/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { font-family: 'Georgia', 'Songti SC', 'Noto Serif SC', serif; background: #1A1A2E; color: #E0E0E0; line-height: 1.7; -webkit-font-smoothing: antialiased; }
ul, ol { list-style: none; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { font: inherit; cursor: pointer; border: none; background: none; }
:focus-visible { outline: 2px solid #D4AF37; outline-offset: 2px; border-radius: 4px; }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; scroll-behavior: auto !important; } }

/* ===== CSS Variables ===== */
:root {
  --color-primary: #D4AF37;
  --color-primary-dark: #B8860B;
  --color-secondary: #C62828;
  --color-secondary-light: #E53935;
  --color-bg: #1A1A2E;
  --color-surface: #16213E;
  --color-text-primary: #FFD700;
  --color-text-body: #E0E0E0;
  --color-accent: #00BCD4;
  --color-border: rgba(212, 175, 55, 0.3);
  --font-heading: 'Georgia', 'Songti SC', 'Noto Serif SC', serif;
  --font-body: 'Arial', 'PingFang SC', 'Noto Sans SC', sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --nav-height: 72px;
  --capsule-radius: 40px;
  --max-width: 1200px;
  --card-shadow: 0 4px 20px rgba(0,0,0,0.4), 0 1px 3px rgba(212,175,55,0.1);
  --card-stack-shadow: 0 8px 32px rgba(0,0,0,0.5), 0 2px 8px rgba(212,175,55,0.15), inset 0 1px 0 rgba(212,175,55,0.08);
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 { font-family: var(--font-heading); font-weight: 700; color: var(--color-primary); line-height: 1.3; }
h1 { font-size: clamp(2rem, 5vw, 3.2rem); letter-spacing: 0.02em; }
h2 { font-size: clamp(1.6rem, 4vw, 2.4rem); letter-spacing: 0.015em; }
h3 { font-size: clamp(1.3rem, 3vw, 1.8rem); }
h4 { font-size: 1.1rem; }
body, p, li, .text-body { font-family: var(--font-body); color: var(--color-text-body); }
.mono { font-family: var(--font-mono); letter-spacing: 0.02em; }

/* ===== Skip Link ===== */
.skip-link { position: absolute; top: -1000px; left: 8px; background: var(--color-primary); color: #1A1A2E; padding: 8px 16px; border-radius: 4px; z-index: 9999; font-weight: 700; transition: top 0.2s; }
.skip-link:focus { top: 8px; }

/* ===== Reading Progress ===== */
.reading-progress { position: fixed; top: 0; left: 0; width: 100%; height: 3px; background: rgba(212,175,55,0.15); z-index: 9998; pointer-events: none; }
.progress-bar-fill { height: 100%; width: 0%; background: linear-gradient(90deg, var(--color-primary), var(--color-secondary)); transition: width 0.15s ease-out; }
@media (prefers-reduced-motion: reduce) { .progress-bar-fill { transition: none; } }

/* ===== Header & Nav Capsule ===== */
.site-header { position: fixed; top: 16px; left: 0; width: 100%; z-index: 1000; display: flex; justify-content: center; pointer-events: none; }
.nav-capsule { display: flex; align-items: center; gap: 8px; background: rgba(26,26,46,0.88); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border: 1px solid var(--color-border); border-radius: var(--capsule-radius); padding: 8px 20px; max-width: var(--max-width); width: calc(100% - 32px); pointer-events: auto; box-shadow: 0 8px 32px rgba(0,0,0,0.5); }
.brand-logo { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.brand-emblem { flex-shrink: 0; }
.brand-name { font-family: var(--font-heading); font-size: 1.4rem; font-weight: 700; color: var(--color-text-primary); letter-spacing: 0.04em; white-space: nowrap; }
.nav-list { flex: 1; display: flex; justify-content: center; }
.nav-list ul { display: flex; gap: 4px; align-items: center; }
.nav-link { font-family: var(--font-body); font-size: 0.95rem; padding: 6px 14px; border-radius: 20px; color: var(--color-text-body); transition: all 0.2s; white-space: nowrap; position: relative; }
.nav-link:hover { color: var(--color-primary); background: rgba(212,175,55,0.08); }
.nav-link[aria-current="page"] { color: var(--color-primary); font-weight: 600; background: rgba(212,175,55,0.12); }
.nav-link[aria-current="page"]::after { content: ''; position: absolute; bottom: 2px; left: 14px; right: 14px; height: 2px; background: var(--color-primary); border-radius: 1px; }
.btn-cta { font-family: var(--font-body); font-size: 0.9rem; font-weight: 600; padding: 8px 20px; border-radius: 24px; background: var(--color-secondary); color: #FFD700; border: 1px solid rgba(255,215,0,0.3); transition: all 0.25s; white-space: nowrap; flex-shrink: 0; }
.btn-cta:hover { background: var(--color-secondary-light); border-color: var(--color-primary); box-shadow: 0 0 20px rgba(198,40,40,0.3); }
.nav-toggle { display: none; width: 40px; height: 40px; align-items: center; justify-content: center; flex-shrink: 0; border-radius: 50%; border: 1px solid var(--color-border); color: var(--color-primary); }
.nav-toggle-icon { display: block; width: 20px; height: 2px; background: var(--color-primary); position: relative; transition: background 0.2s; }
.nav-toggle-icon::before, .nav-toggle-icon::after { content: ''; position: absolute; left: 0; width: 100%; height: 2px; background: var(--color-primary); transition: transform 0.25s; }
.nav-toggle-icon::before { top: -6px; }
.nav-toggle-icon::after { top: 6px; }
[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon { background: transparent; }
[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon::before { transform: translateY(6px) rotate(45deg); }
[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon::after { transform: translateY(-6px) rotate(-45deg); }

/* ===== Mobile Nav ===== */
@media (max-width: 900px) {
  .site-header { top: 12px; }
  .nav-capsule { padding: 6px 12px; gap: 4px; width: calc(100% - 16px); }
  .brand-name { font-size: 1.1rem; }
  .nav-list { position: absolute; top: calc(100% + 8px); left: 0; width: 100%; background: rgba(26,26,46,0.96); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); border: 1px solid var(--color-border); border-radius: 16px; padding: 12px 8px; display: none; box-shadow: 0 16px 48px rgba(0,0,0,0.6); }
  .nav-list[data-open] { display: block; }
  .nav-list ul { flex-direction: column; gap: 2px; }
  .nav-link { display: block; padding: 10px 16px; font-size: 1rem; border-radius: 10px; }
  .nav-link[aria-current="page"]::after { display: none; }
  .nav-link[aria-current="page"] { background: rgba(212,175,55,0.15); }
  .nav-toggle { display: flex; }
  .btn-cta { font-size: 0.8rem; padding: 6px 14px; }
}
@media (max-width: 480px) {
  .nav-capsule { padding: 6px 8px; gap: 2px; }
  .brand-name { font-size: 0.95rem; }
  .brand-emblem { width: 28px; height: 28px; }
  .btn-cta { font-size: 0.7rem; padding: 5px 10px; }
  .nav-toggle { width: 36px; height: 36px; }
}

/* ===== Footer ===== */
.site-footer { background: #0F1A2E; border-top: 2px solid var(--color-border); padding: 60px 0 24px; margin-top: 80px; }
.site-footer .container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1.2fr; gap: 40px; padding-bottom: 40px; border-bottom: 1px solid rgba(212,175,55,0.15); }
.footer-brand .brand-logo { margin-bottom: 12px; }
.footer-brand .brand-name { font-size: 1.2rem; }
.footer-tagline { font-size: 0.9rem; color: rgba(224,224,224,0.7); margin-top: 8px; font-family: var(--font-body); }
.footer-nav ul { display: flex; flex-direction: column; gap: 8px; }
.footer-nav-link { font-family: var(--font-body); font-size: 0.9rem; color: rgba(224,224,224,0.8); transition: color 0.2s; padding: 2px 0; }
.footer-nav-link:hover { color: var(--color-primary); }
.footer-legal-title, .footer-contact-title { font-family: var(--font-heading); font-size: 1rem; color: var(--color-primary); margin-bottom: 14px; font-weight: 600; }
.legal-links { display: flex; flex-direction: column; gap: 8px; }
.legal-link { font-family: var(--font-body); font-size: 0.9rem; color: rgba(224,224,224,0.8); transition: color 0.2s; padding: 2px 0; }
.legal-link:hover { color: var(--color-primary); }
.contact-info { font-family: var(--font-body); font-size: 0.85rem; color: rgba(224,224,224,0.7); margin-bottom: 6px; line-height: 1.6; }
.contact-info a { color: var(--color-primary); border-bottom: 1px solid transparent; transition: border-color 0.2s; }
.contact-info a:hover { border-color: var(--color-primary); }
.footer-bottom { display: flex; justify-content: space-between; align-items: center; padding-top: 20px; gap: 16px; flex-wrap: wrap; }
.icp-info { font-family: var(--font-mono); font-size: 0.75rem; color: rgba(224,224,224,0.5); }
.copyright { font-family: var(--font-body); font-size: 0.8rem; color: rgba(224,224,224,0.5); }
@media (max-width: 900px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .footer-brand { grid-column: 1 / -1; }
}
@media (max-width: 560px) {
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}

/* ===== Container & Grid ===== */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.grid { display: grid; gap: 24px; }
.bento-grid { display: grid; grid-template-columns: repeat(12, 1fr); gap: 16px; }
.bento-item { background: var(--color-surface); border-radius: 12px; padding: 24px; border: 1px solid var(--color-border); box-shadow: var(--card-shadow); transition: transform 0.25s, box-shadow 0.25s; }
.bento-item:hover { transform: translateY(-2px); box-shadow: var(--card-stack-shadow); }
@media (max-width: 768px) { .bento-grid { grid-template-columns: 1fr; gap: 12px; } }

/* ===== Cards & Stack ===== */
.card { background: var(--color-surface); border-radius: 12px; padding: 24px; border: 1px solid var(--color-border); box-shadow: var(--card-shadow); transition: transform 0.25s, box-shadow 0.25s; }
.card:hover { transform: translateY(-2px); box-shadow: var(--card-stack-shadow); }
.card-stack { position: relative; box-shadow: var(--card-stack-shadow); }
.card-stack::before { content: ''; position: absolute; top: 4px; left: 4px; right: -4px; bottom: -4px; background: rgba(212,175,55,0.06); border-radius: 10px; border: 1px solid rgba(212,175,55,0.1); z-index: -1; }
.card-stack::after { content: ''; position: absolute; top: 8px; left: 8px; right: -8px; bottom: -8px; background: rgba(212,175,55,0.03); border-radius: 8px; border: 1px solid rgba(212,175,55,0.05); z-index: -2; }
@media (prefers-reduced-motion: reduce) { .card, .bento-item { transition: none; } }

/* ===== Tags ===== */
.tag { display: inline-block; font-family: var(--font-mono); font-size: 0.7rem; font-weight: 500; padding: 2px 10px; border-radius: 12px; letter-spacing: 0.04em; text-transform: uppercase; }
.tag-gold { background: rgba(212,175,55,0.15); color: var(--color-primary); border: 1px solid rgba(212,175,55,0.3); }
.tag-red { background: rgba(198,40,40,0.15); color: var(--color-secondary); border: 1px solid rgba(198,40,40,0.3); }

/* ===== Buttons ===== */
.btn { display: inline-flex; align-items: center; gap: 8px; font-family: var(--font-body); font-size: 0.95rem; font-weight: 600; padding: 10px 24px; border-radius: 24px; transition: all 0.25s; border: 1px solid transparent; }
.btn-primary { background: var(--color-primary); color: #1A1A2E; border-color: var(--color-primary); }
.btn-primary:hover { background: var(--color-primary-dark); border-color: var(--color-primary-dark); box-shadow: 0 0 24px rgba(212,175,55,0.25); }
.btn-secondary { background: transparent; color: var(--color-primary); border-color: var(--color-primary); }
.btn-secondary:hover { background: rgba(212,175,55,0.08); border-color: var(--color-primary-dark); }
@media (prefers-reduced-motion: reduce) { .btn { transition: none; } }

/* ===== Breadcrumb ===== */
.breadcrumb { display: flex; flex-wrap: wrap; gap: 6px 12px; padding: 12px 0; font-family: var(--font-body); font-size: 0.85rem; color: rgba(224,224,224,0.6); }
.breadcrumb-item { display: flex; align-items: center; gap: 6px; }
.breadcrumb-item + .breadcrumb-item::before { content: '/'; color: rgba(212,175,55,0.4); }
.breadcrumb-item a { color: var(--color-primary); transition: color 0.2s; }
.breadcrumb-item a:hover { color: var(--color-primary-dark); }

/* ===== Theme Strip & Content Column ===== */
.theme-strip { display: flex; gap: 24px; overflow-x: auto; padding: 16px 0; scroll-snap-type: x mandatory; scrollbar-width: thin; scrollbar-color: var(--color-primary) transparent; }
.theme-strip::-webkit-scrollbar { height: 4px; }
.theme-strip::-webkit-scrollbar-thumb { background: var(--color-primary); border-radius: 4px; }
.theme-strip > * { scroll-snap-align: start; flex-shrink: 0; min-width: 260px; }
.content-column { max-width: 720px; margin: 0 auto; padding: 24px 0; }
@media (max-width: 768px) { .theme-strip { gap: 16px; } .theme-strip > * { min-width: 200px; } }

/* ===== Back to Top ===== */
.back-to-top { position: fixed; bottom: 32px; right: 32px; width: 48px; height: 48px; border-radius: 50%; background: var(--color-surface); border: 1px solid var(--color-border); color: var(--color-primary); display: flex; align-items: center; justify-content: center; font-size: 1.4rem; opacity: 0; visibility: hidden; transition: opacity 0.3s, visibility 0.3s, transform 0.3s; transform: translateY(12px); z-index: 900; box-shadow: var(--card-shadow); }
.back-to-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: var(--color-primary); color: #1A1A2E; border-color: var(--color-primary); }
@media (prefers-reduced-motion: reduce) { .back-to-top { transition: none; } }

/* ===== Section Highlight ===== */
.section-highlight { border-left: 3px solid var(--color-primary); padding-left: 20px; transition: border-color 0.3s; }
.section-active { border-left-color: var(--color-secondary); }

/* ===== Scroll Section ===== */
[data-scroll-section] { transition: opacity 0.3s, transform 0.3s; }
@media (prefers-reduced-motion: reduce) { [data-scroll-section] { transition: none; } }

/* ===== Utility ===== */
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }
.text-center { text-align: center; }
.mt-8 { margin-top: 8px; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.mb-8 { margin-bottom: 8px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }
.mb-32 { margin-bottom: 32px; }