:root {
  --color-primary: #4472C4;
  --color-primary-dark: #2f5597;
  --color-bg: #f4f6fa;
  --color-border: #d9dee5;
  --color-text: #1f2937;
  --color-muted: #6b7280;
  --color-danger: #b00000;
  --radius: 10px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  color: var(--color-text);
  padding: 16px;
}

.login-box {
  background: white;
  border-radius: var(--radius);
  padding: 28px 22px;
  width: 100%;
  max-width: 360px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.login-box h1 {
  margin: 0 0 4px;
  font-size: 1.3rem;
  text-align: center;
  color: var(--color-primary);
}
.login-subtitle {
  margin: 0 0 20px;
  text-align: center;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.form-group { margin-bottom: 14px; }
.form-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-muted);
  margin-bottom: 4px;
}
.form-group input {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 1rem;
}

.btn-primary {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: var(--radius);
  background: var(--color-primary);
  color: white;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  margin-top: 6px;
}
.btn-primary:active { background: var(--color-primary-dark); }

.login-error {
  color: var(--color-danger);
  font-size: 0.85rem;
  text-align: center;
  margin-top: 10px;
}
.hidden { display: none; }