:root {
  --bg: #f8f9fa;
  --card: #fff;
  --primary: #4a90d9;
  --danger: #e74c3c;
  --text: #333;
  --muted: #888;
  --border: #e0e0e0;
  --radius: 8px;
}

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

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

.page { min-height: 100vh; }
.hidden { display: none !important; }

.login-box {
  max-width: 320px;
  margin: 120px auto;
  text-align: center;
}

.login-box h1 { margin-bottom: 24px; font-size: 24px; }

.login-box input {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 16px;
  margin-bottom: 12px;
}

.login-box button {
  width: 100%;
  padding: 12px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 16px;
  cursor: pointer;
}

.login-box button:hover { opacity: 0.9; }

.error-msg { color: var(--danger); margin-top: 8px; font-size: 14px; }

nav {
  display: flex;
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 0 16px;
  gap: 4px;
}

.nav-btn {
  padding: 12px 20px;
  border: none;
  background: none;
  cursor: pointer;
  font-size: 15px;
  color: var(--muted);
  border-bottom: 2px solid transparent;
}

.nav-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

#logout-btn { margin-left: auto; color: var(--danger); }

.tab-content { padding: 16px; max-width: 600px; margin: 0 auto; }

.latest-weight {
  text-align: center;
  font-size: 28px;
  font-weight: 600;
  padding: 20px 0;
}

.diff { font-size: 16px; color: var(--muted); font-weight: 400; }

.chart-container { background: var(--card); border-radius: var(--radius); padding: 16px; margin-bottom: 16px; }

.input-area { background: var(--card); border-radius: var(--radius); padding: 16px; }

.ai-input-row { display: flex; gap: 8px; }

.ai-input-row input {
  flex: 1;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 15px;
}

.ai-input-row button {
  padding: 10px 20px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  white-space: nowrap;
}

.feedback {
  margin-top: 8px;
  padding: 8px 12px;
  background: #e8f5e9;
  border-radius: var(--radius);
  font-size: 14px;
  min-height: 0;
}

.feedback:empty { display: none; }

.manual-input { margin-top: 12px; }
.manual-input summary { color: var(--muted); cursor: pointer; font-size: 14px; }
.manual-form { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 8px; }
.manual-form input, .manual-form select {
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 14px;
}

.manual-form button {
  padding: 8px 16px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
}

.bill-controls { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }

.ledger-tabs { display: flex; gap: 4px; }

.ledger-btn {
  padding: 6px 16px;
  border: 1px solid var(--border);
  background: var(--card);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 14px;
}

.ledger-btn.active { background: var(--primary); color: #fff; border-color: var(--primary); }

.bill-summary { background: var(--card); border-radius: var(--radius); padding: 16px; margin-bottom: 16px; }
.bill-total { font-size: 20px; font-weight: 600; margin-bottom: 8px; }
.bill-categories { display: flex; flex-wrap: wrap; gap: 8px; font-size: 13px; color: var(--muted); }

.bill-list { list-style: none; }
.bill-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 12px;
  background: var(--card);
  border-radius: var(--radius);
  margin-bottom: 6px;
}

.bill-item:hover .bill-del { opacity: 1; }

.bill-del {
  opacity: 0;
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 14px;
  transition: opacity 0.2s;
}

.reminder-list { display: flex; flex-direction: column; gap: 8px; }

.reminder-card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.reminder-card.overdue { border-left: 3px solid var(--danger); }
.reminder-card.soon { border-left: 3px solid #f39c12; }

.reminder-info { font-size: 15px; }
.reminder-due { font-size: 13px; color: var(--muted); }

.reminder-done {
  padding: 6px 12px;
  background: #27ae60;
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 13px;
}

.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: #333;
  color: #fff;
  padding: 10px 20px;
  border-radius: var(--radius);
  font-size: 14px;
  z-index: 999;
  transition: opacity 0.3s;
}

.toast.hidden { opacity: 0; pointer-events: none; }