:root {
  --primary: #FF5A00;
  --bg: #F8F9FA;
  --surface: #FFFFFF;
  --text: #1A1A1A;
  --text-muted: #6B7280;
  --border: #E5E7EB;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: sans-serif; }
body { background: var(--bg); color: var(--text); }

.navbar {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.nav-links a {
  margin-right: 1rem;
  text-decoration: none;
  color: var(--text-muted);
}
.nav-links a.active { color: var(--primary); font-weight: bold; }

.container { padding: 1.5rem; max-width: 1200px; margin: 0 auto; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 1.5rem;
  margin-bottom: 1rem;
}

input, select, button {
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 0; /* เหลี่ยม */
  width: 100%;
  margin-bottom: 1rem;
}

button.primary {
  background: var(--primary);
  color: white;
  border: none;
  cursor: pointer;
}

table { width: 100%; border-collapse: collapse; }
th, td { padding: 1rem; text-align: left; border-bottom: 1px solid var(--border); }