@charset "UTF-8";
/* ============================================================
   bubbly AI Chat - 主样式表
   清新活泼 · 简约现代 · 全响应式
   ============================================================ */

/* ---------- CSS 变量 ---------- */
:root {
  /* 主色调 */
  --color-primary: #7C5CFC;
  --color-primary-light: #A78BFA;
  --color-primary-lighter: #EDEAFF;
  --color-secondary: #FF6B9D;
  --color-secondary-light: #FFA3BE;
  --color-accent: #00D2FF;
  --color-accent-light: #6EE7FF;
  --color-success: #4ECDC4;

  /* 中性色 */
  --color-bg: #F8F7FF;
  --color-bg-alt: #F0EFFF;
  --color-white: #FFFFFF;
  --color-text: #1E1145;
  --color-text-light: #6B7280;
  --color-text-lighter: #9CA3AF;
  --color-border: #E8E6F0;

  /* 尺寸 */
  --max-width: 1200px;
  --header-height: 72px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;
  --shadow-sm: 0 2px 8px rgba(124, 92, 252, 0.08);
  --shadow-md: 0 4px 16px rgba(124, 92, 252, 0.12);
  --shadow-lg: 0 8px 32px rgba(124, 92, 252, 0.16);

  /* 间距 */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;
  --space-4xl: 96px;

  /* 过渡 */
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* ---------- 图标系统 ---------- */
.icon {
  display: block;
  width: 100%;
  height: 100%;
}

.icon::before {
  content: '';
  display: block;
  width: 100%;
  height: 100%;
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
}

/* 产品介绍图标 */
.icon-chat::before   { background-image: url(../fonts/icon-chat.svg); }
.icon-qa::before     { background-image: url(../fonts/icon-qa.svg); }
.icon-fun::before    { background-image: url(../fonts/icon-fun.svg); }
.icon-scene::before  { background-image: url(../fonts/icon-scene.svg); }

/* 功能亮点图标 */
.icon-speed::before  { background-image: url(../fonts/icon-speed.svg); }
.icon-smart::before  { background-image: url(../fonts/icon-smart.svg); }
.icon-light::before  { background-image: url(../fonts/icon-light.svg); }
.icon-secure::before { background-image: url(../fonts/icon-secure.svg); }

/* 下载平台图标 */
.icon-android::before { background-image: url(../fonts/icon-android.svg); }
.icon-apple::before   { background-image: url(../fonts/icon-apple.svg); }

/* 关于我们图标 */
.icon-mission::before { background-image: url(../fonts/icon-mission.svg); }
.icon-vision::before  { background-image: url(../fonts/icon-vision.svg); }
.icon-values::before  { background-image: url(../fonts/icon-values.svg); }

/* 箭头图标 */
.icon-arrow-left::before  { background-image: url(../fonts/arrow-left.svg); }
.icon-arrow-right::before { background-image: url(../fonts/arrow-right.svg); }
.icon-arrow-up::before    { background-image: url(../fonts/arrow-up.svg); }

/* 头像占位 */
.icon-avatar::before { background-image: url(../fonts/avatar-placeholder.svg); }

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-height);
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-white);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  -webkit-tap-highlight-color: transparent;
}

/* 禁用移动端点击白色闪动 */
a, button, [role="button"] {
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
}

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

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

ul, ol {
  list-style: none;
}

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

/* ---------- 容器 ---------- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* ---------- 通用区块 ---------- */
.section {
  padding: var(--space-4xl) 0;
}

.section--alt {
  background: var(--color-bg);
}

.section__header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.section__tag {
  display: inline-block;
  padding: var(--space-xs) var(--space-md);
  background: var(--color-primary-lighter);
  color: var(--color-primary);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
}

.section__title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: var(--space-md);
  line-height: 1.3;
}

.section__subtitle {
  font-size: 1.1rem;
  color: var(--color-text-light);
  max-width: 560px;
  margin: 0 auto;
}

.text-gradient {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 12px 28px;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 0.95rem;
  transition: all var(--transition-base);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.btn--primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  color: var(--color-white);
  box-shadow: var(--shadow-md);
}

.btn--primary:hover {
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 8px 28px rgba(124, 92, 252, 0.35);
}

.btn--primary:active {
  transform: translateY(0) scale(0.97);
  box-shadow: var(--shadow-sm);
}

.btn--outline {
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
  background: transparent;
}

.btn--outline:hover {
  background: var(--color-primary);
  color: var(--color-white);
  transform: translateY(-2px);
}

.btn--lg {
  padding: 16px 36px;
  font-size: 1.05rem;
  border-radius: var(--radius-xl);
}

.btn__arrow {
  transition: transform var(--transition-base);
}

.btn--primary:hover .btn__arrow {
  transform: translateX(4px);
}

/* ---------- 1. 导航栏 ---------- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: all var(--transition-base);
}

.header--scrolled {
  background: rgba(255, 255, 255, 0.95);
  border-bottom-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.header__logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.header__logo img {
  width: 50px;
  height: 50px;
  object-fit: contain;
  transition: transform var(--transition-base);
}

.header__logo-text {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  white-space: nowrap;
  margin-left: var(--space-sm);
}

.header__logo:hover img {
  transform: scale(1.05);
}

.header__nav-list {
  display: flex;
  gap: var(--space-xl);
}

.header__nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-light);
  padding: var(--space-sm) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.header__nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  border-radius: 2px;
  transition: width var(--transition-base);
}

.header__nav-link:hover,
.header__nav-link.active {
  color: var(--color-primary);
}

.header__nav-link:hover::after,
.header__nav-link.active::after {
  width: 100%;
}

.header__btn {
  padding: 10px 24px;
  font-size: 0.875rem;
}

.header__btn:hover {
  transform: none;
  box-shadow: var(--shadow-md);
}

/* 汉堡菜单 */
.header__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  position: relative;
  z-index: 1001;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
}

.header__hamburger-line {
  display: block;
  width: 24px;
  height: 2.5px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  transform-origin: center;
}

/* 汉堡 → X 动画 */
.header__hamburger--open .header__hamburger-line:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

.header__hamburger--open .header__hamburger-line:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.header__hamburger--open .header__hamburger-line:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* 遮罩层（默认隐藏，移动端菜单打开时显示） */
.header__nav-overlay {
  display: none;
}

/* ---------- 2. 首屏 Banner ---------- */
.hero {
  position: relative;
  padding: calc(var(--header-height) + var(--space-3xl)) 0 var(--space-4xl);
  background: linear-gradient(170deg, var(--color-bg) 0%, var(--color-bg-alt) 40%, var(--color-white) 100%);
  overflow: hidden;
}

.hero__inner {
  display: flex;
  align-items: center;
  gap: var(--space-3xl);
  position: relative;
  z-index: 1;
}

.hero__content {
  flex: 1;
  max-width: 560px;
}

.hero__badge {
  display: inline-block;
  padding: 6px 16px;
  background: var(--color-primary-lighter);
  color: var(--color-primary);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-lg);
  animation: fadeInUp 0.8s ease forwards;
}

.hero__title {
  font-size: 2.75rem;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 4px;
  animation: fadeInUp 0.8s ease 0.15s forwards;
  opacity: 0;
}

.hero__subtitle {
  font-size: 2.75rem;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: var(--space-lg);
  animation: fadeInUp 0.8s ease 0.2s forwards;
  opacity: 0;
}

.hero__highlight {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__desc {
  font-size: 1.1rem;
  color: var(--color-text-light);
  line-height: 1.8;
  margin-bottom: var(--space-xl);
  animation: fadeInUp 0.8s ease 0.3s forwards;
  opacity: 0;
}

.hero__actions {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-2xl);
  animation: fadeInUp 0.8s ease 0.45s forwards;
  opacity: 0;
}

.hero__btn-main {
  position: relative;
}

.hero__btn-main:hover {
  transform: none;
  box-shadow: var(--shadow-md);
}

.hero__btn-main:active {
  transform: none;
}

.hero__btn-main .btn__arrow {
  display: none;
}

.hero__stats {
  display: flex;
  gap: var(--space-2xl);
  animation: fadeInUp 0.8s ease 0.6s forwards;
  opacity: 0;
}

.hero__stat {
  display: flex;
  flex-direction: column;
}

.hero__stat-num {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-primary);
}

.hero__stat-label {
  font-size: 0.875rem;
  color: var(--color-text-light);
}

.hero__visual {
  flex: 1;
  position: relative;
  display: flex;
  justify-content: center;
  animation: fadeInUp 0.8s ease 0.3s forwards;
  opacity: 0;
}

.hero__image {
  width: 500px;
  height: 400px;
  max-width: 100%;
  position: relative;
  z-index: 1;
  transform: translateY(0);
  transition: transform 0.1s ease-out;
}

.hero__floating {
  position: absolute;
  border-radius: 50%;
  z-index: 0;
}

.hero__floating--1 {
  width: 120px;
  height: 120px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  opacity: 0.15;
  top: 10%;
  left: -5%;
  animation: float 6s ease-in-out infinite;
}

.hero__floating--2 {
  width: 80px;
  height: 80px;
  background: linear-gradient(135deg, var(--color-secondary), var(--color-secondary-light));
  opacity: 0.2;
  bottom: 20%;
  right: 5%;
  animation: float 8s ease-in-out infinite reverse;
}

.hero__floating--3 {
  width: 60px;
  height: 60px;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  opacity: 0.2;
  top: 50%;
  right: -5%;
  animation: float 5s ease-in-out infinite 1s;
}

@keyframes float {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-20px) scale(1.05); }
}

.hero__wave {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  line-height: 0;
}

.hero__wave svg {
  width: 100%;
  height: 80px;
}

/* ---------- 3. 产品介绍 ---------- */
.intro__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

.intro__card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  text-align: center;
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
  cursor: default;
}

.intro__card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.intro__card-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--space-md);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.intro__card:hover .intro__card-icon {
  background: var(--color-primary-lighter);
  transform: scale(1.1);
}

.intro__card-icon .icon {
  width: 48px;
  height: 48px;
  margin: 0 auto;
}

.intro__card-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.intro__card-desc {
  font-size: 0.9rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* ---------- 4. 功能亮点 ---------- */
.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.feature-card {
  display: flex;
  gap: var(--space-md);
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
  cursor: default;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-light);
}

.feature-card__icon-wrap {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
}

.feature-card:hover .feature-card__icon-wrap {
  background: var(--color-primary-lighter);
  transform: rotate(-8deg) scale(1.1);
}

.feature-card__icon-wrap .icon {
  width: 36px;
  height: 36px;
}

.feature-card__title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.feature-card__desc {
  font-size: 0.875rem;
  color: var(--color-text-light);
  line-height: 1.5;
}

/* ---------- 5. 界面预览（轮播） ---------- */
.preview__carousel {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
  overflow: hidden;
}

.preview__track {
  display: flex;
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.preview__slide {
  min-width: 100%;
  display: flex;
  justify-content: center;
  padding: var(--space-lg) 0;
}

.preview__device {
  text-align: center;
}

.preview__device img {
  width: 280px;
  height: 560px;
  margin: 0 auto;
  filter: drop-shadow(0 8px 24px rgba(124, 92, 252, 0.15));
  transition: transform var(--transition-base);
}

.preview__device:hover img {
  transform: translateY(-4px);
}

.preview__label {
  display: inline-block;
  margin-top: var(--space-md);
  padding: 6px 20px;
  background: var(--color-primary-lighter);
  color: var(--color-primary);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
}

.preview__arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 44px;
  height: 44px;
  background: var(--color-white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
  z-index: 2;
}

.preview__arrow:hover {
  background: var(--color-primary);
  box-shadow: var(--shadow-lg);
}

.preview__arrow:hover .icon {
  filter: brightness(0) invert(1);
}

.preview__arrow .icon {
  width: 22px;
  height: 22px;
}

.preview__arrow--left { left: 0; }
.preview__arrow--right { right: 0; }

.preview__dots {
  display: flex;
  justify-content: center;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

.preview__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-border);
  transition: all var(--transition-base);
}

.preview__dot.active {
  background: var(--color-primary);
  width: 28px;
  border-radius: var(--radius-full);
}

.preview__dot:hover {
  background: var(--color-primary-light);
}

/* ---------- 6. 产品优势 ---------- */
.advantages__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

.advantage-item {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.advantage-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-light);
}

.advantage-item__num {
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-sm);
  line-height: 1;
}

.advantage-item__title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.advantage-item__desc {
  font-size: 0.95rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* ---------- 7. 下载专区 ---------- */
.download__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
  max-width: 560px;
  margin: 0 auto var(--space-2xl);
}

.download-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  text-align: center;
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
  position: relative;
}

.download-card--featured {
  border: 2px solid var(--color-primary);
  background: linear-gradient(180deg, var(--color-primary-lighter) 0%, var(--color-white) 30%);
}

.download-card__badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  padding: 4px 16px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  color: var(--color-white);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
}

.download-card__icon {
  width: 72px;
  height: 72px;
  margin: 0 auto var(--space-md);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
}

.download-card__icon .icon {
  width: 42px;
  height: 42px;
  margin: 0 auto;
}

.download-card__title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.download-card__desc {
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-bottom: var(--space-md);
}

.download-card__btn {
  width: 100%;
  margin-bottom: var(--space-sm);
}

.download-card__btn:hover,
.download-card__btn:active {
  transform: none;
  box-shadow: var(--shadow-md);
}

.download-card__hint {
  font-size: 0.75rem;
  color: var(--color-text-lighter);
}

.download__install {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  border: 1px solid var(--color-border);
  max-width: 680px;
  margin: 0 auto;
}

.download__install-title {
  font-size: 1.15rem;
  font-weight: 800;
  margin-bottom: var(--space-lg);
  text-align: center;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* 提示条 */
.install-notice {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  background: #FFF8E7;
  border: 1px solid #FFE4A8;
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  margin-bottom: var(--space-lg);
  font-size: 0.9rem;
  color: #B87A14;
  line-height: 1.5;
}

/* 高亮文字 */
.text-highlight {
  color: var(--color-secondary);
  font-weight: 700;
  background: rgba(255, 107, 157, 0.08);
  padding: 1px 4px;
  border-radius: 3px;
  white-space: nowrap;
}

.install-notice__icon {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  background: #FFB347;
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 800;
}

/* 分区标题 */
.install-section-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.install-section-title::before {
  content: '';
  width: 4px;
  height: 16px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  border-radius: 2px;
}

/* 步骤三卡片 */
.install-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.install-step {
  position: relative;
  background: var(--color-bg);
  border-radius: var(--radius-md);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  transition: all var(--transition-base);
  border: 1px solid transparent;
}

.install-step:hover {
  background: var(--color-white);
  border-color: var(--color-primary-lighter);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.install-step__num {
  position: absolute;
  top: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 22px;
  height: 22px;
  background: var(--color-primary);
  color: var(--color-white);
  border-radius: 50%;
  font-size: 0.7rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
}

.install-step__icon {
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
  display: flex;
  justify-content: center;
}

.install-step__title {
  display: block;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
}

.install-step__desc {
  font-size: 0.8rem;
  color: var(--color-text-light);
  line-height: 1.5;
}

/* 华为提示卡片 */
.install-huawei {
  background: linear-gradient(135deg, rgba(255, 107, 157, 0.06), rgba(124, 92, 252, 0.06));
  border: 1px solid rgba(255, 107, 157, 0.2);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
}

.install-huawei__title {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-secondary);
  margin-bottom: var(--space-sm);
}

.install-huawei__title svg {
  color: var(--color-secondary);
  flex-shrink: 0;
}

.install-huawei__desc {
  font-size: 0.85rem;
  color: var(--color-text-light);
  line-height: 1.7;
  margin: 0;
}

/* ---------- 8. 用户评价 ---------- */
.reviews__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.review-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.review-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-secondary-light);
}

.review-card__stars {
  color: #FFB347;
  font-size: 1rem;
  letter-spacing: 2px;
}

.review-card__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-md);
}

.review-card__score {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.review-card__rating {
  font-size: 0.85rem;
  font-weight: 700;
  color: #FFB347;
  background: #FFF8E7;
  padding: 2px 8px;
  border-radius: 4px;
}

.review-card__verified {
  font-size: 0.75rem;
  color: #4CAF50;
  background: #E8F5E9;
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 600;
}

.review-card__text {
  font-size: 0.95rem;
  color: var(--color-text);
  line-height: 1.7;
  margin-bottom: var(--space-lg);
  font-style: italic;
}

.review-card__footer {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
}

.review-card__author {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.review-card__avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 2px solid var(--color-primary-lighter);
  flex-shrink: 0;
  overflow: hidden;
  display: block;
}

.review-card__name {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
}

.review-card__time {
  font-size: 0.75rem;
  color: var(--color-text-lighter);
}

/* ---------- 9. 关于我们 ---------- */
.about__inner {
  display: flex;
  align-items: center;
  gap: var(--space-3xl);
}

.about__content {
  flex: 1;
}

.about__text {
  font-size: 1rem;
  color: var(--color-text-light);
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

.about__values {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.about__value {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-bg);
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.about__value:hover {
  background: var(--color-primary-lighter);
  transform: translateX(4px);
}

.about__value-icon {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.about__visual {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  min-height: 320px;
}

.about__bubble {
  position: absolute;
  border-radius: 50%;
}

.about__bubble--lg {
  width: 200px;
  height: 200px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  opacity: 0.2;
  animation: float 6s ease-in-out infinite;
}

.about__bubble--md {
  width: 120px;
  height: 120px;
  background: linear-gradient(135deg, var(--color-secondary), var(--color-secondary-light));
  opacity: 0.25;
  top: 20%;
  right: 10%;
  animation: float 8s ease-in-out infinite reverse;
}

.about__bubble--sm {
  width: 60px;
  height: 60px;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  opacity: 0.3;
  bottom: 10%;
  left: 15%;
  animation: float 5s ease-in-out infinite 1s;
}

/* ---------- 10. 页脚 ---------- */
.footer {
  background: var(--color-text);
  color: var(--color-white);
  padding: var(--space-3xl) 0 var(--space-lg);
}

.footer__inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-2xl);
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer__brand img {
  display: block;
  width: 70px;
  height: auto;
  margin-bottom: var(--space-sm);
  border-radius: 14px;
}

.footer__desc {
  font-size: 0.85rem;
  color: var(--color-text-lighter);
  line-height: 1.5;
  max-width: 240px;
}

.footer__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs) var(--space-lg);
  padding-top: 4px;
}

.footer__links a {
  font-size: 0.875rem;
  color: var(--color-text-lighter);
  transition: color var(--transition-fast);
  text-decoration: none;
}

.footer__links a:hover {
  color: var(--color-accent);
}

.footer__bottom {
  display: flex;
  justify-content: center;
  font-size: 0.8rem;
  color: var(--color-text-lighter);
}

/* ---------- 回到顶部 ---------- */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px;
  height: 48px;
  background: var(--color-white);
  border-radius: 50%;
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: all var(--transition-base);
}

.back-to-top--visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary);
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.back-to-top:hover .icon {
  filter: brightness(0) invert(1);
}

.back-to-top .icon {
  width: 20px;
  height: 20px;
}

/* ---------- 滚动动画 ---------- */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.animated {
  opacity: 1;
  transform: translateY(0);
}

/* 动画延迟 */
.intro__card:nth-child(1) { transition-delay: 0s; }
.intro__card:nth-child(2) { transition-delay: 0.1s; }
.intro__card:nth-child(3) { transition-delay: 0.2s; }
.intro__card:nth-child(4) { transition-delay: 0.3s; }

.feature-card:nth-child(1) { transition-delay: 0s; }
.feature-card:nth-child(2) { transition-delay: 0.08s; }
.feature-card:nth-child(3) { transition-delay: 0.16s; }
.feature-card:nth-child(4) { transition-delay: 0.24s; }
.feature-card:nth-child(5) { transition-delay: 0.32s; }
.feature-card:nth-child(6) { transition-delay: 0.4s; }

.advantage-item:nth-child(1) { transition-delay: 0s; }
.advantage-item:nth-child(2) { transition-delay: 0.1s; }
.advantage-item:nth-child(3) { transition-delay: 0.2s; }
.advantage-item:nth-child(4) { transition-delay: 0.3s; }

.download-card:nth-child(1) { transition-delay: 0s; }
.download-card:nth-child(2) { transition-delay: 0.1s; }

.review-card:nth-child(1) { transition-delay: 0s; }
.review-card:nth-child(2) { transition-delay: 0.1s; }
.review-card:nth-child(3) { transition-delay: 0.2s; }

/* ---------- 关键帧动画 ---------- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================================
   响应式 - 平板端 (768px ~ 1199px)
   ============================================================ */
@media (max-width: 1199px) {
  :root {
    --space-4xl: 72px;
    --space-3xl: 48px;
  }

  .section__title {
    font-size: 1.85rem;
  }

  /* 导航 */
  .header__nav-list {
    gap: var(--space-md);
  }

  .header__nav-link {
    font-size: 0.85rem;
  }

  /* Banner */
  .hero__inner {
    flex-direction: column;
    text-align: center;
  }

  .hero__content {
    max-width: 100%;
  }

  .hero__title {
    font-size: 2.25rem;
  }

  .hero__subtitle {
    font-size: 2.25rem;
  }

  .hero__actions {
    justify-content: center;
  }

  .hero__stats {
    justify-content: center;
  }

  .hero__visual {
    order: -1;
    max-width: 400px;
    margin: 0 auto;
  }

  .hero__floating--1 { left: 5%; }
  .hero__floating--3 { right: 5%; }

  /* 产品介绍 */
  .intro__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* 功能亮点 */
  .features__grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

  .reviews__grid .review-card:last-child {
    grid-column: 1 / -1;
    max-width: 400px;
    justify-self: center;
  }

  /* 关于 */
  .about__inner {
    flex-direction: column;
  }

  .about__visual {
    min-height: 240px;
    order: -1;
  }

  .about__bubble--lg { width: 140px; height: 140px; }
  .about__bubble--md { width: 90px; height: 90px; }
  .about__bubble--sm { width: 50px; height: 50px; }

  /* 页脚 */
  .footer__inner {
    flex-direction: column;
    gap: var(--space-lg);
  }
}

/* ============================================================
   响应式 - 移动端 (< 768px)
   ============================================================ */
@media (max-width: 767px) {
  :root {
    --header-height: 64px;
    --space-4xl: 56px;
    --space-3xl: 36px;
    --space-2xl: 32px;
  }

  .container {
    padding: 0 var(--space-md);
  }

  .section__title {
    font-size: 1.6rem;
  }

  .section__subtitle {
    font-size: 0.95rem;
  }

  /* 移动端导航栏布局 */
  .header__inner {
    justify-content: space-between;
    position: relative;
  }

  .header__btn {
    position: absolute;
    right: 25%;
    transform: none;
    display: inline-flex;
    padding: 8px 14px;
    font-size: 0.78rem;
    flex-shrink: 0;
    white-space: nowrap;
  }

  /* 导航 - 移动端右侧抽屉菜单 */
  .header__nav {
    display: flex;
    position: fixed;
    top: 0;
    right: 0;
    width: 280px;
    max-width: 80vw;
    max-height: 100vh;
    background: #fff;
    flex-direction: column;
    justify-content: flex-start;
    padding: 80px var(--space-lg) var(--space-xl);
    transform: translateX(100%);
    transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1);
    z-index: 1001;
    box-shadow: -4px 0 24px rgba(0, 0, 0, 0.12);
    overflow-y: auto;
    pointer-events: none;
  }

  .header__nav--open {
    transform: translateX(0);
    pointer-events: auto;
  }

  /* 遮罩层 */
  .header__nav-overlay {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.4);
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.35s ease;
  }

  .header__nav-overlay--visible {
    opacity: 1;
    pointer-events: auto;
  }

  .header__nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .header__nav-list li {
    opacity: 0;
    transform: translateX(16px);
    transition: all 0.3s cubic-bezier(0.22, 1, 0.36, 1);
  }

  .header__nav--open .header__nav-list li {
    opacity: 1;
    transform: translateX(0);
  }

  .header__nav--open .header__nav-list li:nth-child(1) { transition-delay: 0.04s; }
  .header__nav--open .header__nav-list li:nth-child(2) { transition-delay: 0.08s; }
  .header__nav--open .header__nav-list li:nth-child(3) { transition-delay: 0.12s; }
  .header__nav--open .header__nav-list li:nth-child(4) { transition-delay: 0.16s; }
  .header__nav--open .header__nav-list li:nth-child(5) { transition-delay: 0.20s; }
  .header__nav--open .header__nav-list li:nth-child(6) { transition-delay: 0.24s; }
  .header__nav--open .header__nav-list li:nth-child(7) { transition-delay: 0.28s; }

  .header__nav-link {
    display: block;
    padding: 14px 16px;
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--color-text);
    border-radius: var(--radius-md);
    background: transparent;
    transition: all 0.2s ease;
  }

  .header__nav-link:hover,
  .header__nav-link.active {
    color: var(--color-primary);
    background: var(--color-primary-lighter);
  }

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

  .header__hamburger {
    display: flex;
  }

  /* Banner */
  .hero {
    padding-top: calc(var(--header-height) + var(--space-lg));
    padding-bottom: var(--space-3xl);
  }

  .hero__title {
    font-size: 2rem;
  }

  .hero__subtitle {
    font-size: 1.75rem;
  }

  .hero__desc {
    font-size: 0.95rem;
  }

  .hero__actions {
    flex-direction: column;
    align-items: center;
  }

  .hero__btn-main,
  .hero__actions .btn--outline {
    width: 100%;
    max-width: 280px;
  }

  .hero__stats {
    gap: var(--space-lg);
  }

  .hero__visual {
    max-width: 280px;
  }

  .hero__image {
    width: 100%;
    height: auto;
  }

  .hero__floating--1 { width: 80px; height: 80px; }
  .hero__floating--2 { width: 50px; height: 50px; }
  .hero__floating--3 { width: 40px; height: 40px; }

  /* 产品介绍 */
  .intro__grid {
    grid-template-columns: 1fr;
  }

  /* 功能亮点 */
  .features__grid {
    grid-template-columns: 1fr;
  }

  /* 轮播 */
  .preview__arrow {
    width: 36px;
    height: 36px;
  }

  .preview__arrow .icon {
    width: 18px;
    height: 18px;
  }

  .preview__device img {
    width: 220px;
    height: auto;
  }

  /* 优势 */
  .advantages__grid {
    grid-template-columns: 1fr;
  }

  /* 下载 */
  .download__grid {
    grid-template-columns: 1fr;
    max-width: 360px;
    margin-left: auto;
    margin-right: auto;
  }

  /* 安装步骤卡片 - 移动端纵向排列 */
  .install-steps {
    grid-template-columns: 1fr;
  }

  /* 评价 */
  .reviews__grid {
    grid-template-columns: 1fr;
  }

  .reviews__grid .review-card:last-child {
    max-width: 100%;
  }

  /* 关于 */
  .about__visual {
    min-height: 200px;
  }

  .about__bubble--lg { width: 100px; height: 100px; }
  .about__bubble--md { width: 70px; height: 70px; }
  .about__bubble--sm { width: 40px; height: 40px; }

  /* 页脚 */
  .footer__inner {
    flex-direction: column;
    gap: var(--space-lg);
    text-align: center;
    align-items: center;
  }

  .footer__brand {
    display: flex;
    flex-direction: column;
    align-items: center;
  }

  .footer__brand img {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    margin-left: auto;
    margin-right: auto;
  }

  .footer__links {
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
  }

  .footer__desc {
    max-width: none;
  }

  .footer__bottom {
    text-align: center;
  }

  /* 回到顶部 */
  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 42px;
    height: 42px;
  }

  .back-to-top .icon {
    width: 18px;
    height: 18px;
  }
}

/* ============================================================
   响应式 - 桌面端 (≥1200px)
   ============================================================ */
@media (min-width: 1200px) {
  .container {
    padding: 0;
  }
}