css对话框| 气泡框| css箭头

DOCTYPE html>
html>
  head>
    meta charset="UTF-8" />
    title>Testtitle>
    style>
      .tip {
        position: relative;
        background-color: deepskyblue;
        margin: 20px auto;
        width: 246px;
        height: 43px;
        line-height: 43px;
        color: white;
        text-align: center;
        border-radius: 10px;
        font-family: sans-serif;
      }
      .tip:after {
        content: "";
        position: absolute;
        width: 0;
        height: 0;
        border: 8px solid;
      }
      .top:after {
        border-bottom-color: deepskyblue;
        left: 50%;
        bottom: 100%;
        margin-left: -15px;
      }
      .right:after {
        border-left-color: deepskyblue;
        left: 100%;
        top: 50%;
        margin-top: -7px;
      }
      .bottom:after {
        border-top-color: deepskyblue;
        top: 100%;
        left: 50%;
        margin-left: -15px;
      }
      .left:after {
        border-right-color: deepskyblue;
        top: 50%;
        right: 100%;
        margin-top: -9px;
      }
    style>
  head>
  body>
    div class="tip top">topdiv>
    div class="tip bottom">bottomdiv>
    div class="tip left">leftdiv>
    div class="tip right">rightdiv>
  body>
html>