* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
body {
  font-family: 'Montserrat', sans-serif;
  background-color: #0b0c2a;
  margin: 0;
  color: #333;
}

header {
    text-align: center;
    padding: 4rem 1rem 2rem;
  }
  
  header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #56a9ff;
    ;
  }
  
  header p {
    font-size: 1.2rem;
    color: #e0e0e0;
    max-width: 700px;
    margin: auto;
  }

/* Top Bar */
  .top-bar {
    max-width: 900px;
    margin: 1rem auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .top-bar h2 {
    font-size: 1.5rem;
    color: #56a9ff;
  }

.page-header {
    display: flex;
    flex-direction: column;
    max-width: 900px;
    margin: 2rem auto 1rem;
    padding: 0 2rem;
  }
  
  .page-header h2 {
    font-size: 1.8rem;
    color: #56a9ff;
    margin-bottom: 1rem;
  }
  
  .back-button-right {
    display: flex;
    justify-content: flex-end;
    max-width: 900px;
    margin: 0 auto 1rem auto;
    padding-right: 1.5rem; /* matches padding of file-actions */
  }
  
  .back-button-right a {
    padding: 0.5rem 1.2rem;
    background-color: #1e3a8a;
    color: #f0f0f0;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    transition: background-color 0.2s;
  }
  
  .back-button-right a:hover {
    background-color: #2946b5;
  }

.container {
  max-width: 900px;
  margin: auto;
  background: #1f1359;
  padding: 2rem;
  border-radius: 15px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
  overflow: hidden;
  position: relative;
}

h1 {
  text-align: center;
  color: #223;
}

h2 {
  color: #56a9ff;
  margin-top: 2rem;
  padding-bottom: 0.3rem;
border-bottom: 2px solid #cde8ff;
}
h3 {
  color: #56a9ff;
}
h4 {
  color: #56a9ff;
}

p, ul, ol, figcaption{
  line-height: 1.7;
  text-align: justify;
  color: #d0d0d0;

}

figcaption{
  margin: 0 0 1rem 0;
}

ul {
  padding-left: 1.2rem;
}

ol {
padding-left: 1.2rem;
}

ul li, ol li {
  margin-bottom: 0.5rem;
    text-align: justify;
}
summary {
    font-weight: bold;
    font-size: 1.1rem;
    cursor: pointer;
    margin-bottom: 10px;
  }

  details {
    background: #e6f0ff;
    padding: 15px;
    margin-top: 15px;
    border-radius: 6px;
    border: 1px solid #cce0ff;
  }
code {
    background-color: #eef;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: Consolas, monospace;
  }
.footer {
  text-align: center;
  padding: 20px;
  margin-top: 30px;
  font-size: 0.9em;
  color: #e0e0e0;
  background-color: #1f1359;
}

@media (width < 768px){
.blur-overlay p{
  top: 5rem;
  margin: 2rem;
}
.blur-overlay .btn{
  top: 13rem;
}
}

.video-container {
  position: relative;
  width: 100%;
  padding-top: 56.25%; /* 16:9 aspect ratio */
  margin: 20px 0;
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.graph-mistake-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.graph-card {
  padding: 1rem;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.graph-card img {
  width: 100%;
  border-radius: 8px;
  margin-bottom: 0.75rem;
}

.graph-card h3 {
  margin-bottom: 0.5rem;
}

.graph-card.incorrect {
  border-left: 4px solid #ff4d4d;
}

.graph-card.correct {
  border-left: 4px solid #4caf50;
}