body {
    font-family: Arial, sans-serif;
    background-color: #f2f2f2;
    margin: 0;
    padding: 0;
  }
  .container {
    width: 90%;
    max-width: 1200px;
    margin: auto;
    padding: 20px;
    background-color: #fff;
  }
  h1, h2, h3 {
    color: #333;
  }
  #logbook-list-section, #logbook-detail-section {
    margin-bottom: 20px;
  }
  ul {
    list-style: none;
    padding: 0;
  }
  ul li {
    padding: 10px;
    border-bottom: 1px solid #ddd;
    cursor: pointer;
  }
  ul li:hover {
    background-color: #f9f9f9;
  }
  button {
    padding: 10px 15px;
    margin-top: 10px;
    background-color: #4285f4;
    color: #fff;
    border: none;
    cursor: pointer;
  }
  button:hover {
    background-color: #357ae8;
  }
  .logbook-content {
    display: flex;
    justify-content: space-between;
  }
  .entries-panel, .entry-form-panel {
    width: 48%;
  }
  input[type="text"], textarea {
    width: 100%;
    padding: 10px;
    margin-top: 5px;
    margin-bottom: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
  }
  .modal {
    position: fixed;
    z-index: 100;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.4);
  }
  .modal-content {
    background-color: #fefefe;
    margin: 10% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 50%;
    position: relative;
  }
  .close {
    color: #aaa;
    position: absolute;
    top: 10px;
    right: 20px;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
  }
  .close:hover,
  .close:focus {
    color: black;
    text-decoration: none;
  }
  .refs {
    margin-top: 5px;
  }
  .refs .ref {
    display: inline-block;
    background: #e0e0e0;
    padding: 2px 5px;
    margin-right: 5px;
    border-radius: 3px;
    cursor: pointer;
    font-size: 0.9em;
  }