/* ===== Guide-specific Variables ===== */
body { padding-bottom: env(safe-area-inset-bottom, 0px); line-height: 1.7; }
/* ===== Handbook Layout ===== */
.handbook { max-width: 768px; margin: 0 auto; padding: 0 2rem; }
.section { padding: 4rem 0; border-bottom: 1px solid rgba(255,255,255,0.04); }
.section:last-of-type { border-bottom: none; }
.section-header { margin-bottom: 2.5rem; }
.section-number { font-family: var(--font-heading); font-size: 0.9rem; color: rgba(255,255,255,0.2); letter-spacing: 0.15em; margin-bottom: 0.5rem; display: flex; align-items: center; gap: 0.6rem; }
.section-title { font-family: var(--font-cn); font-weight: 100; font-size: clamp(1.8rem, 4vw, 3.2rem); line-height: 1.2; letter-spacing: 0.04em; margin-bottom: 0.8rem; }
.section-title .hl { color: #fff; font-weight: 400; }
.section-subtitle { font-size: 1.05rem; color: rgba(255,255,255,0.6); max-width: 70%; margin-top: 0.2rem; }
.divider { width: 60px; height: 2px; background: linear-gradient(90deg, rgba(255,255,255,0.3), transparent); margin: 1.5rem 0; }
/* ===== Card Glass ===== */
.card-glass {
  position: relative; background: rgba(255,255,255,0.04); background-blend-mode: luminosity;
  backdrop-filter: blur(2px); -webkit-backdrop-filter: blur(2px);
  box-shadow: inset 0 1px 1px rgba(255,255,255,0.1); overflow: hidden;
  border-radius: 1rem; padding: 2rem 2.2rem; transition: box-shadow 0.25s ease;
}
.card-glass > * { position: relative; z-index: 2; }
.card-glass::before {
  content: ''; position: absolute; inset: 0; border-radius: inherit; padding: 1.4px;
  background: linear-gradient(180deg, rgba(255,255,255,0.45) 0%, rgba(255,255,255,0.15) 20%, rgba(255,255,255,0) 40%, rgba(255,255,255,0) 60%, rgba(255,255,255,0.15) 80%, rgba(255,255,255,0.45) 100%);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude; pointer-events: none; z-index: 1;
}
.card-highlight { backdrop-filter: blur(50px); -webkit-backdrop-filter: blur(50px); box-shadow: 4px 4px 4px rgba(0,0,0,0.05), inset 0 1px 1px rgba(255,255,255,0.15); transition: transform 0.25s ease, box-shadow 0.25s ease; }
.card-highlight:hover { transform: translateY(-4px); box-shadow: 0 12px 40px rgba(0,0,0,0.3), inset 0 1px 1px rgba(255,255,255,0.2); }
.card-highlight::before { background: linear-gradient(180deg, rgba(255,255,255,0.6) 0%, rgba(255,255,255,0.2) 20%, rgba(255,255,255,0) 40%, rgba(255,255,255,0) 60%, rgba(255,255,255,0.2) 80%, rgba(255,255,255,0.6) 100%); }
.card-glass:not(.card-highlight):hover { box-shadow: 0 8px 30px rgba(0,0,0,0.4), inset 0 1px 1px rgba(255,255,255,0.15); }
/* ===== Stats ===== */
.stat-num { font-family: var(--font-heading); font-size: clamp(2.8rem, 5vw, 4rem); color: #fff; line-height: 1; }
.stat-label { font-family: var(--font-body); font-size: 0.75rem; color: rgba(255,255,255,0.7); letter-spacing: 0.08em; margin-top: 0.2rem; }
/* ===== Tags ===== */
.ch-tag { display: inline-block; font-size: 0.6rem; font-weight: 500; letter-spacing: 0.05em; padding: 0.15rem 0.6rem; border-radius: 20px; text-transform: uppercase; vertical-align: middle; }
.ch-tag-core { background: rgba(255,255,255,0.12); color: #fff; }
.ch-tag-bg { background: rgba(255,255,255,0.06); color: rgba(255,255,255,0.6); }
.ch-tag-ref { background: rgba(255,255,255,0.04); color: rgba(255,255,255,0.45); }
/* ===== Takeaway ===== */
.takeaway { margin-top: 2rem; padding: 1.2rem 1.5rem; background: rgba(255,255,255,0.03); border-radius: 12px; border-left: 4px solid rgba(255,255,255,0.25); }
.takeaway-label { font-size: 0.7rem; color: rgba(255,255,255,0.4); letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 0.3rem; }
.takeaway p { font-size: 0.95rem; color: rgba(255,255,255,0.85); }
/* ===== Part Divider ===== */
.part-divider { text-align: center; padding: 3rem 0 1rem; position: relative; }
.part-divider::before { content: ''; position: absolute; left: 0; right: 0; top: 50%; height: 1px; background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent); }
.part-label { position: relative; display: inline-block; background: #000; padding: 0 1.5rem; font-family: var(--font-heading); font-size: 1rem; color: rgba(255,255,255,0.2); letter-spacing: 0.15em; }
.part-title { font-family: var(--font-cn); font-weight: 100; font-size: 1.2rem; color: rgba(255,255,255,0.45); margin-top: 0.3rem; }
/* ===== Cross Reference ===== */
.cross-ref { color: rgba(255,255,255,0.7); border-bottom: 1px solid rgba(255,255,255,0.15); transition: color 0.2s, border-color 0.2s; }
.cross-ref:hover { color: #fff; border-color: #fff; }
/* ===== Chapter Nav ===== */
#chNav { position: fixed; right: 1.2rem; top: 50%; transform: translateY(-50%); z-index: 999; display: flex; flex-direction: column; align-items: flex-end; gap: 0.3rem; pointer-events: none; }
.ch-nav-item { pointer-events: auto; display: flex; align-items: center; gap: 0.5rem; padding: 0.25rem 0.6rem; border-radius: 6px; cursor: pointer; transition: background 0.2s, opacity 0.2s; background: transparent; opacity: 0.35; font-size: 0.7rem; color: rgba(255,255,255,0.6); font-family: var(--font-body); white-space: nowrap; }
.ch-nav-item:hover { background: rgba(255,255,255,0.06); opacity: 0.7; }
.ch-nav-item.active { opacity: 1; color: #fff; background: rgba(255,255,255,0.08); }
.ch-nav-dot { width: 6px; height: 6px; border-radius: 50%; background: rgba(255,255,255,0.25); transition: background 0.2s, transform 0.2s; flex-shrink: 0; }
.ch-nav-item.active .ch-nav-dot { background: #fff; transform: scale(1.4); }
.ch-nav-label { display: none; }
.ch-nav-item:hover .ch-nav-label, .ch-nav-item.active .ch-nav-label { display: inline; }
/* ===== Quick Nav ===== */
.quick-nav { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin: 2rem 0; }
.quick-nav .qn-part { background: rgba(255,255,255,0.03); border-radius: 12px; padding: 1.2rem 1.2rem 1rem; border: 1px solid rgba(255,255,255,0.06); }
.quick-nav .qn-part-label { font-family: var(--font-heading); font-size: 0.8rem; color: rgba(255,255,255,0.2); letter-spacing: 0.1em; margin-bottom: 0.5rem; }
.quick-nav .qn-part-title { font-family: var(--font-cn); font-weight: 100; font-size: 1rem; color: rgba(255,255,255,0.7); margin-bottom: 0.5rem; }
.quick-nav .qn-link { display: block; font-size: 0.8rem; color: rgba(255,255,255,0.45); padding: 0.15rem 0; transition: color 0.2s; }
.quick-nav .qn-link:hover { color: #fff; }
/* ===== Hero (guide) ===== */
.hero { text-align: center; padding: 6rem 0 4rem; position: relative; overflow: hidden; }
.hero .glow { position: absolute; width: 40vw; height: 40vw; top: -20vw; left: 50%; transform: translateX(-50%); background: #fff; filter: blur(100px); opacity: 0.08; border-radius: 50%; pointer-events: none; }
.hero .title-xl { font-family: var(--font-heading); font-size: clamp(2.8rem, 8vw, 6rem); line-height: 1.1; letter-spacing: -0.02em; font-weight: 100; }
.hero .sub { margin-top: 1.5rem; font-size: 1.2rem; color: rgba(255,255,255,0.6); }
/* ===== Checklist (guide) ===== */
.checklist { display: flex; flex-wrap: wrap; justify-content: center; gap: 1.5rem; margin: 2rem 0 1rem; justify-content: flex-start;}
.checklist-item { background: rgba(255,255,255,0.04); padding: 0.6rem 1.5rem; border-radius: var(--radius); font-size: 0.9rem; border: 1px solid rgba(255,255,255,0.06); display: flex; align-items: center; gap: 0.6rem; }
.checklist-item .box { width: 18px; height: 18px; border: 2px solid rgba(255,255,255,0.3); border-radius: 4px; }
/* ===== Grid System (guide) ===== */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1.5rem; }
/* ===== Step Flow ===== */
.step-flow { display: flex; gap: 1.5rem; align-items: stretch; flex-wrap: wrap; }
.step-flow .step { flex: 1; min-width: 120px; text-align: center; padding: 1.5rem 1rem; background: rgba(255,255,255,0.03); border-radius: 12px; border-top: 3px solid rgba(255,255,255,0.2); }
.step-flow .step .num { font-family: var(--font-heading); font-size: 2rem; color: rgba(255,255,255,0.2); display: block; margin-bottom: 0.5rem; }
/* ===== FAQ (guide) ===== */
.faq-item { padding: 1.2rem 0; border-bottom: 1px solid rgba(255,255,255,0.06); }
.faq-item:last-child { border-bottom: none; }
.faq-item .q { font-family: var(--font-cn); font-weight: 400; font-size: 1.1rem; color: #fff; margin-bottom: 0.3rem; display: flex; gap: 0.8rem; }
.faq-item .q::before { content: 'Q'; color: rgba(255,255,255,0.3); font-weight: 600; }
.faq-item .a { font-family: var(--font-body); font-weight: 400; color: rgba(255,255,255,0.85); padding-left: 1.8rem; font-size: 0.95rem; }
/* ===== CTA Grid ===== */
.cta-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1.5rem; margin: 2rem 0; }
/* ===== Details ===== */
details { background: rgba(255,255,255,0.02); border-radius: 12px; padding: 0; border: 1px solid rgba(255,255,255,0.06); }
details summary { cursor: pointer; padding: 0.8rem 1.2rem; font-weight: 500; color: #fff; list-style: none; display: flex; justify-content: space-between; align-items: center; background: rgba(255,255,255,0.02); border-radius: 12px; }
details summary::-webkit-details-marker { display: none; }
details summary .fold-hint { font-size: 0.8rem; color: rgba(255,255,255,0.4); background: rgba(255,255,255,0.06); padding: 0.2rem 0.8rem; border-radius: 20px; }
details .details-content { padding: 0.5rem 1.2rem 1.2rem; }
/* ===== Scroll Progress ===== */
#scrollProgressContainer { position: fixed; right: 1.5vw; top: 50%; transform: translateY(-50%); z-index: 999; display: flex; flex-direction: column; align-items: center; gap: 0.8vw; }
#scrollProgressLabel { font-size: 0.6rem; color: rgba(255,255,255,0.15); letter-spacing: 0.1em; writing-mode: vertical-lr; }
#scrollProgressTrack { width: 2px; height: 40vh; background: rgba(255,255,255,0.08); border-radius: 2px; position: relative; overflow: hidden; }
#scrollProgressBar { position: absolute; top: 0; left: 0; width: 100%; height: 0%; background: rgba(255,255,255,0.3); border-radius: 2px; transition: height 0.1s; }
/* ===== Bullet List ===== */
.bullet-list { list-style: none; display: flex; flex-direction: column; gap: 0.6rem; }
.bullet-list li { font-family: var(--font-body); font-weight: 400; font-size: 0.9rem; color: rgba(255,255,255,0.9); padding-left: 1.5rem; position: relative; line-height: 1.7; }
.bullet-list li::before { content: ''; position: absolute; left: 0; top: 0.65rem; width: 6px; height: 6px; border-radius: 50%; background: rgba(255,255,255,0.4); }
/* ===== Decoration ===== */
.grid-bg { position: absolute; inset: 0; background-image: linear-gradient(rgba(255,255,255,0.02) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,0.02) 1px, transparent 1px); background-size: 40px 40px; pointer-events: none; z-index: 0; }
/* ===== Responsive: Guide ===== */
@media (max-width: 1024px) {
  .section-subtitle { max-width: 100%; }
  #scrollProgressContainer { display: none; }
}
@media (max-width: 768px) {
  .handbook { padding: 0 1.2rem; }
  .section { padding: 3rem 0; }
  .grid-2, .grid-3, .cta-grid, .quick-nav { grid-template-columns: 1fr !important; gap: 1rem; }
  .step-flow { flex-direction: column; }
  .hero { padding: 4rem 0; }
  .hero .title-xl { font-size: clamp(2.2rem, 10vw, 3rem); }
  .hero .sub { font-size: 1rem; }
  .checklist { flex-direction: column; align-items: stretch; gap: 0.8rem; }
  .checklist-item { justify-content: flex-start; }
  .section-subtitle { max-width: 100%; }
  .card-glass { padding: 1.5rem; }
  .faq-item .q { font-size: 1rem; }
  .faq-item .a { font-size: 0.9rem; padding-left: 1.5rem; }
  #chNav { display: none; }
  .body-text, .bullet-list li, .faq-item .a, .card-glass p:not(.stat-label), .step-flow .step p { font-size: 1rem !important; line-height: 1.8 !important; }
  .stat-num { font-size: clamp(2.5rem, 10vw, 3.5rem) !important; }
  .section-title { font-size: 1.6rem; }
  .btn-glass { width: 100%; justify-content: center; }
  details summary { font-size: 0.95rem; }
}
@media (max-width: 480px) {
  .hero .title-xl { font-size: 2rem; }
  .section-title { font-size: 1.4rem; }
}