:root {
  --clr-primary: #0A192F;
  --clr-primary-deep: #1D3557;
  --clr-accent: #FF6B35;
  --clr-neutral-deep: #2B2D42;
  --clr-neutral-light: #F4F1DE;
  --clr-success: #2A9D8F;
  --clr-highlight: #E9C46A;
  --clr-white: #FFFFFF;
  --font-heading: "Space Grotesk", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", monospace;
  --header-height: 72px;
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 999px;
  --max-width: 1280px;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 40px;
  --space-5: 64px;
  --space-6: 96px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow: 0 12px 32px rgba(0, 0, 0, 0.2);
}

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

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

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--clr-primary);
  background: var(--clr-neutral-light);
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  margin: 0 0 0.5em;
  line-height: 1.2;
}

h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 500;
  letter-spacing: -0.01em;
}

h3 {
  font-size: clamp(1.25rem, 2vw, 1.75rem);
  font-weight: 500;
}

p {
  margin: 0 0 1em;
}

a {
  color: var(--clr-accent);
  text-decoration: none;
}

ul, ol {
  margin: 0;
  padding-left: 1.25rem;
}

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

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

::selection {
  background: var(--clr-accent);
  color: var(--clr-primary);
}

:focus-visible {
  outline: 2px solid var(--clr-accent);
  outline-offset: 2px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
  background: linear-gradient(to bottom, rgba(10, 25, 47, 0.92) 0%, rgba(10, 25, 47, 0.4) 60%, rgba(10, 25, 47, 0) 100%);
  transition: background var(--transition), box-shadow var(--transition);
}

.site-header.is-scrolled {
  background: rgba(10, 25, 47, 0.96);
  box-shadow: 0 8px 24px rgba(2, 12, 27, 0.3);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.skip-link {
  position: fixed;
  top: -100%;
  left: var(--space-2);
  z-index: 200;
  background: var(--clr-white);
  color: var(--clr-primary);
  padding: 10px 20px;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-weight: 500;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0;
}

.progress-bar {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 3px;
  background: transparent;
  pointer-events: none;
}

.progress-bar::after {
  content: "";
  display: block;
  height: 100%;
  width: var(--progress, 0%);
  background: linear-gradient(90deg, var(--clr-accent), var(--clr-highlight));
  transition: width 0.2s linear;
}

.header-inner {
  width: min(var(--max-width), 100% - 2 * var(--space-3));
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  height: 100%;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--clr-white);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.25rem;
  line-height: 1;
  text-decoration: none;
  transition: opacity var(--transition);
}

.brand:hover {
  opacity: 0.9;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  background: var(--clr-accent);
  color: var(--clr-primary);
  border-radius: 12px;
  font-size: 20px;
  font-weight: 700;
  transform: rotate(-8deg);
  box-shadow: 0 4px 12px rgba(255, 107, 53, 0.3);
  transition: transform var(--transition);
}

.brand:hover .brand-mark {
  transform: rotate(0deg) scale(1.05);
}

.brand-light .brand-mark {
  background: var(--clr-highlight);
  box-shadow: 0 4px 12px rgba(233, 196, 106, 0.3);
}

.brand-text {
  letter-spacing: 0.05em;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.nav-toggle {
  display: none;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-list li {
  margin: 0;
}

.nav-list a {
  display: inline-block;
  padding: 8px 14px;
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.9rem;
  font-weight: 500;
  border-radius: var(--radius-pill);
  text-decoration: none;
  transition: background var(--transition), color var(--transition);
}

.nav-list a:hover {
  background: rgba(255, 255, 255, 0.12);
  color: var(--clr-white);
}

.nav-list a[aria-current="page"] {
  background: var(--clr-accent);
  color: var(--clr-primary);
  font-weight: 700;
}

.header-cta {
  padding: 10px 24px;
  box-shadow: 0 4px 16px rgba(255, 107, 53, 0.35);
}

.header-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(255, 107, 53, 0.5);
}

/* ---------- Footer ---------- */
.site-footer {
  position: relative;
  background: var(--clr-primary);
  color: rgba(255, 255, 255, 0.85);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -60px;
  right: -60px;
  width: 320px;
  height: 320px;
  background: radial-gradient(circle, rgba(255, 107, 53, 0.25), transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.site-footer::after {
  content: "壹";
  position: absolute;
  bottom: -60px;
  left: -20px;
  font-family: var(--font-heading);
  font-size: 280px;
  line-height: 1;
  color: rgba(255, 255, 255, 0.03);
  pointer-events: none;
}

.footer-inner {
  position: relative;
  z-index: 1;
  width: min(var(--max-width), 100% - 2 * var(--space-3));
  margin-inline: auto;
  padding: var(--space-6) 0;
  display: grid;
  grid-template-columns: 2fr 1fr 1.2fr;
  gap: var(--space-5);
}

.footer-brand .brand {
  margin-bottom: var(--space-2);
}

.footer-about,
.footer-trust,
.footer-note,
.footer-list,
.footer-links ul {
  font-size: 0.9rem;
  line-height: 1.7;
}

.footer-about {
  max-width: 46ch;
  color: rgba(255, 255, 255, 0.8);
}

.footer-trust {
  margin-top: var(--space-2);
  color: var(--clr-highlight);
}

.footer-heading {
  margin-bottom: var(--space-2);
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--clr-highlight);
}

.footer-list,
.footer-links ul {
  list-style: none;
  padding: 0;
}

.footer-list li,
.footer-links li {
  margin-bottom: 8px;
}

.footer-list a,
.footer-links a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: color var(--transition);
}

.footer-list a:hover,
.footer-links a:hover {
  color: var(--clr-accent);
}

.footer-contact-line {
  display: block;
}

.footer-note {
  margin-top: var(--space-3);
  color: rgba(255, 255, 255, 0.7);
}

.footer-bottom {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: space-between;
  gap: var(--space-2);
  width: min(var(--max-width), 100% - 2 * var(--space-3));
  margin-inline: auto;
  padding: var(--space-2) 0 var(--space-3);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
}

.footer-bottom p {
  margin: 0;
}

/* ---------- Common components ---------- */
.container {
  width: min(var(--max-width), 100% - 2 * var(--space-3));
  margin-inline: auto;
}

.section {
  padding-block: var(--space-5);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: none;
  border-radius: var(--radius-pill);
  padding: 12px 24px;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition), color var(--transition), border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.btn-primary {
  background: var(--clr-accent);
  color: var(--clr-primary);
}

.btn-primary:hover {
  background: var(--clr-highlight);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--clr-accent);
  border: 2px solid var(--clr-accent);
}

.btn-outline:hover {
  background: var(--clr-accent);
  color: var(--clr-primary);
}

.grid {
  display: grid;
  gap: var(--space-3);
}

.grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card {
  background: var(--clr-neutral-light);
  border-radius: var(--radius-lg);
  padding: var(--space-3);
  box-shadow: var(--shadow);
}

.card--dark {
  background: var(--clr-neutral-deep);
  color: var(--clr-white);
}

.image-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--clr-primary-deep), var(--clr-primary));
}

.image-frame::before {
  content: "";
  display: block;
  aspect-ratio: 16 / 9;
}

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

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  padding: 0;
  font-size: 0.85rem;
  color: var(--clr-neutral-deep);
}

.breadcrumb a {
  color: var(--clr-accent);
  text-decoration: none;
}

.breadcrumb li + li::before {
  content: "/";
  margin-right: 6px;
  color: rgba(10, 25, 47, 0.4);
}

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .nav-toggle {
    display: flex;
    flex-direction: column;
    gap: 4px;
    width: 44px;
    height: 44px;
    padding: 0;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: border-color var(--transition);
  }

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

  .nav-toggle span {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--clr-white);
    border-radius: 2px;
    transition: transform 0.25s ease, opacity 0.25s ease, background 0.25s ease;
  }

  .nav-toggle[aria-expanded="true"] span:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

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

  .nav-toggle[aria-expanded="true"] span:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }

  .main-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    z-index: 99;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--space-3) var(--space-3) var(--space-4);
    background: rgba(10, 25, 47, 0.98);
    border-bottom: 2px solid var(--clr-accent);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-12px);
    transition: opacity var(--transition), transform var(--transition), visibility var(--transition);
  }

  .main-nav[data-open="true"] {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-1);
  }

  .nav-list a {
    display: block;
    padding: 12px 16px;
    font-size: 1rem;
  }

  .header-cta {
    padding: 8px 16px;
    font-size: 0.85rem;
  }

  .header-inner {
    gap: var(--space-2);
  }

  .brand-text {
    display: none;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: var(--space-4);
    padding: var(--space-5) 0;
  }

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

@media (max-width: 480px) {
  :root {
    --header-height: 64px;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
    font-size: 18px;
    border-radius: 10px;
  }

  .header-cta {
    padding: 8px 12px;
  }
}

/* ---------- 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;
  }

  .brand-mark,
  .header-cta,
  .btn {
    transform: none !important;
  }
}