.rm-block{max-width:760px;margin:0 auto;padding:0 20px;box-sizing:border-box}
.rm-content{position:relative;overflow:hidden;transition:max-height .4s ease}
.rm-content p{margin:0 0 1em}
/* затухание текста снизу; #fff поменяйте на цвет фона блока */
.rm-block:not(.is-open):not(.no-toggle) .rm-content::after{
  content:"";position:absolute;left:0;right:0;bottom:0;height:60px;
  background:linear-gradient(rgba(255,255,255,0),#fff);pointer-events:none}
.rm-btn{margin-top:12px;padding:10px 24px;border:1px solid #000;border-radius:30px;
  background:transparent;color:#000;font:inherit;font-size:15px;cursor:pointer;transition:.2s}
.rm-btn:hover{background:#000;color:#fff}