:root {
  --primary: #2c3e50;
  --accent: #3498db;
  --accent-hover: #2980b9;
  --bg-light: #f8f9fa;
  --text-dark: #2c3e50;
  --text-light: #5f6c7b;
  --white: #ffffff;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
  --radius: 16px;
  --transition: all 0.3s ease;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;
  line-height: 1.6;
  color: var(--text-dark);
  background-color: var(--bg-light);
  padding-bottom: 4rem;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.page-header {
  background: linear-gradient(135deg, var(--primary), #34495e);
  color: var(--white);
  padding: 3rem 1.5rem;
  text-align: center;
  position: relative;
}

.back-link {
  position: absolute;
  top: 1.5rem;
  left: 1.5rem;
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9rem;
  transition: var(--transition);
}

.back-link:hover {
  color: var(--white);
  transform: translateX(-3px);
}

.page-header h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  font-weight: 700;
}

.subtitle {
  opacity: 0.9;
  font-size: 1.1rem;
  font-weight: 300;
}

/* Cards & Sections */
section {
  margin: 2.5rem 0;
}

.step-card,
.os-guide {
  background: var(--white);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  margin-bottom: 2rem;
  border: 1px solid rgba(0, 0, 0, 0.03);
}

.os-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--bg-light);
}

.os-icon {
  font-size: 2rem;
}

.os-header h2 {
  font-size: 1.5rem;
  color: var(--primary);
  font-weight: 700;
}

/* Lists */
.simple-list,
.detailed-steps {
  list-style: none;
  padding-left: 0;
}

.simple-list li,
.detailed-steps li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.8rem;
  color: var(--text-light);
}

.simple-list li::before {
  content: "•";
  color: var(--accent);
  font-weight: bold;
  position: absolute;
  left: 0;
  font-size: 1.2rem;
  line-height: 1.4;
}

.detailed-steps li {
  counter-increment: step-counter;
  padding-left: 2.5rem;
}

.detailed-steps li::before {
  content: counter(step-counter);
  position: absolute;
  left: 0;
  top: 0;
  width: 2rem;
  height: 2rem;
  background: var(--accent);
  color: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 0.9rem;
}

.detailed-steps li strong {
  color: var(--primary);
  font-weight: 600;
}

/* Tips & Notes */
.tip,
.note-box {
  background: #eef7fc;
  border-left: 4px solid var(--accent);
  padding: 1rem 1.2rem;
  margin-top: 1.5rem;
  border-radius: 0 8px 8px 0;
  font-size: 0.95rem;
  color: var(--text-dark);
}

.note-box {
  background: #fff8e1;
  border-left-color: #f1c40f;
}

code {
  background: #f1f3f4;
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-family: monospace;
  color: #d35400;
  font-size: 0.9em;
}

/* Ideas Section */
.ideas-section {
  margin-top: 4rem;
}

.ideas-section h2 {
  text-align: center;
  margin-bottom: 2rem;
  color: var(--primary);
  font-size: 1.8rem;
}

.ideas-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.idea-card {
  background: var(--white);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: var(--transition);
  border: 1px solid rgba(0, 0, 0, 0.03);
}

.idea-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.idea-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
  color: var(--accent);
}

.idea-card p {
  font-size: 0.95rem;
  color: var(--text-light);
}

/* Footer */
footer {
  text-align: center;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid #eee;
  color: var(--text-light);
  font-size: 0.9rem;
}

footer a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}

/* Mobile Responsiveness */
@media (max-width: 600px) {
  .page-header {
    padding: 2rem 1rem;
  }

  .page-header h1 {
    font-size: 1.6rem;
  }

  .step-card,
  .os-guide {
    padding: 1.5rem;
  }

  .os-header h2 {
    font-size: 1.3rem;
  }

  .ideas-grid {
    grid-template-columns: 1fr;
  }

  .back-link {
    top: 1rem;
    left: 1rem;
  }
}