:root {
  --ink: #102c38;
  --ink-deep: #0a202b;
  --paper: #f4eddd;
  --paper-deep: #e8dcc6;
  --vermilion: #c54c32;
  --copper: #a78a58;
  --line: rgba(16, 44, 56, 0.24);
  --space-1: clamp(0.5rem, 0.35rem + 0.5vw, 0.9rem);
  --space-2: clamp(1rem, 0.7rem + 1vw, 1.8rem);
  --space-3: clamp(1.5rem, 0.9rem + 2vw, 3rem);
  --space-4: clamp(2.5rem, 1.3rem + 4vw, 6rem);
  --space-5: clamp(4rem, 2rem + 6vw, 9rem);
  --text-small: clamp(0.78rem, 0.72rem + 0.18vw, 0.92rem);
  --text-body: clamp(1rem, 0.9rem + 0.28vw, 1.16rem);
  --text-lead: clamp(1.1rem, 0.9rem + 0.7vw, 1.55rem);
  --text-heading: clamp(2rem, 1.3rem + 2.7vw, 4.5rem);
  --text-hero: clamp(3rem, 1.9rem + 5.2vw, 8.8rem);
  --serif: "Songti SC", "Noto Serif SC", "STSong", "SimSun", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 6rem;
  background: var(--paper);
}

body {
  margin: 0;
  overflow-x: hidden;
  color: var(--ink);
  background:
    linear-gradient(90deg, transparent 0 8%, rgba(167, 138, 88, 0.1) 8% calc(8% + 1px), transparent calc(8% + 1px) 92%, rgba(167, 138, 88, 0.1) 92% calc(92% + 1px), transparent calc(92% + 1px)),
    var(--paper);
  font-family: var(--sans);
  line-height: 1.8;
}

a {
  color: inherit;
}

.site-header {
  position: fixed;
  z-index: 20;
  top: var(--space-1);
  left: 50%;
  width: min(92%, 86rem);
  min-height: 3.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: 0.55rem 0.7rem 0.55rem var(--space-2);
  border: 1px solid rgba(244, 237, 221, 0.18);
  background: rgba(10, 32, 43, 0.93);
  color: var(--paper);
  transform: translateX(-50%);
  backdrop-filter: blur(14px);
}

.brand {
  max-width: 28rem;
  overflow: hidden;
  font-size: var(--text-small);
  letter-spacing: 0.08em;
  text-decoration: none;
  text-overflow: ellipsis;
  white-space: nowrap;
}

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

.site-nav a {
  position: relative;
  padding: 0.65rem 1rem;
  font-size: var(--text-small);
  text-decoration: none;
}

.site-nav a::after {
  position: absolute;
  right: 1rem;
  bottom: 0.35rem;
  left: 1rem;
  height: 1px;
  background: var(--vermilion);
  content: "";
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 220ms ease;
}

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

.nav-toggle {
  width: 2.75rem;
  height: 2.75rem;
  display: none;
  border: 0;
  background: transparent;
  cursor: pointer;
}

.nav-toggle span {
  width: 1.35rem;
  height: 1px;
  display: block;
  margin: 0.3rem auto;
  background: var(--paper);
  transition: transform 180ms ease, opacity 180ms ease;
}

.hero {
  min-height: max(46rem, 100svh);
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(17rem, 0.88fr);
  align-items: center;
  gap: var(--space-4);
  width: min(86%, 92rem);
  margin: 0 auto;
  padding: clamp(8rem, 13vh, 11rem) 0 var(--space-5);
}

.hero-copy {
  position: relative;
  z-index: 2;
}

.hero-point {
  width: fit-content;
  margin: 0 0 var(--space-3);
  padding-left: 3.5rem;
  color: var(--vermilion);
  font-size: var(--text-small);
  font-weight: 600;
  letter-spacing: 0.12em;
}

.hero-point::before {
  position: absolute;
  width: 2.7rem;
  height: 1px;
  margin: 0.9rem 0 0 -3.5rem;
  background: currentColor;
  content: "";
}

.hero h1 {
  max-width: 9em;
  margin: 0;
  font-family: var(--serif);
  font-size: var(--text-hero);
  font-weight: 600;
  letter-spacing: -0.055em;
  line-height: 1.08;
}

.hero-subtitle {
  max-width: 36rem;
  margin: var(--space-3) 0 0 min(9%, 5rem);
  padding: var(--space-2) 0 var(--space-2) var(--space-2);
  border-left: 1px solid var(--copper);
  font-size: var(--text-lead);
}

.route-origin {
  position: relative;
  min-width: 0;
}

.route-origin::before {
  position: absolute;
  inset: 7% 0 4% 7%;
  border: 1px solid var(--copper);
  content: "";
  transform: rotate(-3deg);
}

.route-origin svg {
  position: relative;
  width: 100%;
  height: auto;
  overflow: visible;
}

.route-grid {
  fill: none;
  stroke: var(--line);
  stroke-width: 1;
}

.route-line {
  fill: none;
  stroke: var(--vermilion);
  stroke-dasharray: 850;
  stroke-dashoffset: 850;
  stroke-linecap: round;
  stroke-width: 4;
}

.is-visible .route-line {
  animation: draw-route 1.8s 250ms cubic-bezier(0.2, 0.7, 0.2, 1) forwards;
}

.route-node {
  fill: var(--paper);
  stroke: var(--ink);
  stroke-width: 3;
  opacity: 0;
  transform-box: fill-box;
  transform-origin: center;
}

.is-visible .route-node {
  animation: light-node 420ms ease forwards;
}

.is-visible .route-node-one { animation-delay: 450ms; }
.is-visible .route-node-two { animation-delay: 850ms; }
.is-visible .route-node-three { animation-delay: 1.2s; }
.is-visible .route-node-four { animation-delay: 1.55s; }

.route-mark {
  fill: none;
  stroke: var(--copper);
  stroke-width: 2;
}

.section-heading,
.advantage-heading {
  width: min(86%, 92rem);
  margin: 0 auto;
}

.section-heading h2,
.advantage-heading h2,
.about-label h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: var(--text-heading);
  font-weight: 600;
  line-height: 1.15;
}

.services {
  position: relative;
  padding: var(--space-5) 0;
  background: var(--ink);
  color: var(--paper);
}

.section-heading {
  padding-bottom: var(--space-4);
  border-bottom: 1px solid rgba(244, 237, 221, 0.24);
}

.service-route {
  position: relative;
  width: min(86%, 92rem);
  margin: 0 auto;
  padding: var(--space-4) 0;
}

.service-line {
  position: absolute;
  top: 0;
  left: 50%;
  width: 6rem;
  height: 100%;
  overflow: visible;
  transform: translateX(-50%);
}

.service-line path {
  fill: none;
  stroke: var(--copper);
  stroke-dasharray: 3 8;
  stroke-linecap: round;
  stroke-width: 1.5;
  vector-effect: non-scaling-stroke;
}

.service-step {
  position: relative;
  width: calc(50% - clamp(2.5rem, 6vw, 7rem));
  min-height: 16rem;
  display: grid;
  align-content: center;
  margin-bottom: var(--space-4);
  padding: var(--space-3) 0;
  border-top: 1px solid rgba(244, 237, 221, 0.2);
}

.service-step-left {
  margin-right: auto;
}

.service-step-right {
  margin-left: auto;
}

.service-step i {
  position: absolute;
  top: -0.45rem;
  width: 0.9rem;
  height: 0.9rem;
  border: 2px solid var(--vermilion);
  border-radius: 50%;
  background: var(--ink);
  box-shadow: 0 0 0 0.5rem rgba(197, 76, 50, 0.12);
}

.service-step-left i { right: calc(clamp(2.5rem, 6vw, 7rem) * -1 - 0.45rem); }
.service-step-right i { left: calc(clamp(2.5rem, 6vw, 7rem) * -1 - 0.45rem); }

.service-title {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(9rem, 0.68fr);
  align-items: end;
  gap: var(--space-2);
}

.service-title h3 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(1.65rem, 1.2rem + 1.5vw, 3rem);
  font-weight: 600;
  line-height: 1.2;
}

.service-title p {
  margin: 0;
  color: var(--copper);
  font-size: var(--text-small);
  font-weight: 600;
  letter-spacing: 0.06em;
  line-height: 1.65;
}

.service-body {
  margin: var(--space-2) 0 0;
  color: rgba(244, 237, 221, 0.82);
  font-size: var(--text-body);
}

.about {
  position: relative;
  width: min(92%, 100rem);
  display: grid;
  grid-template-columns: minmax(13rem, 0.65fr) minmax(0, 1.35fr);
  margin: calc(var(--space-4) * -0.4) auto var(--space-5);
  border: 1px solid var(--copper);
  background: var(--paper-deep);
  box-shadow: 1.15rem 1.15rem 0 var(--vermilion);
  transform: rotate(-0.6deg);
}

.about::after {
  position: absolute;
  top: -1px;
  right: -1px;
  width: clamp(2.8rem, 6vw, 6rem);
  aspect-ratio: 1;
  background: linear-gradient(225deg, var(--paper) 49%, var(--copper) 50%, var(--paper-deep) 51%);
  content: "";
}

.about-label {
  display: flex;
  align-items: flex-end;
  padding: var(--space-4) var(--space-3);
  border-right: 1px solid var(--copper);
  background: var(--ink);
  color: var(--paper);
}

.about-copy {
  columns: 2;
  column-gap: var(--space-3);
  padding: var(--space-4);
  font-family: var(--serif);
  font-size: var(--text-body);
  line-height: 2;
}

.about-copy p {
  margin: 0 0 var(--space-2);
  break-inside: avoid;
}

.advantages {
  width: min(86%, 92rem);
  margin: 0 auto;
  padding: var(--space-5) 0;
}

.advantage-heading {
  width: auto;
  display: flex;
  justify-content: flex-end;
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--ink);
}

.annotation-list {
  display: grid;
  grid-template-columns: minmax(11rem, 0.42fr) minmax(0, 1fr);
}

.annotation-list article {
  display: grid;
  grid-column: 1 / -1;
  grid-template-columns: subgrid;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--line);
}

.annotation-list h3 {
  position: relative;
  margin: 0;
  padding-left: 1.3rem;
  font-family: var(--serif);
  font-size: clamp(1.3rem, 1.05rem + 0.8vw, 2rem);
  line-height: 1.4;
}

.annotation-list h3::before {
  position: absolute;
  top: 0.3em;
  bottom: 0.2em;
  left: 0;
  width: 3px;
  background: var(--vermilion);
  content: "";
}

.annotation-list p {
  max-width: 52rem;
  margin: 0;
  padding-left: var(--space-3);
  border-left: 1px dashed var(--copper);
  font-size: var(--text-body);
}

.site-footer {
  display: grid;
  place-items: center;
  gap: 0.3rem;
  padding: var(--space-4) 6vw;
  background: var(--ink-deep);
  color: rgba(244, 237, 221, 0.78);
  font-size: var(--text-small);
  text-align: center;
}

.site-footer p {
  margin: 0;
}

.site-footer a {
  padding: 0.35rem 0.6rem;
  text-underline-offset: 0.25em;
}

[data-reveal] {
  opacity: 0;
  transform: translateY(1.4rem);
  transition: opacity 700ms ease, transform 700ms cubic-bezier(0.2, 0.75, 0.25, 1);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* 页眉以自身宽度居中，入场位移不能覆盖水平校正。 */
.site-header[data-reveal] {
  transform: translate(-50%, 1.4rem);
}

.site-header[data-reveal].is-visible {
  transform: translate(-50%, 0);
}

.about[data-reveal] {
  transform: translateY(1.4rem) rotate(-0.6deg);
}

.about[data-reveal].is-visible {
  transform: translateY(0) rotate(-0.6deg);
}

@keyframes draw-route {
  to { stroke-dashoffset: 0; }
}

@keyframes light-node {
  0% { opacity: 0; transform: scale(0.4); }
  65% { opacity: 1; transform: scale(1.3); }
  100% { opacity: 1; transform: scale(1); }
}

@media (max-width: 767px) {
  body {
    background:
      linear-gradient(90deg, transparent 0 1rem, rgba(167, 138, 88, 0.1) 1rem calc(1rem + 1px), transparent calc(1rem + 1px)),
      var(--paper);
  }

  .site-header {
    top: 0.5rem;
    width: calc(100% - 1rem);
    padding-left: 1rem;
  }

  .brand {
    max-width: calc(100vw - 5.5rem);
  }

  .nav-toggle {
    display: block;
    flex: 0 0 auto;
  }

  .nav-toggle[aria-expanded="true"] span:first-child { transform: translateY(0.31rem) rotate(45deg); }
  .nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .nav-toggle[aria-expanded="true"] span:last-child { transform: translateY(-0.31rem) rotate(-45deg); }

  .site-nav {
    position: absolute;
    top: calc(100% + 0.4rem);
    right: 0;
    left: 0;
    display: grid;
    border: 1px solid rgba(244, 237, 221, 0.2);
    background: var(--ink-deep);
    opacity: 0;
    pointer-events: none;
    transform: translateY(-0.5rem);
    transition: opacity 180ms ease, transform 180ms ease;
  }

  .site-nav.is-open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
  }

  .site-nav a {
    min-height: 3rem;
    padding: 0.75rem 1.15rem;
    border-bottom: 1px solid rgba(244, 237, 221, 0.12);
  }

  .hero {
    min-height: 100svh;
    grid-template-columns: 1fr;
    align-content: center;
    gap: var(--space-3);
    width: calc(100% - 2.5rem);
    padding: 7rem 0 3.5rem;
  }

  .hero-subtitle {
    margin-left: 0;
  }

  .route-origin {
    width: min(82%, 25rem);
    margin-left: auto;
  }

  .section-heading,
  .service-route,
  .advantages {
    width: calc(100% - 2.5rem);
  }

  .service-line {
    left: 0.45rem;
    width: 3rem;
    transform: none;
  }

  .service-step,
  .service-step-left,
  .service-step-right {
    width: auto;
    min-height: 0;
    margin: 0 0 var(--space-4) 3.6rem;
  }

  .service-step-left i,
  .service-step-right i {
    right: auto;
    left: -3.58rem;
  }

  .service-title {
    grid-template-columns: 1fr;
    gap: 0.6rem;
  }

  .about {
    width: calc(100% - 2.5rem);
    grid-template-columns: 1fr;
    margin-top: 0;
    box-shadow: 0.55rem 0.55rem 0 var(--vermilion);
  }

  .about[data-reveal] {
    transform: translateY(1.4rem) rotate(0);
  }

  .about[data-reveal].is-visible {
    transform: translateY(0) rotate(0);
  }

  .about-label {
    min-height: 9rem;
    padding: var(--space-3);
    border-right: 0;
    border-bottom: 1px solid var(--copper);
  }

  .about-copy {
    columns: auto;
    padding: var(--space-3);
  }

  .advantage-heading {
    justify-content: flex-start;
  }

  .annotation-list,
  .annotation-list article {
    display: block;
  }

  .annotation-list article {
    padding: var(--space-3) 0;
  }

  .annotation-list p {
    margin-top: var(--space-2);
    padding-left: 1.3rem;
  }
}

@media (orientation: landscape) and (max-height: 500px) {
  .site-header {
    top: 0.35rem;
    min-height: 3rem;
  }

  .hero {
    min-height: 32rem;
    grid-template-columns: 1.15fr 0.85fr;
    gap: var(--space-2);
    padding-top: 5rem;
  }

  .hero h1 {
    font-size: clamp(2.7rem, 7vw, 4.5rem);
  }

  .hero-point {
    margin-bottom: 1rem;
  }

  .hero-subtitle {
    margin-top: 1rem;
    padding-block: 0.5rem;
    font-size: 1rem;
  }

  .route-origin {
    width: auto;
  }
}

@media (min-width: 768px) and (max-width: 1099px) {
  .site-header {
    width: 94%;
  }

  .site-nav a {
    padding-inline: 0.7rem;
  }

  .hero,
  .section-heading,
  .service-route,
  .advantages {
    width: 90%;
  }

  .hero {
    grid-template-columns: 1.05fr 0.95fr;
  }

  .service-title {
    grid-template-columns: 1fr;
  }

  .about {
    width: 94%;
  }

  .about-copy {
    columns: auto;
  }
}

@media (min-width: 1100px) {
  .service-step:nth-of-type(odd) {
    transform: translateY(1.5rem);
  }

  .annotation-list article:nth-child(even) h3 {
    padding-left: 3rem;
  }
}

@media (min-width: 1440px) {
  .site-header,
  .hero,
  .section-heading,
  .service-route,
  .advantages {
    max-width: 96rem;
  }

  .hero {
    grid-template-columns: 1.2fr 0.8fr;
  }
}

@media (min-aspect-ratio: 2/1) {
  .hero {
    min-height: 42rem;
    padding-top: 8rem;
  }

  .route-origin {
    max-width: 35rem;
    justify-self: end;
  }

  .service-step {
    min-height: 13rem;
  }
}

@media (max-aspect-ratio: 3/4) {
  .hero {
    min-height: min(100svh, 62rem);
    align-content: center;
  }

  .route-origin {
    max-height: 31vh;
  }

  .route-origin svg {
    max-height: 31vh;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }

  .route-line { stroke-dashoffset: 0; }
  .route-node { opacity: 1; }
}