如何在按钮中心添加两行

.btn {
  position: relative;
  padding: 20px 50px;
  color: #FFFFFF;
  border: 3px solid #E82929;
  font-family: 'Flamenco';
  font-style: normal;
  font-weight: 400;
  font-size: 24px;
  line-height: 25px;
  text-align: center;
  
  background: linear-gradient(90deg, #E82929 40px,#0000 0 calc(100% - 40px), #E82929 0) 50%/100% 3px no-repeat;
  background-color: #000000;
}

<button class="btn">Забронировать столик</button>

.btn {
  position: relative;
  width: 362px;
  height: 71px;
  color: #FFFFFF;
  background-color: #000000;
  border: 3px solid #E82929;
  font-family: 'Flamenco';
  font-style: normal;
  font-weight: 400;
  font-size: 24px;
  line-height: 25px;
  text-align: center;
}

/* extra code comes here */
.btn {
  padding: 0 40px; /* 30px line width + 10px padding */
}

.btn::before,
.btn::after {
  background-color: #E82929; /* border color */
  content: ''; /* content is mandatory for the element to show up */
  height: 3px; /* 3px border width */
  position: absolute;
  top: 50%; /* 50% from the top */
  transform: translateY(-50%); /* half of its height back to the top */
  width: 30px; /* 30px line width */
}

.btn::before {
  left: 0;
}

.btn::after {
  right: 0;
}

<button class="btn">Забронировать столик</button>