/* ===== 01 RESET & TOKENS ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --navy-deep: #0A192F;
  --navy-mid: #0E2A42;
  --navy-bright: #143A5C;
  --off-white: #F5F7FA;
  --blue-gray: #B0C4DE;
  --orange-main: #FF6B35;
  --orange-soft: #FF9A6C;
  --line-blue: #1E3A5F;
  --ok-green: #28A745;

  --font-head: Impact, 'Arial Black', sans-serif;
  --font-body: 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', sans-serif;

  --h1-size: clamp(2.5rem, 8vw, 6rem);
  --h2-size: clamp(1.8rem, 5vw, 3.5rem);
  --body-size: clamp(1rem, 2vw, 1.125rem);

  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;

  --radius-sm: 8px;
  --radius-md: 18px;
  --radius-lg: 44px;

  --max-width: 1280px;
  --header-offset: 0.75rem;
}

[hidden] {
  display: none !important;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  font-size: var(--body-size);
  line-height: 1.6;
  color: var(--off-white);
  background: var(--navy-deep);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse at 12% -10%, rgba(20, 58, 92, 0.55) 0%, transparent 42%),
    radial-gradient(ellipse at 88% 112%, rgba(255, 107, 53, 0.14) 0%, transparent 32%),
    linear-gradient(145deg, var(--navy-deep) 0%, var(--navy-mid) 50%, var(--navy-deep) 100%);
  pointer-events: none;
  z-index: -1;
}

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

a {
  color: var(--orange-main);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

button {
  font-family: var(--font-body);
  cursor: pointer;
}

/* ===== 02 ACCESSIBILITY UTILITIES ===== */
.skip-link {
  position: fixed;
  top: -48px;
  left: 1rem;
  z-index: 3000;
  background: var(--orange-main);
  color: var(--navy-deep);
  font-weight: 700;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: top 0.2s;
}

.skip-link:focus {
  top: 1rem;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--orange-main), var(--orange-soft));
  border-radius: 0 4px 4px 0;
  z-index: 3001;
  pointer-events: none;
}

html.nav-lock,
html.nav-lock body {
  overflow: hidden;
  height: 100%;
}

:focus-visible {
  outline: 3px solid var(--orange-main);
  outline-offset: 2px;
}

::selection {
  background: var(--orange-main);
  color: var(--navy-deep);
}

/* ===== 03 LAYOUT PRIMITIVES ===== */
main#main-content {
  display: block;
  flex: 1 0 auto;
  padding-top: calc(var(--header-offset) + 4.75rem + 0.4rem);
}

.content-wrap {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
}

.section-band {
  padding: var(--space-xl) 1rem;
}

.section-band + .section-band {
  border-top: 1px solid var(--line-blue);
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.split-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}

/* ===== 04 GRID SYSTEMS ===== */
.grid-2,
.grid-3,
.grid-4 {
  display: grid;
  gap: var(--space-md);
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

/* ===== 05 TYPOGRAPHY ===== */
.head-xl {
  font-family: var(--font-head);
  font-size: var(--h1-size);
  line-height: 1.05;
  letter-spacing: 0.015em;
  color: var(--off-white);
  text-transform: uppercase;
  font-weight: 900;
}

.head-lg {
  font-family: var(--font-head);
  font-size: var(--h2-size);
  line-height: 1.1;
  color: var(--off-white);
  font-weight: 900;
}

.head-sm {
  font-family: var(--font-head);
  font-size: clamp(1.2rem, 3vw, 1.6rem);
  line-height: 1.2;
  color: var(--off-white);
  font-weight: 700;
}

.body-text {
  color: var(--blue-gray);
  line-height: 1.65;
  max-width: 65ch;
}

.note-text {
  color: var(--blue-gray);
  font-size: 0.875rem;
  line-height: 1.5;
}

.data-num {
  font-family: var(--font-head);
  font-size: clamp(2rem, 5vw, 3.5rem);
  line-height: 1;
  color: var(--orange-main);
  display: inline-block;
  font-weight: 900;
}

.data-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-family: var(--font-head);
  font-size: 0.85rem;
  color: var(--orange-main);
  background: rgba(20, 58, 92, 0.45);
  border: 1px solid var(--orange-main);
  padding: 0.2rem 0.65rem;
  border-radius: 999px;
  letter-spacing: 0.04em;
}

/* ===== 06 BUTTONS & TAGS ===== */
.btn-solid,
.btn-line {
  display: inline-block;
  padding: 0.7rem 1.4rem;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.95rem;
  line-height: 1.4;
  transition: transform 0.2s, background 0.2s, color 0.2s, box-shadow 0.2s;
  text-align: center;
}

.btn-solid {
  background: var(--orange-main);
  color: var(--navy-deep);
  box-shadow: 0 4px 18px rgba(255, 107, 53, 0.4);
}

.btn-solid:hover,
.btn-solid:focus-visible {
  background: var(--orange-soft);
  color: var(--navy-deep);
  transform: translateY(-2px);
  box-shadow: 0 8px 26px rgba(255, 107, 53, 0.5);
  text-decoration: none;
}

.btn-line {
  background: transparent;
  border: 1px solid var(--orange-main);
  color: var(--orange-main);
}

.btn-line:hover,
.btn-line:focus-visible {
  background: var(--orange-main);
  color: var(--navy-deep);
  transform: translateY(-2px);
  text-decoration: none;
}

.tag-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: transparent;
  border: 1px solid var(--line-blue);
  border-radius: 999px;
  color: var(--blue-gray);
  font-size: 0.9rem;
  padding: 0.4rem 0.9rem;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.tag-chip:hover,
.tag-chip:focus-visible,
.tag-chip[aria-pressed="true"] {
  border-color: var(--orange-main);
  color: var(--orange-main);
  background: rgba(255, 107, 53, 0.08);
}

.tag-chip[aria-pressed="true"] {
  font-weight: 700;
}

/* ===== 07 CARDS & PAPER STACKING ===== */
.stack-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  background: linear-gradient(160deg, var(--navy-mid) 0%, var(--navy-deep) 100%);
  border: 1px solid var(--line-blue);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  position: relative;
  transition: transform 0.25s, border-color 0.25s, box-shadow 0.25s;
}

.stack-card::after {
  content: '';
  position: absolute;
  right: 10px;
  bottom: 8px;
  width: 32px;
  height: 2px;
  background: var(--orange-main);
  transform: rotate(-35deg);
  opacity: 0.35;
  pointer-events: none;
}

.stack-card:hover {
  transform: translateY(-4px);
  border-color: var(--navy-bright);
  box-shadow: 0 18px 42px rgba(10, 25, 47, 0.5);
}

.paper-stack {
  position: relative;
  padding: var(--space-md);
  background: var(--navy-mid);
  border: 1px solid var(--line-blue);
  border-radius: 4px;
}

.paper-stack::before {
  content: '';
  position: absolute;
  top: -6px;
  left: 10px;
  right: -6px;
  bottom: 6px;
  border: 1px solid var(--line-blue);
  background: rgba(20, 58, 92, 0.35);
  border-radius: 4px;
  z-index: -1;
}

.paper-stack::after {
  content: '';
  position: absolute;
  top: -10px;
  left: -10px;
  right: 10px;
  bottom: 10px;
  border: 1px solid rgba(255, 107, 53, 0.25);
  border-radius: 4px;
  z-index: -2;
}

/* ===== 08 ROUTE TREE ===== */
.route-tree {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 1fr;
  gap: var(--space-sm);
  position: relative;
  padding-top: var(--space-lg);
}

.route-tree::before {
  content: '';
  position: absolute;
  top: 2.5rem;
  left: 8%;
  right: 8%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--orange-main), transparent);
}

.tree-node {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-top: 1.5rem;
  text-align: center;
}

.tree-node::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 14px;
  height: 14px;
  background: var(--navy-deep);
  border: 3px solid var(--orange-main);
  border-radius: 50%;
}

/* ===== 09 BREADCRUMB ===== */
.crumb-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  list-style: none;
  margin-bottom: var(--space-md);
}

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

.crumb-item + .crumb-item::before {
  content: '/';
  margin-right: 0.5rem;
  color: var(--blue-gray);
}

.crumb-link {
  color: var(--blue-gray);
  font-size: 0.9rem;
}

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

/* ===== 10 SLANT BAND ===== */
.slant-band {
  position: relative;
  clip-path: polygon(0 2.5%, 100% 0, 100% 97.5%, 0 100%);
  padding: calc(var(--space-xl) + 1.5rem) 1rem;
  background: linear-gradient(135deg, var(--navy-mid) 0%, var(--navy-deep) 100%);
}

/* ===== 11 HEADER ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--header-offset) 1rem 0;
  background: linear-gradient(180deg, rgba(10, 25, 47, 0.78) 0%, rgba(10, 25, 47, 0.35) 70%, transparent 100%);
  pointer-events: none;
}

.site-header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  pointer-events: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: 0.55rem 0.75rem 0.55rem 0.6rem;
  background: linear-gradient(135deg, rgba(14, 42, 66, 0.96), rgba(10, 25, 47, 0.98));
  border: 1px solid var(--line-blue);
  border-radius: var(--radius-lg);
  box-shadow: 0 10px 36px rgba(10, 25, 47, 0.55);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--off-white);
  flex-shrink: 0;
  position: relative;
}

@media (min-width: 961px) {
  .brand-link::after {
    content: '';
    width: 2px;
    height: 28px;
    margin-left: 0.5rem;
    background: linear-gradient(180deg, var(--orange-main), transparent);
    border-radius: 2px;
    opacity: 0.65;
  }
}

.brand-link:hover {
  text-decoration: none;
}

.brand-glyph {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: var(--orange-main);
  color: var(--navy-deep);
  font-family: var(--font-head);
  font-size: 1.25rem;
  font-weight: 900;
  border-radius: 12px;
  transform: rotate(-6deg);
  box-shadow: 0 4px 16px rgba(255, 107, 53, 0.42);
}

.brand-word {
  font-family: var(--font-head);
  font-size: 1.25rem;
  letter-spacing: 0.04em;
}

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

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.125rem;
  list-style: none;
  flex-wrap: wrap;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: block;
  padding: 0.6rem 0.9rem;
  color: var(--blue-gray);
  font-size: 0.95rem;
  font-weight: 500;
  line-height: 1.2;
  border-radius: 999px;
  transition: color 0.2s, background 0.2s;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--off-white);
  background: var(--navy-bright);
  text-decoration: none;
}

.nav-link[aria-current="page"] {
  color: var(--navy-deep);
  background: var(--orange-main);
  font-weight: 700;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 11px;
  background: transparent;
  border: 1px solid var(--line-blue);
  border-radius: 12px;
  position: relative;
  z-index: 1300;
}

.nav-toggle-line {
  display: block;
  height: 2.5px;
  width: 100%;
  background: var(--off-white);
  border-radius: 4px;
  transition: transform 0.25s, opacity 0.25s;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* ===== 12 FOOTER ===== */
.site-footer {
  position: relative;
  flex-shrink: 0;
  padding: 3rem 1rem 2rem;
  background: linear-gradient(180deg, var(--navy-deep) 0%, var(--navy-mid) 100%);
  border-top: 1px solid var(--line-blue);
  overflow: hidden;
}

.site-footer::before {
  content: '北';
  position: absolute;
  right: 2rem;
  top: -1.4rem;
  font-family: var(--font-head);
  font-size: 9rem;
  line-height: 1;
  color: rgba(255, 107, 53, 0.05);
  pointer-events: none;
}

.site-footer::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--orange-main) 0%, transparent 25%, var(--orange-main) 50%, transparent 75%, var(--orange-main));
  opacity: 0.5;
  pointer-events: none;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1.4fr 1fr;
  gap: var(--space-lg);
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  align-items: flex-start;
}

.footer-brand-link {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--off-white);
}

.footer-brand-link:hover {
  text-decoration: none;
}

.footer-brand-glyph {
  width: 40px;
  height: 40px;
  background: var(--orange-main);
  color: var(--navy-deep);
  font-family: var(--font-head);
  font-size: 1.1rem;
  font-weight: 900;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  transform: rotate(-6deg);
}

.footer-brand-name {
  font-family: var(--font-head);
  font-size: 1.2rem;
  letter-spacing: 0.04em;
}

.footer-slogan {
  font-family: var(--font-head);
  font-size: 1rem;
  color: var(--orange-main);
  letter-spacing: 0.08em;
}

.footer-trust {
  font-size: 0.85rem;
  color: var(--blue-gray);
  max-width: 30ch;
  line-height: 1.6;
}

.footer-heading {
  font-family: var(--font-head);
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--off-white);
  margin-bottom: var(--space-sm);
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--orange-main);
  display: inline-block;
  font-weight: 700;
}

.footer-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-list a {
  color: var(--blue-gray);
  font-size: 0.93rem;
  transition: color 0.2s, padding-left 0.2s;
}

.footer-list a:hover,
.footer-list a:focus-visible {
  color: var(--orange-main);
  padding-left: 4px;
  text-decoration: none;
}

.footer-contact .footer-list li {
  color: var(--blue-gray);
  font-size: 0.9rem;
  line-height: 1.6;
}

.footer-copyright {
  margin-top: var(--space-sm);
  font-size: 0.8rem;
  color: var(--blue-gray);
  opacity: 0.85;
}

/* ===== 13 RESPONSIVE ===== */
@media (max-width: 1100px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 960px) {
  main#main-content {
    padding-top: calc(var(--header-offset) + 3.6rem);
  }

  .site-header {
    padding: var(--header-offset) 0.75rem 0;
  }

  .site-header-inner {
    padding: 0.45rem;
    border-radius: 40px;
  }

  .brand-glyph {
    width: 36px;
    height: 36px;
    font-size: 1rem;
    border-radius: 10px;
  }

  .brand-word {
    font-size: 1.05rem;
  }

  .float-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(340px, 86vw);
    height: 100vh;
    background: linear-gradient(160deg, var(--navy-mid) 0%, var(--navy-deep) 100%);
    border-left: 1px solid var(--line-blue);
    border-top: 2px solid var(--orange-main);
    box-shadow: -18px 0 54px rgba(10, 25, 47, 0.4);
    justify-content: flex-start;
    align-items: stretch;
    padding: 5rem 1.5rem 1.5rem;
    transform: translateX(100%);
    transition: transform 0.35s ease;
    z-index: 1200;
    overflow-y: auto;
  }

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

  .nav-list {
    flex-direction: column;
    gap: 0.25rem;
    width: 100%;
  }

  .nav-link {
    width: 100%;
    border-radius: var(--radius-sm);
    padding: 0.8rem 1rem;
    font-size: 1.05rem;
  }

  .nav-toggle {
    display: flex;
  }

  .split-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }

  .slant-band {
    clip-path: polygon(0 1.5%, 100% 0, 100% 98.5%, 0 100%);
    padding: var(--space-xl) 1rem;
  }

  .route-tree {
    grid-auto-flow: row;
    grid-auto-columns: 1fr;
  }

  .route-tree::before {
    display: none;
  }

  .tree-node {
    padding-top: 0;
  }

  .tree-node::before {
    display: none;
  }
}

/* ===== 14 REDUCED MOTION ===== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .scroll-progress {
    display: none;
  }
}