style.css

img {
  width: 150px;
  max-height: 150px;
}

#main {
  width: 70%;
  margin: 0 auto;
  min-width: 580px;
  font-size: 20px;
  font-family: Helvetica, Arial, sans-serif;
}

#header {
  height: 50px;
  width: 100%;
  background-color: #1F2833;
  padding: 10px;
}

#app {
  width: 100%;
  background-color: #C5C6C7;
  padding: 10px;
}

#app::after {
  content: "";
  clear: both;
  display: table;
}

#asset {
  display: block;
  float: left;
  margin-right: 5px;
  font-size: 14px;
}

button {
  background-color: #45A29E;
  border: none;
  color: white;
  padding: 15px 30px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
}

input[type=text] {
  width: 100%;
  padding: 12px 20px;
  margin: 4px 0;
  display: inline-block;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-sizing: border-box;
  font-size: 16px;
}