/* ============================================================
   邻里之间 · 官网样式
   绿色主色 #66BB6A | 响应式三端 | 深色模式跟随系统
   ============================================================ */

/* ---------- CSS 变量（浅色默认） ---------- */
:root {
  --color-primary: #66BB6A;
  --color-primary-dark: #4CAF50;
  --color-primary-light: #A5D6A7;

  --color-bg: #FFFFFF;
  --color-bg-soft: #F5F8F5;
  --color-bg-card: #FFFFFF;

  --color-text: #1F2D22;
  --color-text-secondary: #5B6B60;

  --color-border: #E4ECE6;
  --color-shadow: rgba(46, 90, 55, 0.08);
  --color-shadow-hover: rgba(46, 90, 55, 0.16);

  --radius-card: 16px;
  --radius-btn: 999px;

  --transition: all 0.3s ease;

  --container-width: 1200px;
}

/* ---------- 深色模式（跟随系统） ---------- */
@media (prefers-color-scheme: dark) {
  :root {
    --color-primary: #81C784;
    --color-primary-dark: #66BB6A;
    --color-primary-light: #4CAF50;

    --color-bg: #121814;
    --color-bg-soft: #182019;
    --color-bg-card: #1E2B21;

    --color-text: #E8F0EA;
    --color-text-secondary: #9DB3A4;

    --color-border: #2C3E30;
    --color-shadow: rgba(0, 0, 0, 0.35);
    --color-shadow-hover: rgba(0, 0, 0, 0.5);
  }
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: var(--transition);
}

img {
  max-width: 100%;
}

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

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

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  color: var(--color-text);
}

.section-sub {
  margin-top: 8px;
  font-size: 1rem;
  text-align: center;
  color: var(--color-text-secondary);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block;
  padding: 14px 34px;
  border-radius: var(--radius-btn);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: 2px solid transparent;
  transition: var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 8px 20px var(--color-shadow);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 12px 28px var(--color-shadow-hover);
}

.btn-ghost {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-ghost:hover {
  background: var(--color-primary);
  color: #fff;
  transform: translateY(-2px);
}

/* ---------- Hero 区 ---------- */
.hero {
  position: relative;
  padding-bottom: 96px;
  background: linear-gradient(160deg, var(--color-bg-soft) 0%, var(--color-bg) 70%);
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -140px;
  right: -140px;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--color-primary-light) 0%, transparent 70%);
  opacity: 0.35;
  pointer-events: none;
}

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

.nav-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.nav-cta {
  padding: 8px 20px;
  border-radius: var(--radius-btn);
  background: var(--color-primary);
  color: #fff;
  font-size: 0.9rem;
  font-weight: 600;
  transition: var(--transition);
}

.nav-cta:hover {
  background: var(--color-primary-dark);
}

.hero-content {
  position: relative;
  padding-top: 72px;
  text-align: center;
}

.hero-title {
  font-size: 3.4rem;
  font-weight: 800;
  letter-spacing: 2px;
  color: var(--color-text);
}

.hero-slogan {
  margin-top: 12px;
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-primary-dark);
}

.hero-desc {
  margin: 24px auto 0;
  max-width: 720px;
  font-size: 1.05rem;
  color: var(--color-text-secondary);
}

.hero-actions {
  margin-top: 40px;
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ---------- 特性区 ---------- */
.features {
  padding: 96px 24px;
}

.feature-grid {
  margin-top: 48px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  padding: 32px 24px;
  text-align: center;
  box-shadow: 0 6px 18px var(--color-shadow);
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 14px 32px var(--color-shadow-hover);
  border-color: var(--color-primary-light);
}

.feature-icon {
  font-size: 2.6rem;
  line-height: 1;
}

.feature-title {
  margin-top: 16px;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
}

.feature-desc {
  margin-top: 8px;
  font-size: 0.92rem;
  color: var(--color-text-secondary);
}

/* ---------- 下载区 ---------- */
.download {
  padding: 96px 0;
  background: var(--color-bg-soft);
}

.download-grid {
  margin-top: 48px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.download-card {
  display: block;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  padding: 32px 20px;
  text-align: center;
  box-shadow: 0 6px 18px var(--color-shadow);
  transition: var(--transition);
  cursor: pointer;
}

.download-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 14px 32px var(--color-shadow-hover);
  border-color: var(--color-primary);
}

.download-icon {
  font-size: 2.6rem;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 56px;
}

/* ---------- 平台官方品牌图标（内联 SVG） ---------- */
.brand-icon {
  width: 56px;
  height: 56px;
  display: block;
  fill: currentColor;
  transition: var(--transition);
}

/* Android 官方绿 */
.brand-icon--android {
  color: #3DDC84;
}

/* HarmonyOS 官方蓝 */
.brand-icon--harmony {
  color: #0A59F7;
}

/* Apple 黑（深色模式下转白，见下方媒体查询） */
.brand-icon--apple {
  color: #1F2D22;
}

@media (prefers-color-scheme: dark) {
  /* Android 绿在暗背景稍提亮 */
  .brand-icon--android {
    color: #5CE39B;
  }

  /* HarmonyOS 蓝在暗背景稍提亮 */
  .brand-icon--harmony {
    color: #4C8DFF;
  }

  /* Apple 转白色适配暗背景 */
  .brand-icon--apple {
    color: #E8F0EA;
  }
}

.download-title {
  margin-top: 16px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
}

.download-desc {
  margin-top: 6px;
  font-size: 0.88rem;
  color: var(--color-text-secondary);
}

.download-card--h5 {
  border-color: var(--color-primary);
  background: linear-gradient(160deg, var(--color-bg-card) 0%, var(--color-bg-soft) 100%);
}

/* ---------- Footer ---------- */
.footer {
  padding: 32px 0;
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

/* ============================================================
   响应式断点
   PC ≥1024px（默认） | 平板 768~1023px | 手机 <768px
   ============================================================ */

/* ---------- 平板（<1024px） ---------- */
@media (max-width: 1023px) {
  .hero-title {
    font-size: 2.8rem;
  }

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

/* ---------- 手机（<768px） ---------- */
@media (max-width: 767px) {
  .section-title {
    font-size: 1.6rem;
  }

  .hero {
    padding-bottom: 64px;
  }

  .hero-content {
    padding-top: 48px;
  }

  .hero-title {
    font-size: 2.2rem;
  }

  .hero-slogan {
    font-size: 1.2rem;
  }

  .hero-desc {
    font-size: 0.95rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    width: 100%;
    text-align: center;
  }

  .features,
  .download {
    padding: 64px 0;
  }

  .feature-grid,
  .download-grid {
    grid-template-columns: 1fr;
  }

  .feature-card,
  .download-card {
    padding: 28px 20px;
  }
}

/* ---------- Toast 提示（占位链接点击反馈） ---------- */
.site-toast {
  position: fixed;
  left: 50%;
  bottom: 60px;
  transform: translateX(-50%) translateY(20px);
  max-width: 80vw;
  padding: 12px 24px;
  background: rgba(0, 0, 0, 0.78);
  color: #fff;
  font-size: 0.9rem;
  border-radius: var(--radius-btn);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.25);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s ease;
  z-index: 9999;
}

.site-toast--show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

@media (prefers-color-scheme: dark) {
  .site-toast {
    background: rgba(255, 255, 255, 0.9);
    color: #1f2d22;
  }
}