* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: Arial, Helvetica, sans-serif;
}

body {
  background: #f4f6f8;
  color: #222;
}

.app-header {
  background: #0d6efd;
  color: #fff;
  padding: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.app-header h1 {
  font-size: 20px;
}

.install-btn {
  border: none;
  background: #fff;
  color: #0d6efd;
  padding: 8px 14px;
  border-radius: 6px;
  font-weight: bold;
  cursor: pointer;
}

.container {
  padding: 16px;
  display: grid;
  gap: 16px;
}

.card {
  background: #fff;
  padding: 16px;
  border-radius: 10px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
}

.card h2 {
  font-size: 16px;
  margin-bottom: 8px;
}

#salesTotal {
  font-size: 28px;
  font-weight: bold;
  color: #0d6efd;
}

ul {
  list-style: none;
}

li {
  padding: 8px 0;
  border-bottom: 1px solid #eee;
}

.offline {
  background: #fff3cd;
  border: 1px solid #ffeeba;
  color: #856404;
  padding: 10px;
  border-radius: 8px;
}