body {
  font-family: 'Raleway', sans-serif;
  margin: 0;
  padding: 0;
  line-height: 1.6;
  color: #333;
  background-color: #f9f9f9;
}

#introduction p {
  text-align: justify;
}

.challenge-nav {
  position: sticky;
  top: 0;
  background-color: #fff;
  padding: 0.5rem 1rem;
  border-bottom: 1px solid #eee;
  z-index: 1000;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}
.challenge-nav .nav-container {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}
.challenge-nav a {
  color: #275dbd;
  font-weight: 600;
  text-decoration: none;
  padding: 0.5rem;
}
.challenge-nav a:hover {
  text-decoration: underline;
}

.access-button {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.6rem 1.2rem;
  background-color: #fff;
  color: #275dbd;
  border: 2px solid #fff;
  border-radius: 4px;
  font-weight: 600;
  text-decoration: none;
  transition: background-color 0.3s, color 0.3s;
}
.access-button:hover {
  background-color: #fff;
  color: #275dbd;
  border-color: #f4f4f4;
}

header {
  background: #275dbd;
  color: white;
  padding: 4rem 2rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

/* Imagem */
.header-logo {
  position: absolute;
  top: -7%;
  left: -4.7%;
  width: 60vw;
  height: 60vw;
  max-width: 450px;
  max-height: 450px;
  border-radius: 70%;
  overflow: hidden;
  z-index: 0;
}

.header-logo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  opacity: 0.6;
}

/* TODOS os elementos do header acima da imagem */
header * {
  position: relative;
  z-index: 2;
}

/* EXCETO a logo */
.header-logo,
.header-logo * {
  z-index: 0;
}
.inline-logo {
  height: 4rem; /* adjust to match text height */
  margin-left: 0.4rem;
  vertical-align: middle;
}

.header-text {
  position: relative;
  z-index: 1;
}

header h1 {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}
header p {
  font-size: 1.5rem;
  font-weight: 500;
  margin: 0;
}

.container {
  padding: 2rem;
  max-width: 1400px;
  margin: auto;
  background-color: #ffffff;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
}
section {
  margin-bottom: 3rem;
}
section h2 {
  font-size: 2rem;
  color: #275dbd;
  display: inline-block;
  border-bottom: 1px solid #275dbd;
  padding-bottom: 0.3rem;
  margin-bottom: 1rem;
}
p {
      font-size: 1.2rem;
      font-weight: 500;
    }
iframe {
  width: 100%;
  height: 600px;
  border: none;
}

h3{
  color: #275dbd;
}

h1, h2, h3 {
  font-weight: 600;
}
ul li {
  margin-bottom: 0.5rem;
}
#intro p {
  font-size: 1.56rem;
  font-weight: 500;
  text-align: center;
  border-radius: 2px;
}

@media (max-width: 600px) {
  iframe {
    height: 400px;
  }
  header h1 {
    font-size: 2rem;
  }
  header p {
    font-size: 1.2rem;
  }
  #intro p {
    font-size: 1.2rem;
    padding: 1rem;
  }
}

@media (max-width: 768px) {
  .header-logo {
    top: -30%;
    left: -50%;
    width: 80vw;
    height: 80vw;
  }

  header h1 {
    font-size: 2.4rem;
  }

  header p {
    font-size: 1.2rem;
  }
}

/* Dataset flex two columns section */
.dataset-flex {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: space-between;
  align-items: flex-start;
}

.dataset-text {
  flex: 1 1 45%;
  min-width: 300px;
}

.dataset-figure {
  flex: 1 1 40%;
  min-width: 250px;
  text-align: center;
}

/* Citation part of the dataset section */

.dataset-reference-box {
  margin-top: 2rem;
  padding: 1rem 1.5rem;
  border: 1px solid #eee;
  border-radius: 8px;
  background-color: #fafafa;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  line-height: 1.4;
}

.dataset-reference-box p {
  font-size: 1rem;
  font-weight: 500;
}

.citation-tabs {
  margin-top: 1rem;
  margin-bottom: 1rem;
}

.tab-button {
  padding: 0.4rem 1rem;
  margin-right: 0.5rem;
  border: 1px solid #275dbd;
  background: white;
  color: #275dbd;
  cursor: pointer;
  font-weight: 600;
  border-radius: 4px;
}

.tab-button.active {
  background-color: #275dbd;
  color: white;
}

.citation-content {
  display: none;
  font-size: 0.10rem;
  background: #fff;
  border-left: 4px solid #275dbd;
  padding: 0.3rem;
  border-radius: 4px;
  font-family: monospace;
  white-space: pre-wrap;
}

.citation-content.active {
  display: block;
}

.citation-content pre {
  background-color: #fff;
  /* border-left: 4px solid #275dbd; */
  padding: 1rem;
  border-radius: 4px;
  font-family: monospace;
  font-size: 0.95rem;
  overflow-x: auto;
  white-space: pre-wrap;
  margin: 0;
}