https://idea-hack.com/recipe/109439/

headerの背景画像を斜線で区切るCSSサンプルコード

RECIPE

HTML
<div class="header">
   <div class="header__bg"></div>
   <div class="header__logo">
      <svg viewBox="0 0 24 24">
  <path d="M11.83,1.73C8.43,1.79 6.23,3.32 6.23,3.32C5.95,3.5 5.88,3.91 6.07,4.19C6.27,4.5 6.66,4.55 6.96,4.34C6.96,4.34 11.27,1.15 17.46,4.38C17.75,4.55 18.14,4.45 18.31,4.15C18.5,3.85 18.37,3.47 18.03,3.28C16.36,2.4 14.78,1.96 13.36,1.8C12.83,1.74 12.32,1.72 11.83,1.73M12.22,4.34C6.26,4.26 3.41,9.05 3.41,9.05C3.22,9.34 3.3,9.72 3.58,9.91C3.87,10.1 4.26,10 4.5,9.68C4.5,9.68 6.92,5.5 12.2,5.59C17.5,5.66 19.82,9.65 19.82,9.65C20,9.94 20.38,10.04 20.68,9.87C21,9.69 21.07,9.31 20.9,9C20.9,9 18.15,4.42 12.22,4.34M11.5,6.82C9.82,6.94 8.21,7.55 7,8.56C4.62,10.53 3.1,14.14 4.77,19C4.88,19.33 5.24,19.5 5.57,19.39C5.89,19.28 6.07,18.92 5.95,18.6V18.6C4.41,14.13 5.78,11.2 7.8,9.5C9.77,7.89 13.25,7.5 15.84,9.1C17.11,9.9 18.1,11.28 18.6,12.64C19.11,14 19.08,15.32 18.67,15.94C18.25,16.59 17.4,16.83 16.65,16.64C15.9,16.45 15.29,15.91 15.26,14.77C15.23,13.06 13.89,12 12.5,11.84C11.16,11.68 9.61,12.4 9.21,14C8.45,16.92 10.36,21.07 14.78,22.45C15.11,22.55 15.46,22.37 15.57,22.04C15.67,21.71 15.5,21.35 15.15,21.25C11.32,20.06 9.87,16.43 10.42,14.29C10.66,13.33 11.5,13 12.38,13.08C13.25,13.18 14,13.7 14,14.79C14.05,16.43 15.12,17.54 16.34,17.85C17.56,18.16 18.97,17.77 19.72,16.62C20.5,15.45 20.37,13.8 19.78,12.21C19.18,10.61 18.07,9.03 16.5,8.04C14.96,7.08 13.19,6.7 11.5,6.82M11.86,9.25V9.26C10.08,9.32 8.3,10.24 7.28,12.18C5.96,14.67 6.56,17.21 7.44,19.04C8.33,20.88 9.54,22.1 9.54,22.1C9.78,22.35 10.17,22.35 10.42,22.11C10.67,21.87 10.67,21.5 10.43,21.23C10.43,21.23 9.36,20.13 8.57,18.5C7.78,16.87 7.3,14.81 8.38,12.77C9.5,10.67 11.5,10.16 13.26,10.67C15.04,11.19 16.53,12.74 16.5,15.03C16.46,15.38 16.71,15.68 17.06,15.7C17.4,15.73 17.7,15.47 17.73,15.06C17.79,12.2 15.87,10.13 13.61,9.47C13.04,9.31 12.45,9.23 11.86,9.25M12.08,14.25C11.73,14.26 11.46,14.55 11.47,14.89C11.47,14.89 11.5,16.37 12.31,17.8C13.15,19.23 14.93,20.59 18.03,20.3C18.37,20.28 18.64,20 18.62,19.64C18.6,19.29 18.3,19.03 17.91,19.06C15.19,19.31 14.04,18.28 13.39,17.17C12.74,16.07 12.72,14.88 12.72,14.88C12.72,14.53 12.44,14.25 12.08,14.25Z"></path>
</svg>
   </div>
   <h1 class="header__title">Come code with us.</h1>
   <div class="header__log">
      <svg class="header__log--icon" width="24" height="24" viewBox="0 0 24 24">
  <path d="M12,4A4,4 0 0,1 16,8A4,4 0 0,1 12,12A4,4 0 0,1 8,8A4,4 0 0,1 12,4M12,14C16.42,14 20,15.79 20,18V20H4V18C4,15.79 7.58,14 12,14Z"></path>
</svg>
      <p class="header__log--text">Sign Up</p>
   </div>
</div>

<div class="about">
   <div class="about__title">
      <h2 class="about__title--text">Who we are?</h2>
   </div>
   <div class="about__text">
      <p class="about__text--content">
         Lorem ipsum dolor sit amet consectetur, adipisicing elit. Neque officiis impedit exercitationem aperiam culpa repudiandae, architecto fugiat cumque dignissimos perferendis rerum eum aliquid assumenda consequatur aspernatur accusantium adipisci rem quasi!
         
         <br>
         
         Lorem ipsum dolor sit amet consectetur adipisicing elit. Ex provident asperiores quisquam voluptatum dolorem. Hic animi asperiores quibusdam eum recusandae, similique obcaecati dolore, porro saepe consequuntur, ad reprehenderit voluptatibus voluptas!
         
         <br>
         
         Lorem ipsum dolor sit amet consectetur adipisicing elit. Iure, at qui quisquam sed maiores, rerum pariatur accusantium cum voluptates nihil ut aperiam nobis, suscipit dicta itaque obcaecati omnis culpa magnam.
      </p>
   </div>
</div>
SCSS
@import url("https://fonts.googleapis.com/css?family=Raleway:400,400i,700");

*,
*::before,
*::after {
   margin: 0;
   padding: 0;
}

body {
   background-color: #e4e9ed;
   font-family: Raleway, sans-serif;
}

br {
   margin-bottom: 2%;
}

.header {
   width: 100%;
   height: 80vh;
   position: relative;
   display: grid;
   grid-template-rows: max-content 1fr;
   grid-template-columns: 1fr max-content;
   
   &__logo {
      fill: white;
      width: 3rem;
      padding: 1rem;
      cursor: pointer;
   }
   
   &__bg {
      width: 100%;
      height: 100%;
         background-image: url("https://images.unsplash.com/photo-1523240795612-9a054b0db644?ixlib=rb-1.2.1&q=85&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjE0NTg5fQ");
   background-size: cover;
   background-position: center;
      filter: brightness(50%);
      clip-path: polygon(0 0, 100% 0, 100% 80%, 0 100%);
      position: absolute;
      top: 0;
      left: 0;
      z-index: -1;
   }
   
   &__title {
      grid-area: 2 / 1 / 2 / 3;
      align-self: center;
      justify-self: center;
      color: white;
      text-transform: uppercase;
      font-size: 4rem;
      text-shadow: 0px 2px 4px rgba(0,0,0,.4);
      margin-top: -5rem;
   }
   
   &__log {
      display: flex;
      align-items: center;
      grid-area: 1 / 2 / 1 / 3;
      padding: 1rem 2rem;
      color: white;
      cursor: pointer;
      text-shadow: 0px 2px 4px rgba(0,0,0,.4);
      
      &--icon {
         fill: currentColor;
         margin-right: .5rem;
        filter: drop-shadow(0px 2px 4px rgba(0,0,0,.5));
      }
      
      &--text {
         text-transform: capitalize;
      }
   }
}

.about {
   width: 100%;
   height: 60vh;
   margin-top: -7rem;
   clip-path: polygon(0 27%, 100% 0, 100% 100%, 0 100%);
   background-image: url('data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" width="4" height="4" viewBox="0 0 4 4"%3E%3Cpath fill="%239C92AC" fill-opacity="0.4" d="M1 3h1v1H1V3zm2-2h1v1H3V1z"%3E%3C/path%3E%3C/svg%3E');
   
   &__title {
      padding-top: 7rem;
      text-align: center;
      text-transform: uppercase;
      
      &--text {
         color: #232323;
      }
   }
   
   &__text {
      width: 80%;
      margin: 5% auto;
      
      &--content {
         text-align: justify;
      }
   }
}