/* Basic layout and typography */
body {
  font-family: 'Segoe UI', Arial, sans-serif;
  background: linear-gradient(120deg, #f0e6fa 0%, #e3f6fd 100%);
  margin: 0;
  padding: 0;
  color: #222;
}
.page-header {
  background: #8e44ad;
  color: #fff;
  padding: 2rem 1rem 1rem 1rem;
  text-align: center;
  box-shadow: 0 2px 8px rgba(52, 152, 219, 0.08);
}
.subtitle {
  font-size: 1.2rem;
  color: #ffd200;
  margin-top: 0.5rem;
}
main {
  max-width: 800px;
  margin: 2rem auto;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(52, 152, 219, 0.10);
  padding: 2rem 1.5rem 3rem 1.5rem;
}
.theory-section, .best-practices {
  margin-bottom: 2.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid #e3f6fd;
}
.theory-section h2, .demo-section h2, .best-practices h2 {
  color: #8e44ad;
}
.demo-section {
  margin-bottom: 2.5rem;
}
.demo-block {
  margin-bottom: 2rem;
  padding: 1.2rem 1rem;
  background: #f9f6ff;
  border-radius: 8px;
  box-shadow: 0 1px 4px rgba(52, 152, 219, 0.06);
}
.demo-block h3 {
  margin-top: 0;
  color: #3498db;
}
pre {
  background: #222;
  color: #ffd200;
  padding: 0.8em 1em;
  border-radius: 6px;
  overflow-x: auto;
  font-size: 0.98em;
  margin-top: 1em;
}
code {
  background: #f0e6fa;
  color: #8e44ad;
  padding: 0.1em 0.3em;
  border-radius: 4px;
  font-size: 1em;
}
.columns-demo {
  margin: 1em 0;
  padding: 1em;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 1px 4px rgba(52, 152, 219, 0.04);
}
.columns-count {
  column-count: 3;
}
.columns-gap {
  column-count: 3;
  column-gap: 2.5em;
}
.columns-rule {
  column-count: 3;
  column-rule: 3px dashed #8e44ad;
}
.columns-width {
  column-width: 180px;
}
.columns-span {
  column-count: 3;
}
.span-all {
  column-span: all;
  background: #ffd200;
  color: #8e44ad;
  padding: 0.5em 1em;
  border-radius: 5px;
  margin-bottom: 1em;
}
.columns-shorthand {
  columns: 180px 3;
}
.back-btn {
  display: inline-block;
  margin-top: 2rem;
  background: #ffd200;
  color: #8e44ad;
  padding: 0.7em 1.5em;
  border-radius: 6px;
  text-decoration: none;
  font-weight: bold;
  transition: background 0.2s, color 0.2s;
  margin-bottom: 0.5em;
  box-shadow: 0 2px 8px rgba(52, 152, 219, 0.08);
}
.back-btn:hover,
.back-btn:focus {
  background: #8e44ad;
  color: #fff;
  outline: 2px solid #f7971e;
  outline-offset: 2px;
}
.back-btn:active {
  background: #3498db;
}

@media (max-width: 600px) {
  main {
    padding: 1rem 0.5rem 2rem 0.5rem;
  }
  .page-header {
    padding: 1.2rem 0.5rem 0.7rem 0.5rem;
  }
  .demo-block {
    padding: 0.7rem 0.5rem;
  }
  .columns-demo {
    padding: 0.7em;
  }
}