:root {
  color-scheme: dark;
  --color-primary: #22d3ee;
  --color-primary-hover: #67e8f9;
  --color-accent: #fb923c;
  --color-accent-hover: #fdba74;
  --color-background: #0a0e17;
  --color-surface: #111726;
  --color-surface-2: #161e30;
  --color-text: #e6ebf5;
  --color-muted-text: #93a0b8;
  --color-border: #232d42;
  --color-focus: #22d3ee;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-display: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "JetBrains Mono", "SF Mono", Consolas, Menlo,
    "Courier New", monospace;
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --space-unit: 0.25rem;
  --content-width: 72rem;
  --header-height: 4.25rem;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--color-background);
  color: var(--color-text);
  font-family: var(--font-body);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  margin: 0;
  min-height: 100dvh;
  line-height: 1.7;
}

button,
input,
select,
textarea {
  font: inherit;
}

h1,
h2,
h3,
.brand,
.btn {
  font-family: var(--font-display);
}

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

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

img,
svg {
  max-width: 100%;
}

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

.skip-link {
  left: 1rem;
  position: fixed;
  top: 1rem;
  transform: translateY(-250%);
  z-index: 200;
  background: var(--color-primary);
  color: #04222a;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.skip-link:focus {
  transform: translateY(0);
}

/* ---------- 布局容器 ---------- */
.container {
  width: 100%;
  max-width: var(--content-width);
  margin-inline: auto;
  padding-inline: 1.5rem;
}

main {
  min-height: 60dvh;
}

main:focus {
  outline: none;
}

.section {
  padding: 5.5rem 0;
}

.section--alt {
  background: var(--color-surface);
  border-block: 1px solid var(--color-border);
}

.section-head {
  max-width: 46rem;
  margin-bottom: 3rem;
}

.section-head--center {
  margin-inline: auto;
  text-align: center;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-primary);
  display: inline-block;
  margin-bottom: 0.875rem;
}

.section-title {
  font-size: clamp(1.6rem, 3.2vw, 2.25rem);
  line-height: 1.25;
  margin: 0 0 1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.section-desc {
  color: var(--color-muted-text);
  margin: 0;
  font-size: 1.025rem;
}

/* ---------- 顶部导航 ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--header-height);
  background: rgba(10, 14, 23, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-border);
}

.nav-bar {
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  color: var(--color-text);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: 0.02em;
}

.brand:hover {
  color: var(--color-text);
}

.brand-name small {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.625rem;
  font-weight: 400;
  letter-spacing: 0.14em;
  color: var(--color-muted-text);
  text-transform: uppercase;
}

.brand-mark {
  flex: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--color-muted-text);
  font-size: 0.9375rem;
  font-weight: 500;
  padding: 0.25rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.nav-links a:hover {
  color: var(--color-text);
}

.nav-links a[aria-current="page"] {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.nav-cta {
  margin-left: 0.5rem;
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  width: 2.6rem;
  height: 2.6rem;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

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

.nav-toggle-icon {
  display: block;
  position: relative;
  width: 1.15rem;
  height: 2px;
  background: currentColor;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 1.15rem;
  height: 2px;
  background: currentColor;
  transition: transform 0.2s ease;
}

.nav-toggle-icon::before {
  top: -0.45rem;
}

.nav-toggle-icon::after {
  top: 0.45rem;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.6rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease,
    transform 0.15s ease;
  text-decoration: none;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--color-primary);
  color: #04222a;
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  color: #04222a;
}

.btn-accent {
  background: var(--color-accent);
  color: #2a1503;
}

.btn-accent:hover {
  background: var(--color-accent-hover);
  color: #2a1503;
}

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

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

.btn-sm {
  padding: 0.55rem 1.1rem;
  font-size: 0.875rem;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: calc(var(--header-height) + 5.5rem) 0 6rem;
  overflow: hidden;
  border-bottom: 1px solid var(--color-border);
}

.hero-grid-bg {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(34, 211, 238, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34, 211, 238, 0.05) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 0%, black 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 0%, black 30%, transparent 75%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  max-width: 52rem;
}

.hero-title {
  font-size: clamp(2.1rem, 5.2vw, 3.6rem);
  line-height: 1.18;
  margin: 0 0 1.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.hero-title .hl {
  color: var(--color-primary);
}

.hero-sub {
  font-size: clamp(1.025rem, 1.6vw, 1.2rem);
  color: var(--color-muted-text);
  margin: 0 0 2.25rem;
  max-width: 42rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.hero-meta {
  margin-top: 2.75rem;
  display: flex;
  flex-wrap: wrap;
  gap: 2.5rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-muted-text);
  letter-spacing: 0.06em;
}

.hero-meta strong {
  display: block;
  font-family: var(--font-body);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.01em;
  margin-bottom: 0.15rem;
}

.hero-meta strong em {
  font-style: normal;
  color: var(--color-primary);
}

/* ---------- 卡片网格 ---------- */
.grid {
  display: grid;
  gap: 1.5rem;
}

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

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

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.card:hover {
  border-color: rgba(34, 211, 238, 0.45);
  transform: translateY(-3px);
}

.card-icon {
  width: 2.75rem;
  height: 2.75rem;
  border-radius: var(--radius-sm);
  background: rgba(34, 211, 238, 0.08);
  border: 1px solid rgba(34, 211, 238, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  margin-bottom: 1.25rem;
}

.card h3 {
  margin: 0 0 0.6rem;
  font-size: 1.125rem;
  font-weight: 650;
}

.card p {
  margin: 0;
  color: var(--color-muted-text);
  font-size: 0.95rem;
}

.card ul {
  margin: 0.875rem 0 0;
  padding-left: 1.1rem;
  color: var(--color-muted-text);
  font-size: 0.9rem;
}

.card ul li {
  margin-bottom: 0.35rem;
}

.card-link {
  display: inline-block;
  margin-top: 1.1rem;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
}

/* ---------- 案例 ---------- */
.case-card {
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow: hidden;
}

.case-thumb {
  height: 10rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: rgba(230, 235, 245, 0.75);
  border-bottom: 1px solid var(--color-border);
  position: relative;
  overflow: hidden;
}

.case-thumb::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
  background-size: 22px 22px;
}

.case-thumb span {
  position: relative;
  z-index: 1;
}

.case-body {
  padding: 1.5rem 1.75rem 1.75rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.case-tag {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 0.6rem;
}

.case-body h3 {
  margin: 0 0 0.5rem;
  font-size: 1.075rem;
}

.case-body p {
  margin: 0;
  color: var(--color-muted-text);
  font-size: 0.9rem;
  flex: 1;
}

.case-meta {
  margin-top: 1.1rem;
  padding-top: 0.9rem;
  border-top: 1px dashed var(--color-border);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-muted-text);
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
}

/* ---------- 技术栈 ---------- */
.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.tech-tag {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-text);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 0.45rem 1.05rem;
}

.tech-tag:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ---------- CTA 横幅 ---------- */
.cta-band {
  border: 1px solid rgba(34, 211, 238, 0.3);
  background:
    radial-gradient(ellipse 60% 120% at 50% 0%, rgba(34, 211, 238, 0.1), transparent 70%),
    var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 3.25rem 2rem;
  text-align: center;
}

.cta-band h2 {
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  margin: 0 0 0.875rem;
}

.cta-band p {
  color: var(--color-muted-text);
  margin: 0 auto 2rem;
  max-width: 36rem;
}

/* ---------- 流程时间线 ---------- */
.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  counter-reset: step;
}

.steps li {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.6rem 1.5rem 1.5rem;
  counter-increment: step;
}

.steps li::before {
  content: "0" counter(step);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--color-primary);
  letter-spacing: 0.1em;
  display: block;
  margin-bottom: 0.75rem;
}

.steps h3 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
}

.steps p {
  margin: 0;
  color: var(--color-muted-text);
  font-size: 0.9rem;
}

/* ---------- 关于页：时间线 ---------- */
.timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.75rem;
  position: relative;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 0.3rem;
  top: 0.4rem;
  bottom: 0.4rem;
  width: 2px;
  background: linear-gradient(var(--color-primary), rgba(34, 211, 238, 0.08));
}

.timeline li {
  position: relative;
  padding-bottom: 2.25rem;
}

.timeline li:last-child {
  padding-bottom: 0;
}

.timeline li::before {
  content: "";
  position: absolute;
  left: -1.75rem;
  top: 0.45rem;
  width: 0.85rem;
  height: 0.85rem;
  border-radius: 50%;
  background: var(--color-background);
  border: 2px solid var(--color-primary);
  box-shadow: 0 0 0 4px rgba(34, 211, 238, 0.12);
}

.timeline time {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-primary);
  letter-spacing: 0.08em;
}

.timeline h3 {
  margin: 0.3rem 0 0.35rem;
  font-size: 1.05rem;
}

.timeline p {
  margin: 0;
  color: var(--color-muted-text);
  font-size: 0.925rem;
}

/* ---------- 联系页 ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 2.5rem;
  align-items: start;
}

.contact-list {
  display: grid;
  gap: 1.25rem;
}

.contact-item {
  display: flex;
  gap: 1.1rem;
  align-items: flex-start;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.4rem 1.5rem;
}

.contact-item .card-icon {
  margin-bottom: 0;
  flex: none;
}

.contact-item h3 {
  margin: 0 0 0.25rem;
  font-size: 0.95rem;
  color: var(--color-muted-text);
  font-weight: 500;
  font-family: var(--font-mono);
  letter-spacing: 0.05em;
}

.contact-item p {
  margin: 0;
  font-size: 1.025rem;
  font-weight: 600;
  word-break: break-all;
}

.contact-item .placeholder {
  color: var(--color-accent);
  font-weight: 500;
  font-size: 0.95rem;
}

.form-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 2rem;
}

.form-card h3 {
  margin: 0 0 0.4rem;
  font-size: 1.2rem;
}

.form-card > p {
  margin: 0 0 1.5rem;
  color: var(--color-muted-text);
  font-size: 0.9rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-field {
  margin-bottom: 1.1rem;
}

.form-field label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 0.45rem;
}

.form-field label .req {
  color: var(--color-accent);
}

.form-field input,
.form-field select,
.form-field textarea {
  width: 100%;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  padding: 0.75rem 0.9rem;
  font-size: 0.95rem;
  transition: border-color 0.15s ease;
}

.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(34, 211, 238, 0.15);
}

.form-field textarea {
  resize: vertical;
  min-height: 7.5rem;
}

.form-note {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-muted-text);
  margin: 0.5rem 0 1.25rem;
}

.form-feedback {
  display: none;
  border: 1px solid rgba(34, 211, 238, 0.4);
  background: rgba(34, 211, 238, 0.08);
  color: var(--color-primary);
  border-radius: var(--radius-sm);
  padding: 0.9rem 1.1rem;
  font-size: 0.9rem;
  margin-top: 1rem;
}

.form-feedback[data-state="complete"] {
  display: block;
}

/* ---------- 占位提示条（交付后替换） ---------- */
.placeholder-banner {
  border: 1px dashed var(--color-accent);
  background: rgba(251, 146, 60, 0.07);
  color: var(--color-accent-hover);
  border-radius: var(--radius-sm);
  padding: 0.8rem 1.1rem;
  font-size: 0.85rem;
  margin: 1.5rem 0 0;
}

/* ---------- 页脚 ---------- */
.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  padding: 3.5rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 2.75rem;
}

.footer-brand p {
  color: var(--color-muted-text);
  font-size: 0.9rem;
  margin: 1rem 0 0;
  max-width: 20rem;
}

.footer-col h4 {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-muted-text);
  margin: 0 0 1rem;
  font-weight: 500;
}

.footer-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.65rem;
}

.footer-col a {
  color: var(--color-text);
  font-size: 0.9rem;
  opacity: 0.85;
}

.footer-col a:hover {
  color: var(--color-primary);
  opacity: 1;
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.75rem;
  font-size: 0.8125rem;
  color: var(--color-muted-text);
}

.footer-bottom a {
  color: var(--color-muted-text);
}

.footer-bottom a:hover {
  color: var(--color-primary);
}

/* ---------- 页面内 hero（子页面） ---------- */
.page-hero {
  padding: calc(var(--header-height) + 4rem) 0 3.5rem;
  border-bottom: 1px solid var(--color-border);
  background:
    radial-gradient(ellipse 70% 90% at 50% 0%, rgba(34, 211, 238, 0.07), transparent 70%);
}

.page-hero h1 {
  font-size: clamp(1.9rem, 4vw, 2.8rem);
  margin: 0 0 1rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.page-hero p {
  margin: 0;
  color: var(--color-muted-text);
  font-size: 1.05rem;
  max-width: 44rem;
}

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  .steps {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

@media (max-width: 860px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav-links {
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(10, 14, 23, 0.97);
    border-bottom: 1px solid var(--color-border);
    padding: 0.5rem 1.5rem 1.25rem;
    display: none;
  }

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

  .nav-links li {
    border-top: 1px solid var(--color-border);
  }

  .nav-links a {
    display: block;
    padding: 0.9rem 0;
    border-bottom: none;
  }

  .nav-links a[aria-current="page"] {
    border-bottom: none;
  }

  .nav-cta {
    margin: 0.75rem 0 0;
  }

  .grid-2,
  .grid-3,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .form-row {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .section {
    padding: 3.75rem 0;
  }

  .grid-4,
  .steps {
    grid-template-columns: 1fr;
  }

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

  .hero-meta {
    gap: 1.5rem;
  }

  .cta-band {
    padding: 2.25rem 1.25rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}