html - 如何解决CSS中的嵌套选择器？

Question

表格的padding应该是8px，但是当有modal的时候，padding应该是0，这样才能填满整个单元格，见图

如何解决嵌套在表中以及不同类别和 ID 下的特定选择器？

我尝试过组合:#tabletu .modal #myBtn2 td 但都没有使填充消失。例如:

// Get the modal
var modal = document.getElementById("myModal");

// Get the button that opens the modal
var btn = document.getElementById("myBtn2");

// Get the <span> element that closes the modal
var span = document.getElementsByClassName("close")[0];

// When the user clicks the button, open the modal 
btn.onclick = function() {
  modal.style.display = "block";
}

// When the user clicks on <span> (x), close the modal
span.onclick = function() {
  modal.style.display = "none";
}

// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
  if (event.target == modal) {
    modal.style.display = "none";
  }
}

#tabletu .modal {
  padding: 0px;
}

#tabletu {
  background-color: transparent;
  border-collapse: collapse;
  width: 100%;
}

#tabletu td,
th {
  border: 1px solid #000000;
  padding: 8px;
}

#tabletu th {
  padding: 8px;
  text-align: left;
  border: 1px solid #000000;
  background-color: rgba(0, 110, 167, 1);
  color: white;
}


/* The Modal (background) */

.modal {
  display: none;
  /* Hidden by default */
  position: fixed;
  /* Stay in place */
  z-index: 1;
  /* Sit on top */
  padding-top: 100px;
  /* Location of the box */
  left: 0;
  top: 0;
  width: 100%;
  /* Full width */
  height: 100%;
  /* Full height */
  overflow: auto;
  /* Enable scroll if needed */
  background-color: rgb(0, 0, 0);
  /* Fallback color */
  background-color: rgba(0, 0, 0, 0.4);
  /* Black w/ opacity */
}


/* Modal Content */

.modal-content {
  background-color: #fefefe;
  margin: auto;
  padding: 20px;
  border: 1px solid #888;
  width: 80%;
}

.modal td {
  padding: 0px;
}


/* The Close Button */

.close {
  color: #aaaaaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
}

.close:hover,
.close:focus {
  color: #000;
  text-decoration: none;
  cursor: pointer;
}

.notebook {
  border-collapse: collapse;
  width: 70%;
}

.notebook td:hover {
  background-color: #ddd;
}

.notebook td,
.notebook th {
  border: 1px solid #ddd;
  padding: 0px;
}

.block {
  display: block;
  width: 100%;
  border: none;
  background-color: rgba(0, 166, 214, 1);
  padding: 14px 28px;
  font-size: 16px;
  cursor: pointer;
  text-align: center;
  box-sizing: border-box;
}

.block:hover {
  background-color: rgba(0, 166, 214, 0.78);
  color: black;
}

.month {
  text-align: center;
}

#category {
  padding: 8px;
}

<h2>Experiment Notebook</h2>
<center>
  <table id="tabletu" class="notebook">
    <tr id="category">
      <th></th>
      <th id="category">Test1</th>
      <th>Test2</th>
      <th>Other</th>
    </tr>
    <tr>
      <td rowspan=2 class="month">April</td>
      <td>
        <!-- Trigger/Open The Modal -->
        <button id="myBtn2" class="block">Open Modal</button>

        <!-- The Modal -->
        <div id="myModal" class="modal">

          <!-- Modal content -->
          <div class="modal-content">
            <span class="close">&times;</span>
            <p>Some text in the Modal..</p>
          </div>

        </div>
      </td>
      <td><button id="myBtn2" class="block">Open Modal</button></td>
      <td>Germany</td>
    </tr>
    <tr>

      <td>Berglunds snabbköp</td>
      <td>Christina Berglund</td>
      <td>Sweden</td>
    </tr>
    <tr>
      <td></td>
      <td>Centro comercial Moctezuma</td>
      <td>Francisco Chang</td>
      <td>Mexico</td>
    </tr>
    <tr>
      <td></td>
      <td>Ernst Handel</td>
      <td>Roland Mendel</td>
      <td>Austria</td>
    </tr>
    <tr>
      <td></td>
      <td>Island Trading</td>
      <td>Helen Bennett</td>
      <td>UK</td>
    </tr>
    <tr>
      <td></td>
      <td>Königlich Essen</td>
      <td>Philip Cramer</td>
      <td>Germany</td>
    </tr>
    <tr>
      <td></td>
      <td>Laughing Bacchus Winecellars</td>
      <td>Yoshi Tannamuri</td>
      <td>Canada</td>
    </tr>
    <tr>
      <td></td>
      <td>Magazzini Alimentari Riuniti</td>
      <td>Giovanni Rovelli</td>
      <td>Italy</td>
    </tr>
    <tr>
      <td></td>
      <td>North/South</td>
      <td>Simon Crowther</td>
      <td>UK</td>
    </tr>
    <tr>
      <td></td>
      <td>Paris spécialités</td>
      <td>Marie Bertrand</td>
      <td>France</td>
    </tr>
  </table>

</center>

在 A. Meshu 的帮助下，我到目前为止已经完成了，但模态框下方仍然有一条细小的白线。

Answer 1

你可以通过给所有的 <td> 添加一个类来解决它拥有 button然后用 !important 设置样式.在这个例子中我使用了 modalTD类:

.modalTD {padding: 0!important;} // remove horizontal padding
.modalTD button {height: 65px!important;} // make the button height wrap the entire cell

html 看起来像这样:

.
.
.
<td class="modalTD"><!-- Trigger/Open The Modal -->
  <button id="myBtn2" class="block">Open Modal</button>
.
.
.

旁注:有一天 :has pseudo-class将使我们的生活更轻松，但目前它不支持任何......

编辑

另一种解决方案会更有效率，但它会影响整行(我必须说视觉上不是那么糟糕)，您可以尝试的是:

#tabletu tr:nth-of-type(2) td {padding: 0;}