純 CSS 的小魔法：做一套會“發光”的響應式畫廊

作者：前端小智 2025-08-26 07:33:26

今天我們用純 CSS 完成了一套圖片畫廊：既有響應式布局，又具備“點擊放大 + 鍵盤導航”的交互；既輕量易集成，又不依賴任何 JavaScript。

我想在應用里展示一組圖片，同時不引入任何笨重腳本。結果發現，只用 CSS 就能優雅解決：零 JavaScript 也能實現“點按放大”的動效與無障礙導航。

關鍵思路：結合 tabindex 屬性與 :focus、:focus-within 這兩個 CSS 偽類，在不犧牲性能的前提下，創造順滑而輕量的交互體驗。與此同時，我們還能兼顧鍵盤可達性與布局自適應，這讓組件在移動端與桌面端都更易用、更穩定。

結構搭建（Setting Up the Structure）

如果你希望容納彈性數量的圖片，先準備一份可擴展的 HTML 結構，類似下面這樣。通過給根節點添加諸如 .image-gallery--4 的修飾類，我們可以按圖片數量輕松切換布局策略；因此，在后續樣式中會很方便地定制 1/2/3/4 張圖以及更多張圖的排布。

<div class="image-gallery image-gallery--4">
  <div class="image-gallery__item">
    <div class="image-gallery__backdrop" tabindex="-1">
      <img
        class="image-gallery__image"
        src="https://picsum.photos/seed/7cb42b45/1500/750"
        tabindex="0"
      />
    </div>
</div>

<div class="image-gallery__item">
    <div class="image-gallery__backdrop" tabindex="-1">
      <img
        class="image-gallery__image"
        src="https://picsum.photos/seed/4dd8300c/1500/750"
        tabindex="0"
      />
    </div>
</div>

<div class="image-gallery__item">
    <div class="image-gallery__backdrop" tabindex="-1">
      <img
        class="image-gallery__image"
        src="https://picsum.photos/seed/b66a4549/1500/750"
        tabindex="0"
      />
    </div>
</div>

<div class="image-gallery__item">
    <div class="image-gallery__backdrop" tabindex="-1">
      <img
        class="image-gallery__image"
        src="https://picsum.photos/seed/5783fa29/1500/750"
        tabindex="0"
      />
    </div>
</div>
</div>

.image-gallery 根元素帶有“數量修飾類”（如 .image-gallery--4），因此后續可以用選擇器精確地調整行列與跨度。
每個 .image-gallery__item 內含“背板”元素，并設置 tabindex="-1"：它可被點擊聚焦，但在鍵盤 Tab 導航時會被跳過，避免無意義的停留。
內層的 <img> 設置 tabindex="0"，用戶既可點擊，也能通過 Tab / Shift+Tab 依次聚焦圖片。

基礎樣式（Let’s add some styles）

下面是畫廊的基礎網格、響應式斷點與單元尺寸。通過較為克制的漸變背景，我們還為圖片加載前提供了一個優雅的占位態。

.image-gallery {
width: 100%;
display: grid;
grid-template-columns: repeat(2, 1fr);
gap: 1px;
margin: 0 auto;
}

@media (min-width:1001px) {
.image-gallery {
    grid-template-columns: repeat(4, 1fr);
  }
}

.image-gallery__item {
width: 100%;
height: 100%;
aspect-ratio: 1400 / 650;
}

.image-gallery--1.image-gallery__item {
grid-column: 1 / -1;
}

@media (min-width:1001px) {
.image-gallery:is(.image-gallery--1) {
    grid-template-rows: 1fr;
  }

.image-gallery:not(.image-gallery--1, .image-gallery--3) {
    grid-template-rows: 250px250px;
  }
}

.image-gallery__item {
background: linear-gradient(
    to bottom right,
    #f5f5f5 0%,
    #c5c5c5 50%,
    #fff 100%
  );
}

@media (min-width:1001px) {
.image-gallery:is(.image-gallery--2, .image-gallery--3)
    .image-gallery__item:not(:nth-child(1)),
.image-gallery:not(.image-gallery--1, .image-gallery--2, .image-gallery--3)
    .image-gallery__item:nth-child(4),
.image-gallery:not(
      .image-gallery--1,
      .image-gallery--2,
      .image-gallery--3,
      .image-gallery--4
    )
    .image-gallery__item:nth-child(n + 5) {
    grid-column: span 2;
  }

.image-gallery:not(.image-gallery--1).image-gallery__item:nth-child(1),
.image-gallery--2.image-gallery__item:nth-child(2) {
    grid-column: span 2;
    grid-row: span 2;
  }
}

.image-gallery__backdrop {
width: 100%;
height: 100%;
transition: background-color 160ms;
z-index: 1;
}

.image-gallery__image {
width: 100%;
height: 100%;
object-fit: cover;
border-radius: inherit;
cursor: zoom-in;
user-select: none;
outline: none;
}

加入交互（Adding Interactivity）

現在讓畫廊“活起來”。思路是：當子元素圖片被聚焦時，通過 :focus-within 讓父級背板切換為 position: fixed 的“遮罩層”，并在其中居中展示被點開的圖片；點擊遮罩區域即可收起。

.image-gallery__backdrop:not(:focus):focus-within {
position: fixed;
top: 0;
left: 0;
display: flex;
align-items: center;
justify-content: center;
background-color: rgba(0, 0, 0, 0.1);
cursor: zoom-out;
z-index: 2;
user-select: none;
}

接著，當圖片本身處于 :focus 時，設置其尺寸為自適應容器，并以 object-fit: contain 居中完整顯示，同時用一個簡短的 @keyframes 提升放大動效的順滑度。

.image-gallery__image:focus {
width: auto;
max-width: 90%;
height: auto;
max-height: 90%;
object-fit: contain;
border-radius: 8px;
pointer-events: none;
z-index: 3;
animation: image-gallery-zoom-in 160ms;
}

@keyframes image-gallery-zoom-in {
  0% {
    opacity: 0;
    transform: scale(0.98);
  }
}

這里加入了 pointer-events: none，因此用戶在放大態點擊圖片時，事件會“穿透”至背板，從而一鍵關閉。與此同時，tabindex="0" 讓圖片天然可聚焦——你可以用 Tab 前進、用 Shift+Tab 后退，順暢瀏覽整組圖片。

為了向用戶明確鍵盤用法，我們再加一個輕量指示條：

<div class="image-gallery__keyboard-indicator">
  Use <code>Tab</code> or <code>Shift</code>+<code>Tab</code> to navigate between images
</div>

.image-gallery__keyboard-indicator {
display: none;
position: fixed;
bottom: 26px;
left: 50%;
padding: 8px12px;
font-size: 14px;
background-color: #f5f5f5;
border-radius: 4px;
transform: translateX(-50%);
z-index: 4;
}

@media (pointer: fine) {
.image-gallery:has(.image-gallery__image:focus)
    .image-gallery__keyboard-indicator {
    display: block;
  }
}

.image-gallery__keyboard-indicator > code {
padding: 2px4px;
font-size: calc(1rem - 2px);
background-color: #fff;
border: 1px solid #c2c2c2;
border-radius: 4px;
}

完整示例（Full Demo）

下面是整套實現的可運行示例，包含結構、樣式與交互邏輯。你可以直接復制到本地文件中打開，或集成到你的組件庫里。

圖片

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Three-Column Grid With Subgrid</title>
    <style>
      .image-gallery {
        width: 100%;
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 1px;
        margin: 0 auto;
      }

      @media (min-width:1001px) {
        .image-gallery {
          grid-template-columns: repeat(4, 1fr);
        }
      }

      .image-gallery__item {
        width: 100%;
        height: 100%;
        aspect-ratio: 1400 / 650;
      }

      .image-gallery--1.image-gallery__item {
        grid-column: 1 / -1;
      }

      @media (min-width:1001px) {
        .image-gallery:is(.image-gallery--1) {
          grid-template-rows: 1fr;
        }

        .image-gallery:not(.image-gallery--1, .image-gallery--3) {
          grid-template-rows: 250px250px;
        }
      }

      .image-gallery__item {
        background: linear-gradient(
          to bottom right,
          #f5f5f5 0%,
          #c5c5c5 50%,
          #fff 100%
        );
      }

      @media (min-width:1001px) {
        .image-gallery:is(.image-gallery--2, .image-gallery--3)
          .image-gallery__item:not(:nth-child(1)),
        .image-gallery:not(
            .image-gallery--1,
            .image-gallery--2,
            .image-gallery--3
          )
          .image-gallery__item:nth-child(4),
        .image-gallery:not(
            .image-gallery--1,
            .image-gallery--2,
            .image-gallery--3,
            .image-gallery--4
          )
          .image-gallery__item:nth-child(n + 5) {
          grid-column: span 2;
        }

        .image-gallery:not(.image-gallery--1).image-gallery__item:nth-child(1),
        .image-gallery--2.image-gallery__item:nth-child(2) {
          grid-column: span 2;
          grid-row: span 2;
        }
      }

      .image-gallery__backdrop {
        width: 100%;
        height: 100%;
        transition: background-color 160ms;
        z-index: 1;
      }

      .image-gallery__backdrop:not(:focus):focus-within {
        position: fixed;
        top: 0;
        left: 0;
        display: flex;
        align-items: center;
        justify-content: center;
        background-color: rgba(0, 0, 0, 0.1);
        cursor: zoom-out;
        z-index: 2;
        user-select: none;
      }

      .image-gallery__image {
        width: 100%;
        height: 100%;
        object-fit: cover;
        border-radius: inherit;
        cursor: zoom-in;
        user-select: none;
        outline: none;
      }

      .image-gallery__image:focus {
        width: auto;
        max-width: 90%;
        height: auto;
        max-height: 90%;
        object-fit: contain;
        border-radius: 8px;
        pointer-events: none;
        z-index: 3;
        animation: image-gallery-zoom-in 160ms;
      }

      @keyframes image-gallery-zoom-in {
        0% {
          opacity: 0;
          transform: scale(0.98);
        }
      }

      .image-gallery__keyboard-indicator {
        display: none;
        position: fixed;
        bottom: 26px;
        left: 50%;
        padding: 8px12px;
        font-size: 14px;
        background-color: #f5f5f5;
        border-radius: 4px;
        transform: translateX(-50%);
        z-index: 4;
      }

      @media (pointer: fine) {
        .image-gallery:has(.image-gallery__image:focus)
          .image-gallery__keyboard-indicator {
          display: block;
        }
      }

      .image-gallery__keyboard-indicator > code {
        padding: 2px4px;
        font-size: calc(1rem - 2px);
        background-color: #fff;
        border: 1px solid #c2c2c2;
        border-radius: 4px;
      }
    </style>
</head>
<body>
    <div class="image-gallery image-gallery--4">
      <div class="image-gallery__item">
        <div class="image-gallery__backdrop" tabindex="-1">
          <img
            class="image-gallery__image"
            src="https://picsum.photos/seed/7cb42b45/1500/750"
            tabindex="0"
          />
        </div>
      </div>

      <div class="image-gallery__item">
        <div class="image-gallery__backdrop" tabindex="-1">
          <img
            class="image-gallery__image"
            src="https://picsum.photos/seed/4dd8300c/1500/750"
            tabindex="0"
          />
        </div>
      </div>

      <div class="image-gallery__item">
        <div class="image-gallery__backdrop" tabindex="-1">
          <img
            class="image-gallery__image"
            src="https://picsum.photos/seed/b66a4549/1500/750"
            tabindex="0"
          />
        </div>
      </div>

      <div class="image-gallery__item">
        <div class="image-gallery__backdrop" tabindex="-1">
          <img
            class="image-gallery__image"
            src="https://picsum.photos/seed/5783fa29/1500/750"
            tabindex="0"
          />
        </div>
      </div>

      <div class="image-gallery__keyboard-indicator">
        Use <code>Tab</code> or <code>Shift</code>+<code>Tab</code> to navigate
        between images
      </div>
    </div>
</body>
</html>

結語

今天我們用純 CSS 完成了一套圖片畫廊：既有響應式布局，又具備“點擊放大 + 鍵盤導航”的交互；既輕量易集成，又不依賴任何 JavaScript。因此你可以把重心放在圖片質量與內容組織上，與此同時保持頁面性能與可訪問性；盡管如此，若你后續確實需要更復雜的縮略圖預覽、分組輪播或拖拽排序，也可以在這個基礎上再按需加上一點腳本擴展。

責任編輯：武曉燕來源：大遷世界

CSS 響應式鍵盤