header {
    --_animationStartsAfter: 50vh;
    --_animationDistance: 120px;
    --_surfaceColorStart: #001e37;
    --_surfaceColorEnd: hsla(0, 0%, 100%, 0.95);
    --_textColorStart: hsl(0, 40%, 92%);
    --_textColorEnd: #001e37;
    --_selectedColor: rgb(from currentColor 11 11);
    --_logo_src: "https://techuk.org/assets/img/logo-alt.svg";
  
    padding: 1rem 3rem;
    margin-inline: auto;
    margin-block: 0rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
  
    color: var(--_textColorStart);
    background-color: var(--_surfaceColorStart);
  
    position: sticky;
    z-index: 1000;
    top: 0;
    animation: stickyNav linear forwards;
  
    @supports (animation-timeline: view()) {
      animation-timeline: view();
      animation-range-start: calc(100vh + var(--_animationStartsAfter));
      animation-range-end: calc(
        100vh + var(--_animationStartsAfter) + var(--_animationDistance)
      );
    }
  
    .logo {
      fill: currentColor;
      height: 3rem;
    }
  
    ul {
      display: flex;
      gap: 2rem;
      list-style: none;
      margin: 0;
      padding: 0;
    }
  
    a {
      color: inherit;
      text-decoration: none;
      font-weight: 550;
  
      &:hover,
      &:focus {
        color: var(--_selectedColor);
        text-decoration: underline;
        text-decoration-thickness: 0.07lh;
        text-underline-offset: 0.35lh;
        text-decoration-color: #6BC5D4;
      }
    }
  }
  
  @keyframes stickyNav {
    100% {
      color: var(--_textColorEnd);
      background-color: var(--_surfaceColorEnd);
      box-shadow: 0 0 0.75rem hsl(0 0% 0% / 0.3);
    }
  }
  
  @layer not-demo-related {
    :root {
      --content-max-width: 75ch;
  
      --font-family: Roboto, sans-serif;
  
      --fs-300: clamp(0.94rem, calc(0.92rem + 0.08vw), 0.98rem);
      --fs-350: clamp(1.00rem, calc(1.00rem + 0.20vw), 1.15rem);
      --fs-400: clamp(1.13rem, calc(1.06rem + 0.33vw), 1.31rem);
      --fs-500: clamp(1.35rem, calc(1.21rem + 0.69vw), 1.75rem);
      --fs-600: clamp(1.62rem, calc(1.37rem + 1.24vw), 2.33rem);
      --fs-700: clamp(1.94rem, calc(1.54rem + 2.03vw), 3.11rem);
      --fs-800: clamp(2.33rem, calc(1.7rem + 3.15vw), 4.14rem);
      --fs-900: clamp(2.8rem, calc(1.85rem + 4.74vw), 5.52rem);
  
      --clr-primary-700: hsl(219, 76%, 75%);
      --clr-primary-600: hsl(219, 76%, 50%);
      --clr-primary-500: hsl(219, 76%, 35%);
      --clr-primary-400: hsl(219, 76%, 25%);
      --clr-primary-300: hsl(219, 76%, 15%);
  
      --clr-secondary-700: hsl(269, 75%, 75%);
      --clr-secondary-600: hsl(269, 75%, 50%);
      --clr-secondary-500: hsl(269, 75%, 35%);
      --clr-secondary-400: hsl(269, 75%, 20%);
      --clr-secondary-300: hsl(269, 75%, 15%);
  
      --clr-accent-700: hsl(358, 72%, 75%);
      --clr-accent-600: hsl(358, 72%, 50%);
      --clr-accent-500: hsl(358, 72%, 35%);
      --clr-accent-400: hsl(358, 72%, 20%);
      --clr-accent-300: hsl(358, 72%, 15%);
  
      --clr-neutral-900: hsl(219, 15%, 90%);
      --clr-neutral-700: hsl(219, 15%, 75%);
      --clr-neutral-600: hsl(219, 15%, 50%);
      --clr-neutral-500: hsl(219, 15%, 35%);
      --clr-neutral-400: hsl(219, 15%, 20%);
      --clr-neutral-300: hsl(219, 15%, 15%);
      --clr-neutral-100: hsl(219, 15%, 5%);
    }
  
    /* @media (prefers-color-scheme: dark) {
      :root {
        --clr-primary-300: hsl(219, 76%, 75%);
        --clr-primary-400: hsl(219, 76%, 50%);
        --clr-primary-500: hsl(219, 76%, 35%);
        --clr-primary-600: hsl(219, 76%, 25%);
        --clr-primary-700: hsl(219, 76%, 15%);
  
        --clr-secondary-300: hsl(269, 75%, 75%);
        --clr-secondary-400: hsl(269, 75%, 50%);
        --clr-secondary-500: hsl(269, 75%, 35%);
        --clr-secondary-600: hsl(269, 75%, 20%);
        --clr-secondary-700: hsl(269, 75%, 15%);
  
        --clr-accent-300: hsl(358, 72%, 75%);
        --clr-accent-400: hsl(358, 72%, 50%);
        --clr-accent-500: hsl(358, 72%, 35%);
        --clr-accent-600: hsl(358, 72%, 20%);
        --clr-accent-700: hsl(358, 72%, 15%);
  
        --clr-neutral-100: hsl(219, 15%, 90%);
        --clr-neutral-300: hsl(219, 15%, 75%);
        --clr-neutral-400: hsl(219, 15%, 50%);
        --clr-neutral-500: hsl(219, 15%, 35%);
        --clr-neutral-600: hsl(219, 15%, 20%);
        --clr-neutral-700: hsl(219, 15%, 15%);
        --clr-neutral-900: hsl(219, 15%, 5%);
      }
    } */
  
    *,
    *::before,
    *::after {
      box-sizing: border-box;
    }
  
    /* html {
      color-scheme: dark;
    } */
  
    body {
      margin: 0;
      color: var(--clr-neutral-300);
      font-family: var(--font-family);
      font-size: var(--fs-350);
      line-height: 1.6;
    }
  
    img {
      max-width: 100%;
      display: block;
    }
    
    .btn {
      border: solid;
      border-radius: 3vh;
      padding: 0.3vh;
      padding-right: 3vh;
      padding-left: 3vh;
    }

    h1,
    h2,
    h3,
    h4 {
      color: var(--clr-neutral-100);
      text-align: center;
    }
  
    h1 {
      font-size: var(--fs-800);
      line-height: 1.05;
      font-weight: 900;
      text-wrap: balance;
      text-align: center;
  
      > span {
        color: var(--clr-primary-700);
      }
    }

    li {
      text-align: center;
      align-self: center;
    }
  
    p {
      text-wrap: pretty;
      text-align: center;
    }
  
    .wrapper {
      width: min(var(--content-max-width), 100% - 2rem);
      margin-inline: auto;
    }
  
    .section-title {
      font-size: var(--fs-800);
      line-height: 1.1;
    }
  
    .flow > * + * {
      margin-top: 1em;
    }
  
    .visually-hidden {
      clip: rect(0 0 0 0);
      clip-path: inset(50%);
      height: 1px;
      overflow: hidden;
      position: absolute;
      white-space: nowrap;
      width: 1px;
    }
  
    .hero {
      padding-block: max(10rem, 10svh);
      text-align: center;
  
      color: var(--clr-neutral-900);
      margin-block-end: 5rem;
      background-color: var(--clr-neutral-700);
      background-position: center;
      background-image: url("Header_image_1.webp");
      background-size: cover;
      background-blend-mode: multiply;
  
      h1 {
        color: inherit;
      }
  
      > * {
        margin-inline: auto;
      }
    }
  
    main > img {
      width: 100%;
      max-height: 20vh;
      object-fit: cover;
    }
  
    .content-grid {
      display: grid;
      grid-template-columns:
        [full-width-start] minmax(1rem, 4fr)
        [content-start sidebar-start main-start] min(
          100% - 2rem,
          var(--content-max-width)
        )
        [content-end sidebar-end main-end] minmax(1rem, 1fr) [full-width-end];
    }
    

  
    :where(.content-grid, .full-width) > * {
      margin: 0;
    }
  
    @media (min-width: 900px) {
      .content-grid {
        grid-template-columns:
          [full-width-start] minmax(1rem, 1fr)
          [content-start sidebar-start] min(
            33% - 2rem,
            var(--content-max-width) / 3
          )
          [sidebar-end main-start] min(33% - 2rem, var(--content-max-width) / 3)
          min(33% - 2rem, var(--content-max-width) / 3)
          [content-end main-end] minmax(1rem, 1fr) [full-width-end];
      }
    }
  
    .content-grid > *,
    .full-width > * {
      grid-column: content;
    }
  
    .content-grid > .full-width {
      grid-column: full-width;
  
      display: grid;
      grid-template-columns: inherit;
    }
  }
  
  .programme_list {
    display: grid;
    gap: 1.5rem;
    grid-template-columns: 1fr 1fr 1fr;
    padding-block: 2rem;
    width: min(95%, 250rem);
    margin-inline: auto;
  }

  .programme_item {
    font-size: var(--fs-400);
    border-radius: 0.5rem;
    border: aqua;
    box-shadow: 2.5rem 3.75rem 3rem -3rem hsl(var(--clr-secondary-400) / 0.25);
    flex-grow: 1;
  }

  .programme_item img {
    width: auto;
  }

  .programme_item h2 {
    font-size: large;
    background-color: #001e37;
    color: azure;
    margin: 0%;
    height:4rem;
    display:block;
  }

  .container {
    max-width: 1000px;
    margin: 0 auto;
    background-color: inherit;
  }

  nav {
    background-color: inherit;
  }

  nav ul {
    margin-left:1rem;
    padding: 0;
    list-style: none;
    position: relative;
    text-align:center;
    gap: 1.5rem;
    background-color: inherit;
  }


  nav li {
    display: inline;
    background-color: inherit;
  }

  nav a {
    display:block;
    padding: 0.5em 0.2em;
    text-wrap:nowrap;
  }

  .menu-sub {
    position:absolute;
    background-color: inherit;
    width: auto;
    display:none;
    border-radius: 5px;
    padding-top: 2vh;
    padding: 2vh;
  }

  .menu-sub ul {
    display: contents;
    background-color: inherit;
  }

  nav li:hover .menu-sub {
    display:block;
    background-color: inherit;
  }

  .menu-sub li a {
    display:block;
    text-align: left;
    font-weight: 300;
    background-color: inherit;
  }