:root {
  --c-primary: #0B1D3A;
  --c-accent: #FF7A00;
  --c-secondary: #1F3A5F;
  --c-cyan: #3E9BCC;
  --c-bg: #F7F9FC;
  --c-text: #17202A;
  --c-muted: #7B8A99;
  --c-success: #27AE60;
  --c-warning: #F1C40F;
  --c-error: #E74C3C;
  --c-card: #EAECEE;
  --font-main: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-caption: "DIN Alternate", "Noto Sans SC", sans-serif;
  --container: 1200px;
  --radius-lg: 24px;
  --radius-md: 16px;
  --radius-pill: 999px;
  --shadow-soft: 0 12px 32px rgba(11, 29, 58, 0.12);
  --transition: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-main);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  line-height: 1.2;
  color: var(--c-text);
  font-weight: 700;
}

h1 {
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  font-weight: 900;
}

h2 {
  font-size: clamp(1.6rem, 3vw, 2.5rem);
}

h3 {
  font-size: 1.2rem;
}

img {
  max-width: 100%;
  display: block;
  height: auto;
}

a {
  color: var(--c-cyan);
  text-decoration: none;
}

button,
input,
select,
textarea {
  font: inherit;
}

::selection {
  background: var(--c-accent);
  color: #fff;
}

:focus-visible {
  outline: 3px solid var(--c-accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 9999;
  padding: 0.8rem 1.2rem;
  background: var(--c-accent);
  color: var(--c-primary);
  font-weight: 700;
  border-radius: 0 0 12px 0;
  transform: translateY(-150%);
  transition: transform var(--transition);
}

.skip-link:focus-visible {
  transform: translateY(0);
  outline: none;
}

.container {
  width: min(100% - 2.5rem, var(--container));
  margin-inline: auto;
}

.site-header {
  position: relative;
  background: var(--c-primary);
  color: #fff;
}

.site-header::before,
.site-header::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  width: 6px;
  z-index: 2;
  pointer-events: none;
  background: linear-gradient(180deg, var(--c-accent), var(--c-cyan));
  opacity: 0.85;
}

.site-header::before {
  left: 0;
}

.site-header::after {
  right: 0;
}

.notice-bar {
  background: var(--c-secondary);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.notice-content {
  max-width: var(--container);
  margin-inline: auto;
  padding: 0.3rem 1.5rem;
  font-size: 0.875rem;
  letter-spacing: 0.02em;
  color: rgba(255, 255, 255, 0.92);
}

.header-frame {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem;
  padding-block: 0.75rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  width: max-content;
  color: #fff;
  text-decoration: none;
}

.brand-mark {
  position: relative;
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--c-accent), var(--c-cyan));
  border: 2px solid rgba(255, 255, 255, 0.4);
  transform: rotate(45deg);
  flex: 0 0 auto;
}

.brand-mark::after {
  content: "";
  position: absolute;
  inset: 6px;
  border-radius: 50%;
  background: var(--c-primary);
  opacity: 0.8;
}

.brand-text {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: 0.04em;
}

.primary-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.15rem;
}

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  color: rgba(255, 255, 255, 0.88);
  font-weight: 600;
  padding: 0.55rem 1rem;
  border-radius: var(--radius-pill);
  transition: background 0.25s ease, color 0.25s ease;
}

.nav-link:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

.nav-link[aria-current="page"] {
  background: var(--c-accent);
  color: var(--c-primary);
  box-shadow: 0 8px 20px rgba(255, 122, 0, 0.25);
}

.header-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.5rem;
}

.drawer-toggle,
.member-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-pill);
  background: rgba(255, 255, 255, 0.06);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.14);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.25s ease, border-color 0.25s ease;
}

.drawer-toggle:hover,
.member-link:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.3);
}

.drawer-toggle[aria-expanded="true"] {
  background: var(--c-accent);
  border-color: var(--c-accent);
  color: var(--c-primary);
}

.icon {
  position: relative;
  display: inline-block;
  width: 16px;
  height: 16px;
  vertical-align: middle;
  flex: 0 0 auto;
}

.icon-grid::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 4px;
  height: 4px;
  transform: translate(-50%, -50%);
  background: currentColor;
  box-shadow: 6px 0 0 currentColor, 0 6px 0 currentColor, 6px 6px 0 currentColor;
  border-radius: 1px;
}

.icon-user::before {
  content: "";
  position: absolute;
  top: 2px;
  left: 50%;
  transform: translateX(-50%);
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: currentColor;
}

.icon-user::after {
  content: "";
  position: absolute;
  bottom: 1px;
  left: 50%;
  transform: translateX(-50%);
  width: 12px;
  height: 6px;
  border-radius: 6px 6px 4px 4px;
  background: currentColor;
  opacity: 0.8;
}

.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 0;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 12px;
  color: #fff;
  cursor: pointer;
}

.nav-toggle-lines {
  position: relative;
  width: 20px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: background 0.2s ease;
}

.nav-toggle-lines::before,
.nav-toggle-lines::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform 0.3s ease;
}

.nav-toggle-lines::before {
  top: -6px;
}

.nav-toggle-lines::after {
  top: 6px;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-lines {
  background: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-lines::before {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-lines::after {
  transform: translateY(-6px) rotate(-45deg);
}

.drawer {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  z-index: 60;
  background: var(--c-secondary);
  border-bottom: 4px solid var(--c-accent);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  transition: opacity var(--transition), transform var(--transition), visibility var(--transition);
}

.drawer[data-open] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.drawer-inner {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding-block: 0.75rem;
}

.drawer-inner a {
  color: #fff;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-pill);
  background: rgba(255, 255, 255, 0.06);
}

.drawer-inner a:hover,
.drawer-inner a:focus-visible {
  background: var(--c-accent);
  color: var(--c-primary);
}

.site-footer {
  position: relative;
  background: var(--c-primary);
  color: rgba(255, 255, 255, 0.85);
  padding-top: 4rem;
  padding-bottom: 2rem;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 6px;
  background: repeating-linear-gradient(
    90deg,
    var(--c-accent) 0 28px,
    transparent 28px 56px,
    var(--c-cyan) 56px 84px,
    transparent 84px 112px
  );
}

.footer-frame {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.6fr;
  gap: 2.5rem;
}

.footer-column {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-column a {
  color: rgba(255, 255, 255, 0.78);
  width: fit-content;
}

.footer-column a:hover {
  color: var(--c-accent);
}

.footer-kicker {
  margin: 0;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--c-cyan);
  padding-left: 0.5rem;
  border-left: 3px solid var(--c-accent);
}

.footer-brand {
  margin: 0;
  font-size: 2rem;
  font-weight: 800;
  color: #fff;
}

.footer-intro {
  margin: 0;
  color: rgba(255, 255, 255, 0.65);
  line-height: 1.7;
  max-width: 34ch;
}

.footer-title {
  margin: 0 0 0.5rem;
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: #fff;
}

.footer-column p {
  margin: 0;
  line-height: 1.7;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.15);
}

.copyright {
  margin: 0;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.6);
}

.english-guide-link {
  margin-left: auto;
  color: var(--c-accent);
  font-weight: 600;
  padding: 0.45rem 0.9rem;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-pill);
  transition: background 0.25s ease;
}

.english-guide-link:hover {
  background: rgba(255, 255, 255, 0.08);
}

.footer-icp {
  margin-top: 1.5rem;
  text-align: center;
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.5);
}

.back-top {
  position: fixed;
  right: 1.25rem;
  bottom: 1.25rem;
  z-index: 100;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.25);
  background: var(--c-accent);
  color: #fff;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity var(--transition), transform var(--transition), visibility var(--transition), box-shadow 0.25s ease;
}

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

.back-top:hover {
  box-shadow: 0 10px 24px rgba(255, 122, 0, 0.35);
  filter: brightness(1.08);
}

.back-top-line {
  display: block;
  width: 14px;
  height: 14px;
  margin: 6px auto 0;
  border-top: 2px solid currentColor;
  border-left: 2px solid currentColor;
  transform: rotate(45deg);
}

.grid {
  display: grid;
  gap: 1.5rem;
}

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

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

.card {
  background: #fff;
  border: 1px solid var(--c-card);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: 0 4px 16px rgba(11, 29, 58, 0.05);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-soft);
}

.card-head {
  margin: 0 0 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
}

.card-body {
  margin: 0;
  color: var(--c-muted);
  line-height: 1.7;
}

.media-frame {
  position: relative;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: linear-gradient(135deg, var(--c-secondary) 0%, var(--c-cyan) 70%);
  isolation: isolate;
}

.media-frame::before {
  content: "";
  position: absolute;
  inset: 12%;
  z-index: -1;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.35), transparent 60%);
  opacity: 0.8;
}

.media-frame::after {
  content: "";
  position: absolute;
  left: -10%;
  bottom: -20%;
  width: 45%;
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  border: 24px solid rgba(255, 255, 255, 0.1);
}

.media-frame img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  margin: 0 0 1.5rem;
  font-size: 0.9rem;
  color: var(--c-muted);
}

.breadcrumb a {
  color: var(--c-muted);
}

.breadcrumb a:hover {
  color: var(--c-accent);
}

.breadcrumb li::after {
  content: "/";
  margin-left: 0.5rem;
  color: rgba(0, 0, 0, 0.2);
}

.breadcrumb li:last-child::after {
  display: none;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  border-radius: var(--radius-pill);
  padding: 0.3rem 0.8rem;
  background: rgba(11, 29, 58, 0.06);
  color: var(--c-secondary);
  font-size: 0.8rem;
  font-weight: 600;
}

.pill--accent {
  background: var(--c-accent);
  color: #fff;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.6rem;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font-weight: 700;
  font-size: 1rem;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.25s ease, transform 0.25s ease, box-shadow 0.25s ease;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn--primary {
  background: var(--c-accent);
  color: #fff;
  box-shadow: 0 12px 24px rgba(255, 122, 0, 0.25);
}

.btn--primary:hover {
  background: #ff8c1a;
  box-shadow: 0 16px 32px rgba(255, 122, 0, 0.3);
}

.btn--dark {
  background: var(--c-primary);
  color: #fff;
}

.btn--dark:hover {
  background: var(--c-secondary);
}

.btn--outline {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.4);
  color: #fff;
}

.btn--outline:hover {
  background: rgba(255, 255, 255, 0.1);
}

.section-head {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 2rem;
}

.section-index {
  font-family: var(--font-caption);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--c-accent);
  padding-left: 0.75rem;
  border-left: 3px solid var(--c-accent);
}

.side-note {
  writing-mode: vertical-rl;
  transform: rotate(180deg);
  font-size: 0.75rem;
  letter-spacing: 0.3em;
  color: var(--c-muted);
  white-space: nowrap;
}

html.js .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity var(--transition), transform var(--transition);
}

html.js .reveal.is-inview {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 960px) {
  .header-frame {
    grid-template-columns: 1fr auto;
  }

  .header-actions {
    grid-column: 2;
  }

  .primary-nav {
    grid-column: 1 / -1;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
    padding-block: 0.5rem;
  }

  .primary-nav[data-open] {
    display: flex;
  }

  .primary-nav .nav-link {
    width: 100%;
    justify-content: flex-start;
    padding: 0.7rem 1rem;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .footer-frame {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

@media (max-width: 640px) {
  .drawer-toggle-text,
  .member-text {
    display: none;
  }

  .drawer-toggle,
  .member-link {
    padding: 0.55rem;
  }

  .brand-text {
    font-size: 1.1rem;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
  }

  .container {
    width: min(100% - 1.5rem, var(--container));
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .english-guide-link {
    margin-left: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }

  html.js .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .back-top {
    transition: none;
  }
}