body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      margin: 0;
      height: 100vh;
      display: flex;
      flex-direction: column;
      background: #f4f6f9;
      color: #333;
    }

    .navbar {
      background: #222;
      color: white;
      padding: 10px 20px;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .navbar a {
      color: white;
      margin-right: 15px;
      text-decoration: none;
    }

    .navbar a.active {
      text-decoration: underline;
    }

    .container {
      flex: 1;
      display: flex;
      height: calc(100vh - 50px);
    }

    .sidebar {
      width: 300px;
      background: #fff;
      border-right: 1px solid #ddd;
      padding: 10px;
      overflow-y: auto;
    }

    .main {
      flex: 1;
      display: flex;
      flex-direction: column;
    }

    .main textarea {
      flex: 1;
      font-size: 1rem;
      padding: 20px;
      border: none;
      outline: none;
      resize: none;
      background: #fff;
    }

    h2 {
      margin: 10px 0;
    }

    ul {
      list-style: none;
      padding: 0;
    }

    li {
      padding: 6px;
      border-radius: 4px;
      cursor: pointer;
    }

    li:hover {
      background: #eee;
    }

    li.active {
      background: #dfefff;
    }

    .delete {
      color: red;
      float: right;
      cursor: pointer;
    }

    input[type=text] {
      width: 100%;
      padding: 6px;
      margin: 6px 0;
      box-sizing: border-box;
    }

    .editable {
      display: inline-block;
    }

    .editable[contenteditable="true"] {
      background: #fff9c4;
      padding: 2px 4px;
    }

    #note-title {
      padding: 10px 20px;
      background: #fff;
      border-bottom: 1px solid #ccc;
      margin: 0;
    }