:root {
  --white: rgb(255, 255, 255);
  --dark-green: darkgreen;
  --dark-red: darkred;
  --light-gray: rgb(177, 177, 177);
  --dark-gray: rgb(49, 45, 45);
  --light-green: rgb(140, 255, 140);
  --light-red: rgb(255, 171, 162);
}

html {
  font-size: 62.5%;
  min-height: 100vh;
}

body {
  background-image: linear-gradient(
      to bottom,
      rgba(189, 189, 189, 0.85),
      rgba(153, 138, 138, 0.85)
    ),
    url('../images/station.jpg');
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
    Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  font-size: 1.4rem;
  font-weight: bold;
  text-align: center;
  margin: 0;
  padding: 0;
}

header h1 {
  font-size: 2.5rem;
  color: var(--dark-gray);
}

.app__title {
  margin-top: 0.5em;
  margin-bottom: 1.5em;
  color: var(--dark-gray);
}

.app__counter {
  font-size: 5rem;
  margin-bottom: 1em;
  margin-top: 0;
  color: var(--dark-red);
}

.app__actions,
.app__messages {
  align-items: center;
  color: var(--dark-gray);
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  margin: 0 auto;
  width: 70%;
}

.btn {
  border: none;
  border-radius: 0.3em;
  color: var(--white);
  cursor: pointer;
  font-weight: bold;
  margin-bottom: 1em;
  padding: 2em 0;
  width: 100%;
}

.btn-increment {
  background: var(--dark-red);
}

.btn-increment:hover {
  background-color: var(--light-red);
  color: var(--dark-red);
}

.btn-save {
  background: var(--dark-green);
}

.btn-save:disabled {
  background-color: var(--light-gray);
  cursor: auto;
}

.btn-save:hover:not(:disabled) {
  background-color: var(--light-green);
  color: var(--dark-green);
}

.link {
  color: darkgreen;
  font-weight: normal;
  text-decoration: none;
  transition: font-weight 0.3s ease;
}

.link:hover {
  font-weight: 500;
}

footer {
  bottom: 0;
  margin: 15em auto 1em auto;
  width: 100%;
}

@media (min-width: 500px) {
  body {
    font-size: 1.6rem;
  }

  header h1 {
    font-size: 3rem;
  }

  .app__title {
    margin-top: 2em;
  }

  .app__counter {
    margin-bottom: 2em;
  }

  .app__actions,
  .app__messages {
    margin-bottom: 2em;
    width: 350px;
  }

  footer {
    bottom: 0;
    margin: 10em auto 1em auto;
    width: 100%;
  }
}