<header class="header">
  <img src="https://placeholder.com/wp-content/uploads/2018/10/placeholder.com-logo1.png" alt="" class="header__logo">
</header>

body
  margin: 0
  padding: 0
.header
  display: flex
  align-items: center
  width: 100%
  height: 60px
  background-color: #fede35
  position: relative
  padding: 0 15px
  &__logo
    width: 150px
    max-height: 40px
  &:before
    content: ''
    display: block
    height: 30px
    width: 10%
    min-width: 220px
    position: absolute
    bottom: -30px
    left: -15px
    background-color: inherit
    z-index: -1
    transform: skew(-45deg)