:root {
  color-scheme: dark;
  --ink: #070809;
  --surface: #0d0f10;
  --paper: #f3f3f1;
  --soft: #d2d3d1;
  --muted: #8d908f;
  --line: rgba(243, 243, 241, 0.18);
  --line-strong: rgba(243, 243, 241, 0.38);
  --accent: #f04421;
  --header-height: 72px;
}

* { box-sizing: border-box; }

html {
  min-width: 320px;
  scroll-behavior: smooth;
  background: var(--ink);
  scrollbar-width: thin;
  scrollbar-color: var(--accent) var(--ink);
}

body {
  min-width: 320px;
  min-height: 100%;
  margin: 0;
  background: var(--ink);
  color: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

body::selection { background: var(--accent); color: var(--paper); }

a { color: inherit; }

img { max-width: 100%; }

.eco-header {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 20;
  display: flex;
  height: var(--header-height);
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(24px, 4vw, 68px);
  border-bottom: 1px solid rgba(243, 243, 241, 0.12);
  background: rgba(7, 8, 9, 0.96);
}

.eco-identity {
  display: flex;
  min-width: 0;
  align-items: center;
  gap: 22px;
  text-decoration: none;
}

.eco-identity img {
  display: block;
  width: clamp(156px, 12vw, 205px);
  height: auto;
}

.sub-brand {
  display: grid;
  gap: 4px;
  padding-left: 22px;
  border-left: 1px solid var(--line-strong);
  white-space: nowrap;
}

.sub-brand strong {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.16em;
}

.sub-brand small {
  color: var(--muted);
  font: 400 8px/1 Arial, sans-serif;
  letter-spacing: 0.16em;
}

.eco-nav {
  display: flex;
  align-items: center;
  gap: clamp(24px, 3vw, 48px);
}

.eco-nav a {
  position: relative;
  padding: 12px 0;
  color: #c8cac8;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-decoration: none;
  white-space: nowrap;
}

.eco-nav a::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 6px;
  left: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 240ms cubic-bezier(0.16, 1, 0.3, 1);
}

.eco-nav a:hover::after,
.eco-nav a:focus-visible::after,
.eco-nav a[aria-current="page"]::after {
  transform: scaleX(1);
  transform-origin: left;
}

.eco-nav .return-link { color: var(--paper); }

.section-shell {
  width: min(100% - clamp(40px, 8vw, 136px), 1480px);
  margin-inline: auto;
}

.overline {
  margin: 0 0 20px;
  color: var(--accent);
  font: 600 10px/1 Arial, sans-serif;
  letter-spacing: 0.2em;
}

.text-link,
.solid-link {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: 18px;
  padding: 0 2px;
  color: var(--paper);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-decoration: none;
  white-space: nowrap;
  transition: color 220ms ease, transform 220ms cubic-bezier(0.16, 1, 0.3, 1);
}

.text-link {
  border-bottom: 1px solid var(--accent);
}

.solid-link {
  min-width: 168px;
  padding-inline: 22px;
  border: 1px solid var(--line-strong);
}

.text-link:hover,
.solid-link:hover { color: var(--accent); transform: translateX(4px); }

.text-link:active,
.solid-link:active { transform: translateX(4px) translateY(1px); }

a:focus-visible {
  outline: 1px solid var(--accent);
  outline-offset: 5px;
}

.eco-footer {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  padding: 42px clamp(24px, 4vw, 68px) max(34px, env(safe-area-inset-bottom));
  border-top: 1px solid var(--line);
  color: var(--muted);
}

.eco-footer p { margin: 0; font-size: 11px; letter-spacing: 0.08em; }
.eco-footer a { color: var(--soft); text-decoration: none; }

@media (max-width: 820px) {
  :root { --header-height: 64px; }

  .eco-header {
    padding-right: max(18px, env(safe-area-inset-right));
    padding-left: max(18px, env(safe-area-inset-left));
  }

  .eco-identity { gap: 12px; }
  .eco-identity img { width: 138px; }
  .sub-brand { padding-left: 12px; }
  .sub-brand small { display: none; }

  .eco-nav { gap: 18px; }
  .eco-nav .optional { display: none; }

  .section-shell { width: min(100% - 40px, 1480px); }

  .eco-footer {
    display: grid;
    padding-inline: 20px;
  }
}

@media (max-width: 480px) {
  .eco-identity img { width: 126px; }
  .sub-brand { display: none; }
  .eco-nav a { font-size: 10px; }
}

@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;
  }
}