/* ==========================================================================
   贵州快雪科技有限公司 —— 官网样式
   单文件样式表：CSS 变量 + Grid/Flex + 三断点响应式
   断点：<768 手机 / 768–1023 平板 / ≥1024 桌面
   ========================================================================== */

/* ------------------------------------------------------------ 1. 变量 */
:root {
  --deep: #0B2A5B;
  --blue: #1E6FFF;
  --blue-dark: #1558D6;
  --cyan: #38BDF8;
  --white: #FFFFFF;
  --gray: #F5F7FA;
  --ink: #1F2937;
  --muted: #6B7280;
  --line: #E3E9F2;
  --soft: #EAF2FF;

  --radius-card: 12px;
  --radius-btn: 8px;
  --shadow: 0 4px 20px rgba(11, 42, 91, .08);
  --shadow-lg: 0 12px 36px rgba(11, 42, 91, .14);

  --max: 1200px;
  --gap: 24px;
  --header-h: 72px;

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --t: .28s cubic-bezier(.4, 0, .2, 1);
}

/* ------------------------------------------------------------ 2. 基础 */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body.nav-open { overflow: hidden; }

h1, h2, h3, h4 {
  margin: 0 0 16px;
  line-height: 1.3;
  color: var(--deep);
  font-weight: 700;
}

h1 { font-size: 30px; }
h2 { font-size: 24px; }
h3 { font-size: 18px; }

p { margin: 0 0 16px; }
p:last-child { margin-bottom: 0; }

a { color: var(--blue); text-decoration: none; transition: color var(--t); }
a:hover { color: var(--blue-dark); }

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

ul, ol { margin: 0; padding: 0; list-style: none; }

button { font: inherit; cursor: pointer; }

:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ------------------------------------------------------------ 3. 布局 */
.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 20px;
}

.section { padding: 56px 0; }
.section--alt { background: var(--gray); }

.section-head {
  max-width: 720px;
  margin: 0 auto 36px;
  text-align: center;
}

.section-title { margin-bottom: 0; position: relative; padding-bottom: 16px; }

.section-title::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 48px;
  height: 3px;
  margin-left: -24px;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--blue), var(--cyan));
}

.section-sub { margin-top: 16px; color: var(--muted); }

/* 左对齐的区块标题（联系信息 / 在线留言 等） */
.section-title--left { text-align: left; margin: 0 0 24px; padding-bottom: 14px; }
.section-title--left::after { left: 0; margin-left: 0; width: 44px; }

.grid { display: grid; gap: var(--gap); }

/* --------------------------------------------------------- 4. 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border: 1px solid transparent;
  border-radius: var(--radius-btn);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  text-align: center;
  cursor: pointer;
  transition: background var(--t), color var(--t), border-color var(--t),
              box-shadow var(--t), transform var(--t);
}

.btn-primary {
  background: var(--blue);
  color: var(--white);
  box-shadow: 0 6px 16px rgba(30, 111, 255, .28);
}
.btn-primary:hover {
  background: var(--blue-dark);
  color: var(--white);
  transform: translateY(-2px);
  box-shadow: 0 10px 22px rgba(30, 111, 255, .34);
}

.btn-ghost {
  background: var(--white);
  color: var(--deep);
  border-color: var(--line);
}
.btn-ghost:hover {
  color: var(--blue);
  border-color: var(--blue);
  transform: translateY(-2px);
}

.btn:disabled { opacity: .6; cursor: not-allowed; transform: none; }

/* --------------------------------------------------------- 5. 页头导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .96);
  border-bottom: 1px solid var(--line);
  transition: box-shadow var(--t);
}
.site-header.is-scrolled { box-shadow: 0 4px 18px rgba(11, 42, 91, .07); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: var(--header-h);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0; /* 英文公司名较长，窄屏时允许收缩省略，避免撑破页头 */
  color: var(--deep);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .2px;
}
.brand:hover { color: var(--deep); }
.brand-logo { width: 36px; height: 36px; flex: none; }
.brand-name {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  padding: 0 10px;
  background: none;
  border: 1px solid var(--line);
  border-radius: var(--radius-btn);
  flex: none;
}
.nav-toggle span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--deep);
  transition: transform var(--t), opacity var(--t);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.site-nav {
  position: fixed;
  top: var(--header-h);
  left: 0;
  right: 0;
  max-height: calc(100vh - var(--header-h));
  overflow-y: auto;
  padding: 8px 20px 24px;
  background: var(--white);
  border-top: 1px solid var(--line);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: opacity var(--t), transform var(--t), visibility var(--t);
}
.site-nav.is-open { opacity: 1; visibility: visible; transform: none; }

.nav-list { display: block; }
.nav-link {
  display: block;
  padding: 12px 4px;
  color: var(--ink);
  font-size: 16px;
  font-weight: 500;
  border-bottom: 1px solid var(--line);
}
.nav-link:hover { color: var(--blue); }
.nav-link.is-active { color: var(--blue); font-weight: 600; }

.lang-switch {
  display: inline-flex;
  margin-top: 18px;
  padding: 3px;
  background: var(--gray);
  border: 1px solid var(--line);
  border-radius: var(--radius-btn);
}
.lang-btn {
  min-width: 46px;
  padding: 6px 10px;
  background: none;
  border: 0;
  border-radius: 6px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 600;
  transition: background var(--t), color var(--t);
}
.lang-btn.is-active { background: var(--blue); color: var(--white); }

/* --------------------------------------------------------- 6. 首屏 */
.hero {
  position: relative;
  padding: 48px 0 56px;
  background:
    radial-gradient(900px 420px at 12% -10%, rgba(56, 189, 248, .16), transparent 70%),
    radial-gradient(760px 420px at 92% 8%, rgba(30, 111, 255, .12), transparent 72%),
    var(--white);
  overflow: hidden;
}
.hero-inner { display: grid; gap: 32px; align-items: center; }

.hero-title { font-size: 30px; margin-bottom: 18px; letter-spacing: -.2px; }
.hero-sub { color: var(--muted); font-size: 16px; margin-bottom: 28px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }

.hero-art {
  width: 100%;
  max-width: 560px;
  margin: 0 auto;
  animation: hero-float 7s ease-in-out infinite;
}
@keyframes hero-float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-12px); }
}

/* --------------------------------------------------------- 7. 卡片 */
.card {
  display: flex;
  flex-direction: column;
  padding: 28px 24px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow);
  transition: transform var(--t), box-shadow var(--t), border-color var(--t);
}
.card:hover {
  transform: translateY(-6px);
  border-color: rgba(30, 111, 255, .35);
  box-shadow: var(--shadow-lg);
}
.card-icon { width: 56px; height: 56px; margin-bottom: 20px; }
.card-title { margin-bottom: 12px; font-size: 19px; }
.card-text { color: var(--muted); font-size: 15px; margin-bottom: 20px; }
.card-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: auto;
  font-size: 15px;
  font-weight: 600;
  color: var(--blue);
}
.card-link img { width: 18px; height: 18px; transition: transform var(--t); }
.card-link:hover img { transform: translateX(4px); }

/* 优势 / 价值观 图标卡 */
.mini-card {
  padding: 24px 22px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow);
  transition: transform var(--t), box-shadow var(--t), border-color var(--t);
}
.mini-card:hover {
  transform: translateY(-4px);
  border-color: rgba(30, 111, 255, .35);
  box-shadow: var(--shadow-lg);
}
.mini-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  margin-bottom: 16px;
  border-radius: 12px;
  background: var(--soft);
}
.mini-icon img { width: 26px; height: 26px; }
.mini-title { margin-bottom: 8px; font-size: 17px; }
.mini-text { color: var(--muted); font-size: 15px; }

/* --------------------------------------------------------- 8. 服务流程 */
.steps { counter-reset: step; display: grid; gap: 18px; }
.step {
  position: relative;
  padding: 22px 20px 22px 68px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow);
}
.step::before {
  counter-increment: step;
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 18px;
  top: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  color: var(--white);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .3px;
}
.step-title { margin: 0; font-size: 16px; padding-top: 6px; }

/* --------------------------------------------------------- 9. CTA 条 */
.cta-band {
  padding: 44px 28px;
  border-radius: 16px;
  background: linear-gradient(120deg, var(--deep) 0%, #14418C 55%, var(--blue) 100%);
  color: var(--white);
  text-align: center;
}
.cta-title { color: var(--white); font-size: 24px; margin-bottom: 22px; }
.cta-band .btn-primary {
  background: var(--white);
  color: var(--deep);
  box-shadow: 0 8px 20px rgba(0, 0, 0, .18);
}
.cta-band .btn-primary:hover { background: var(--soft); color: var(--blue); }

/* --------------------------------------------------------- 10. 页面标题 */
/* 404 页在用 */
.page-title { margin-bottom: 12px; font-size: 28px; }

/* --------------------------------------------------------- 11. 业务与服务 */
.svc { padding: 48px 0; border-bottom: 1px solid var(--line); }
.svc:last-of-type { border-bottom: 0; }
.svc-inner { display: grid; gap: 28px; align-items: center; }
.svc-art { width: 100%; max-width: 420px; margin: 0 auto; }
.svc-body .section-title { text-align: left; padding-bottom: 14px; }
.svc-body .section-title::after { left: 0; margin-left: 0; }
.svc-desc { margin: 20px 0 24px; color: var(--muted); }

.svc-list { display: grid; gap: 12px; }
.svc-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 16px;
  background: var(--gray);
  border-radius: var(--radius-card);
  font-size: 15px;
  transition: background var(--t), transform var(--t);
}
.svc-item:hover { background: var(--soft); transform: translateX(4px); }
.svc-item img { width: 22px; height: 22px; flex: none; margin-top: 3px; }

/* --------------------------------------------------------- 12. 解决方案 */
.solution-card { padding: 0; overflow: hidden; }
.solution-art {
  width: 100%;
  padding: 18px;
  background: var(--gray);
  border-bottom: 1px solid var(--line);
}
.solution-body { padding: 24px; }
.solution-body .card-title { font-size: 18px; }
.solution-body .card-text { margin-bottom: 0; }

/* --------------------------------------------------------- 13. 联系我们 */
.contact-grid { display: grid; gap: 28px; align-items: start; }

.info-list { display: grid; gap: 16px; }
.info-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 18px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow);
}
.info-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 42px;
  height: 42px;
  border-radius: 11px;
  background: var(--soft);
}
.info-icon img { width: 22px; height: 22px; }
.info-label {
  display: block;
  margin-bottom: 2px;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: .2px;
}
.info-value { font-size: 15px; font-weight: 600; color: var(--deep); word-break: break-word; }
.info-value a { font-weight: 600; }

.form-card {
  padding: 28px 24px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow);
}

.contact-form { display: grid; gap: 18px; }
.form-field { display: grid; gap: 7px; }
.form-label { font-size: 14px; font-weight: 600; color: var(--deep); }
.form-label .req { color: #E5484D; margin-left: 2px; }

.form-input {
  width: 100%;
  padding: 12px 14px;
  font: inherit;
  font-size: 15px;
  color: var(--ink);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-btn);
  transition: border-color var(--t), box-shadow var(--t);
}
.form-input::placeholder { color: #9AA5B4; }
.form-input:focus {
  outline: none;
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(30, 111, 255, .15);
}
.form-input.is-invalid { border-color: #E5484D; box-shadow: 0 0 0 3px rgba(229, 72, 77, .12); }
textarea.form-input { min-height: 130px; resize: vertical; }

.form-error {
  display: none;
  color: #E5484D;
  font-size: 13px;
}
.form-error.is-shown { display: block; }

.form-note {
  display: none;
  align-items: flex-start;
  gap: 8px;
  padding: 12px 14px;
  border-radius: var(--radius-btn);
  font-size: 14px;
}
.form-note.is-shown { display: flex; }
.form-note.is-ok { background: #E8F7EE; color: #1B7A44; border: 1px solid #B7E4C7; }
.form-note.is-err { background: #FDECEC; color: #B4232A; border: 1px solid #F6C6C8; }

/* --------------------------------------------- 13.1 关于我们补充区块 */
.prose { max-width: 860px; margin: 0 auto; }
.prose p { color: var(--muted); font-size: 16px; margin-bottom: 18px; }
.prose p:last-child { margin-bottom: 0; }

.vision-card {
  display: flex;
  align-items: flex-start;
  gap: 18px;
  max-width: 860px;
  margin: 0 auto;
  padding: 28px 26px;
  background: var(--white);
  border: 1px solid var(--line);
  border-left: 4px solid var(--blue);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow);
}
.vision-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--soft);
}
.vision-icon img { width: 26px; height: 26px; }
.vision-text { margin: 0; color: var(--deep); font-size: 18px; font-weight: 600; line-height: 1.6; }

.contact-grid .info-list { grid-template-columns: 1fr; }

/* --------------------------------------------------------- 14. 页脚 */
.site-footer {
  margin-top: 0;
  padding: 44px 0 24px;
  background: var(--deep);
  color: #C7D4E8;
  font-size: 14px;
}
.footer-grid { display: grid; gap: 28px; }
.footer-brand { display: grid; gap: 12px; }
/* logo 与公司名同一行 */
.footer-brand-line { display: flex; align-items: center; gap: 12px; }
.footer-brand .brand-logo { width: 40px; height: 40px; flex: none; }
.footer-company { color: var(--white); font-size: 16px; font-weight: 600; margin: 0; }
.footer-addr { margin: 0; color: #9FB2CE; line-height: 1.7; }

.footer-title {
  margin: 0 0 14px;
  color: var(--white);
  font-size: 15px;
  font-weight: 600;
}
.footer-list { display: grid; gap: 10px; }
.footer-list a { color: #C7D4E8; }
.footer-list a:hover { color: var(--cyan); }

.footer-contact li { display: flex; align-items: flex-start; gap: 10px; }
.footer-contact img {
  width: 18px;
  height: 18px;
  flex: none;
  margin-top: 3px;
  filter: brightness(0) invert(1);
  opacity: .75;
}
.footer-contact a { color: #C7D4E8; }
.footer-contact a:hover { color: var(--cyan); }

.footer-bottom {
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, .14);
  display: grid;
  gap: 8px;
  text-align: center;
  font-size: 13px;
  color: #9FB2CE;
}
.footer-bottom a { color: #9FB2CE; }
.footer-bottom a:hover { color: var(--cyan); }
.footer-bottom p { margin: 0; }

/* --------------------------------------------------------- 15. 404 */
.err-page {
  display: grid;
  place-items: center;
  min-height: 52vh;
  padding: 64px 0;
  text-align: center;
}
.err-code {
  font-size: 64px;
  font-weight: 800;
  line-height: 1;
  background: linear-gradient(135deg, var(--deep), var(--blue) 55%, var(--cyan));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 16px;
}
.err-text { color: var(--muted); margin-bottom: 26px; }

/* --------------------------------------------------------- 16. 滚动动效 */
.js .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity .6s ease, transform .6s ease;
  will-change: opacity, transform;
}
.js .reveal.is-visible { opacity: 1; transform: none; }

/* ==========================================================================
   17. 平板 768–1023
   ========================================================================== */
@media (min-width: 768px) {
  h1 { font-size: 36px; }
  h2 { font-size: 28px; }

  .container { padding: 0 32px; }
  .section { padding: 72px 0; }
  .section-head { margin-bottom: 44px; }

  .hero { padding: 64px 0 72px; }
  .hero-title { font-size: 36px; }
  .hero-sub { font-size: 17px; }

  .grid-2, .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }

  .steps { grid-template-columns: repeat(3, 1fr); gap: 20px; }

  .page-title { font-size: 32px; }

  .svc { padding: 60px 0; }

  .contact-grid { grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr); }
  .info-list { grid-template-columns: repeat(2, 1fr); }

  .footer-grid { grid-template-columns: 1.3fr 1.2fr; gap: 32px; }
  .footer-bottom { grid-template-columns: 1fr; }

  .cta-band { padding: 56px 40px; }
  .cta-title { font-size: 28px; }
}

/* ==========================================================================
   18. 桌面 ≥1024
   ========================================================================== */
@media (min-width: 1024px) {
  h1 { font-size: 42px; }
  h2 { font-size: 32px; }

  .section { padding: 88px 0; }

  /* 导航展开成横排 */
  .nav-toggle { display: none; }

  .site-nav {
    position: static;
    display: flex;
    align-items: center;
    gap: 28px;
    max-height: none;
    overflow: visible;
    padding: 0;
    background: none;
    border: 0;
    box-shadow: none;
    opacity: 1;
    visibility: visible;
    transform: none;
  }
  .nav-list { display: flex; align-items: center; gap: 4px; }
  .nav-link {
    position: relative;
    padding: 8px 12px;
    font-size: 15px;
    border-bottom: 0;
    border-radius: 6px;
  }
  .nav-link::after {
    content: "";
    position: absolute;
    left: 12px;
    right: 12px;
    bottom: 2px;
    height: 2px;
    border-radius: 2px;
    background: var(--blue);
    transform: scaleX(0);
    transition: transform var(--t);
  }
  .nav-link:hover::after, .nav-link.is-active::after { transform: scaleX(1); }
  .lang-switch { margin-top: 0; }

  .hero { padding: 84px 0 92px; }
  .hero-inner { grid-template-columns: 1.05fr .95fr; gap: 56px; }
  .hero-title { font-size: 44px; }
  .hero-art { max-width: 620px; }

  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }

  .steps { grid-template-columns: repeat(6, 1fr); gap: 16px; }
  .step { padding: 68px 16px 20px; text-align: center; }
  .step::before { left: 50%; top: 20px; margin-left: -17px; }
  .step::after {
    content: "";
    position: absolute;
    top: 36px;
    left: calc(50% + 24px);
    right: calc(-50% + 24px);
    height: 2px;
    background: linear-gradient(90deg, var(--blue), rgba(56, 189, 248, .35));
  }
  .step:last-child::after { display: none; }
  .step-title { padding-top: 0; }

  .svc-inner { grid-template-columns: .85fr 1.15fr; gap: 56px; }
  .svc-inner--reverse .svc-art { order: 2; }
  .svc-list { grid-template-columns: repeat(2, 1fr); }

  .cta-band { padding: 64px 56px; }

  .grid-2.solutions-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { gap: 40px; }
  .form-card { padding: 32px; }
}

/* ==========================================================================
   19. 降级动效（尊重系统「减少动态效果」设置）
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  .js .reveal { opacity: 1; transform: none; }
  .hero-art { animation: none; }
  .card:hover, .mini-card:hover, .btn:hover, .svc-item:hover { transform: none; }
}