css rewrite for iDevs chat app or Nova Chat

rewrite.css

@import url('https://fonts.googleapis.com/css2?family=Rubik:wght@300&display=swap');
body {
  background-color: #000000;
  font-family: 'Rubik', sans-serif;
}

h1{
  font-family: 'Century Gothic', sans-serif;
  font-size: 2.5rem;
  color: #fff;
  text-align: center;
  margin-top: 2rem;
}

.App {
  text-align: center;
  margin: 0 auto;
}

.App header {
  background-color: #181717;
  height: 10vh;
  min-height: 50px;
  color: white;
  position: fixed;
  width: 100%;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 99;
  padding: 10px;
  box-sizing: border-box;
}

.App section {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background-color: rgb(0, 0, 0);
  color: #ffffff;
}

main {
  width: 100%;
  height: 80vh;
  overflow-y: scroll;
}
main::-webkit-scrollbar {
  width: 0.25rem;
}

main::-webkit-scrollbar-track {
  background: #1e1e24;
}

main::-webkit-scrollbar-thumb {
  background: #6649b8;
}

.MessageSender {
  height: 10vh;
  position: fixed;
  bottom: 0;
  background-color: rgb(24, 23, 23);
  width: 100%;

  display: flex;
  font-size: 1.5rem;
}

form button {
  width: 20%;
  background-color: rgb(56, 56, 143);
}


input {
  line-height: 1.5;
  width: 100%;
  font-size: 1.5rem;
  background: rgb(58, 58, 58);
  color: white;
  outline: none;
  border: none;
  padding: 0 10px;
}

button {
  background-color: #282c34; /* Green */
  border: none;
  color: white;
  padding: 15px 32px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  cursor: pointer;
  font-size: 1.25rem;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}


.sign-in {
  color: #282c34;
  background: white;
  max-width: 400px;
  margin: 10px auto;
  border-radius: 20px;
}




ul, li {
  text-align: left;
  list-style: none;
}

p {
  max-width: 500px;
  margin-bottom: 12px;
  line-height: 24px;
  padding: 10px 20px;
  border-radius: 25px;
  position: relative;
  color: white;
  text-align: center;
}

.message {
  display: flex;
  align-items: center;
}


.sent {
  flex-direction: row-reverse;
}

.sent p {
  color: rgb(0, 0, 0);
  background: #00baca;
  align-self: flex-end;
}
.received p {
  background: #ffffff;
  color: black;
}

img {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  margin: 2px 5px;
}

a{
  color: white;
}

a:hover{
  color: #6649b8;
}

.link {
  background-color: #18171700;
  color: white;
  text-decoration: underline;
}

.link:hover {
  color: #6649b8;
}

.grid {
  display: grid;
  grid-template-columns: auto auto;
}
label {
text-align: left;
}
.popup-box {
  position: fixed;
  background: #00000050;
  width: 100%;
  height: 100vh;
  top: 0;
  left: 0;
}
 
.box {
  position: relative;
  width: 70%;
  margin: 0 auto;
  height: auto;
  max-height: 70vh;
  margin-top: calc(100vh - 85vh - 20px);
  background: rgb(0, 0, 0);
  border-radius: 4px;
  padding: 20px;
  border: 1px solid #999;
  overflow: auto;
}
 
.close-icon {
  cursor: pointer;
  position: fixed;
  right: calc(15% - 30px);
  top: calc(100vh - 85vh - 33px);
  background: #ff0000;
  width: 25px;
  height: 25px;
  border-radius: 50%;
  line-height: 20px;
  text-align: center;
  border: 1px solid #999;
  font-size: 20px;
}