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：

<p class="coffee-machine">
 <span class="body"></span>
 <span class="spout"></span>
 <span class="cup"></span>
 <span class="button"></span>
 <span class="coffee"></span>
</p>

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！