body {
    counter-reset: thmcnt;
    counter-reset: egcnt;
    counter-reset: defcnt;
}

.eg {
    display: block;
    margin: 20px 0 40px 0;
    counter-increment: egcnt;
    background-color: AntiqueWhite;
    border-left: 6px solid;
    border-color: BurlyWood;
    padding:10px 10px 10px 20px;
}

/*
.eg:before {
    content: "例子"counter(theorem-counter)".";
    font-weight: bold;
    font-style: normal;
    
}
*/

.prop {
    display: block;
    margin: 20px 0 40px 0;
    counter-increment: thmcnt;
    background-color: Lavender;
    border-left: 6px solid;
    border-color: DarkGrey;
    padding:10px 10px 10px 20px;
}
/*
.prop:before {
    content: "Proposition " counter(thmcnt) attr(btit) ". ";
    font-weight: bold;
    font-style: normal;
    
}
*/

.rmk {
    display: block;
    margin: 20px 0 40px 0;
    
    background-color:  #cefdce;
    border-left: 6px solid;
    border-color: DarkGreen;
    padding:10px 10px 10px 20px
}
.rmk:before {
    content: "评注.";
    font-weight: bold;
    font-style: normal;
    
}

.thm {
    display: block;
    margin: 20px 0 40px 0;
    counter-increment: thmcnt;
    background-color: LemonChiffon;
    border-left: 6px solid;
    border-color: Tomato;
    padding:10px 10px 10px 20px;
}

/*
.thm:before {
    content: "定理 " counter(thmcnt)   attr(btit) ". ";
    font-weight: bold;
    font-style: normal;
}
*/

.lem {
    display: block;
    margin: 20px 0 40px 0;
    counter-increment: thmcnt;
    background-color: Lavender;
    border-left: 6px solid;
    border-color: DarkGrey;
    padding:10px 10px 10px 20px;
}

/*
.lem:before {
    content: "引理 " attr(btit) ". ";
    font-weight: bold;
    font-style: normal;
}
*/

.prf {
    display: block;
    margin: 20px 0 0 30px;
    font-style: normal;
    padding:10px 10px 10px 30px;
    border-left: 6px solid;
    border-color: DarkGrey;
}
.prf:before {
    content: "证明.";
    
}
.prf:after {
    content: "\25FC";
    float:right;
}

.def {
    display: block;
    counter-increment: defcnt;
    margin: 20px 0 40px 0;
    font-style: normal;
    background-color: LightCyan;
    border-left: 6px solid;
    border-color: DarkCyan;
    padding:10px 20px 10px 20px;
}

  .gossip {
    font-size: small;
    text-align: right;
    width: 80%;
    margin-left: auto; 
    border: 1px solid black; 
    padding: 10px; 
    box-sizing: border-box; 
  }

/*
.def:before {
    content: "定义" counter(defcnt) ".";
    font-weight: bold;
    font-style: normal;
}
*/

.tip {
  background-color: #e7f3fe;
  border-left: 6px solid #2196F3;
  padding: 15px;
  margin-bottom: 15px;
  font-family: Arial, sans-serif;
  color: #333;
}

.qst:before {
    content: "❓ 问题"
}

.qst {
  background-color: #E6E6FA;
  border-left: 6px solid #e700ee;
  padding: 15px;
  margin-bottom: 15px;
  font-family: Arial, sans-serif;
  color: #333;
}

.tip h4 {
  margin-top: 0;
  margin-bottom: 10px;
  font-weight: bold;
  color: #2196F3;
}

.tip p {
  margin: 0;
}