CSS Box Shadow 完全指南 2026

为按钮增添立体感，为卡片增加深度，为UI增添精致感的 box-shadow。在2026年的网页设计中，阴影不仅仅是装饰，更是用户体验的核心要素。

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box-shadow 基本语法

box-shadow: offset-x offset-y blur spread color;

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基本示例

简单阴影

/* 基础投影 */
.card {
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* 更强的阴影 */
.card-elevated {
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

方向性阴影

/* 右下 */
.shadow-br { box-shadow: 4px 4px 8px rgba(0,0,0,0.2); }

/* 左上 */
.shadow-tl { box-shadow: -4px -4px 8px rgba(0,0,0,0.2); }

/* 全方向 */
.shadow-all { box-shadow: 0 0 15px rgba(0,0,0,0.3); }

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多重阴影

使用逗号组合多个阴影。

/* 柔和的多层阴影 */
.soft-shadow {
  box-shadow:
    0 1px 2px rgba(0,0,0,0.07),
    0 2px 4px rgba(0,0,0,0.07),
    0 4px 8px rgba(0,0,0,0.07),
    0 8px 16px rgba(0,0,0,0.07);
}

/* 真实感阴影 */
.realistic {
  box-shadow:
    0 2.8px 2.2px rgba(0,0,0,0.02),
    0 6.7px 5.3px rgba(0,0,0,0.028),
    0 12.5px 10px rgba(0,0,0,0.035),
    0 22.3px 17.9px rgba(0,0,0,0.042),
    0 41.8px 33.4px rgba(0,0,0,0.05),
    0 100px 80px rgba(0,0,0,0.07);
}

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inset 阴影

使用 inset 关键字创建内阴影。

/* 基础 inset */
.inset-shadow {
  box-shadow: inset 0 2px 4px rgba(0,0,0,0.2);
}

/* 按下按钮效果 */
.pressed-button {
  box-shadow:
    inset 0 2px 4px rgba(0,0,0,0.3),
    inset 0 -1px 2px rgba(255,255,255,0.1);
}

/* 输入框聚焦 */
.input:focus {
  box-shadow: inset 0 1px 2px rgba(0,0,0,0.1),
              0 0 0 3px rgba(59,130,246,0.3);
}

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设计趋势示例

1. Material Design 阴影

/* Elevation 1 */
.md-1 { box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24); }

/* Elevation 2 */
.md-2 { box-shadow: 0 3px 6px rgba(0,0,0,0.15), 0 2px 4px rgba(0,0,0,0.12); }

/* Elevation 3 */
.md-3 { box-shadow: 0 10px 20px rgba(0,0,0,0.15), 0 3px 6px rgba(0,0,0,0.10); }

/* Elevation 4 */
.md-4 { box-shadow: 0 15px 25px rgba(0,0,0,0.15), 0 5px 10px rgba(0,0,0,0.05); }

/* Elevation 5 */
.md-5 { box-shadow: 0 20px 40px rgba(0,0,0,0.2); }

2. 新拟态设计 (Neumorphism)

/* 新拟态背景 */
.neumorphism {
  background: #e0e5ec;
  box-shadow:
    9px 9px 16px rgba(163,177,198,0.6),
    -9px -9px 16px rgba(255,255,255,0.5);
}

/* 新拟态按下状态 */
.neumorphism-pressed {
  background: #e0e5ec;
  box-shadow:
    inset 6px 6px 10px rgba(163,177,198,0.6),
    inset -6px -6px 10px rgba(255,255,255,0.5);
}

/* 新拟态按钮 */
.neumorphism-button {
  background: linear-gradient(145deg, #cacfd6, #f0f5fc);
  box-shadow:
    5px 5px 10px #a3b1c6,
    -5px -5px 10px #ffffff;
}

3. 玻璃拟态 (Glassmorphism)

.glassmorphism {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  box-shadow:
    0 8px 32px rgba(0, 0, 0, 0.1),
    inset 0 0 0 1px rgba(255,255,255,0.1);
}

4. 霓虹效果

/* 霓虹发光 */
.neon-blue {
  box-shadow:
    0 0 5px #00f,
    0 0 10px #00f,
    0 0 20px #00f,
    0 0 40px #00f;
}

.neon-pink {
  box-shadow:
    0 0 5px #ff00ff,
    0 0 10px #ff00ff,
    0 0 20px #ff00ff,
    0 0 40px #ff00ff;
}

/* 动画霓虹 */
@keyframes neon-pulse {
  0%, 100% { box-shadow: 0 0 5px #0ff, 0 0 20px #0ff; }
  50% { box-shadow: 0 0 10px #0ff, 0 0 40px #0ff, 0 0 60px #0ff; }
}

.neon-animated {
  animation: neon-pulse 2s infinite;
}

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彩色阴影

品牌色阴影

/* 蓝色阴影 */
.shadow-blue {
  box-shadow: 0 10px 30px rgba(59, 130, 246, 0.4);
}

/* 紫色阴影 */
.shadow-purple {
  box-shadow: 0 10px 30px rgba(139, 92, 246, 0.4);
}

/* 渐变感多色阴影 */
.shadow-gradient {
  box-shadow:
    -10px 0 30px rgba(255, 0, 128, 0.3),
    10px 0 30px rgba(0, 128, 255, 0.3);
}

悬停效果

.card {
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  transition: box-shadow 0.3s ease, transform 0.3s ease;
}

.card:hover {
  box-shadow: 0 20px 40px rgba(0,0,0,0.2);
  transform: translateY(-5px);
}

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实用组件

卡片组件

.card {
  background: white;
  border-radius: 12px;
  padding: 24px;
  box-shadow:
    0 1px 3px rgba(0,0,0,0.1),
    0 1px 2px rgba(0,0,0,0.06);
  transition: box-shadow 0.2s;
}

.card:hover {
  box-shadow:
    0 10px 15px -3px rgba(0,0,0,0.1),
    0 4px 6px -2px rgba(0,0,0,0.05);
}

按钮

.button {
  background: #3b82f6;
  color: white;
  padding: 12px 24px;
  border: none;
  border-radius: 8px;
  box-shadow: 0 4px 14px rgba(59,130,246,0.4);
  transition: all 0.2s;
}

.button:hover {
  box-shadow: 0 6px 20px rgba(59,130,246,0.5);
  transform: translateY(-2px);
}

.button:active {
  box-shadow: 0 2px 8px rgba(59,130,246,0.4);
  transform: translateY(0);
}

模态框/弹窗

.modal {
  background: white;
  border-radius: 16px;
  box-shadow:
    0 25px 50px -12px rgba(0,0,0,0.25),
    0 0 0 1px rgba(0,0,0,0.05);
}

/* 暗色模式 */
.modal-dark {
  background: #1f2937;
  box-shadow:
    0 25px 50px -12px rgba(0,0,0,0.5),
    0 0 0 1px rgba(255,255,255,0.1);
}

输入框

.input {
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  padding: 12px 16px;
  transition: all 0.2s;
}

.input:focus {
  outline: none;
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59,130,246,0.2);
}

.input-error {
  border-color: #ef4444;
  box-shadow: 0 0 0 3px rgba(239,68,68,0.2);
}

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性能优化

使用 will-change

.animated-shadow {
  will-change: box-shadow;
  transition: box-shadow 0.3s ease;
}

/* 动画后移除 */
.animated-shadow:not(:hover) {
  will-change: auto;
}

替代方案：filter drop-shadow

/* 不规则形状的阴影 */
.drop-shadow {
  filter: drop-shadow(0 4px 6px rgba(0,0,0,0.1));
}

/* 应用于 PNG 图片 */
.icon {
  filter: drop-shadow(2px 2px 4px rgba(0,0,0,0.3));
}

box-shadow vs filter

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Tailwind CSS

<!-- 基础阴影 -->
<div class="shadow-sm">小阴影</div>
<div class="shadow">默认阴影</div>
<div class="shadow-md">中等阴影</div>
<div class="shadow-lg">大阴影</div>
<div class="shadow-xl">超大阴影</div>
<div class="shadow-2xl">最大阴影</div>

<!-- 彩色阴影 -->
<div class="shadow-lg shadow-blue-500/50">蓝色阴影</div>

<!-- 悬停 -->
<div class="shadow hover:shadow-xl transition-shadow">悬停效果</div>

<!-- inset -->
<div class="shadow-inner">内阴影</div>

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常见问题

Q1: 阴影被裁剪？

A: 父元素有 overflow: hidden，或者阴影没有扩展空间。

/* 解决方案 */
.parent {
  overflow: visible; /* 或删除 */
  padding: 20px; /* 为阴影预留空间 */
}

Q2: 性能问题？

A: 在多个元素上应用复杂的 box-shadow 可能导致性能下降。

• 最小化多重阴影
• 适当使用 will-change
• 滚动时简化阴影

Q3: 圆角处阴影显示异常？

A: box-shadow 会自动跟随 border-radius。如有问题，请检查浏览器兼容性。

Q4: 推荐的阴影颜色？

A:

• 浅色模式: rgba(0,0,0,0.1) 到 rgba(0,0,0,0.2)
• 暗色模式: rgba(0,0,0,0.3) 到 rgba(0,0,0,0.5)
• 彩色阴影: 背景色的 30-50% 不透明度

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总结

box-shadow 要点：

1. 基本语法: offset-x, offset-y, blur, spread, color
2. 多重阴影: 用逗号叠加
3. inset: 内阴影
4. 趋势: 新拟态、玻璃拟态、霓虹
5. 性能: will-change，避免过度使用阴影

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