JSFiddle - React, Tailwind, and code Playground

HTML

<body>
  <div class="page">
    <header></header>
    <main>
      <div class="chats">
        <div class="search-chats">
          <input type="text" placeholder="Search">
        </div>
        <div class="chats">
        
          <div class="chat">
            <img src="https://hips.hearstapps.com/hmg-prod/images/marcus-aurelius-gettyimages-122316830.jpg" alt="Avatar">
            <div class="info">
              
              <div class="top">
                <div class="username">Marcus Aurelius</div>
                <div class="time">10:55PM</div>
              </div>
              
              <div class="buttom">
                <div class="message">Lorem ipsum dolor, sit amet consectetur adipisicing elit</div>
                <div class="unread-messages">
                  <div class="number">3</div>
                </div>
              </div>
            </div>
          </div>
          
          <div class="chat">
            <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQSBG6Cwh5aj_a_6WW9HNap8azuJG-ITmSdhQ&s" alt="Avatar">
            <div class="info">
              <div class="top">
                <div class="username">Antoninus Pius</div>
                <div class="time">10:55PM</div>
              </div>
              <div class="buttom">
                <div class="message">Lorem ipsum dolor, sit amet consectetur adipisicing elit</div>
                <div class="unread-messages">
                  <div class="number">1</div>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>
      <div class="dialog">

      </div>
    </main>
  </div>
</body>

CSS

:root {
  --header-color: #242f3d;
  --chats-background-color: #17212b;
  --dialog-background-color: #0e1621;
  --header-height: 1.2rem;
  --chat-hover-color: #2b5278;
  --unread-message-color: #4082bc;
  --passive-text-color: #637283;
  --primary-text-color: #e4e9ee;
}

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

.page {
  height: 100vh;
  color: var(--primary-text-color);
  font-family:'Courier New', Courier, monospace;
}

header {
  height: var(--header-height);
  background-color: var(--header-color);
}

main {
  display: flex;
  height: calc(100% - var(--header-height));
}

.chats {
  flex: 1;
  background-color: var(--chats-background-color);
  display: flex;
  flex-direction: column;
  min-width: 20ch;
}

.search-chats {
  display: flex;
  justify-content: center;
  align-content: center;
  padding: 0.5rem;
}

.search-chats input {
  outline: 0;
  border: 2px solid var(--header-color);
  border-radius: 1rem;
  background-color: var(--header-color);
  color: inherit;
  width: 100%;
  padding: 0.5rem;
}

.chat:hover  {
  background-color: var(--chat-hover-color);
  cursor: pointer;
  color: var(--primary-text-color);
}

.chat:hover .time,
.chat:hover .message {
  color: var(--primary-text-color);
}

.chat {
  display: flex;
  gap: 0.5rem;
  padding: 0.25rem 0.5rem;
}

.chat img {
  width: 4rem;
  height: 4rem;
  border-radius: 2rem;
  display: block;
}

.chat .info {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  overflow: hidden;
}

.chat .info > * {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.chat .info .time {
  flex: end;
}

.chat .info .message,
.chat .info .username {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.dialog {
  flex: 2;
  background-color: var(--dialog-background-color);
}