:root {
  --color-graphite: #1c2228;
  --color-amber: #c88719;
  --color-teal: #2a9d8f;
  --color-paper: #f4f1ea;
  --color-paper-dim: #e8e4db;
  --color-ink: #14181c;
  --color-ink-muted: #9aa3ad;

  --font-sans: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --font-serif: "Songti SC", "Noto Serif SC", "STSong", "SimSun", serif;

  --space-xs: 0.5rem;
  --space-sm: 0.875rem;
  --space-md: 1.25rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4.5rem;

  --text-sm: clamp(0.8125rem, 2.4vw, 0.9375rem);
  --text-base: clamp(0.9375rem, 2.8vw, 1.0625rem);
  --text-lead: clamp(1.0625rem, 3.2vw, 1.25rem);
  --text-hero: clamp(1.625rem, 5vw, 2.375rem);
  --text-section: clamp(1.375rem, 4vw, 1.875rem);

  --rail-width: 0;
  --content-max: 72rem;
  --drawer-ease: 0.35s ease;
  --scroll-offset: 5rem;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--scroll-offset);
}

#shouping,
#guanyu,
#yewu,
#youshi {
  scroll-margin-top: var(--scroll-offset);
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--color-paper);
  background: var(--color-graphite);
  overflow-x: hidden;
}

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

a {
  color: var(--color-teal);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--color-amber);
}

.site-shell {
  display: flex;
  min-height: 100vh;
  width: 100%;
}

.brand-rail {
  display: none;
}

.main-wrap {
  flex: 1;
  min-width: 0;
  width: 100%;
}

.top-bar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: color-mix(in srgb, var(--color-graphite) 92%, transparent);
  border-bottom: 1px solid color-mix(in srgb, var(--color-teal) 35%, transparent);
  backdrop-filter: blur(6px);
}

.logo-mark {
  font-family: var(--font-serif);
  font-size: clamp(1.125rem, 4vw, 1.375rem);
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--color-paper);
  text-decoration: none;
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid color-mix(in srgb, var(--color-amber) 50%, transparent);
  background: transparent;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 22px;
  margin: 0 auto;
  background: var(--color-amber);
  transition: transform var(--drawer-ease);
}

.site-nav {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  flex-direction: column;
  background: var(--color-ink);
  border-bottom: 1px solid color-mix(in srgb, var(--color-teal) 40%, transparent);
  padding: var(--space-sm) var(--space-md) var(--space-md);
}

.site-nav.is-open {
  display: flex;
}

.site-nav a {
  padding: 0.65rem 0;
  color: var(--color-paper);
  text-decoration: none;
  font-size: var(--text-lead);
  border-bottom: 1px solid color-mix(in srgb, var(--color-paper) 8%, transparent);
}

.site-nav a:last-child {
  border-bottom: none;
}

.site-nav a:focus-visible {
  outline: 2px solid var(--color-amber);
  outline-offset: 2px;
}

/* 首屏 */
.hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  padding: var(--space-lg) var(--space-md) var(--space-xl);
  max-width: var(--content-max);
}

.hero-copy {
  max-width: 36rem;
}

.hero-headline {
  margin: 0 0 var(--space-sm);
  font-family: var(--font-serif);
  font-size: var(--text-hero);
  font-weight: 600;
  line-height: 1.25;
  color: var(--color-paper);
  scroll-margin-top: var(--scroll-offset);
}

.hero-hook {
  margin: 0 0 var(--space-md);
  font-size: var(--text-lead);
  color: var(--color-teal);
}

.hero-sub {
  margin: 0 0 var(--space-lg);
  color: var(--color-paper-dim);
  max-width: 32rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.btn-anchor {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.55rem 1.15rem;
  font-size: var(--text-base);
  font-family: inherit;
  text-decoration: none;
  border-radius: 2px;
  transition: background var(--drawer-ease), color var(--drawer-ease), border-color var(--drawer-ease);
}

.btn-primary {
  color: var(--color-graphite);
  background: var(--color-teal);
  border: 1px solid var(--color-teal);
}

.btn-primary:hover {
  background: var(--color-amber);
  border-color: var(--color-amber);
  color: var(--color-graphite);
}

.btn-ghost {
  color: var(--color-paper);
  background: transparent;
  border: 1px solid color-mix(in srgb, var(--color-paper) 35%, transparent);
}

.btn-ghost:hover {
  border-color: var(--color-amber);
  color: var(--color-amber);
}

.hero-visual {
  position: relative;
  min-height: 12rem;
  padding: var(--space-md);
  border: 1px dashed color-mix(in srgb, var(--color-teal) 45%, transparent);
  background: color-mix(in srgb, var(--color-ink) 55%, var(--color-graphite));
}

.hero-visual::before {
  content: "";
  position: absolute;
  bottom: var(--space-sm);
  left: var(--space-sm);
  right: var(--space-sm);
  height: 3px;
  background: color-mix(in srgb, var(--color-graphite) 70%, transparent);
  border-radius: 1px;
  overflow: hidden;
}

.hero-visual::after {
  content: "";
  position: absolute;
  bottom: var(--space-sm);
  left: var(--space-sm);
  height: 3px;
  width: 0;
  max-width: calc(100% - 2 * var(--space-sm));
  background: var(--color-teal);
  border-radius: 1px;
  animation: charge-fill 2.8s ease-in-out infinite;
}

@keyframes charge-fill {
  0% {
    width: 0;
  }
  55% {
    width: 72%;
  }
  100% {
    width: 72%;
  }
}

.hero-visual img {
  margin: 0 auto;
  width: min(100%, 18rem);
  opacity: 0.95;
}

.hero-visual .stroke-wrench path,
.hero-visual .stroke-wrench circle {
  stroke-dasharray: 480;
  stroke-dashoffset: 480;
  animation: draw-stroke 1.4s ease forwards;
}

.hero-visual .stroke-charger rect,
.hero-visual .stroke-charger path,
.hero-visual .stroke-charger circle {
  stroke-dasharray: 520;
  stroke-dashoffset: 520;
  animation: draw-stroke 1.6s ease 0.35s forwards;
}

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

.status-dot {
  animation: breathe 2.4s ease-in-out infinite;
}

@keyframes breathe {
  0%,
  100% {
    opacity: 0.45;
    transform: scale(0.92);
  }
  50% {
    opacity: 1;
    transform: scale(1);
  }
}

.section-head {
  margin: 0 0 var(--space-lg);
  font-family: var(--font-serif);
  font-size: var(--text-section);
  font-weight: 600;
  color: var(--color-paper);
  scroll-margin-top: var(--scroll-offset);
}

/* 关于我们 */
.about {
  position: relative;
  padding: var(--space-xl) var(--space-md);
  margin: var(--space-lg) 0;
  overflow: hidden;
}

.about::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    165deg,
    color-mix(in srgb, var(--color-teal) 22%, var(--color-graphite)) 0%,
    var(--color-graphite) 48%,
    color-mix(in srgb, var(--color-amber) 15%, var(--color-graphite)) 100%
  );
  transform: skewY(-2.5deg);
  transform-origin: top left;
  z-index: 0;
}

.about-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  max-width: var(--content-max);
  margin: 0 auto;
}

.keyword-rail {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  gap: var(--space-sm);
  list-style: none;
  margin: 0;
  padding: 0;
}

.keyword-rail li {
  writing-mode: horizontal-tb;
  padding: 0.35rem 0.75rem;
  font-family: var(--font-serif);
  font-size: var(--text-sm);
  letter-spacing: 0.2em;
  color: var(--color-amber);
  border: 1px solid color-mix(in srgb, var(--color-amber) 40%, transparent);
}

.about-text {
  margin: 0;
  padding: var(--space-md);
  background: color-mix(in srgb, var(--color-paper) 6%, transparent);
  border-left: 4px solid var(--color-teal);
  color: var(--color-paper-dim);
  font-size: var(--text-lead);
  line-height: 1.75;
  max-width: 42rem;
}

/* 核心业务 */
.services {
  padding: var(--space-xl) var(--space-md);
  max-width: var(--content-max);
  margin: 0 auto;
}

.service-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

.service-card {
  padding: var(--space-md);
  background: color-mix(in srgb, var(--color-ink) 80%, var(--color-graphite));
  border: 1px solid color-mix(in srgb, var(--color-teal) 30%, transparent);
  border-radius: 2px;
  opacity: 0;
  transform: translateX(-1.25rem);
  transition: opacity var(--drawer-ease), transform var(--drawer-ease), border-color var(--drawer-ease);
}

.service-card.is-visible {
  opacity: 1;
  transform: translateX(0);
}

.service-card:nth-child(even).is-visible {
  transform: translateX(0);
}

.service-card:hover {
  border-color: color-mix(in srgb, var(--color-amber) 55%, transparent);
}

.service-card h3 {
  margin: 0 0 var(--space-xs);
  font-size: var(--text-lead);
  font-weight: 600;
  color: var(--color-paper);
}

.service-hook {
  margin: 0 0 var(--space-sm);
  font-size: var(--text-sm);
  color: var(--color-teal);
}

.service-card p {
  margin: 0;
  color: var(--color-paper-dim);
  font-size: var(--text-base);
}

.service-card--large {
  min-height: auto;
}

/* 核心优势 */
.advantages {
  padding: var(--space-xl) var(--space-md) var(--space-2xl);
  max-width: var(--content-max);
  margin: 0 auto;
}

.advantage-wall {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

.advantage-brick {
  padding: var(--space-md);
  background: var(--color-paper);
  color: var(--color-ink);
  border-radius: 2px;
  border-top: 3px solid var(--color-teal);
  opacity: 0;
  transform: translateY(0.75rem);
  transition: opacity var(--drawer-ease), transform var(--drawer-ease);
}

.advantage-brick.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.advantage-brick h3 {
  margin: 0 0 var(--space-sm);
  font-size: var(--text-lead);
  font-weight: 600;
  color: var(--color-graphite);
}

.advantage-brick p {
  margin: 0;
  font-size: var(--text-base);
  color: color-mix(in srgb, var(--color-ink) 75%, var(--color-graphite));
}

.site-footer {
  width: 100%;
  max-width: 100%;
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  background: var(--color-ink);
  border-top: 1px solid color-mix(in srgb, var(--color-teal) 35%, transparent);
}

.site-footer p {
  margin: 0 0 var(--space-xs);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.site-footer a {
  color: var(--color-paper-dim);
  text-decoration: none;
}

.site-footer a:hover {
  color: var(--color-teal);
}

/* 手机横屏矮屏 */
@media (orientation: landscape) and (max-height: 500px) {
  .hero {
    padding-top: var(--space-sm);
    padding-bottom: var(--space-md);
    gap: var(--space-md);
  }

  .hero-visual {
    min-height: 8rem;
  }

  .hero-headline {
    font-size: clamp(1.25rem, 4vw, 1.5rem);
  }

  .hero-sub {
    margin-bottom: var(--space-sm);
    font-size: var(--text-sm);
  }

  .top-bar {
    position: relative;
  }

  html {
    scroll-padding-top: 0;
  }

  #shouping,
  #guanyu,
  #yewu,
  #youshi,
  .section-head,
  .hero-headline {
    scroll-margin-top: 0;
  }
}

/* 偏高竖屏 */
@media (max-aspect-ratio: 3/4) {
  .hero {
    padding-bottom: var(--space-2xl);
  }

  .hero-visual {
    min-height: 14rem;
  }
}

@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }

  .site-nav {
    display: flex;
    position: static;
    flex-direction: row;
    gap: var(--space-md);
    padding: 0;
    background: transparent;
    border: none;
  }

  .site-nav a {
    font-size: var(--text-base);
    padding: 0.35rem 0;
    border-bottom: 2px solid transparent;
  }

  .site-nav a:hover {
    border-bottom-color: var(--color-amber);
    color: var(--color-amber);
  }

  .hero {
    grid-template-columns: 1.28fr 0.72fr;
    align-items: center;
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
  }

  .hero-copy {
    max-width: none;
    min-width: 0;
  }

  .hero-headline {
    font-size: clamp(1.4375rem, 2.05vw, 1.8125rem);
    line-height: 1.2;
  }

  .hero-visual {
    justify-self: end;
    max-width: 100%;
  }

  .about-inner {
    grid-template-columns: auto 1fr;
    align-items: start;
  }

  .keyword-rail {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: var(--space-md);
    padding-top: var(--space-sm);
  }

  .keyword-rail li {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    letter-spacing: 0.35em;
    padding: var(--space-sm) 0.4rem;
  }

  .service-grid {
    grid-template-columns: 1fr 1fr;
    grid-template-areas:
      "a b"
      "d c";
    gap: var(--space-lg);
  }

  .service-card:nth-child(1) {
    grid-area: a;
  }

  .service-card:nth-child(2) {
    grid-area: b;
  }

  .service-card:nth-child(3) {
    grid-area: c;
  }

  .service-card:nth-child(4) {
    grid-area: d;
  }

  .service-card--large {
    min-height: 15rem;
    padding: var(--space-lg);
  }

  .service-card:not(.service-card--large) {
    align-self: end;
    max-width: 92%;
  }

  .service-card:nth-child(3) {
    justify-self: end;
  }

  .service-card:nth-child(4) {
    justify-self: start;
  }

  .advantage-wall {
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: auto auto;
    gap: var(--space-md) var(--space-sm);
    align-items: start;
    padding-top: 0.65rem;
  }

  .advantage-brick:nth-child(1) {
    grid-column: 1;
    grid-row: 1;
  }

  .advantage-brick:nth-child(2) {
    grid-column: 2;
    grid-row: 1;
    transform: translateY(-0.65rem);
  }

  .advantage-brick:nth-child(2).is-visible {
    transform: translateY(-0.65rem);
  }

  .advantage-brick:nth-child(3) {
    grid-column: 3;
    grid-row: 1;
  }

  .advantage-brick:nth-child(4) {
    grid-column: 1;
    grid-row: 2;
  }

  .advantage-brick:nth-child(5) {
    grid-column: 3;
    grid-row: 2;
    transform: translateY(0.5rem);
  }

  .advantage-brick:nth-child(5).is-visible {
    transform: translateY(0.5rem);
  }
}

@media (min-width: 768px) and (max-width: 1099px) {
  .hero-headline {
    white-space: nowrap;
  }
}

@media (min-width: 1100px) {
  :root {
    --rail-width: 4.5rem;
  }

  .brand-rail {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    width: var(--rail-width);
    flex-shrink: 0;
    padding: var(--space-lg) var(--space-xs);
    writing-mode: vertical-rl;
    text-orientation: mixed;
    font-family: var(--font-serif);
    font-size: 1rem;
    letter-spacing: 0.45em;
    color: var(--color-amber);
    background: var(--color-ink);
    border-right: 2px solid var(--color-teal);
  }

  .hero {
    padding-right: 12%;
  }

  .hero-visual {
    margin-right: 0;
  }
}

@media (min-width: 1440px) {
  .main-wrap {
    max-width: calc(var(--content-max) + var(--rail-width));
    margin: 0 auto;
  }

  .hero,
  .about-inner,
  .services,
  .advantages {
    margin-left: auto;
    margin-right: auto;
  }
}

@media (min-aspect-ratio: 2/1) {
  .hero {
    grid-template-columns: 1fr 0.75fr;
    max-width: 56rem;
  }

  .about-text {
    max-width: 36rem;
  }

  .service-grid {
    max-width: 52rem;
    margin: 0 auto;
  }
}