einundzwanzig.space/src/css/sections/meetups.css

@keyframes pulse {
  0% { transform: scale(.75); }
  1% { transform: scale(1.5); }
  3% { transform: scale(.75);  }
}

#meetups {
  & #map {
    @media (--up_to_L) {
      margin-top: var(--space-xl);

      & img,
      & .dot {
        display: none;
      }
    }

    @media (--L_and_up) {
      position: relative;
      margin-top: var(--space-xxl);

      & h2 {
        display: none;
      }

      & img {
        display: block;
        width: 100%;
        opacity: .5;
      }

      & ul {
        margin: 0;
        list-style: none;
      }

      & li {
        position: absolute;
        z-index: 1;
        font-size: var(--font-size-xs);

        &.unmapped {
          display: none;
        }

        &.official {
          color: var(--color-accent);
        }

        &:not(.official) {
          color: var(--color-secondary);
        }

        & a {
          color: inherit;
          display: inline-block;
          margin-top: .2rem;
        }

        & .dot {
          content: '';
          position: absolute;
          top: .275rem;
          left: -1.25rem;
          background: radial-gradient(currentColor 0%, rgba(255, 255, 255, 0) 100%);
          animation-timing-function: linear;
          animation-iteration-count: infinite;
          will-change: transform;
          transform-origin: 50%;
          border-radius: 50%;
          width: 1rem;
          height: 1rem;
          transform: scale(.75);
          animation-name: pulse;
        }
      }
    }
  }

  & #unmapped {
    @media (--up_to_L) {
      display: none;
    }
    @media (--L_and_up) {
      margin-top: var(--space-xxl);
    }
  }
}