:root {
  --teal: #16a085;
  --teal-hover: #138d75;
  --bg: #f5f6f8;
  --card-bg: #ffffff;
  --text: #2c3e50;
  --text-muted: #7f8c8d;
  --border: #e8e9eb;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container {
  max-width: 960px;
  margin: 24px auto;
  padding: 24px;
  background: #fff;
  border-radius: 24px;
}

.page-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.page-header h1 {
  font-size: 24px;
  font-weight: 600;
}

.help-link {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.2s;
}

.help-link:hover {
  color: var(--teal);
}

.platform-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.platform-card {
  background: var(--card-bg);
  border-radius: 8px;
  padding: 20px;
  border: 1px solid #e3eaf4;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  transition: box-shadow 0.2s;
}

.platform-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.platform-card h2 {
  font-size: 22px;
  font-weight: 600;
  margin-bottom: 8px;
}

.platform-desc {
  color: var(--text-muted);
  font-size: 17px;
  margin-bottom: 12px;
}

.platform-button {
  display: block;
  width: 100%;
  padding: 14px 20px;
  background: var(--teal);
  color: white;
  text-align: center;
  text-decoration: none;
  border-radius: 6px;
  font-weight: 600;
  font-size: 15px;
  transition: background 0.2s;
}

.platform-button:hover {
  background: var(--teal-hover);
}

.tutorial-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 40px 20px;
}

.tutorial-section {
  background: var(--card-bg);
  border-left: 4px solid #f39c12;
  border-radius: 8px;
  padding: 32px;
  margin-bottom: 24px;
}

.tutorial-section h2 {
  color: white;
  background: #2563eb;
  display: inline-block;
  padding: 8px 16px;
  border-radius: 20px;
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 20px;
}

.tutorial-section h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 16px;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  background: #ecf0f1;
  padding: 20px;
  border-radius: 6px;
  margin-bottom: 24px;
}

.step-item {
  display: flex;
  gap: 12px;
}

.step-number {
  width: 32px;
  height: 32px;
  background: #3498db;
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  flex-shrink: 0;
}

.step-content {
  flex: 1;
}

.apple-id-link {
  color: #3498db;
  text-decoration: none;
  font-weight: 500;
}

.apple-id-link:hover {
  text-decoration: underline;
}

.warning-box {
  background: #fff9e6;
  border: 2px solid #f39c12;
  border-radius: 6px;
  padding: 20px;
  margin-bottom: 24px;
}

.warning-box h4 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 12px;
}

.warning-box p {
  margin-bottom: 8px;
}

.shared-id-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  margin-top: 20px;
}

.shared-id-button {
  display: block;
  padding: 14px 20px;
  background: #fff;
  color: #2563eb;
  text-align: left;
  text-decoration: none;
  border-radius: 6px;
  font-weight: 600;
  transition: all 0.2s;
  border: 1px solid #dce6fa;
}

a:focus-visible { outline: 3px solid #2563eb; outline-offset: 4px; }
.tutorial-section p { overflow-wrap: anywhere; }
.step-content { min-width: 0; }
.release-status { margin: 18px 0; color: #64748b; }
.installer-name { margin-top: 12px; font-size: 13px; overflow-wrap: anywhere; color: #64748b; }
.install-steps { padding-left: 24px; }
.install-steps li { margin: 12px 0; }
.linux-downloads { display: flex; flex-wrap: wrap; gap: 12px 24px; margin: 16px 0; }
.linux-downloads a { color: #2563eb; }
.install-command { max-width: 100%; overflow-x: auto; padding: 14px; background: #eff6ff; border-radius: 6px; font-size: 14px; }
.steps-grid { background: transparent; padding: 0; }
.step-item { background: #eff6ff; padding: 18px; border-radius: 8px; }
.step-number { background: #2563eb; }
.apple-id-link { display: inline-block; padding: 12px 0; color: #2563eb; }
.warning-box { border: 0; border-left: 4px solid #ff922b; background: #fff8ef; }

.shared-id-button:hover {
  background: #3498db;
  color: white;
  border-color: #3498db;
}

@media (max-width: 768px) {
  .container { margin: 12px; padding: 20px; }
  .tutorial-container { padding: 24px 12px; }
  .tutorial-section { padding: 20px; }
  .platform-grid {
    grid-template-columns: 1fr;
  }
  
  .page-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  
  .steps-grid {
    grid-template-columns: 1fr;
  }
  
  .shared-id-grid {
    grid-template-columns: 1fr;
  }
}