

/* ---------------------------------------------------------------------------
   Top bar right (whoami + theme toggle)
--------------------------------------------------------------------------- */

.top-bar-right {
  display: flex;
  align-items: center;
  gap: 14px;
}

#whoami-bar {
  color: var(--muted);
  font-size: 0.9rem;
  white-space: nowrap;
}

/* ---------------------------------------------------------------------------
   Groups dashboard
--------------------------------------------------------------------------- */

#groups-list, #invitations-list, #members-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.group-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.group-item:last-child { border-bottom: none; }

.group-item-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.muted-sm {
  font-size: 0.82rem;
  color: var(--muted);
}

.open-btn {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 6px 12px;
  font-size: 0.88rem;
}

.open-btn:hover {
  background: var(--accent);
  color: #fff;
}

/* ---------------------------------------------------------------------------
   Invitations
--------------------------------------------------------------------------- */

.invitation-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
}

.invitation-item:last-child { border-bottom: none; }

.invitation-actions {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}

.accept-btn {
  padding: 6px 12px;
  font-size: 0.85rem;
}

.decline-btn {
  background: transparent;
  color: var(--owe);
  border: 1px solid var(--owe);
  padding: 6px 12px;
  font-size: 0.85rem;
}

.decline-btn:hover {
  background: var(--owe);
  color: #fff;
}

/* ---------------------------------------------------------------------------
   Group detail
--------------------------------------------------------------------------- */

.group-nav {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 20px;
}

.back-btn {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 6px 14px;
  font-size: 0.88rem;
  white-space: nowrap;
}

.back-btn:hover {
  background: var(--accent);
  color: #fff;
}

.group-title-inline {
  margin: 0;
  font-size: 1.3rem;
}

.member-item {
  padding: 6px 0;
  border-bottom: 1px solid var(--border);
}

.member-item:last-child { border-bottom: none; }

/* Invite form sits below the member list */
.inline-form {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}

.inline-form input {
  flex: 1;
  margin-top: 0;
}

.inline-form button {
  flex-shrink: 0;
}

/* ---------------------------------------------------------------------------
   Generic message elements
--------------------------------------------------------------------------- */

.error   { color: var(--owe);  font-size: 0.9rem; min-height: 1.2em; }
.success { color: var(--owed); font-size: 0.9rem; min-height: 1.2em; }