/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 15px; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: #00323e;
  color: #fdf7f0;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ── */
.container { max-width: 720px; margin: 0 auto; padding: 40px 24px 80px; }

/* ── Site Header ── */
.site-header {
  text-align: center;
  padding: 48px 0 32px;
  border-bottom: 1px solid rgba(253, 247, 240, 0.1);
  margin-bottom: 40px;
}
.site-header h1 {
  font-size: 1.5rem; font-weight: 700; letter-spacing: -0.01em;
  color: #fdf7f0;
  margin-bottom: 6px;
}
.site-header p {
  font-size: .85rem; color: rgba(253, 247, 240, 0.5);
}

/* ── TOC ── */
.toc {
  margin-bottom: 48px;
  padding: 20px 0;
  border-bottom: 1px solid rgba(253, 247, 240, 0.08);
}
.toc h3 {
  font-size: .7rem; text-transform: uppercase; letter-spacing: .12em;
  color: rgba(253, 247, 240, 0.35);
  margin-bottom: 12px;
}
.toc-grid {
  display: flex; flex-wrap: wrap; gap: 0;
  list-style: none;
}
.toc-grid a {
  display: inline-block;
  padding: 3px 16px 3px 0;
  font-size: .8rem; color: rgba(253, 247, 240, 0.6);
  text-decoration: none; width: 50%;
}
.toc-grid a:hover { color: #ccff66; }

/* ── Part Header ── */
.part {
  margin-bottom: 40px;
}
.part-num {
  font-size: .7rem; text-transform: uppercase; letter-spacing: .15em;
  color: rgba(253, 247, 240, 0.3);
  margin-bottom: 4px;
}
.part h2 {
  font-size: 1.25rem; font-weight: 700; color: #fdf7f0;
  margin-bottom: 10px;
}
.part p {
  font-size: .85rem; line-height: 1.7;
  color: rgba(253, 247, 240, 0.65);
}

/* ── Prompt Card ── */
.prompt {
  margin-bottom: 28px;
  border: 1px solid rgba(253, 247, 240, 0.12);
  border-radius: 8px;
  padding: 20px 24px;
  background: rgba(0, 0, 0, 0.15);
}
.prompt-head {
  font-size: .85rem;
  margin-bottom: 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(253, 247, 240, 0.06);
}
.prompt-num {
  font-weight: 700; color: #ccff66;
  text-transform: uppercase; letter-spacing: .04em;
}
.sep {
  margin: 0 10px;
  color: rgba(253, 247, 240, 0.15);
}
.prompt-title {
  font-weight: 600; color: rgba(253, 247, 240, 0.85);
  font-size: 1rem;
}

/* ── Prompt Description ── */
.prompt-desc {
  font-size: .85rem; line-height: 1.7;
}
.prompt-desc p {
  margin-bottom: 6px;
}
.prompt-desc > p:first-child {
  margin-bottom: 10px;
}
.prompt-desc strong {
  color: #fdf7f0; font-weight: 600;
}

/* ── Prompt Code Block ── */
.prompt-code {
  background: rgba(0, 0, 0, 0.25);
  border: 1px solid rgba(253, 247, 240, 0.08);
  border-radius: 6px;
  padding: 16px 18px;
  margin: 8px 0 0;
  overflow-x: auto;
  white-space: pre-wrap;
  word-wrap: break-word;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: .82rem;
  line-height: 1.65;
  color: rgba(253, 247, 240, 0.75);
  -webkit-font-smoothing: antialiased;
  user-select: all;
  cursor: text;
}
.prompt-code code {
  font-family: inherit;
  color: inherit;
  background: none;
  padding: 0;
  font-size: inherit;
  white-space: pre-wrap;
}

/* ── Milestone ── */
.milestone {
  margin: 40px 0;
  padding: 20px 24px;
  border: 1px solid rgba(204, 255, 102, 0.2);
  border-radius: 8px;
  background: rgba(204, 255, 102, 0.04);
}
.milestone h3 {
  font-size: .85rem; font-weight: 700; color: #ccff66;
  margin-bottom: 6px;
}
.milestone p {
  font-size: .82rem; color: rgba(253, 247, 240, 0.55);
}

/* ── Footer ── */
.footer {
  margin-top: 60px;
  padding-top: 20px;
  border-top: 1px solid rgba(253, 247, 240, 0.08);
  text-align: center;
  font-size: .78rem;
  color: rgba(253, 247, 240, 0.3);
}

/* ── Responsive ── */
@media (max-width: 640px) {
  .container { padding: 24px 16px 60px; }
  .toc-grid a { width: 100%; }
  .site-header h1 { font-size: 1.2rem; }
  .part h2 { font-size: 1.1rem; }
  .prompt { padding: 16px; }
}