:root {
  --primary-color: #5fbaa7;
}

html {
  box-sizing: border-box; /* https://css-tricks.com/box-sizing/ */
}

*,
*:before,
*:after {
  box-sizing: inherit;
}

body {
  background-color: #f4f4f4;
  font-family: Arial, Helvetica, sans-serif;
  height: 100vh;
  margin: 0;
  padding: 20px;
}

body,
header {
  align-items: center;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.main-image {
  width: 10rem;
}

.main-title {
  color: var(--primary-color);
}

p {
  text-align: center;
}

.btn {
  background-color: var(--primary-color);
  border: 0;
  border-radius: 5px;
  color: #fff;
  cursor: pointer;
  font-size: 1rem;
  padding: 0.66em 1.5em;
  transition: box-shadow 0.2s ease;
}

.btn:hover {
  box-shadow: 1px 1px 5px rgba(0, 0, 0, 0.2);
}

.currency-container {
  align-items: center;
  display: flex;
  justify-content: space-between;
  padding: 2.5rem 0;
}

.currency__select {
  appearance: none;
  background: transparent;
  background-image: url('data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%20000002%22%20d%3D%22M287%2069.4a17.6%2017.6%200%200%200-13-5.4H18.4c-5%200-9.3%201.8-12.9%205.4A17.6%2017.6%200%200%200%200%2082.2c0%205%201.8%209.3%205.4%2012.9l128%20127.9c3.6%203.6%207.8%205.4%2012.8%205.4s9.2-1.8%2012.8-5.4L287%2095c3.5-3.5%205.4-7.8%205.4-12.8%200-5-1.9-9.2-5.5-12.8z%22%2F%3E%3C%2Fsvg%3E');
  background-position: right 5px top 50%, 0, 0;
  background-repeat: no-repeat;
  background-size: 1em auto, 100%;
  border: 1px solid #dedede;
  font-size: 1rem;
  padding: 0.65em 2em 0.65em 1.25em;
}

.currency__input {
  border: 0;
  background: transparent;
  font-size: 1.9rem;
  text-align: right;
  width: 200px;
}

.swap-container {
  align-items: center;
  display: flex;
  justify-content: space-between;
}

.rate {
  color: var(--primary-color);
  font-size: 1rem;
  padding: 0 0.65em;
}

.btn:focus,
.currency__select:focus,
.currency__input:focus {
  outline: none;
}

@media (min-width: 600px) {
  .currency__input {
    width: 100%;
  }
}