/* Reset and base styles */
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, sans-serif;
  background: #f4f4f4;
  color: #333;
}
a { color: #2563eb; text-decoration: none; }

/* Login */
.container {
  max-width: 400px;
  margin: 120px auto;
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  text-align: center;
}
input {
  width: 100%;
  padding: 0.6rem;
  margin: 0.4rem 0;
  border: 1px solid #ccc;
  border-radius: 4px;
}
button {
  width: 100%;
  padding: 0.6rem;
  background: #2563eb;
  border: none;
  color: #fff;
  border-radius: 4px;
  cursor: pointer;
  margin-top: 0.5rem;
}
button:hover { background: #1d4ed8; }

/* App layout */
.app nav {
  background: #111827;
  color: #fff;
  padding: 0.75rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.app nav button {
  background: transparent;
  border: 1px solid #fff;
  padding: 0.4rem 0.8rem;
  margin-left: 0.5rem;
}
.app main { padding: 2rem; }
.hidden { display: none; }

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
}
.modal-content {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  width: 320px;
}

/* Cards */
.card {
  background: #fff;
  padding: 1rem;
  margin: 0.5rem 0;
  border-radius: 6px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}
.status {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-size: 0.75rem;
  text-transform: uppercase;
}
.status.pagado { background: #bbf7d0; color: #14532d; }
.status.pendiente { background: #fde047; color: #713f12; }
.status.atrasado { background: #fecaca; color: #7f1d1d; }