:root {
  --lava: #FF4D1A;
  --ember: #D91E18;
  --signal: #00E5C7;
  --coal: #141414;
  --graphite: #2A2A2A;
  --smoke: #3A3A3A;
  --bone: #F2F0EC;
  --muted: #9C9C9C;
  --violet: #6E4BE0;
  --glow: rgba(255, 77, 26, 0.16);

  --rail-w: 112px;
  --content-max: 1180px;
  --gutter: clamp(18px, 4vw, 48px);

  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  margin: 0;
  padding-left: var(--rail-w);
  min-height: 100vh;
  background: var(--coal);
  color: var(--bone);
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.6;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; }
table { border-collapse: collapse; }
main { display: block; }

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

#main-content { scroll-margin-top: 20px; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ============ 通用容器与排版 ============ */
.wrap {
  width: 100%;
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}

.eyebrow::before {
  content: "";
  flex: 0 0 auto;
  width: 22px;
  height: 2px;
  background: var(--lava);
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 8px 22px;
  margin-bottom: clamp(18px, 2.6vw, 34px);
}

.section-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(52px, 9vw, 132px);
  font-weight: 200;
  line-height: 0.78;
  letter-spacing: -0.04em;
  color: var(--violet);
  opacity: 0.9;
}

.section-title {
  font-size: clamp(24px, 3.4vw, 40px);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.01em;
  transform: skewX(-4deg);
  transform-origin: left bottom;
}

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 0 22px;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--bone);
  background: #1E1E1E;
  border: 1px solid var(--smoke);
  border-radius: 14px 4px 14px 4px;
  cursor: pointer;
  transition: background-color 0.18s var(--ease), border-color 0.18s var(--ease),
              color 0.18s var(--ease), transform 0.18s var(--ease),
              box-shadow 0.18s var(--ease);
}

.btn:hover { border-color: var(--lava); transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn--lava {
  color: #FFFFFF;
  background: linear-gradient(96deg, var(--lava), var(--ember));
  border-color: transparent;
  box-shadow: 0 10px 30px -14px rgba(255, 77, 26, 0.9);
}

.btn--lava:hover { box-shadow: 0 14px 34px -12px rgba(255, 77, 26, 1); }

.btn--ghost {
  background: transparent;
  border-color: var(--smoke);
}

.btn--signal {
  color: #00201C;
  background: var(--signal);
  border-color: transparent;
  font-weight: 700;
}

/* ============ 标签 / 索引牌 ============ */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 13px;
  font-family: var(--font-sans);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--muted);
  background: #1B1B1B;
  border: 1px solid var(--smoke);
  border-radius: 999px 999px 999px 4px;
  cursor: pointer;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease),
              background-color 0.16s var(--ease), box-shadow 0.16s var(--ease);
}

.tag:hover { color: var(--bone); border-color: #565656; }

.tag[aria-pressed="true"],
.tag.is-active {
  color: #00201C;
  background: var(--signal);
  border-color: var(--signal);
  box-shadow: 0 0 0 4px rgba(0, 229, 199, 0.16);
}

/* ============ 面包屑 ============ */
.crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 18px 0;
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.crumb a { color: var(--muted); transition: color 0.18s var(--ease); }
.crumb a:hover { color: var(--bone); }
.crumb__sep { color: var(--smoke); }
.crumb [aria-current="page"] { color: var(--bone); }

/* ============ 横向切片 ============ */
.tape {
  position: relative;
  display: flex;
  gap: 12px;
  overflow-x: auto;
  padding-bottom: 10px;
  scroll-snap-type: x proximity;
  scrollbar-width: thin;
  scrollbar-color: var(--smoke) transparent;
  overscroll-behavior-x: contain;
}

.tape > * {
  flex: 0 0 auto;
  scroll-snap-align: start;
}

.tape::-webkit-scrollbar { height: 6px; }
.tape::-webkit-scrollbar-track { background: transparent; }
.tape::-webkit-scrollbar-thumb { background: var(--smoke); border-radius: 3px; }

/* ============ 图片容器基础规则 ============ */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  isolation: isolate;
  background: #1B1B1B;
  border-radius: 20px 6px 20px 6px;
}

.media::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background:
    radial-gradient(120% 95% at 6% 0%, rgba(255, 77, 26, 0.26), transparent 58%),
    linear-gradient(180deg, rgba(20, 20, 20, 0) 42%, rgba(12, 12, 12, 0.74));
}

.media::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  opacity: 0.14;
  mix-blend-mode: overlay;
  background-image: repeating-linear-gradient(
    115deg,
    rgba(255, 255, 255, 0.16) 0 1px,
    transparent 1px 4px
  );
}

.media > img,
.media__img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.9) contrast(1.07) brightness(0.95);
}

.media--ratio-21x9 { aspect-ratio: 21 / 9; }
.media--ratio-16x9 { aspect-ratio: 16 / 9; }
.media--ratio-4x3 { aspect-ratio: 4 / 3; }
.media--ratio-1x1 { aspect-ratio: 1 / 1; }
.media--ratio-3x4 { aspect-ratio: 3 / 4; }

.media__plate {
  position: absolute;
  right: 0;
  bottom: 0;
  z-index: 3;
  max-width: min(82%, 340px);
  padding: 10px 14px 11px;
  background: rgba(20, 20, 20, 0.88);
  border-left: 2px solid var(--lava);
  font-size: 12px;
  line-height: 1.5;
  color: var(--muted);
}

.media__plate-label {
  display: block;
  margin-bottom: 2px;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--lava);
}

/* ============ 页头 / 左侧轨道 ============ */
.site-header {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  width: var(--rail-w);
  z-index: 90;
  display: flex;
  flex-direction: column;
  background: linear-gradient(180deg, #191919 0%, #101010 100%);
  border-right: 1px solid var(--smoke);
}

.site-header::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 220px;
  pointer-events: none;
  background: radial-gradient(90% 100% at 50% 0%, rgba(255, 77, 26, 0.15), transparent 70%);
}

.site-header[data-scrolled] { border-right-color: rgba(255, 77, 26, 0.34); }

.skip-link {
  position: fixed;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 200;
  padding: 12px 22px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: #00201C;
  background: var(--signal);
  border-radius: 0 0 12px 4px;
  transition: top 0.18s var(--ease);
}

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

.scroll-progress {
  position: fixed;
  top: 0;
  left: var(--rail-w);
  right: 0;
  height: 3px;
  z-index: 95;
  pointer-events: none;
  background: rgba(58, 58, 58, 0.45);
}

.scroll-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--lava), var(--ember));
  transition: width 0.08s linear;
}

.rail {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100%;
  padding: 18px 0 22px;
}

.rail__top {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.rail-brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 9px;
  padding: 4px 8px 20px;
  transition: opacity 0.18s var(--ease);
}

.rail-brand:hover { opacity: 0.86; }

.rail-brand__glyph {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  font-size: 17px;
  font-weight: 900;
  line-height: 1;
  color: #FFFFFF;
  background: linear-gradient(145deg, var(--lava), var(--ember));
  border-radius: 12px 3px 12px 3px;
  box-shadow: 0 0 22px rgba(255, 77, 26, 0.34);
}

.rail-brand__name {
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0.06em;
  color: var(--bone);
  white-space: nowrap;
}

.rail-brand__sub {
  max-width: 84px;
  font-size: 10px;
  font-weight: 400;
  letter-spacing: 0.2em;
  line-height: 1.5;
  text-align: center;
  color: var(--muted);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 8px 13px;
  color: var(--bone);
  background: #1C1C1C;
  border: 1px solid var(--smoke);
  border-radius: 10px 3px 10px 3px;
  cursor: pointer;
  transition: border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}

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

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  gap: 3px;
  width: 16px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.22s var(--ease), opacity 0.18s var(--ease);
}

.nav-toggle__bars span:nth-child(2) { width: 68%; }

[data-open] .nav-toggle__bars span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
[data-open] .nav-toggle__bars span:nth-child(2) { opacity: 0; }
[data-open] .nav-toggle__bars span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

.nav-toggle__label {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
}

.rail-nav {
  width: 100%;
  border-top: 1px solid var(--smoke);
}

.rail-nav__list {
  display: flex;
  flex-direction: column;
}

.rail-nav__link {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  padding: 12px 6px;
  color: var(--muted);
  border-top: 1px solid rgba(58, 58, 58, 0.55);
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.rail-nav__item:first-child .rail-nav__link { border-top: 0; }

.rail-nav__item:last-child .rail-nav__link {
  border-bottom: 1px solid rgba(58, 58, 58, 0.55);
}

.rail-nav__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: transparent;
  transition: background-color 0.18s var(--ease), box-shadow 0.18s var(--ease);
}

.rail-nav__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--muted);
  opacity: 0.7;
  transition: color 0.18s var(--ease), opacity 0.18s var(--ease);
}

.rail-nav__label {
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.04em;
  line-height: 1.25;
  text-align: center;
  white-space: nowrap;
}

.rail-nav__link:hover {
  color: var(--bone);
  background: linear-gradient(90deg, rgba(255, 77, 26, 0.12), transparent 85%);
}

.rail-nav__link[aria-current="page"] {
  color: var(--bone);
  background: linear-gradient(90deg, rgba(255, 77, 26, 0.24), rgba(255, 77, 26, 0.02) 78%);
}

.rail-nav__link[aria-current="page"]::before {
  background: linear-gradient(180deg, var(--lava), var(--ember));
  box-shadow: 0 0 14px rgba(255, 77, 26, 0.8);
}

.rail-nav__link[aria-current="page"] .rail-nav__num {
  color: var(--lava);
  opacity: 1;
}

/* ============ 页脚 ============ */
.site-footer {
  position: relative;
  margin-top: clamp(40px, 6vw, 88px);
  background: #0D0D0D;
  border-top: 1px solid var(--smoke);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: min(440px, 62%);
  height: 2px;
  background: linear-gradient(90deg, var(--lava), var(--ember), transparent);
}

.footer-slice { padding: clamp(26px, 3.6vw, 46px) 0; }

.footer-slice--brand {
  background:
    radial-gradient(120% 200% at 0% 0%, rgba(255, 77, 26, 0.17), transparent 62%),
    #131313;
}

.footer-slice--nav {
  background: #171717;
  border-top: 1px solid var(--smoke);
}

.footer-slice--legal {
  background: #0D0D0D;
  border-top: 1px solid var(--smoke);
  padding-bottom: clamp(28px, 4vw, 42px);
}

.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px 32px;
}

.footer-brand__mark {
  display: inline-block;
  font-size: clamp(26px, 4.4vw, 46px);
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--bone);
  transform: skewX(-4deg);
  transform-origin: left bottom;
}

@supports ((-webkit-background-clip: text) or (background-clip: text)) {
  .footer-brand__mark {
    background: linear-gradient(96deg, var(--bone) 40%, var(--lava));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
  }
}

.footer-brand__claim {
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.footer-nav__list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
}

.footer-nav__link {
  position: relative;
  display: inline-block;
  padding-bottom: 3px;
  font-size: 14px;
  color: var(--muted);
  transition: color 0.18s var(--ease);
}

.footer-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 0;
  height: 1px;
  background: var(--lava);
  transition: right 0.22s var(--ease);
}

.footer-nav__link:hover { color: var(--bone); }
.footer-nav__link:hover::after { right: 0; }

.footer-legal {
  display: grid;
  grid-template-columns: minmax(180px, 1fr) minmax(300px, 1.5fr);
  gap: clamp(20px, 3vw, 48px);
  align-items: start;
}

.footer-legal__links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
}

.footer-legal__link {
  display: inline-block;
  padding-bottom: 2px;
  font-size: 13px;
  color: var(--muted);
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.footer-legal__link:hover {
  color: var(--bone);
  border-bottom-color: var(--lava);
}

.footer-contact {
  display: grid;
  gap: 7px;
  font-style: normal;
}

.footer-contact__row {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 10px;
  font-size: 12.5px;
  line-height: 1.55;
  color: var(--muted);
}

.footer-contact__key {
  padding-top: 2px;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--lava);
}

.footer-contact__val {
  color: #C9C6C1;
  word-break: break-word;
}

.footer-legal__copy {
  grid-column: 1 / -1;
  padding-top: 10px;
  border-top: 1px solid rgba(58, 58, 58, 0.6);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

/* ============ 平板 ============ */
@media (max-width: 1080px) {
  :root { --rail-w: 100px; }

  .rail-brand__sub { max-width: 76px; letter-spacing: 0.14em; }
  .rail-nav__label { font-size: 12px; }
}

/* ============ 移动端 ============ */
@media (max-width: 900px) {
  body {
    padding-left: 0;
    padding-top: 64px;
  }

  #main-content { scroll-margin-top: 76px; }

  .site-header {
    top: 0;
    bottom: auto;
    left: 0;
    right: 0;
    width: 100%;
    flex-direction: column;
    background: #141414;
    border-right: 0;
    border-bottom: 1px solid var(--smoke);
  }

  .site-header::after { height: 64px; }

  .site-header[data-scrolled] { border-right-color: transparent; border-bottom-color: rgba(255, 77, 26, 0.34); }

  .scroll-progress { left: 0; }

  .rail { padding: 0; height: auto; }

  .rail__top {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    height: 63px;
    padding: 0 16px;
  }

  .rail-brand {
    flex-direction: row;
    align-items: center;
    gap: 10px;
    padding: 0;
  }

  .rail-brand__glyph {
    width: 30px;
    height: 30px;
    font-size: 14px;
    border-radius: 9px 3px 9px 3px;
  }

  .rail-brand__name { font-size: 14px; letter-spacing: 0.04em; }
  .rail-brand__sub { display: none; }

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

  .rail-nav {
    max-height: 0;
    overflow: hidden;
    border-top: 1px solid transparent;
    transition: max-height 0.32s var(--ease), border-color 0.32s var(--ease);
  }

  .site-header[data-open] .rail-nav {
    max-height: min(72vh, 540px);
    overflow-y: auto;
    border-top-color: var(--smoke);
  }

  .rail-nav__list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    padding: 14px 16px 18px;
  }

  .rail-nav__link {
    flex-direction: row;
    align-items: baseline;
    justify-content: flex-start;
    gap: 9px;
    padding: 14px 12px;
    background: #1A1A1A;
    border: 1px solid var(--smoke);
    border-radius: 12px 4px 12px 4px;
    text-align: left;
  }

  .rail-nav__item:first-child .rail-nav__link,
  .rail-nav__item:last-child .rail-nav__link { border: 1px solid var(--smoke); }

  .rail-nav__link::before { display: none; }

  .rail-nav__link[aria-current="page"] {
    background: rgba(0, 229, 199, 0.09);
    border-color: var(--signal);
  }

  .rail-nav__link[aria-current="page"] .rail-nav__num { color: var(--signal); }

  .rail-nav__label { white-space: normal; text-align: left; }

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

@media (max-width: 560px) {
  .rail-nav__list { grid-template-columns: 1fr; }

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

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

/* ============ 动效降级 ============ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}