效果预览
按下右侧的“点击预览”按钮可以在当前页面预览，点击链接可以全屏预览。
https://codepen.io/comehope/pen/rKPLMW
可交互视频
此视频是可以交互的，你可以随时暂停视频，编辑视频中的代码。
请用 chrome, safari, edge 打开观看。
https://scrimba.com/p/pEgDAM/c6NzPfK
源代码下载
每日前端实战系列的全部源代码请从 github 下载：
https://github.com/comehope/front-end-daily-challenges
代码解读
定义 dom，容器中包含机体、出水口、咖啡杯、按钮和咖啡：
<div class="coffee-machine">
<span class="body"></span>
<span class="spout"></span>
<span class="cup"></span>
<span class="button"></span>
<span class="coffee"></span>
</div>居中显示：
body {
margin: 0;
height: 100vh;
display: flex;
align-items: center;
justify-content: center;
background: linear-gradient(to right bottom, sandybrown, darkred);
}定义容器尺寸：
.coffee-machine {
width: 15em;
height: 15em;
background-color: white;
font-size: 20px;
border-radius: 50%;
border: 2em solid white;
}画出机体的外框：
.coffee-machine {
position: relative;
display: flex;
justify-content: center;
}
.body {
position: absolute;
width: 8em;
height: 12em;
background-color: sandybrown;
border-radius: 1.2em;
top: 1.5em;
border-right: 0.6em solid peru;
}用伪元素画出机体的中间部分：
.body::after {
content: '';
position: absolute;
width: 8em;
height: 8em;
background-color: darkslategray;
top: 2em;
border-right: 0.6em solid black;
}画出出水口：
.spout {
position: absolute;
width: 3em;
height: 1em;
background-color: white;
top: 3.5em;
border-radius: 0.5em;
border-right: 0.5em solid silver;
}画出咖啡杯的杯体：
.cup {
position: absolute;
width: 3em;
height: 2em;
background-color: white;
bottom: 3.5em;
border-radius: 0 0 1.4em 1.4em;
border-right: 0.5em solid silver;
}用伪元素画出咖啡杯的把手：
.cup::after {
content: '';
position: absolute;
width: 0.6em;
height: 0.6em;
border: 0.3em solid silver;
border-radius: 50%;
right: -1.2em;
top: 0.2em;
}画出按钮：
.button {
position: absolute;
width: 1.2em;
height: 1.2em;
background-color: tomato;
border-radius: 50%;
bottom: 2em;
right: 4.5em;
}画出咖啡：
.coffee::before,
.coffee::after {
content: '';
position: absolute;
width: 0.7em;
height: 5em;
background-color: chocolate;
top: 4.5em;
left: calc((15em - 0.7em) / 2);
}接下来润色一下。
为咖啡机增加光影：
.coffee-machine {
z-index: 1;
}
.coffee-machine::before,
.coffee-machine::after {
content: '';
position: absolute;
width: 2em;
height: 2em;
border: 0.3em solid transparent;
z-index: 2;
border-radius: 50%;
border-left-color: white;
left: 3.8em;
}
.coffee-machine::before {
top: 1.8em;
transform: rotate(40deg);
}
.coffee-machine::after {
bottom: 1.8em;
transform: rotate(-40deg);
}定义咖啡流动的前半段动画，即咖啡从出水口流到杯中：
.coffee::before {
animation: 2s linear infinite;
animation-name: pouring-before;
transform-origin: top;
}
@keyframes pouring-before {
0%, 20% {
transform: scaleY(0);
}
30%, 100% {
transform: scaleY(1);
}
70%, 100% {
visibility: hidden;
}
}定义咖啡流动的后半段动画，即出水口停止流出咖啡，剩余咖啡流到杯中：
.coffee::after {
animation: 2s linear infinite;
animation-name: pouring-after;
transform-origin: bottom;
}
@keyframes pouring-after {
0%, 70% {
visibility: hidden;
transform: scaleY(1);
}
80%, 100% {
transform: scaleY(0);
}
}大功告成！