html, body {
  font-family: 'Montserrat', sans-serif;
  margin: 0;
  padding: 0;
}

h1 {
  border-left: 2px solid #00f28f;
  font-size: 48px;
  font-weight: 400;
  margin: 0;
  padding-left: 20px;
}

.header {
  margin: 80px 0 100px 80px;
}

.main {
  margin: 0 0 0 80px;
  max-height: 1100px;
  overflow: hidden;
}

form {
  margin: 0 0 100px 0;
}

form input {
  background: #f0f0f0;
  border: none;
  border-left: 2px solid #fff;
  font-size: 36px;
  font-family: 'Montserrat', sans-serif;
  padding: 20px;
  transition: background 2s, border-left 2s;
  width: 600px;
}

form input:focus {
  background: #fff;
  border-left: 2px solid #000;
  box-shadow: none;
  outline: none;
  transition: background 2s, border-left 2s;
}

button.btn {
  background: transparent;
  border: none;
  color: #00f28f;
  cursor: pointer;
  font-size: 36px;
  padding: 20px 24px;
  transition: background 2s, color 1s;
}

button.btn:hover {
  background: #00f28f;
  color: #fff;
  transition: background 2s, color 1s;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

li {
  border-left: 2px solid #000;
  font-size: 36px;
  margin: 0 0 36px;
  opacity: 0;
  padding-left: 20px;
}

li:nth-child(1) {
  opacity: 1;
}
li:nth-child(2) {
  opacity: 0.9;
}
li:nth-child(3) {
  opacity: 0.8;
}
li:nth-child(4) {
  opacity: 0.7;
}
li:nth-child(5) {
  opacity: 0.6;
}
li:nth-child(6) {
  opacity: 0.5;
}
li:nth-child(7) {
  opacity: 0.4;
}
li:nth-child(8) {
  opacity: 0.3;
}
li:nth-child(9) {
  opacity: 0.2;
}
li:nth-child(10) {
  opacity: 0.1;
}
li:nth-child(11) {
  opacity: 0;
}

@media (max-width: 840px) {
  .header {
    margin: 40px 0 100px 40px;
  }
  
  .main {
    margin: 0 0 0 40px;
    max-height: 2000px;
  }
  form input {
    font-size: 24px;
    width: 50%;
  }
  li, button.btn {
    font-size: 24px;
  }
}