/* ============================================================
   硅佳智能科技（天津）有限公司 官方主页
   设计基调：墨色/深蓝灰 × 暖白底 · 简约专业 · 点缀克制
   无外部字体与资源依赖，全部使用系统中文字体栈
   ============================================================ */

:root {
  --ink: #1d2b3a;         /* 墨色 / 深蓝灰（主色） */
  --ink-2: #46586a;       /* 正文次级色 */
  --ink-3: #5c6b7a;       /* 辅助说明色 */
  --paper: #faf9f4;       /* 暖白底 */
  --card: #ffffff;
  --line: #e7e4da;
  --line-strong: #d8d4c8;
  --accent: #2f5d8c;      /* 点缀：克制的钢蓝 */
  --accent-soft: #eef4f9;
  --header-h: 64px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", "Noto Sans CJK SC", "WenQuanYi Micro Hei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --shadow-card: 0 1px 2px rgba(29, 43, 58, 0.04), 0 10px 30px rgba(29, 43, 58, 0.05);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  -webkit-tap-highlight-color: transparent;
}

::selection { background: #dce8f2; }

.container {
  width: 100%;
  max-width: 1040px;
  margin-inline: auto;
  padding-inline: clamp(20px, 5vw, 32px);
}

.container-narrow { max-width: 880px; }

/* ---------- 无障碍辅助 ---------- */

.visually-hidden {
  position: absolute !important;
  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;
}

.skip-link {
  position: fixed;
  top: -60px;
  left: 16px;
  z-index: 200;
  padding: 10px 16px;
  background: var(--ink);
  color: #f6f5f0;
  border-radius: 8px;
  font-size: 14px;
  text-decoration: none;
  transition: top 0.15s ease;
}
.skip-link:focus { top: 12px; }

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 顶部导航 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 249, 244, 0.93);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 28px;
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-right: auto;
  color: var(--ink);
  text-decoration: none;
}
.brand-name {
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.site-nav ul {
  display: flex;
  align-items: center;
  gap: 30px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.site-nav a {
  color: var(--ink-2);
  text-decoration: none;
  font-size: 15px;
  transition: color 0.15s ease;
}
.site-nav a:hover { color: var(--ink); }

.header-cta {
  flex: none;
  font-size: 14px;
  font-weight: 500;
  color: #f6f5f0;
  background: var(--ink);
  padding: 8px 16px;
  border-radius: 999px;
  text-decoration: none;
  transition: background-color 0.15s ease;
}
.header-cta:hover { background: #2b3f52; }

.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  background: var(--card);
  color: var(--ink);
  cursor: pointer;
}

/* 桌面端隐藏「平台直达」菜单项（仅出现在移动端菜单中） */
@media (min-width: 761px) {
  .nav-external { display: none; }
}

/* ---------- 首屏 ---------- */

.hero {
  text-align: center;
  padding-block: clamp(76px, 12vw, 130px) clamp(64px, 9vw, 104px);
}

.hero-eyebrow {
  margin: 0 0 20px;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.34em;
  text-indent: 0.34em;
  color: var(--ink-3);
}

.hero-title {
  margin: 0 0 18px;
  font-size: clamp(1.65rem, 1.1rem + 2.8vw, 2.6rem);
  font-weight: 700;
  letter-spacing: 0.015em;
  line-height: 1.35;
}

.hero-lead {
  margin: 0 auto;
  max-width: 37em;
  font-size: clamp(1rem, 0.95rem + 0.4vw, 1.125rem);
  color: var(--ink-2);
}

.hero-actions {
  margin-top: 40px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
}

.hero-more { margin: 30px 0 0; font-size: 14px; }
.hero-more a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--ink-3);
  text-decoration: none;
  transition: color 0.15s ease;
}
.hero-more a:hover { color: var(--accent); }

/* ---------- 按钮 ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 22px;
  border: 1px solid transparent;
  border-radius: 8px;
  font: inherit;
  font-size: 15px;
  font-weight: 500;
  line-height: 1.6;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.btn svg { flex: none; }

.btn-primary { background: var(--ink); color: #f6f5f0; }
.btn-primary:hover { background: #2b3f52; }

.btn-outline { border-color: var(--ink); color: var(--ink); background: transparent; }
.btn-outline:hover { background: var(--card); }

/* ---------- 分区通用 ---------- */

.section { padding-block: clamp(68px, 9vw, 100px); }

.section-white {
  background: var(--card);
  border-block: 1px solid var(--line);
}

.section-head {
  margin: 0 0 clamp(36px, 5vw, 52px);
  max-width: 44em;
}

.title-bar {
  width: 26px;
  height: 3px;
  margin-bottom: 18px;
  border-radius: 2px;
  background: var(--accent);
}

h2 {
  margin: 0 0 10px;
  font-size: clamp(1.4rem, 1.2rem + 1vw, 1.7rem);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.section-lead {
  margin: 0;
  color: var(--ink-2);
  font-size: 15.5px;
}

.section-note {
  margin: 26px 0 0;
  font-size: 13px;
  color: var(--ink-3);
}

/* ---------- 关于我们 ---------- */

.about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(280px, 1fr);
  gap: clamp(32px, 5vw, 56px);
  align-items: start;
}

.about-text p {
  margin: 0 0 1.2em;
  color: var(--ink-2);
  font-size: 16px;
}
.about-text p:last-child { margin-bottom: 0; }

.about-facts {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 26px 26px 14px;
  box-shadow: var(--shadow-card);
}
.facts-title {
  margin: 0 0 6px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--ink-3);
}
.fact-row {
  display: grid;
  grid-template-columns: 5.5em 1fr;
  gap: 14px;
  padding: 12px 0;
  border-bottom: 1px dashed var(--line);
}
.fact-row:last-child { border-bottom: 0; }
.fact-row dt {
  margin: 0;
  color: var(--ink-3);
  font-size: 13px;
  letter-spacing: 0.05em;
}
.fact-row dd {
  margin: 0;
  font-size: 14.5px;
  font-weight: 500;
  color: var(--ink);
}

@media (max-width: 860px) {
  .about-grid { grid-template-columns: 1fr; }
}

/* ---------- 业务能力 ---------- */

.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 20px;
}

.service-card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 26px 24px 28px;
}

.service-icon {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  margin-bottom: 18px;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: var(--card);
  color: var(--accent);
}

.service-card h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
}
.service-card p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--ink-2);
}

/* ---------- 平台与服务 ---------- */

.platform-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.platform-card {
  display: flex;
  flex-direction: column;
  background: var(--card);
  border: 1px solid var(--line);
  border-top: 3px solid var(--accent);
  border-radius: 12px;
  padding: 30px 30px 32px;
  box-shadow: var(--shadow-card);
}

.platform-tag {
  margin: 0;
  align-self: flex-start;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid #d5e2ee;
  border-radius: 999px;
  padding: 3px 12px;
}

.platform-card h3 {
  margin: 16px 0 10px;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.platform-desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--ink-2);
}

.platform-url {
  margin: 18px 0 24px;
  align-self: flex-start;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--ink-2);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 6px;
}

.platform-card .btn {
  margin-top: auto;
  align-self: flex-start;
}

/* ---------- 联系我们 ---------- */

.contact-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(28px, 5vw, 48px);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: clamp(28px, 5vw, 44px);
}

.contact-label {
  margin: 0 0 18px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--ink-3);
}

.contact-org {
  margin: 0 0 12px;
  font-size: 18px;
  font-weight: 600;
}

.contact-person {
  margin: 0 0 14px;
  font-size: 15px;
  color: var(--ink-2);
}
.contact-person-label {
  display: inline-block;
  margin-right: 12px;
  color: var(--ink-3);
  font-size: 13.5px;
}

.contact-hint {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--ink-3);
}

.wechat-number {
  margin: 0 0 20px;
  font-size: clamp(1.45rem, 1.2rem + 1vw, 1.8rem);
  font-weight: 600;
  letter-spacing: 0.1em;
  font-variant-numeric: tabular-nums;
  user-select: all;
}

.copy-status {
  min-height: 22px;
  margin: 10px 0 0;
  font-size: 13.5px;
  color: var(--accent);
}

@media (max-width: 720px) {
  .contact-card { grid-template-columns: 1fr; }
  .contact-card .contact-col + .contact-col {
    border-top: 1px dashed var(--line-strong);
    padding-top: 26px;
  }
}

/* ---------- 页脚 ---------- */

.site-footer {
  background: var(--ink);
  color: #c3cbd4;
}

.footer-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 36px 48px;
  padding-block: 60px 48px;
}

.footer-brand {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: #f2f0ea;
}
.footer-desc {
  margin: 0;
  max-width: 24em;
  font-size: 13.5px;
  line-height: 1.9;
  color: #8f9aa6;
}

.footer-nav {
  display: flex;
  gap: clamp(32px, 6vw, 72px);
}

.footer-col-title {
  margin: 0 0 14px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: #8f9aa6;
}

.footer-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
}
.footer-col li + li { margin-top: 8px; }

.footer-col a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: #c3cbd4;
  text-decoration: none;
  transition: color 0.15s ease;
}
.footer-col a:hover { color: #f2f0ea; }
.footer-col a svg { width: 12px; height: 12px; opacity: 0.7; }

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 8px 24px;
  padding-block: 20px 26px;
  border-top: 1px solid rgba(242, 240, 234, 0.14);
  font-size: 12.5px;
  color: #8f9aa6;
}
.footer-bottom p { margin: 0; }

.footer-beian a {
  color: #c3cbd4;
  text-decoration: none;
}
.footer-beian a:hover {
  color: #f2f0ea;
  text-decoration: underline;
  text-underline-offset: 3px;
}
/* 公安备案启用后，与 ICP 备案之间自动出现分隔符 */
.footer-beian a + a::before {
  content: "·";
  margin: 0 0.55em;
  color: #8f9aa6;
}

/* ---------- 404 页 ---------- */

.error-page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding-block: 60px;
  text-align: center;
}
.error-inner .error-code {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 56px;
  font-weight: 700;
  line-height: 1;
  color: var(--ink-3);
}
.error-inner h1 {
  margin: 0 0 14px;
  font-size: 24px;
  font-weight: 600;
}
.error-inner p { color: var(--ink-2); }
.error-inner .btn { margin-top: 20px; }

/* ---------- 移动端 ---------- */

@media (max-width: 760px) {
  .header-inner { gap: 14px; }
  .header-cta { display: none; }

  .nav-toggle {
    display: inline-flex;
    flex: none;
  }
  .nav-toggle .icon-close { display: none; }
  .site-header.nav-open .nav-toggle .icon-close { display: block; }
  .site-header.nav-open .nav-toggle .icon-open { display: none; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 16px 32px rgba(29, 43, 58, 0.08);
  }
  .site-header.nav-open .site-nav { display: block; }

  .site-nav ul {
    display: block;
    gap: 0;
    padding: 6px 24px 18px;
  }
  .site-nav li {
    border-bottom: 1px solid var(--line);
  }
  .site-nav li:last-child { border-bottom: 0; }
  .site-nav a {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    padding: 14px 0;
    font-size: 16px;
    color: var(--ink);
  }
  .nav-external a { color: var(--accent); }
  .nav-external a svg { margin-left: auto; }

  .footer-grid { padding-block: 48px 40px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; gap: 6px; }
}

/* ---------- 动效偏好 ---------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
  }
}