body {
  font-family: system-ui, -apple-system, sans-serif;
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1rem;
  background-color: #f9f9f9;
  color: #333;
}

h1 {
  border-bottom: 2px solid #ddd;
  padding-bottom: 0.5rem;
}

.class-group {
  margin-bottom: 2rem;
}

.class-title {
  color: #2c3e50;
  border-bottom: 1px solid #ccc;
  padding-bottom: 0.25rem;
}

.feed-list {
  list-style: none;
  padding: 0;
}

.feed-item {
  background: #fff;
  margin-bottom: 0.75rem;
  padding: 1rem 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.feed-item h3 {
  margin: 0 0 0.5rem 0;
  font-size: 1.1rem;
}

.feed-item a {
  color: #0066cc;
  text-decoration: none;
}

.feed-item a:hover {
  text-decoration: underline;
}

.meta {
  font-size: 0.85rem;
  color: #666;
}

.loading {
  color: #666;
  font-style: italic;
}

header {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 1.5rem 0 1rem 0;
  margin-bottom: 2rem;

  .header-logo-link {
    display: inline-block;
    color: #0066cc;
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s ease;

    &:hover {
      color: #004499;
      text-decoration: underline;
    }
  }

  .header-info {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;

    h1 {
      margin: 0;
      font-size: 2rem;
      color: #1a1a1a;
      letter-spacing: -0.02em;
    }

    time, .class-tag {
      font-size: 0.875rem;
      color: #666;
    }

    .class-tag {
      font-weight: 600;
      color: #4a5568;
    }
  }

  hr {
    border: none;
    border-top: 1px solid #e2e8f0;
    margin-top: 0.5rem;
    margin-bottom: 0;
  }
}

.quiz-list {
  padding-left: 1.2rem;

  & > li {
    margin-bottom: 2rem;
  }
}

.options {
  list-style: none;
  padding: 0;
  margin-top: 0.5rem;

  li {
    padding: 0.5rem 0.75rem;
    margin-bottom: 0.35rem;
    border: 1px solid #e2e8f0;
    border-radius: 6px;
    background-color: #fff;
    color: #4a5568;

    &.correct {
      border-color: #86efac;
      background-color: #f0fdf4;
      color: #166534;
      font-weight: 600;
      position: relative;
    }
  }
}