:root {
  --blue: rgb(60, 137, 224);
  --dark-blue: rgb(19, 70, 128);
  --light-blue: rgb(0, 208, 255);
  --black: #000000;
  --white: #ffffff;
  --common-font-size: 16px;
  --bigger-font-size: 20px;
  --big-font-size: 24px;
  --section-horizontal-padding: 13%;
  --section-vertical-padding: 40px;
}

* {
  margin: 0;
  padding: 0;
}

body {
  color: var(--white);
  letter-spacing: 1px;
  line-height: 22px;
}

button {
  padding: 15px 30px;
  background-color: var(--white);
  color: var(--dark-blue);
  border: none;
  font-weight: bold;
  cursor: pointer;
  font-size: var(--common-font-size);
}
button:hover {
  background-color: var(--dark-blue);
  color: var(--white);
}

nav {
  width: 100%;
  background-color: var(--blue);
  border-bottom: solid 1px var(--dark-blue);
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0px;
  z-index: 1000;
}

nav h1 {
  margin: 0 15px;
  font-size: var(--big-font-size);
}

header {
  background-image: url("./assets/header.jpg");
  display: flex;
  background-repeat: no-repeat;
  background-position: center;
  background-size: cover;
}
header .info {
  margin: var(--section-vertical-padding) var(--section-horizontal-padding);
  padding: 30px 5%;
  background-color: rgba(4, 2, 74, 0.9);
}
header h2 {
  margin-bottom: 20px;
  font-size: var(--big-font-size);
  text-align: center;
}
header p {
  font-size: var(--common-font-size);
}
header ul {
  margin: 7px 0 20px 30px;
}

#sell-items-section {
  padding: var(--section-vertical-padding) var(--section-horizontal-padding);
}
#sell-items-header {
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  color: var(--black);
}
#sell-items-header img {
  width: 50px;
  z-index: 0;
}
#sell-items-header img:first-child {
  -webkit-transform: scaleX(-1);
  transform: scaleX(-1);
}

#sell-items {
  margin-top: 20px;
  font-weight: bold;
  display: grid;
  justify-items: center;
  justify-content: space-between;
  align-items: center;
  gap: 40px 20px;
  grid-template-columns: repeat(auto-fill, minmax(200px, 300px));
}

#sell-items .sell-item {
  color: var(--black);
  text-align: center;
  padding: 0;
  text-transform: uppercase;
}

#sell-items .sell-item img {
  max-height: 150px;
  max-width: 100%;
  margin-bottom: 15px;
}

#form {
  background-color: var(--blue);
  text-transform: uppercase;
  display: flex;
  flex-direction: column;
  align-items: start;
  padding: var(--section-vertical-padding) var(--section-horizontal-padding);
}
#form input,
#form textarea {
  padding: 10px;
  border: none;
  width: 100%;
  margin-bottom: 15px;
  font-size: var(--common-font-size);
}
#form label {
  margin-bottom: 4px;
  font-weight: bold;
}

footer {
  border-top: solid 1px var(--white);
  background: var(--blue);
  padding: var(--section-vertical-padding) var(--section-horizontal-padding);
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
}
footer a {
  width: 30%;
  text-decoration: none;
  color: var(--white);
}
footer .item {
  display: flex;
  align-items: center;
  flex-direction: column;
}
footer img {
  width: 100%;
  max-width: 90px;
  fill: var(--white);
}
footer h3 {
  text-align: center;
  margin: 10px 0 30px 0;
}

@media screen and (max-width: 700px) {
  #sell-items {
    justify-content: center;
  }

  footer {
    flex-direction: column;
    align-items: center;
  }
  footer a {
    width: 100%;
  }
}