h2{
position: relative;
padding: 0.5em;
background: #a6d3c8;
color: white;
}

h2::before {
position: absolute;
content: '';
top: 100%;
left: 0;
border: none;
border-bottom: solid 15px transparent;
border-right: solid 20px rgb(149, 158, 155);
}

p.sample0 {border: solid 10px #0000ff;}
p.sample1 {border: double 10px #0000ff;}
p.sample2 {border: inset 10px #ff0000;}
p.sample3 {
 margin: 30px 30px;
 padding: 10px;
 border: medium solid #0000ff;
 }

.box3 {
    padding: 0.5em 1em;
    margin: 2em 0;
    color: #2c2c2f;
    background: #cde4ff;/*背景色*/
}
.box3 p {
    margin: 0; 
    padding: 0;
}

.box5 {
    padding: 0.5em 1em;
    margin: 2em 0;
    border: double 5px #4ec4d3;
}
.box5 p {
    margin: 0; 
    padding: 0;
}


.box2 {
    padding:0.5em 1em;
    margin:2em 0;
    color: #2c2c2f;
    background: #e6e6fa;/*背景色*/
}

.box2 p {
    margin: 0;
    padding: 0;
}