* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: sans-serif, serif;
}

.container {
  width: 100%;
  height: 100vh;
  background: #141414;
  display: flex;
  align-items: center;
  justify-content: center;
}

.container form {
  width: 90%;
  max-width: 500px;
  padding: 50px 30px 20px;
  background: #ffffff;
  border-radius: 4px;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
  position: relative;
}

.fa-paper-plane {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #ffffff;
  font-size: 26px;
  padding: 20px;
  border-radius: 50%;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
}

.input-group {
  width: 100%;
  display: flex;
  align-items: center;
  margin: 10px 0;
  position: relative;
}

.input-group label {
  flex-basis: 28%;
}

.input-group input,
.input-group textarea {
  flex-basis: 68%;
  background: transparent;
  border: 0;
  outline: 0;
  padding: 10px 0;
  border-bottom: 1px solid #999999;
  color: #333;
  font-size: 16px;
}

::placeholder {
  font-size: 14px;
}

form button {
  background: #141414;
  color: #ffffff;
  border-radius: 4px;
  border: 1px solid rgba(255, 255, 255, 0.7);
  padding: 10px 40px;
  outline: 0;
  cursor: pointer;
  display: block;
  margin: 30px auto 10px;
}

.input-group span {
  position: absolute;
  bottom: 12px;
  right: 17px;
  font-size: 14px;
  color: red;
}

#submit-error {
  color: red;
}

.input-group span i {
  color: green;
}

/* Mobile version (max-width: 568px) */
@media (max-width: 568px) {
  .container {
    padding: 20px;
  }
  .container form {
    width: 100%;
    max-width: none;
    padding: 30px 4px;
  }
  .input-group {
    flex-direction: column;
  }
  .input-group label {
    flex-basis: 100%;
    margin-bottom: 10px;
  }
  .input-group input,
  .input-group textarea {
    flex-basis: 100%;
    padding: 10px;
  }
  form button {
    padding: 10px 20px;
  }
}