* {
  margin: 0;
  padding: 0;
  text-decoration: none;
  list-style: none;
  box-sizing: border-box;
}

body {
  font-family: "SourceHanSansCN", "Microsoft YaHei", "PingFang SC";
  margin: 0;
}

/* flex布局 */
.flex {
  display: flex;
}

/* 纵向排列 */
.flex_c {
  display: flex;
  flex-direction: column;
}

/* 水平居中 */
.j_center {
  display: flex;
  justify-content: center;
}

/* 两端对齐 */
.j_btween {
  display: flex;
  justify-content: space-between;
}

.j_evenly {
  display: flex;
  justify-content: space-evenly;
}

/* 垂直居中 */
.a_center {
  display: flex;
  align-items: center;
}

/* 靠底 */
.a_start {
  display: flex;
  align-items: flex-start;
}


/* 靠底 */
.a_end {
  display: flex;
  align-items: flex-end;
}

.j_end {
  display: flex;
  justify-content: flex-end;
}

/* 字内容绝对居中 */
.j_a_center {
  display: flex;
  justify-content: center;
  align-items: center;
}

.flex_c_r {
  display: flex;
  flex-direction: column-reverse;
}

/* flex:1 */
.flex_full {
  flex: 1;
}

/* flex_wrap */
.flex_wrap {
  flex-wrap: wrap;
}

.font-b {
  font-weight: bold;
}

.black {
  color: #303133;
}

.gray {
  color: #606266;
}

.white {
  color: white;
}

.blue {
  color: #3F86FA;
}

.lighter {
  font-weight: lighter;
}