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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: 'Helvetica Neue', 'PingFang SC', sans-serif;
  background-color: #0A1C3E;
  color: #F0F5FF;
  line-height: 1.75;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  padding-top: 80px;
  overflow-x: hidden;
}

img, svg {
  display: block;
  max-width: 100%;
}

ul, ol {
  list-style: none;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  border: none;
  background: none;
  cursor: pointer;
  color: inherit;
}

:root {
  --color-space: #0A1C3E;
  --color-deep: #0F3B4A;
  --color-orange: #FF6B35;
  --color-gold: #F5B300;
  --color-ice: #F0F5FF;
  --color-slate: #A0B4C8;
  --color-wine: #8A2A4B;
  --color-indigo: #4B0082;
  --font-display: Impact, 'PingFang SC Heavy', sans-serif;
  --font-body: 'Helvetica Neue', 'PingFang SC', sans-serif;
  --header-h: 80px;
  --header-h-mobile: 64px;
  --container-w: 1280px;
  --radius: 4px;
  --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --shadow-card: 0 8px 28px rgba(0, 0, 0, 0.35);
  --shadow-float: 0 14px 40px rgba(0, 0, 0, 0.45);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.15;
  color: var(--color-ice);
}

h1 { font-size: clamp(32px, 5vw, 64px); }
h2 { font-size: clamp(26px, 4vw, 48px); }
h3 { font-size: clamp(20px, 2.5vw, 32px); }

em {
  font-style: italic;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--color-orange);
  outline-offset: 3px;
  border-radius: 2px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

.content-shell {
  width: min(100% - 40px, var(--container-w));
  margin-inline: auto;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  padding: 32px 0 16px;
  font-size: 14px;
  color: var(--color-slate);
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.breadcrumb-item {
  display: flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb-item + .breadcrumb-item::before {
  content: '/';
  color: var(--color-slate);
  opacity: 0.6;
}

.breadcrumb-item a:hover {
  color: var(--color-orange);
}

.breadcrumb-current {
  color: var(--color-ice);
  font-weight: 600;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 32px;
  font-family: var(--font-display);
  font-size: 16px;
  letter-spacing: 0.05em;
  border-radius: var(--radius);
  line-height: 1.2;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), border-color 0.25s ease, color 0.25s ease;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-orange) 0%, #e2561e 100%);
  color: var(--color-space);
  font-weight: 700;
  box-shadow: 0 4px 18px rgba(255, 107, 53, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(255, 107, 53, 0.45);
}

.btn-ghost {
  border: 1px solid rgba(240, 245, 255, 0.35);
  color: var(--color-ice);
  background: transparent;
}

.btn-ghost:hover {
  border-color: var(--color-orange);
  color: var(--color-orange);
}

.btn-small {
  padding: 8px 18px;
  font-size: 14px;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  z-index: 9999;
  display: inline-block;
  padding: 12px 22px;
  background: var(--color-orange);
  color: var(--color-space);
  font-weight: 700;
  border-radius: 0 0 6px 6px;
  transition: top 0.3s var(--ease);
}

.skip-link:focus-visible {
  top: 0;
  outline: 3px solid var(--color-gold);
  outline-offset: 2px;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-orange), var(--color-gold));
  z-index: 2000;
  pointer-events: none;
  will-change: width;
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 28, 62, 0.88);
  -webkit-backdrop-filter: blur(18px);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(160, 180, 200, 0.15);
  box-shadow: 0 4px 20px rgba(2, 6, 20, 0.4);
}

.site-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-orange) 0%, var(--color-gold) 35%, rgba(245, 179, 0, 0.15) 70%, transparent 100%);
  pointer-events: none;
}

.header-inner {
  max-width: var(--container-w);
  margin-inline: auto;
  height: var(--header-h);
  padding-inline: 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.brand-icon {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.brand-text {
  font-family: var(--font-display);
  font-size: 26px;
  line-height: 1;
  letter-spacing: 0.08em;
  color: var(--color-ice);
}

.brand-text em {
  color: var(--color-orange);
  font-style: normal;
  font-weight: 700;
}

.nav-frame {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-item {
  display: flex;
  align-items: center;
}

.nav-item + .nav-item::before {
  content: '';
  width: 1px;
  height: 18px;
  margin: 0 12px;
  background: rgba(160, 180, 200, 0.25);
}

.nav-link {
  position: relative;
  display: inline-block;
  padding: 8px 2px;
  font-size: 15px;
  letter-spacing: 0.06em;
  color: var(--color-slate);
  transition: color 0.3s ease;
  white-space: nowrap;
}

.nav-link::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-orange), var(--color-gold));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s var(--ease);
}

.nav-link:hover {
  color: var(--color-ice);
}

.nav-link:hover::after,
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--color-ice);
  font-weight: 600;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  padding: 10px;
  border: 1px solid rgba(160, 180, 200, 0.25);
  border-radius: var(--radius);
  background: rgba(10, 28, 62, 0.6);
  transition: border-color 0.3s ease, background-color 0.3s ease;
}

.nav-toggle:hover {
  border-color: var(--color-orange);
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-ice);
  border-radius: 1px;
  transition: transform 0.3s var(--ease), opacity 0.3s ease, background-color 0.3s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
  background: var(--color-orange);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
  background: var(--color-orange);
}

.site-footer {
  background: linear-gradient(180deg, var(--color-space) 0%, #060e20 100%);
  border-top: 1px solid rgba(160, 180, 200, 0.12);
  position: relative;
}

.footer-main {
  padding: 72px 0 48px;
}

.footer-grid {
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: 20px;
  display: grid;
  grid-template-columns: 1.6fr 1fr 1.4fr;
  gap: 48px;
}

.footer-brand-block {
  max-width: 420px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-icon-lg {
  width: 48px;
  height: 48px;
}

.footer-brand-text {
  font-family: var(--font-display);
  font-size: 32px;
  color: var(--color-ice);
  letter-spacing: 0.08em;
}

.footer-tagline {
  margin-top: 8px;
  font-size: 14px;
  letter-spacing: 0.12em;
  color: var(--color-orange);
  border-left: 3px solid var(--color-gold);
  padding-left: 12px;
}

.footer-trust {
  margin-top: 20px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--color-slate);
}

.footer-nav-col,
.footer-contact-col {
  padding-top: 4px;
}

.footer-col-title {
  font-family: var(--font-display);
  font-size: 18px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-ice);
  margin-bottom: 20px;
  position: relative;
  padding-bottom: 10px;
}

.footer-col-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 36px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-orange), var(--color-gold));
}

.footer-nav-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.footer-nav-link {
  color: var(--color-slate);
  font-size: 15px;
  transition: color 0.25s ease, padding-left 0.25s var(--ease);
}

.footer-nav-link:hover {
  color: var(--color-orange);
  padding-left: 4px;
}

.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  font-style: normal;
  font-size: 15px;
  line-height: 1.6;
  color: var(--color-slate);
}

.footer-contact-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.footer-contact-address {
  word-break: break-word;
}

.footer-field-label {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-gold);
}

.footer-contact-link {
  color: var(--color-ice);
  transition: color 0.25s ease;
  word-break: break-word;
}

.footer-contact-link:hover {
  color: var(--color-orange);
}

.footer-legal {
  border-top: 1px solid rgba(160, 180, 200, 0.1);
  background: rgba(4, 10, 24, 0.6);
  padding: 20px 0;
}

.footer-legal-inner {
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: 20px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px 32px;
  font-size: 14px;
  color: var(--color-slate);
}

.footer-copyright {
  margin-right: auto;
}

.footer-icp {
  color: var(--color-slate);
  letter-spacing: 0.08em;
}

.footer-legal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-legal-link {
  color: var(--color-slate);
  transition: color 0.25s ease;
  font-size: 14px;
}

.footer-legal-link:hover {
  color: var(--color-orange);
}

.back-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 990;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(10, 28, 62, 0.9);
  border: 1px solid rgba(255, 107, 53, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-orange);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.4);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.35s var(--ease), transform 0.35s var(--ease), visibility 0.35s ease;
}

.back-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-top:hover {
  border-color: var(--color-gold);
  color: var(--color-gold);
  box-shadow: 0 8px 30px rgba(255, 107, 53, 0.3);
}

.back-top-icon {
  width: 22px;
  height: 22px;
}

.card {
  position: relative;
  background: linear-gradient(145deg, rgba(240, 245, 255, 0.06), rgba(240, 245, 255, 0.02));
  border: 1px solid rgba(160, 180, 200, 0.12);
  border-radius: var(--radius);
  padding: 28px;
  transition: border-color 0.3s ease, transform 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.card:hover {
  border-color: rgba(255, 107, 53, 0.4);
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
}

.card-accent {
  border-top: 3px solid var(--color-orange);
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-orange);
}

.section-tag::before {
  content: '';
  width: 36px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-orange), var(--color-gold));
  flex-shrink: 0;
}

.section-index {
  font-family: var(--font-display);
  font-size: clamp(56px, 7vw, 96px);
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px rgba(255, 107, 53, 0.5);
  user-select: none;
  pointer-events: none;
}

.stat-block {
  display: grid;
  gap: 6px;
}

.stat-num {
  font-family: var(--font-display);
  font-size: clamp(40px, 5vw, 72px);
  line-height: 1;
  color: var(--color-gold);
  letter-spacing: 0.04em;
}

.stat-label {
  font-size: 14px;
  color: var(--color-slate);
  letter-spacing: 0.08em;
}

.img-block {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--color-deep), var(--color-space));
  border-radius: var(--radius);
  border: 1px solid rgba(160, 180, 200, 0.15);
}

.img-block::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255, 107, 53, 0.15), transparent 45%);
  pointer-events: none;
  mix-blend-mode: screen;
}

.img-block img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s var(--ease);
}

.img-block:hover img {
  transform: scale(1.04);
}

.img-block-16x9 {
  aspect-ratio: 16 / 9;
}

.img-block-4x5 {
  aspect-ratio: 4 / 5;
}

.img-block-1x1 {
  aspect-ratio: 1 / 1;
}

.img-solid {
  background:
    linear-gradient(135deg, rgba(240, 245, 255, 0.1) 25%, transparent 25%),
    linear-gradient(225deg, rgba(240, 245, 255, 0.1) 25%, transparent 25%),
    linear-gradient(45deg, rgba(240, 245, 255, 0.08) 25%, transparent 25%),
    linear-gradient(315deg, rgba(240, 245, 255, 0.08) 25%, transparent 25%);
  background-size: 20px 20px;
}

.chapter-nav {
  position: sticky;
  top: calc(var(--header-h) + 24px);
  z-index: 50;
  background: rgba(10, 28, 62, 0.92);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(160, 180, 200, 0.15);
  border-radius: var(--radius);
  padding: 18px 24px;
}

.chapter-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
}

.chapter-link {
  font-size: 14px;
  color: var(--color-slate);
  letter-spacing: 0.06em;
  transition: color 0.25s ease, border-color 0.25s ease;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
}

.chapter-link:hover,
.chapter-link.is-active {
  color: var(--color-orange);
  border-bottom-color: var(--color-orange);
}

.divider-diagonal {
  height: 24px;
  background: linear-gradient(135deg, var(--color-orange) 0%, var(--color-gold) 100%);
  clip-path: polygon(0 0, 100% 0, calc(100% - 60px) 100%, 60px 100%);
  opacity: 0.35;
  border: none;
  margin: 40px 0;
}

.field-group {
  display: grid;
  gap: 8px;
}

.field-label {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--color-ice);
}

.field-input,
.field-textarea {
  display: block;
  width: 100%;
  background: rgba(10, 28, 62, 0.7);
  border: 1px solid rgba(160, 180, 200, 0.25);
  border-radius: var(--radius);
  color: var(--color-ice);
  padding: 12px 16px;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.5;
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.field-input:focus,
.field-textarea:focus {
  outline: none;
  border-color: var(--color-orange);
  box-shadow: 0 0 0 3px rgba(255, 107, 53, 0.2);
}

.field-textarea {
  min-height: 140px;
  resize: vertical;
}

@media (min-width: 1024px) {
  .nav-frame {
    border: 1px solid rgba(160, 180, 200, 0.18);
    border-radius: 2px;
    padding: 0 8px;
    background: rgba(10, 28, 62, 0.5);
  }
}

@media (max-width: 1023px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 767px) {
  body {
    padding-top: var(--header-h-mobile);
  }

  .header-inner {
    height: var(--header-h-mobile);
  }

  .brand-text {
    font-size: 22px;
  }

  .brand-icon {
    width: 30px;
    height: 30px;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-frame {
    display: block;
    position: fixed;
    top: var(--header-h-mobile);
    right: 0;
    bottom: 0;
    width: min(80vw, 340px);
    background: rgba(6, 18, 40, 0.98);
    border-left: 1px solid rgba(160, 180, 200, 0.15);
    border-top: 1px solid rgba(160, 180, 200, 0.08);
    box-shadow: -10px 0 40px rgba(0, 0, 0, 0.5);
    padding: 24px;
    transform: translateX(110%);
    transition: transform 0.35s var(--ease);
    overflow-y: auto;
    z-index: 1005;
  }

  .nav-frame[data-open] {
    transform: translateX(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    width: 100%;
  }

  .nav-item {
    border-bottom: 1px solid rgba(160, 180, 200, 0.12);
  }

  .nav-item + .nav-item::before {
    display: none;
  }

  .nav-link {
    display: block;
    padding: 16px 8px;
    font-size: 18px;
    color: var(--color-slate);
    white-space: normal;
  }

  .nav-link::after {
    left: 8px;
    right: auto;
    width: 32px;
    height: 3px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .footer-main {
    padding: 48px 0 32px;
  }

  .footer-legal-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .footer-copyright {
    margin-right: 0;
  }

  .back-top {
    right: 16px;
    bottom: 16px;
    width: 44px;
    height: 44px;
  }

  .back-top-icon {
    width: 20px;
    height: 20px;
  }

  .chapter-nav {
    top: calc(var(--header-h-mobile) + 16px);
    padding: 14px 18px;
  }
}