devto-clone/src/Scss/_content.scss

.main-content {
  header {
    display: flex;
    align-items: center;
    padding: 0.5rem 0;

    h1 {
      font-size: 1.25rem;
      flex: 1;
    }
    nav {
      a {
        margin: 0 0.5rem;
        padding: 0.5rem;

        border-radius: 5px;
        &:hover {
          background-color: rgba(#3b49df, 0.1);
          color: var(--main-theme);
        }

        &:first-child {
          border: none;
          position: relative;
          font-weight:700;

          &:after {
            content: "";
            height: 3px;
            background-color: var(--main-theme);
            position: absolute;
            left: 0;
            right: 0;
            bottom: 0;
            border-radius: 5px;
            margin: 0 0.5rem;
            transition: all 0.2s;
          }

          &:hover:after {
            margin: 0;
            border-top-left-radius: 0;
            border-top-right-radius: 0;
          }
        }
      }
    }

    select {
      display: none;
      padding: 0.5rem;

      outline: none;
      border-radius: 5px;

      font-size: 1rem;
      color: var(--font-color);
      background-color: var(--main-0);

      border: 1px solid var(--main-3);

      &:focus {
        box-shadow: 0px 0px 1px 1px var(--main-theme);
      }
    }
  }
}