一直对css不在行，今天面试有道题要求用 css 写正三角形，回来之后搜了一下样式发现几个有意思的，就选了几个贴上来，想看更多请 点击这里
//正方形
#square { width: 100px; height: 100px; background: blue; }
//圆形
#circle { width: 100px; height: 100px; background: red; -moz-border-radius: 50px; -webkit-border-radius: 50px; border-radius: 50px; }
//椭圆
#oval { width: 200px; height: 100px; background: red; -moz-border-radius: 100px / 50px; -webkit-border-radius: 100px / 50px; border-radius: 100px / 50px; }
//正三角形
#triangle-up { width: 0; height: 0; border-left: 50px solid transparent; border-right: 50px solid transparent; border-bottom: 100px solid red; }
// 倒三角
#triangle-down { width: 0; height: 0; border-left: 50px solid transparent; border-right: 50px solid transparent; border-top: 100px solid red; }
// 左三角
#triangle-left { width: 0; height: 0; border-top: 50px solid transparent; border-right: 100px solid red; border-bottom: 50px solid transparent; }
// 左上三角
#triangle-topleft { width: 0; height: 0; border-top: 100px solid red; border-right: 100px solid transparent; }
//左下三角
#triangle-bottomleft { width: 0; height: 0; border-bottom: 100px solid red; border-right: 100px solid transparent; }
// 平行四边形
#parallelogram { width: 150px; height: 100px; margin-left:20px; -webkit-transform: skew(20deg); -moz-transform: skew(20deg); -o-transform: skew(20deg); background: red; }
// 梯形
#trapezoid { border-bottom: 100px solid red; border-left: 50px solid transparent; border-right: 50px solid transparent; height: 0; width: 100px; }
//五角星
#star-five { margin: 50px 0; position: relative; display: block; color: red; width: 0px; height: 0px; border-right: 100px solid transparent; border-bottom: 70px solid red; border-left: 100px solid transparent; -moz-transform: rotate(35deg); -webkit-transform: rotate(35deg); -ms-transform: rotate(35deg); -o-transform: rotate(35deg); }
#star-five:before { border-bottom: 80px solid red; border-left: 30px solid transparent; border-right: 30px solid transparent; position: absolute; height: 0; width: 0; top: -45px; left: -65px; display: block; content: ''; -webkit-transform: rotate(-35deg); -moz-transform: rotate(-35deg); -ms-transform: rotate(-35deg); -o-transform: rotate(-35deg); }
#star-five:after { position: absolute; display: block; color: red; top: 3px; left: -105px; width: 0px; height: 0px; border-right: 100px solid transparent; border-bottom: 70px solid red; border-left: 100px solid transparent; -webkit-transform: rotate(-70deg); -moz-transform: rotate(-70deg); -ms-transform: rotate(-70deg); -o-transform: rotate(-70deg); content: ''; }
// 8角星
#burst-8 { background: red; width: 80px; height: 80px; position: relative; text-align: center; -webkit-transform: rotate(20deg); -moz-transform: rotate(20deg); -ms-transform: rotate(20deg); -o-transform: rotate(20eg); transform: rotate(20deg); }
#burst-8:before { content: ""; position: absolute; top: 0; left: 0; height: 80px; width: 80px; background: red; -webkit-transform: rotate(135deg); -moz-transform: rotate(135deg); -ms-transform: rotate(135deg); -o-transform: rotate(135deg); transform: rotate(135deg); }
// 食逗人（Pac-Man）
#pacman { width: 0px; height: 0px; border-right: 60px solid transparent; border-top: 60px solid red; border-left: 60px solid red; border-bottom: 60px solid red; border-top-left-radius: 60px; border-top-right-radius: 60px; border-bottom-left-radius: 60px; border-bottom-right-radius: 60px; }
//爱心
#heart { position: relative; width: 100px; height: 90px; }
#heart:before,
#heart:after { position: absolute; content: ""; left: 50px; top: 0; width: 50px; height: 80px; background: red; -moz-border-radius: 50px 50px 0 0; border-radius: 50px 50px 0 0; -webkit-transform: rotate(-45deg); -moz-transform: rotate(-45deg); -ms-transform: rotate(-45deg); -o-transform: rotate(-45deg); transform: rotate(-45deg); -webkit-transform-origin: 0 100%; -moz-transform-origin: 0 100%; -ms-transform-origin: 0 100%; -o-transform-origin: 0 100%; transform-origin: 0 100%; }
#heart:after { left: 0; -webkit-transform: rotate(45deg); -moz-transform: rotate(45deg); -ms-transform: rotate(45deg); -o-transform: rotate(45deg); transform: rotate(45deg); -webkit-transform-origin: 100% 100%; -moz-transform-origin: 100% 100%; -ms-transform-origin: 100% 100%; -o-transform-origin: 100% 100%; transform-origin :100% 100%; }
//钻石
#cut-diamond { border-style: solid; border-color: transparent transparent red transparent; border-width: 0 25px 25px 25px; height: 0; width: 50px; position: relative; margin: 20px 0 50px 0; }
#cut-diamond:after { content: ""; position: absolute; top: 25px; left: -25px; width: 0; height: 0; border-style: solid; border-color: red transparent transparent transparent; border-width: 70px 50px 0 50px; }
//阴阳八卦
#yin-yang { width: 96px; height: 48px; background: #eee; border-color: #444; border-style: solid; border-width: 2px 2px 50px 2px; border-radius: 100%; position: relative; }
#yin-yang:before { content: ""; position: absolute; top: 50%; left: 0; background: #fff; border: 18px solid #444; border-radius: 100%; width: 12px; height: 12px; }
#yin-yang:after { content: ""; position: absolute; top: 50%; left: 50%; background: #444; border: 18px solid #eee; border-radius:100%; width: 12px; height: 12px; }