:root {
  --bg: #f4f6f8;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --border: #e5e7eb;
  --danger: #dc2626;
  --success: #16a34a;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}
.topbar {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 14px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
}
.brand { font-weight: 700; font-size: 18px; }
.topbar nav a {
  margin-left: 18px;
  text-decoration: none;
  color: var(--text);
  font-size: 14px;
}
.topbar nav a:hover { color: var(--primary); }
.container {
  max-width: 900px;
  margin: 32px auto;
  padding: 0 20px;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px;
  margin-bottom: 20px;
}
h1 { font-size: 22px; margin-top: 0; }
h2 { font-size: 18px; }
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 10px 8px; border-bottom: 1px solid var(--border); font-size: 14px; }
th { color: var(--muted); font-weight: 600; }
.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 10px 16px;
  border-radius: 6px;
  border: none;
  text-decoration: none;
  font-size: 14px;
  cursor: pointer;
}
.btn:hover { background: var(--primary-dark); }
.btn-danger { background: var(--danger); }
.btn-secondary { background: var(--muted); }
input[type=text], input[type=password], input[type=file], select {
  width: 100%;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 14px;
  margin-bottom: 14px;
}
label { font-size: 13px; color: var(--muted); display: block; margin-bottom: 4px; }
.alert { padding: 12px 14px; border-radius: 6px; margin-bottom: 16px; font-size: 14px; }
.alert-error { background: #fee2e2; color: var(--danger); }
.alert-success { background: #dcfce7; color: var(--success); }
.login-wrap {
  max-width: 380px;
  margin: 90px auto;
}
.muted { color: var(--muted); font-size: 13px; }