Chat App CSS

styles.min.css

button,button:hover{border:none;color:#fff;padding:10px}.chat__messages,.chat__sidebar ul{list-style-type:none}*{box-sizing:border-box;margin:0;padding:0;font-family:HelveticaNeue-Light,"Helvetica Neue Light","Helvetica Neue",Helvetica,Arial,"Lucida Grande",sans-serif;font-weight:300;font-size:.95rem}li,ul{list-style-position:inside}h3{font-weight:600;text-align:center;font-size:1.5rem}button{background:#265f82;cursor:pointer;transition:background .3s ease}button:hover{background:#1F4C69}button:disabled{cursor:default;background:#698ea5}.centered-form{display:flex;align-items:center;height:100vh;width:100vw;justify-content:center;background:-moz-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:-webkit-gradient(linear,left top,right bottom,color-stop(0,rgba(49,84,129,1)),color-stop(100%,rgba(39,107,130,1)));background:-webkit-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:-o-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:-ms-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:linear-gradient(325deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%)}.centered-form__form{background:rgba(250,250,250,.9);border:1px solid #e1e1e1;border-radius:5px;padding:0 20px;margin:20px;width:230px}.form-field{margin:20px 0}.form-field>*{width:100%}.form-field label{display:block;margin-bottom:7px}.form-field input,.form-field select{border:1px solid #e1e1e1;padding:10px}.chat{display:flex}.chat__sidebar{overflow-y:scroll;width:260px;height:100vh;background:-moz-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:-webkit-gradient(linear,left top,right bottom,color-stop(0,rgba(49,84,129,1)),color-stop(100%,rgba(39,107,130,1)));background:-webkit-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:-o-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:-ms-linear-gradient(125deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%);background:linear-gradient(325deg,rgba(39,107,130,1) 0,rgba(49,84,129,1) 100%)}.chat__footer,.chat__sidebar li{background:#e6eaee;padding:10px}.chat__sidebar h3{color:#e6eaee;margin:10px 20px;text-align:left}.chat__sidebar li{border:1px solid #e1e1e1;border-radius:5px;margin:10px}.chat__main{display:flex;flex-direction:column;height:100vh;width:100%}.chat__messages{flex-grow:1;overflow-y:scroll;-webkit-overflow-scrolling:touch;padding:10px}.chat__footer{display:flex;flex-shrink:0}.chat__footer form{flex-grow:1;display:flex}.chat__footer form *{margin-right:10px}.chat__footer input{border:none;padding:10px;flex-grow:1}.message{padding:10px}.message__title{display:flex;margin-bottom:5px}.message__title h4{font-weight:600;margin-right:10px}.message__title span{color:#999}@media (max-width:600px){*{font-size:1rem}.chat__sidebar{display:none}.chat__footer{flex-direction:column}.chat__footer form{margin-bottom:10px}.chat__footer button{margin-right:0}}

styles.css

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif;
  font-weight: 300;
  font-size: .95rem;
}

ul, li {
  list-style-position: inside;
}

h3 {
  font-weight: 600;
  text-align: center;
  font-size: 1.5rem;
}

button {
  border: none;
  background: #265f82;
  color: white;
  cursor: pointer;
  padding: 10px;
  transition: background .3s ease;
}

button:hover {
  border: none;
  background: #1F4C69;
  color: white;
  padding: 10px;
}

button:disabled {
  cursor: default;
  background: #698ea5;
}

.centered-form {
  display: flex;
  align-items: center;
  height: 100vh;
  width: 100vw;
  justify-content: center;
  background: -moz-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* ff3.6+ */
  background: -webkit-gradient(linear, left top, right bottom, color-stop(0%, rgba(49,84,129,1)), color-stop(100%, rgba(39,107,130,1))); /* safari4+,chrome */
  background: -webkit-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* safari5.1+,chrome10+ */
  background: -o-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* opera 11.10+ */
  background: -ms-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* ie10+ */
  background: linear-gradient(325deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* w3c */
}

.centered-form__form {
  background: rgba(250, 250, 250, 0.9);
  border: 1px solid #e1e1e1;
  border-radius: 5px;
  padding: 0px 20px;
  margin: 20px;
  width: 230px;
}

.form-field {
  margin: 20px 0;
}

.form-field > * {
  width: 100%;
}

.form-field label {
  display: block;
  margin-bottom: 7px;
}

.form-field input, .form-field select {
  border: 1px solid #e1e1e1;
  padding: 10px;
}

.chat {
  display: flex;
}

.chat__sidebar {
  overflow-y: scroll;
  width: 260px;
  height: 100vh;
  background: -moz-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* ff3.6+ */
  background: -webkit-gradient(linear, left top, right bottom, color-stop(0%, rgba(49,84,129,1)), color-stop(100%, rgba(39,107,130,1))); /* safari4+,chrome */
  background: -webkit-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* safari5.1+,chrome10+ */
  background: -o-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* opera 11.10+ */
  background: -ms-linear-gradient(125deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* ie10+ */
  background: linear-gradient(325deg, rgba(39,107,130,1) 0%, rgba(49,84,129,1) 100%); /* w3c */
}

.chat__sidebar h3 {
  color: #e6eaee;
  margin: 10px 20px;
  text-align: left;
}

.chat__sidebar ul {
  list-style-type: none;
}

.chat__sidebar li {
  background: #e6eaee;
  border: 1px solid #e1e1e1;
  border-radius: 5px;
  padding: 10px;
  margin: 10px;
}

.chat__main {
  display: flex;
  flex-direction: column;
  height: 100vh;
  width: 100%;
}

.chat__messages {
  flex-grow: 1;
  overflow-y: scroll;
  -webkit-overflow-scrolling: touch;
}

.chat__footer {
  background: #e6eaee;
  display: flex;
  padding: 10px;
  /*height: 60px;*/
  flex-shrink: 0;
}

.chat__footer form {
  flex-grow: 1;
  display: flex;
}

.chat__footer form * {
  margin-right: 10px;
}

.chat__footer input {
  border: none;
  padding: 10px;
  flex-grow: 1;
}

.chat__messages {
  list-style-type: none;
  padding: 10px;
}

.message {
  padding: 10px;
}

.message__title {
  display: flex;
  margin-bottom: 5px;
}

.message__title h4 {
  font-weight: 600;
  margin-right: 10px;
}

.message__title span {
  color: #999;
}

@media (max-width: 600px) {
  * {
    font-size: 1rem;
  }

  .chat__sidebar {
    display: none;
  }

  .chat__footer {
    flex-direction: column;
  }

  .chat__footer form {
    margin-bottom: 10px;
  }

  .chat__footer button {
    margin-right: 0px;
  }
}

While working on section 9, Lecture 116 I ran into having the main section of the chat be displayed below the sidebar (this is on MACOS on Chrome Version 67.0.3396.99 (64-bit).

Coming from a native development background (mostly iOS, some C++ and other stuff) I don't know much CSS so I had to ask a friend for help on figuring that one out.
I ended up adding a div that included the main section and sidebar like so:
.main__container { display: flex; flex-direction: row; }

And the issue was fixed.

I also set the sidebar overflow-y to "auto" to prevent the scrollbar from showing if not needed.
These two things differed from the video and stood out right away. I realize the course is not about CSS but you may want to consider Going over this style file a bit for newbies like myself, so we know where/what to look for when things break :)

While working on section 9, Lecture 116 I ran into having the main section of the chat be displayed below the sidebar (this is on MACOS on Chrome Version 67.0.3396.99 (64-bit).

I think you made the same mistake I did: The main_chat div is supposed to encompass the chat__footer div. It should not be closed before the chat__footer div.