<div class="drop">
  <div class="option active placeholder" data-value="placeholder">
    Choose wisely
  </div>
  <div class="option" data-value="wow">
    Wow!
  </div>
  <div class="option" data-value="drop">
    So dropdown!
  </div>
  <div class="option" data-value="select">
    Very select!
  </div>
  <div class="option" data-value="custom">
    Much custom!
  </div>
  <div class="option" data-value="animation"> 
    Such animation!
  </div>
</div>
@import "compass/css3";

$dark: #35414a;
$semilight: #86919a;
$blue: #5aafee;
*, *:before, *:after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
@font-face {
  font-family: pfs-bold;
  src: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/PFSquareSansPro-Bold.otf');
}
body {
  background: $dark;
}
.drop {
  width: 20em;
  margin: 5em auto;
  font-family: pfs-bold;
  color: $semilight;
  text-transform: uppercase;
  position: relative;
  transition: width 0.5s;
  will-change: width;
  
  .option {
    padding: 1em;
    cursor: pointer;
    background-color: #485761;
    
    &:not(.active) {
      display: none;
      opacity: 0;
      transform: translateY(-50%);
    }
  }
  
  &.visible {
    animation: bounce 1s;
    width: 24em;
    
    &:before, &:after {
      border-color: #fff;
    }
    &:before {
      opacity: 0;
    }
    &:after {
      opacity: 1;
    }
    
    .option {
      color: #fff;
      display: block;
    }
  }
  
  &.opacity {
    
    .option {
      transform: translateZ(0);
      opacity: 1;
      
      @for $i from 0 to 10 {
        &:nth-child(#{$i}) {
          transition: opacity 0.5s 0.1s*$i, transform 0.5s 0.1s*$i;
        }
      }
    }
  }

&.withBG {
  
  .option {
    transition: background-color 0.1s;

    &:not(.placeholder):hover {
      background-color: $blue;
    }

    &:not(.placeholder).active {
      background-color: $blue;
    }
  }
}
  
  &:after, &:before {
    content: "";
    position: absolute;
    top: 1.5em;
    right: 1em;
    width: 0.75em;
    height: 0.75em;
    border: 0.2em solid $semilight;
    transform: rotate(45deg);
    transform-origin: 50% 50%;
    transition: opacity 0.2s;
  }
  &:before {
    border-left: none;
    border-top: none;
    top: 1.2em;
  }
  &:after {
    border-right: none;
    border-bottom: none;
    opacity: 0;
  }
}

.mini-hack {
  opacity: 0;
  transform: translateY(-50%);
}
View Compiled
$(document).ready(function() {
  $(".drop .option").click(function() {
    var val = $(this).attr("data-value"),
        $drop = $(".drop"),
        prevActive = $(".drop .option.active").attr("data-value"),
        options = $(".drop .option").length;
    $drop.find(".option.active").addClass("mini-hack");
    $drop.toggleClass("visible");
    $drop.removeClass("withBG");
    $(this).css("top");
    $drop.toggleClass("opacity");
    $(".mini-hack").removeClass("mini-hack");
    if ($drop.hasClass("visible")) {
      setTimeout(function() {
        $drop.addClass("withBG");
      }, 400 + options*100); 
    }
    triggerAnimation();
    if (val !== "placeholder" || prevActive === "placeholder") {
      $(".drop .option").removeClass("active");
      $(this).addClass("active");
    };
  });
  
  function triggerAnimation() {
    var finalWidth = $(".drop").hasClass("visible") ? 22 : 20;
    $(".drop").css("width", "24em");
    setTimeout(function() {
      $(".drop").css("width", finalWidth + "em");
    }, 400);
  }
});
Run Pen

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. //cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js