:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --text: #1a1a1a;
  --text-muted: #555;
  --border: #e5e5e5;
  --accent: #0a7c5b;
  --accent-soft: #e6f3ee;
  --code-bg: #0f172a;
  --code-text: #f1f5f9;
  --callout-bg: #fff7ed;
  --callout-border: #f59e0b;
  --tag-bg: #fde68a;
  --tag-text: #78350f;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", Meiryo, sans-serif;
  line-height: 1.75;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 24px;
}

.site-header {
  background: linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
  color: #fff;
  padding: 64px 0 56px;
  margin-bottom: 48px;
}

.site-header .eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 12px;
  color: #94a3b8;
  margin: 0 0 12px;
}

.site-header h1 {
  font-size: 32px;
  line-height: 1.4;
  margin: 0 0 24px;
  font-weight: 700;
}

.site-header .title-sub {
  display: inline-block;
  margin-top: 6px;
  font-size: 20px;
  color: #cbd5e1;
  font-weight: 500;
}

.site-header .lede {
  font-size: 16px;
  color: #cbd5e1;
  margin: 0 0 12px;
  max-width: 720px;
}

main {
  padding-bottom: 64px;
}

section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 32px;
  margin-bottom: 24px;
}

section h2 {
  font-size: 22px;
  margin: 0 0 16px;
  font-weight: 700;
}

section h3 {
  font-size: 16px;
  margin: 24px 0 12px;
  color: var(--text-muted);
  font-weight: 600;
}

section p {
  margin: 0 0 12px;
}

.bullet {
  margin: 12px 0;
  padding-left: 22px;
}

.bullet li {
  margin-bottom: 6px;
}

code {
  background: #f1f5f9;
  border-radius: 4px;
  padding: 2px 6px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.92em;
  color: #0f172a;
}

pre {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 18px 20px;
  border-radius: 10px;
  overflow-x: auto;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13.5px;
  line-height: 1.7;
  margin: 12px 0;
}

pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  font-size: inherit;
}

a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

a:hover {
  color: #065f46;
}

.video-wrap {
  position: relative;
  padding-top: 56.25%;
  border-radius: 10px;
  overflow: hidden;
  background: #000;
  margin: 16px 0 0;
}

.callout {
  background: var(--callout-bg);
  border-left: 4px solid var(--callout-border);
}

.callout h2 {
  color: #92400e;
}

.step {
  position: relative;
}

.step-number {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: 4px 12px;
  border-radius: 999px;
  margin-bottom: 12px;
}

.tag {
  display: inline-block;
  background: var(--tag-bg);
  color: var(--tag-text);
  font-size: 12px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 999px;
  margin-left: 8px;
  vertical-align: middle;
}

.hint {
  background: var(--accent-soft);
  border-radius: 8px;
  padding: 12px 16px;
  font-size: 14px;
  color: #064e3b;
  margin-top: 16px;
}

.prompt-section {
  background: #f8fafc;
}

.prompt-wrap {
  position: relative;
}

.copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  background: #334155;
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  z-index: 2;
  font-family: inherit;
  transition: background 0.15s;
}

.copy-btn:hover { background: #1e293b; }
.copy-btn.copied { background: var(--accent); }

.site-footer {
  background: #0f172a;
  color: #94a3b8;
  padding: 24px 0;
  font-size: 13px;
  text-align: center;
}

@media (max-width: 600px) {
  .site-header { padding: 40px 0 36px; margin-bottom: 32px; }
  .site-header h1 { font-size: 24px; }
  .site-header .title-sub { font-size: 16px; }
  section { padding: 24px 20px; }
  section h2 { font-size: 18px; }
  pre { font-size: 12px; padding: 14px; }
  .copy-btn { top: 8px; right: 8px; }
}