/* ============================================================
   XControl 设计系统 — 深色科技风官网
   色板 / 字体 / 组件类,Task 2-5 全部复用
   ============================================================ */

/* ---------- 1. 设计令牌 ---------- */
:root {
  /* 色板(Global Constraints 固定) */
  --bg: #0f1419;
  --surface: #161d26;
  --raised: #1c2530;
  --accent: #1d9bf0;
  --text: #e7e9ea;
  --dim: #8899a6;

  /* 语义扩展色(由主色板派生,不引入新色相) */
  --accent-soft: rgba(29, 155, 240, 0.14);
  --line: rgba(231, 233, 234, 0.09);
  --line-strong: rgba(231, 233, 234, 0.18);
  --glass: rgba(22, 29, 38, 0.62);
  --ok: #3ba55d;
  --warn: #f0a93b;

  /* 字体:Noto Sans SC 优先,Inter fallback */
  --font: "Noto Sans SC", "Inter", -apple-system, BlinkMacSystemFont,
    "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;

  /* 玻璃拟态 */
  --blur: 14px;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --shadow-lift: 0 18px 44px rgba(0, 0, 0, 0.5);

  /* 渐变光效 */
  --grad-accent: linear-gradient(135deg, #1d9bf0 0%, #7c5cff 100%);
  --grad-glow: radial-gradient(
    60% 50% at 50% 0%,
    rgba(29, 155, 240, 0.16) 0%,
    rgba(29, 155, 240, 0) 100%
  );

  /* 动效 */
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur: 0.32s;

  /* 布局 */
  --container: 1120px;
  --gap: 24px;
}

/* ---------- 2. 基础 ---------- */
html {
  background: var(--bg);
}

body {
  font-family: var(--font);
  background:
    var(--grad-glow),
    var(--bg);
  color: var(--text);
  overflow-x: hidden;
}

::selection {
  background: var(--accent-soft);
  color: var(--accent);
}

::-webkit-scrollbar {
  width: 10px;
}
::-webkit-scrollbar-track {
  background: var(--bg);
}
::-webkit-scrollbar-thumb {
  background: var(--raised);
  border-radius: 5px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--line-strong);
}

/* ---------- 3. 布局容器 ---------- */
.container {
  width: min(var(--container), 100% - 48px);
  margin-inline: auto;
}

.section {
  padding: 88px 0;
  position: relative;
}

.section__head {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 48px;
}

.section__kicker {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid rgba(29, 155, 240, 0.28);
  padding: 5px 14px;
  border-radius: 999px;
  margin-bottom: 18px;
}

.section__title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  letter-spacing: -0.02em;
}

.section__sub {
  color: var(--dim);
  font-size: 1.05rem;
  margin-top: 14px;
}

/* ---------- 4. 导航 ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  background: rgba(15, 20, 25, 0.72);
  border-bottom: 1px solid var(--line);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav__brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.01em;
}

.nav__logo {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--grad-accent);
  display: grid;
  place-items: center;
  font-size: 0.95rem;
  color: #fff;
  box-shadow: 0 0 18px rgba(29, 155, 240, 0.45);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 26px;
  font-size: 0.92rem;
}

.nav__links a {
  color: var(--dim);
  transition: color var(--dur) var(--ease);
}

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

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  white-space: nowrap;
  transition:
    transform var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease),
    background var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.btn:hover {
  transform: translateY(-2px);
}

.btn--primary {
  background: var(--grad-accent);
  color: #fff;
  box-shadow: 0 8px 24px rgba(29, 155, 240, 0.35);
}

.btn--primary:hover {
  box-shadow: 0 12px 32px rgba(29, 155, 240, 0.5);
}

.btn--ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--line-strong);
}

.btn--ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
}

.btn--lg {
  padding: 14px 32px;
  font-size: 1.02rem;
}

/* ---------- 6. 卡片(玻璃拟态) ---------- */
.card {
  background: var(--glass);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  padding: 28px;
  transition:
    transform var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease);
}

.card:hover {
  transform: translateY(-6px);
  border-color: rgba(29, 155, 240, 0.4);
  box-shadow: var(--shadow-lift);
}

.card__title {
  font-size: 1.15rem;
  margin-bottom: 10px;
}

.card__text {
  color: var(--dim);
  font-size: 0.95rem;
}

/* ---------- 7. 视频 ---------- */
.video-wrap {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  background: #000;
  box-shadow: var(--shadow);
}

.video-wrap video {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.video-wrap__poster {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  cursor: pointer;
  z-index: 2;
  transition: opacity 0.4s var(--ease);
}

.video-wrap__play {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.video-wrap__play i {
  width: 68px;
  height: 68px;
  border-radius: 50%;
  background: rgba(15, 20, 25, 0.55);
  border: 1px solid var(--line-strong);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  display: grid;
  place-items: center;
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease);
}

.video-wrap__play i::after {
  content: "";
  width: 0;
  height: 0;
  margin-left: 4px;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-left: 16px solid #fff;
}

.video-wrap__play:hover i {
  transform: scale(1.08);
  background: rgba(29, 155, 240, 0.6);
}

/* 播放中隐藏海报与按钮 */
.video-wrap.is-playing .video-wrap__poster,
.video-wrap.is-playing .video-wrap__play {
  opacity: 0;
  pointer-events: none;
}

/* ---------- 8. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid rgba(29, 155, 240, 0.24);
  padding: 4px 12px;
  border-radius: 999px;
}

.tag--dim {
  color: var(--dim);
  background: rgba(136, 153, 166, 0.1);
  border-color: var(--line);
}

/* ---------- 9. 栅格 ---------- */
.grid {
  display: grid;
  gap: var(--gap);
}

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

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

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

/* ---------- 10. Hero ---------- */
.hero {
  position: relative;
  padding: 110px 0 90px;
  text-align: center;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -30%;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 560px;
  background: radial-gradient(
    ellipse at center,
    rgba(29, 155, 240, 0.2) 0%,
    rgba(124, 92, 255, 0.08) 45%,
    transparent 70%
  );
  pointer-events: none;
}

.hero__title {
  font-size: clamp(2.2rem, 6vw, 3.6rem);
  letter-spacing: -0.03em;
  line-height: 1.15;
  max-width: 860px;
  margin: 0 auto 22px;
}

.hero__title em {
  font-style: normal;
  background: var(--grad-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero__sub {
  color: var(--dim);
  font-size: clamp(1rem, 2.4vw, 1.2rem);
  max-width: 640px;
  margin: 0 auto 36px;
}

.hero__actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* ---------- 11. 页脚 ---------- */
.footer {
  border-top: 1px solid var(--line);
  padding: 40px 0;
  color: var(--dim);
  font-size: 0.88rem;
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

/* ---------- 12. 滚动渐显(配合 main.js) ---------- */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition:
    opacity 0.7s var(--ease),
    transform 0.7s var(--ease);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 13. 响应式断点:1024px / 768px ---------- */
@media (max-width: 1024px) {
  .grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .section {
    padding: 72px 0;
  }

  .nav__links {
    gap: 18px;
  }
}

@media (max-width: 768px) {
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 56px 0;
  }

  .hero {
    padding: 78px 0 64px;
  }

  /* 移动端导航收敛为品牌 + CTA */
  .nav__links {
    display: none;
  }

  .nav__inner {
    height: 56px;
  }

  .btn--lg {
    width: 100%;
  }

  .hero__actions {
    flex-direction: column;
    align-items: stretch;
    padding: 0 24px;
  }

  .footer__inner {
    flex-direction: column;
    text-align: center;
  }
}

/* ---------- 14. 无障碍:尊重减弱动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ============================================================
   Task 2 专属样式:Hero 徽章/视频、信任条、闭环 SVG
   ============================================================ */

/* ---------- 15. Hero 徽章 ---------- */
.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--text);
  background: linear-gradient(
    135deg,
    rgba(29, 155, 240, 0.16),
    rgba(124, 92, 255, 0.14)
  );
  border: 1px solid rgba(29, 155, 240, 0.32);
  border-radius: 999px;
  padding: 7px 18px;
  margin-bottom: 26px;
  box-shadow:
    0 0 24px rgba(29, 155, 240, 0.22),
    inset 0 0 12px rgba(29, 155, 240, 0.08);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
}

/* ---------- 16. Hero 视频(玻璃卡片) ---------- */
.hero__video {
  position: relative;
  max-width: 880px;
  margin: 56px auto 0;
}

/* 渐变描边玻璃卡 */
.hero__video::before {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: calc(var(--radius) + 10px);
  padding: 1px;
  background: linear-gradient(
    135deg,
    rgba(29, 155, 240, 0.55),
    rgba(124, 92, 255, 0.25) 45%,
    rgba(29, 155, 240, 0.08)
  );
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask-composite: exclude;
  pointer-events: none;
  z-index: 1;
}

.hero__video .video-wrap {
  background:
    radial-gradient(120% 90% at 50% 0%, rgba(29, 155, 240, 0.12), transparent 60%),
    var(--glass);
  border: 1px solid rgba(29, 155, 240, 0.22);
  border-radius: calc(var(--radius) + 9px);
  box-shadow: var(--shadow-lift);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
}

.hero__video .video-wrap video {
  aspect-ratio: 16 / 9;
  border-radius: calc(var(--radius) + 8px);
  display: block;
}

/* 视频底部光晕 */
.hero__video::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -34px;
  transform: translateX(-50%);
  width: 72%;
  height: 70px;
  background: radial-gradient(
    ellipse at center,
    rgba(29, 155, 240, 0.32) 0%,
    transparent 70%
  );
  filter: blur(18px);
  pointer-events: none;
  z-index: 0;
}

/* ---------- 17. 信任条 ---------- */
.trust {
  padding-top: 0;
}

.trust__bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(
    180deg,
    rgba(28, 37, 48, 0.55),
    rgba(22, 29, 38, 0.35)
  );
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  overflow: hidden;
}

.trust__item {
  position: relative;
  text-align: center;
  font-size: clamp(1.15rem, 2.6vw, 1.55rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  padding: 34px 20px;
  color: var(--text);
  white-space: nowrap;
}

/* 分隔线 */
.trust__item + .trust__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 22%;
  bottom: 22%;
  width: 1px;
  background: var(--line);
}

.trust__num {
  background: var(--grad-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-right: 8px;
  filter: drop-shadow(0 0 14px rgba(29, 155, 240, 0.35));
}

/* ---------- 18. 闭环 SVG ---------- */
.loop__svg {
  max-width: 620px;
  margin: 0 auto;
}

.loop__svg svg {
  width: 100%;
  height: auto;
  display: block;
  filter: drop-shadow(0 14px 40px rgba(29, 155, 240, 0.12));
}

/* 轨道缓慢旋转 */
.loop__orbit {
  transform-origin: 300px 300px;
  animation: loop-spin 46s linear infinite;
}

/* 沿弧流动的虚线光点 */
.loop__flow path {
  stroke-dasharray: 3 26;
  animation: loop-dash 1.6s linear infinite;
}

.loop__flow path:nth-child(2) { animation-delay: 0.26s; }
.loop__flow path:nth-child(3) { animation-delay: 0.52s; }
.loop__flow path:nth-child(4) { animation-delay: 0.78s; }
.loop__flow path:nth-child(5) { animation-delay: 1.04s; }
.loop__flow path:nth-child(6) { animation-delay: 1.3s; }

@keyframes loop-spin {
  to { transform: rotate(360deg); }
}

@keyframes loop-dash {
  to { stroke-dashoffset: -29; }
}

.loop__note {
  text-align: center;
  color: var(--dim);
  font-size: 1.05rem;
  margin-top: 30px;
}

/* ---------- 19. Task 2 响应式 ---------- */
@media (max-width: 1024px) {
  .trust__item {
    font-size: clamp(1.05rem, 2.6vw, 1.35rem);
  }
}

@media (max-width: 768px) {
  .trust__bar {
    grid-template-columns: repeat(2, 1fr);
  }

  .trust__item {
    padding: 24px 14px;
    white-space: normal;
  }

  /* 2 列布局下,第 3 项起换行,分隔线改为顶部横线 */
  .trust__item:nth-child(3)::before {
    left: 0;
    right: 0;
    top: 0;
    bottom: auto;
    width: auto;
    height: 1px;
  }

  .trust__item + .trust__item::before {
    top: 0;
    bottom: 0;
  }

  .trust__item:nth-child(odd)::before {
    display: none;
  }

  .trust__item:nth-child(3)::before {
    display: block;
  }

  .hero__video {
    margin-top: 42px;
  }
}

@media (max-width: 420px) {
  .trust__bar {
    grid-template-columns: 1fr;
  }

  .trust__item + .trust__item::before {
    left: 20%;
    right: 20%;
    top: 0;
    bottom: auto;
    width: auto;
    height: 1px;
  }
}

/* ============================================================
   Task 3 专属样式:AI 增长引擎 4 卡(顶部视频 + 标签胶囊)
   ============================================================ */

/* ---------- 20. 增长引擎卡片 ---------- */
.growth__grid,
.agent__grid {
  align-items: stretch;
}

/* 卡片零内边距,顶部视频通栏出血,圆角由卡片 overflow 裁剪 */
.growth__card,
.agent__card {
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow: hidden;
}

/* 卡内视频:通栏顶部,去除独立边框阴影,下方分隔线 */
.growth__video,
.agent__video {
  border-radius: 0;
  border: 0;
  border-bottom: 1px solid var(--line);
  box-shadow: none;
}

.growth__video video,
.agent__video video {
  display: block;
  cursor: pointer;
}

/* 卡身:标题 / 一句话 / 标签 */
.growth__body,
.agent__body {
  display: flex;
  flex-direction: column;
  gap: 12px;
  flex: 1;
  padding: 24px 28px 28px;
}

.growth__body .card__title,
.agent__body .card__title {
  margin-bottom: 0;
}

/* 标签胶囊行:靠底对齐,统一换行间距 */
.growth__tags,
.agent__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: auto;
  padding-top: 8px;
}

@media (max-width: 768px) {
  .growth__body,
  .agent__body {
    padding: 20px 20px 24px;
  }
}

/* ============================================================
   Task 4 专属样式:安全底座(四象限 + 三层架构图)
   ============================================================ */

/* ---------- 21. 安全底座:四象限(flex 4 列 / 2 列 / 1 列响应) ---------- */
.security__quads {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap);
  justify-content: center;
  margin-bottom: 72px;
}

.security__quad {
  flex: 1 1 220px;
  max-width: 264px;
  background: var(--glass);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  padding: 26px 20px 24px;
  text-align: center;
  transition:
    transform var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease);
}

.security__quad:hover {
  transform: translateY(-6px);
  border-color: rgba(29, 155, 240, 0.4);
  box-shadow: var(--shadow-lift);
}

.security__quad-icon {
  display: block;
  font-size: 1.7rem;
  line-height: 1;
  margin-bottom: 14px;
}

.security__quad-title {
  font-size: 0.98rem;
  font-weight: 600;
  line-height: 1.55;
}

/* ---------- 22. 安全底座:三层架构图(accent 描边) ---------- */
.arch {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 720px;
  margin: 0 auto;
}

.arch__layer {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--gap);
  width: 100%;
}

.arch__node {
  flex: 1 1 200px;
  max-width: 320px;
  text-align: center;
  padding: 20px 18px;
  border-radius: var(--radius);
  background: var(--glass);
  border: 1px solid rgba(29, 155, 240, 0.5);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  font-weight: 600;
  font-size: 1.05rem;
  letter-spacing: 0.02em;
  box-shadow: var(--shadow);
}

/* 顶部 AI 层:渐变微光 + 紫色描边 */
.arch__node--ai {
  background: linear-gradient(
    135deg,
    rgba(29, 155, 240, 0.18),
    rgba(124, 92, 255, 0.12)
  );
  border-color: rgba(124, 92, 255, 0.55);
}

/* 底部安全底座:accent 实色描边 + 光晕 */
.arch__node--base {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
  box-shadow:
    0 0 30px rgba(29, 155, 240, 0.2),
    var(--shadow);
}

/* 层间连接线(向下箭头) */
.arch__conn {
  position: relative;
  width: 2px;
  height: 30px;
  background: linear-gradient(
    180deg,
    rgba(29, 155, 240, 0.7),
    rgba(124, 92, 255, 0.7)
  );
}

.arch__conn::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -3px;
  transform: translateX(-50%);
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-top: 6px solid #7c5cff;
}

/* ---------- 23. Task 4 响应式 ---------- */
@media (max-width: 768px) {
  .security__quads {
    margin-bottom: 56px;
  }

  .arch__node {
    padding: 16px 14px;
    font-size: 0.98rem;
  }

  /* 中部双框在小屏保持并排(各 ~46%),不换行 */
  .arch__layer--duo .arch__node {
    flex: 1 1 44%;
    max-width: none;
  }
}

/* ============================================================
   Task 5 专属样式:AI 亮点 / 适用场景 / 对比表 / FAQ / CTA / Footer
   ============================================================ */

/* ---------- 24. AI 亮点横条 ---------- */
.ai__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--gap);
}

.ai__item {
  display: flex;
  align-items: flex-start;
  gap: 18px;
  background: var(--glass);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  padding: 24px 26px;
  transition:
    transform var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease);
}

.ai__item:hover {
  transform: translateY(-4px);
  border-color: rgba(29, 155, 240, 0.4);
  box-shadow: var(--shadow-lift);
}

.ai__icon {
  flex-shrink: 0;
  width: 52px;
  height: 52px;
  display: grid;
  place-items: center;
  font-size: 1.5rem;
  border-radius: 14px;
  background: var(--accent-soft);
  border: 1px solid rgba(29, 155, 240, 0.28);
}

.ai__title {
  font-size: 1.05rem;
  margin-bottom: 6px;
}

.ai__text {
  color: var(--dim);
  font-size: 0.92rem;
  line-height: 1.6;
}

/* ---------- 25. 适用场景卡片 ---------- */
.scene__card {
  text-align: center;
  padding: 34px 24px;
}

.scene__title {
  font-size: 1.1rem;
  margin-bottom: 10px;
}

.scene__text {
  color: var(--dim);
  font-size: 0.92rem;
  line-height: 1.6;
}

/* ---------- 26. 竞品对比表(深色玻璃容器 + accent 表头 + 行 hover) ---------- */
.compare__wrap {
  max-width: 920px;
  margin: 0 auto;
  overflow-x: auto;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--glass);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  box-shadow: var(--shadow);
}

.compare__table {
  width: 100%;
  min-width: 660px;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.compare__table th,
.compare__table td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--line);
}

/* 表头:accent 渐变 */
.compare__table thead th {
  background: linear-gradient(
    135deg,
    rgba(29, 155, 240, 0.24),
    rgba(124, 92, 255, 0.16)
  );
  color: var(--text);
  font-weight: 700;
  letter-spacing: 0.03em;
  white-space: nowrap;
}

/* XControl 列强调 */
.compare__table thead th:nth-child(2),
.compare__table tbody td:nth-child(2) {
  color: var(--accent);
  font-weight: 600;
}

.compare__table tbody th {
  color: var(--dim);
  font-weight: 600;
  white-space: nowrap;
}

.compare__table tbody tr:last-child th,
.compare__table tbody tr:last-child td {
  border-bottom: 0;
}

.compare__table tbody tr {
  transition: background var(--dur) var(--ease);
}

.compare__table tbody tr:hover {
  background: var(--accent-soft);
}

/* ---------- 27. FAQ 手风琴(原生 details/summary,零 JS) ---------- */
.faq__list {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq__item {
  background: var(--glass);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  transition: border-color var(--dur) var(--ease);
}

.faq__item[open] {
  border-color: rgba(29, 155, 240, 0.42);
}

.faq__item summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 18px 22px;
  font-weight: 600;
  font-size: 1.02rem;
  user-select: none;
}

/* 隐藏默认三角,自绘 + 号徽章 */
.faq__item summary::-webkit-details-marker {
  display: none;
}

.faq__item summary::after {
  content: "+";
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--accent-soft);
  border: 1px solid rgba(29, 155, 240, 0.3);
  color: var(--accent);
  font-weight: 700;
  transition:
    transform var(--dur) var(--ease),
    background var(--dur) var(--ease);
}

.faq__item[open] summary::after {
  transform: rotate(45deg);
  background: var(--accent);
  color: #fff;
}

.faq__item p {
  color: var(--dim);
  font-size: 0.95rem;
  line-height: 1.7;
  padding: 0 22px 20px;
}

/* ---------- 28. CTA 转化区 ---------- */
.cta {
  position: relative;
  overflow: hidden;
}

/* 中心光晕背景 */
.cta::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 760px;
  height: 340px;
  background: radial-gradient(
    ellipse at center,
    rgba(29, 155, 240, 0.18) 0%,
    rgba(124, 92, 255, 0.08) 50%,
    transparent 72%
  );
  pointer-events: none;
}

.cta .section__head,
.cta__actions {
  position: relative;
}

.cta__actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* ---------- 29. Footer 增强(语言切换胶囊,由 .lang-switch 组件承载) ---------- */
.footer__lang {
  display: inline-flex;
}

/* ---------- 30. Task 5 响应式 ---------- */
@media (max-width: 768px) {
  .ai__grid {
    grid-template-columns: 1fr;
  }

  .compare__table th,
  .compare__table td {
    padding: 13px 14px;
  }
}

@media (max-width: 420px) {
  .cta__actions .btn--lg {
    width: 100%;
  }
}

/* ---------- 31. 语言切换组件(导航 + 页脚胶囊,Task 7) ---------- */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 3px;
  background: var(--surface);
  font-size: 0.82rem;
  font-weight: 600;
  line-height: 1;
  flex-shrink: 0;
}

.lang-switch a {
  color: var(--dim);
  padding: 5px 11px;
  border-radius: 999px;
  text-decoration: none;
  transition:
    color var(--dur) var(--ease),
    background var(--dur) var(--ease);
}

.lang-switch a:hover {
  color: var(--text);
  background: var(--accent-soft);
}

.lang-switch a.is-active {
  color: #fff;
  background: var(--grad-accent);
  box-shadow: 0 0 12px rgba(29, 155, 240, 0.35);
}

/* 页脚胶囊略放大,与导航区分 */
.footer__lang .lang-switch {
  padding: 4px;
}

.footer__lang .lang-switch a {
  padding: 6px 14px;
}

/* ===== 免责声明 ===== */
.disclaimer__card {
  background: var(--surface);
  border: 1px solid rgba(255,255,255,.08);
  border-radius: 16px;
  padding: 2rem 2.4rem;
  max-width: 860px;
  margin: 0 auto;
}
.disclaimer__list {
  margin: 0;
  padding-left: 1.4em;
  color: var(--dim);
  font-size: .92rem;
  line-height: 1.9;
  display: grid;
  gap: .7rem;
}
.disclaimer__list li::marker { color: var(--accent); font-weight: 600; }
.disclaimer__note {
  margin-top: 1.4rem;
  padding-top: 1.2rem;
  border-top: 1px dashed rgba(255,255,255,.12);
  color: var(--text);
  font-size: .95rem;
  font-weight: 500;
}
@media (max-width: 768px) {
  .disclaimer__card { padding: 1.4rem 1.2rem; }
}