/* ==========================================================
   安笙新媒体科技｜AnsungAI 企业官网 - 全局样式
   主题：现代 B 端科技商务风
   主色：#0f172a（深蓝） 辅助色：#2563eb（科技蓝）
   ========================================================== */

/* ---------- 设计变量 ---------- */
:root {
  --color-primary: #0f172a;      /* 主色：深蓝 */
  --color-accent: #2563eb;       /* 辅助色：科技蓝 */
  --color-accent-dark: #1d4ed8;  /* 科技蓝悬停态 */
  --color-bg: #f1f5f9;           /* 页面浅灰背景 */
  --color-bg-alt: #e2e8f0;       /* 浅灰背景加深 */
  --color-card: #ffffff;         /* 卡片白底 */
  --color-text: #0f172a;         /* 主文字色 */
  --color-text-secondary: #475569; /* 次级文字色 */
  --color-text-muted: #64748b;   /* 弱化文字色 */
  --color-border: #e2e8f0;       /* 边框色 */
  --radius: 16px;                /* 卡片圆角 */
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);          /* 柔和阴影 */
  --shadow-hover: 0 18px 40px rgba(37, 99, 235, 0.16);   /* 悬停阴影 */
  --header-height: 64px;
  --container-max: 1200px;
  --transition: 0.3s ease;
}

/* ---------- 基础重置 ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth; /* 配合 main.js 的锚点平滑滚动 */
}

body {
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  background: none;
  border: none;
}

/* 键盘可达性焦点样式 */
:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.55);
  outline-offset: 2px;
  border-radius: 4px;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

/* ==========================================================
   1. 导航栏（滚动吸顶 + 移动端汉堡菜单）
   ========================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
  background: transparent; /* 首屏透明，滚动后由 main.js 切换 .scrolled */
  color: #ffffff;
  transition: background var(--transition), box-shadow var(--transition);
}

/* 滚动后由 main.js 添加的吸顶深色背景 */
.site-header.scrolled {
  background: rgba(15, 23, 42, 0.96);
  box-shadow: 0 4px 20px rgba(15, 23, 42, 0.25);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  white-space: nowrap;
}

.logo-mark {
  width: 38px;
  height: 38px;
  flex-shrink: 0;
  border-radius: 9px;
}

.logo-text {
  display: inline-flex;
  align-items: baseline;
  gap: 4px;
}

.logo-cn {
  font-size: 17px;
  letter-spacing: 0.5px;
}

.logo-en {
  font-size: 13px;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.82);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 26px;
}

.nav-link {
  position: relative;
  display: inline-block;
  padding: 6px 2px;
  font-size: 15px;
  color: rgba(255, 255, 255, 0.85);
  transition: color var(--transition);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.nav-link:hover,
.nav-link.is-active {
  color: #ffffff;
}

.nav-link:hover::after,
.nav-link.is-active::after {
  transform: scaleX(1);
}

/* 汉堡菜单按钮：默认隐藏，移动端显示 */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  padding: 8px;
  border-radius: 8px;
}

.nav-toggle-bar {
  display: block;
  width: 100%;
  height: 2px;
  border-radius: 2px;
  background: #ffffff;
  transition: transform var(--transition), opacity var(--transition);
}

/* 展开状态的汉堡按钮（三线变 X） */
.nav-toggle.is-open .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.is-open .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle.is-open .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ==========================================================
   2. Hero 首屏 Banner
   背景图 images/banner.jpg（picsum id 0），见 index.html 注释
   ========================================================== */
.hero {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 100vh;
  padding: calc(var(--header-height) + 56px) 0 72px;
  color: #ffffff;
  background-color: var(--color-primary);
  background-image: url("images/banner.jpg");
  background-size: cover;
  background-position: center;
  overflow: hidden;
}

/* 深色遮罩保证白字可读 */
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    120deg,
    rgba(15, 23, 42, 0.88) 0%,
    rgba(15, 23, 42, 0.62) 55%,
    rgba(37, 99, 235, 0.35) 100%
  );
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 760px;
}

.hero-eyebrow {
  display: inline-block;
  margin-bottom: 18px;
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 2px;
  color: #bfdbfe;
  border: 1px solid rgba(191, 219, 254, 0.4);
  border-radius: 999px;
  background: rgba(37, 99, 235, 0.18);
}

.hero-title {
  font-size: clamp(32px, 5.4vw, 56px);
  line-height: 1.2;
  letter-spacing: 1px;
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: clamp(16px, 2vw, 20px);
  color: rgba(255, 255, 255, 0.88);
  margin-bottom: 36px;
}

.hero-btn {
  font-size: 16px;
  padding: 14px 34px;
}

/* 通用按钮 */
.btn {
  display: inline-block;
  border-radius: 999px;
  font-weight: 600;
  letter-spacing: 0.5px;
  transition: background var(--transition), transform var(--transition),
    box-shadow var(--transition);
}

.btn-primary {
  color: #ffffff;
  background: var(--color-accent);
  box-shadow: 0 10px 26px rgba(37, 99, 235, 0.42);
}

.btn-primary:hover {
  background: var(--color-accent-dark);
  transform: translateY(-2px);
  box-shadow: 0 14px 32px rgba(37, 99, 235, 0.5);
}

/* ==========================================================
   3. 通用板块布局
   ========================================================== */
.section {
  padding: 92px 0;
  scroll-margin-top: calc(var(--header-height) + 12px); /* 锚点定位避开吸顶导航 */
}

.section:nth-of-type(even) {
  background: var(--color-card);
}

.section-head {
  max-width: 860px;
  margin: 0 auto 52px;
  text-align: center;
}

.section-tag {
  display: inline-block;
  margin-bottom: 12px;
  padding: 5px 14px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--color-accent);
  border-radius: 999px;
  background: rgba(37, 99, 235, 0.1);
}

.section-title {
  font-size: clamp(26px, 3.4vw, 38px);
  line-height: 1.3;
  margin-bottom: 18px;
  color: var(--color-primary);
}

.section-intro {
  color: var(--color-text-secondary);
  font-size: 16px;
}

.section-footnote {
  margin-top: 40px;
  padding: 18px 26px;
  text-align: center;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-primary);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius-sm);
  background: rgba(37, 99, 235, 0.06);
}

/* ---------- 通用卡片 ---------- */
.card {
  background: var(--color-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.card-index {
  display: inline-block;
  margin-bottom: 12px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--color-accent);
}

.card-title {
  font-size: 19px;
  line-height: 1.45;
  margin-bottom: 12px;
  color: var(--color-primary);
}

.card-text {
  font-size: 15px;
  color: var(--color-text-secondary);
}

.card-text + .card-text {
  margin-top: 12px;
}

.section-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: var(--radius);
}

figure {
  margin: 0;
}

/* ==========================================================
   4. 技术挑战板块
   ========================================================== */
.challenge-wrap {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 40px;
  align-items: stretch;
}

.challenge-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
}

.challenge-card {
  padding: 28px 30px;
}

.challenge-figure {
  overflow: hidden;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ==========================================================
   5. 双层次技术架构板块
   ========================================================== */
.arch-wrap {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 44px;
  align-items: center;
}

.arch-figure {
  overflow: hidden;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.arch-stack {
  display: flex;
  flex-direction: column;
}

.arch-layer {
  padding: 30px 32px;
}

/* 上层中台：科技蓝描边 */
.arch-top {
  border: 2px solid var(--color-accent);
}

/* 底层底座：主深蓝色描边 */
.arch-bottom {
  border: 2px solid var(--color-primary);
}

.arch-layer-head {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 14px;
}

.arch-layer-head .card-title {
  margin-bottom: 0;
}

.arch-badge {
  flex-shrink: 0;
  padding: 4px 12px;
  font-size: 12px;
  font-weight: 700;
  color: #ffffff;
  border-radius: 999px;
  background: var(--color-accent);
}

.arch-badge-base {
  background: var(--color-primary);
}

.arch-connector {
  align-self: center;
  padding: 6px 0;
  font-size: 15px;
  color: var(--color-accent);
  letter-spacing: 2px;
}

.arch-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.arch-tags li {
  padding: 6px 13px;
  font-size: 13px;
  font-weight: 600;
  color: var(--color-accent);
  border-radius: 999px;
  background: rgba(37, 99, 235, 0.1);
}

/* ==========================================================
   6. 五大核心模块板块
   ========================================================== */
.module-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.module-card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.module-figure {
  overflow: hidden;
}

.module-figure img {
  width: 100%;
  height: 210px;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.module-card:hover .module-figure img {
  transform: scale(1.05);
}

.module-body {
  padding: 28px 30px 32px;
}

/* 第 5 张卡片在桌面端横跨整行，左右布局平衡 2 列网格 */
.module-card:last-child {
  grid-column: 1 / -1;
  flex-direction: row;
}

.module-card:last-child .module-figure {
  flex: 0 0 44%;
}

.module-card:last-child .module-figure img {
  height: 100%;
  min-height: 100%;
}

.module-card:last-child .module-body {
  flex: 1;
}

/* ==========================================================
   7. 五大核心应用场景板块
   ========================================================== */
.scenes-banner {
  margin-bottom: 44px;
  overflow: hidden;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.scenes-banner .section-img {
  height: 320px;
}

.scene-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

/* 第 1 张场景卡片作为重点卡片横跨整行 */
.scene-card:first-child {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: 240px 1fr;
  align-items: center;
  gap: 28px;
  padding: 34px 38px;
  background: linear-gradient(
    135deg,
    rgba(37, 99, 235, 0.1),
    var(--color-card) 60%
  );
}

.scene-card {
  padding: 28px 30px;
}

.scene-card .card-title {
  font-size: 18px;
}

/* ==========================================================
   8. 推理成本与性能优化板块
   ========================================================== */
.optimize-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
}

.optimize-card {
  padding: 32px 30px;
}

.optimize-card .card-index {
  font-size: 22px;
}

/* ==========================================================
   9. 团队与技术生态板块
   ========================================================== */
.ecology-wrap {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 44px;
  align-items: center;
}

.ecology-text .card-text + .card-text {
  margin-top: 16px;
}

.ecology-partners {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.partner-chip {
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-primary);
  border-radius: 999px;
  border: 1px solid rgba(37, 99, 235, 0.35);
  background: rgba(37, 99, 235, 0.08);
}

.ecology-figure {
  overflow: hidden;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ==========================================================
   10. 页脚
   ========================================================== */
.site-footer {
  padding: 34px 0;
  color: rgba(255, 255, 255, 0.82);
  background: var(--color-primary);
  text-align: center;
  font-size: 14px;
}

/* ==========================================================
   11. 响应式布局（平板 / 手机）
   ========================================================== */

/* ---------- 平板（≤1024px） ---------- */
@media (max-width: 1024px) {
  .nav-menu {
    gap: 18px;
  }

  .challenge-wrap,
  .arch-wrap,
  .ecology-wrap {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .challenge-figure,
  .arch-figure,
  .ecology-figure {
    max-height: 420px;
  }

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

  .module-card:last-child {
    grid-column: auto;
    flex-direction: column;
  }

  .module-card:last-child .module-figure {
    flex: none;
  }

  .module-card:last-child .module-figure img {
    height: 210px;
  }

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

/* ---------- 移动端（≤768px） ---------- */
@media (max-width: 768px) {
  .section {
    padding: 64px 0;
  }

  .section-head {
    margin-bottom: 38px;
  }

  /* 导航切换为汉堡菜单 */
  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0 24px;
    background: rgba(15, 23, 42, 0.98);
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, opacity 0.3s ease;
  }

  /* 展开状态由 main.js 切换 .is-open */
  .nav-menu.is-open {
    max-height: 460px;
    opacity: 1;
    padding-top: 8px;
    padding-bottom: 20px;
  }

  .nav-menu li {
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .nav-link {
    display: block;
    padding: 14px 4px;
    font-size: 16px;
  }

  .nav-link::after {
    display: none;
  }

  /* Hero */
  .hero {
    min-height: 92vh;
    padding: calc(var(--header-height) + 40px) 0 56px;
  }

  .hero-title {
    letter-spacing: 0.5px;
  }

  /* 挑战卡片 */
  .challenge-card {
    padding: 24px;
  }

  /* 架构层 */
  .arch-layer {
    padding: 26px 24px;
  }

  .arch-layer-head {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  /* 场景卡片 */
  .scene-grid {
    grid-template-columns: 1fr;
  }

  .scene-card:first-child {
    grid-column: auto;
    grid-template-columns: 1fr;
    gap: 12px;
    padding: 26px 24px;
  }

  .scenes-banner .section-img {
    height: 220px;
  }

}

/* ---------- 小屏手机（≤576px） ---------- */
@media (max-width: 576px) {
  .container {
    padding: 0 18px;
  }

  .logo-cn {
    font-size: 17px;
  }

  .logo-en {
    font-size: 13px;
  }

  .logo-mark {
    width: 28px;
    height: 28px;
    border-radius: 7px;
  }

  .hero-eyebrow {
    font-size: 12px;
  }

  .section-title {
    font-size: 24px;
  }

  .module-body {
    padding: 24px 22px 28px;
  }

  .optimize-card,
  .scene-card {
    padding: 24px 22px;
  }

  .section-footnote {
    padding: 16px 18px;
    font-size: 14px;
  }

}

/* ---------- 超小屏（≤360px） ---------- */
@media (max-width: 360px) {
  .nav {
    gap: 10px;
  }

  .logo {
    gap: 8px;
  }
}