Step 1: Write the nav menu structure:
<ul class="nav-links">
<li class="li-box"><a class="a-menu-item" href="">Inicio</a></li>
<li class="li-box"><a class="a-menu-item" href="">Curaduría</a></li>
<li class="li-box"><a class="a-menu-item" href="">Servicios</a></li>
<li class="li-box"><a class="a-menu-item" href="">Documentos</a></li>
<li class="li-box"><a class="a-menu-item" href="">Contacto</a></li>
</ul>
Step 2: On your css file, we’re going to define the height of the a tag (I’m using a class called li-box).
.li-box{ list-style: none; padding-left: 15px; padding-right: 15px; height: 20vh; }
Step 3: Set the line height to fit with the same hight of the li element. Set position relative and display inline-block, this is for the underline be visible.
.a-menu-item{ color: rgb(255, 103, 64); text-decoration: none; letter-spacing: 3px; font-weight: bold; font-size: 14px; line-height: 20vh; position: relative; display: inline-block; }
Step 4: Use the selector after from the a tag and set the features of the underlined we want to show. Content empty string, position absolute, top and left, the height of the underlined and width, the color of the line (background-color) and a transition for getting a smooth movement.
.a-menu-item:after{ content: ""; position: absolute; top: 85%; height: 2px; width: 40%; left: 30%; background-color: rgba(255, 103, 64, 0.6); transition: 0.4s ease-out all .1s; }
Step 5: We have to modify the a tag using the after selector when we hover on li element. Here we’re going to modify the width and initial position on x axis (left), and a transition for a better result.
.li-box:hover .a-menu-item::after { width: 90%; left: 5%; transition: 0.5s ease all; }

Great content! Super high-quality! Keep it up! 🙂
Thanks for your comment. I hope it has helped you.
You actually make it seem so easy with your presentation but I find this topic to be actually something that I think I would never understand. It seems too complicated and extremely broad for me. I am looking forward for your next post, I’ll try to get the hang of it!
Thanks for your comment Magnolia. This topic was a little bit confusing to me too at the beginning, you just need to practice over and over until you get the concept of all these CSS topics. Regards!
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