* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Segoe UI", sans-serif;
  }
  
  body {
    display: flex;
    background: #f3f4f6;
    height: 100vh;
  }
  
  /* SIDEBAR */
  .sidebar {
    width: 240px;
    background: #1e293b;
    color: white;
    padding: 20px;
  }
  
  .sidebar h2 {
    margin-bottom: 30px;
  }
  
  .sidebar ul {
    list-style: none;
  }
  
  .sidebar li {
    padding: 12px;
    margin-bottom: 10px;
    border-radius: 6px;
    cursor: pointer;
  }
  
  .sidebar li:hover {
    background: #334155;
  }
  
  .sidebar .active {
    background: #3b82f6;
  }
  
  /* MAIN CONTENT */
  .main {
    flex: 1;
    padding: 30px;
  }
  
  h1 {
    margin-bottom: 20px;
    color: #1e293b;
  }
  
  /* FORM */
  form {
    background: white;
    padding: 20px;
    width: 350px;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.08);
    display: flex;
    flex-direction: column;
    gap: 10px;
  }
  
  input {
    padding: 10px;
    border: 1px solid #cbd5e1;
    border-radius: 6px;
  }
  
  button {
    margin-top: 10px;
    padding: 12px;
    background: #3b82f6;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
  }
  
  button:hover {
    background: #2563eb;
  }
  
  /* MENSAJE */
  .msg {
    margin-top: 15px;
    color: green;
  }
  
  /* SECTIONS */
  .section {
    display: none;
  }
  
  .section.active {
    display: block;
  }
  
  /* TABLE */
  table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 10px rgba(0,0,0,0.08);
  }
  
  th, td {
    padding: 12px;
    border-bottom: 1px solid #e2e8f0;
  }
  
  th {
    background: #e2e8f0;
    text-align: left;
  }