/* ============================================================
 * FlyMail 飞邮 · 共享设计系统
 * 风格：macOS 液态玻璃 + 新拟态内凹 + 清新分割 + 秀气字体
 * 三页（首页 / 隐私政策 / 服务条款）共用本文件，保证视觉一致
 * ============================================================ */

/* ---------- 设计令牌（Design Tokens）---------- */
:root {
  /* 文字 */
  --text: #17202a;            /* 主文字 */
  --muted: #657482;           /* 次要文字 */
  --subtle: #8a98a5;          /* 辅助文字 */
  /* 表面 */
  --bg: #fbfdfc;              /* 页面底色 */
  --surface: rgba(255, 255, 255, .82);   /* 玻璃表面 */
  --surface-solid: #ffffff;   /* 实心卡片 */
  --line: rgba(23, 32, 42, .08);         /* 分割线 */
  /* 主题色 */
  --blue: #2563eb;
  --blue-soft: #eef5ff;
  --mint: #eaf8f3;
  --mint-strong: #24a77a;
  --cream: #fff7e6;
  /* 形状与阴影 */
  --radius: 22px;
  --shadow: 0 18px 50px rgba(23, 32, 42, .07);
  /* 新拟态内凹阴影：右上暗 / 左下亮，营造柔和凹陷 */
  --neu-inset: inset 3px 3px 7px rgba(23, 32, 42, .06),
               inset -3px -3px 7px rgba(255, 255, 255, .9);
  --neu-inset-soft: inset 2px 2px 5px rgba(23, 32, 42, .045),
                    inset -2px -2px 5px rgba(255, 255, 255, .85);
}

/* ---------- 基础重置 ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--text);
  /* 多层径向渐变营造清新氛围，替代生硬纯色背景 */
  background:
    radial-gradient(circle at 16% 6%, rgba(84, 203, 164, .18), transparent 24rem),
    radial-gradient(circle at 84% 12%, rgba(74, 144, 255, .14), transparent 25rem),
    linear-gradient(180deg, #fbfdfc 0%, #f7fbfa 48%, #ffffff 100%);
  /* 秀气字体栈：优先 SF Pro / PingFang，字重偏轻 */
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue",
               "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 14px;            /* 整体字号收窄，符合秀气偏好 */
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  line-height: 1.65;
}

a { color: inherit; }
ul { margin: 0; }

/* ---------- 顶部导航（液态玻璃）---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid rgba(23, 32, 42, .06);
  background: rgba(255, 255, 255, .74);
  backdrop-filter: blur(22px) saturate(180%);
}

.nav-inner {
  width: min(1080px, calc(100% - 36px));
  min-height: 56px;           /* 导航高度收窄一点更秀气 */
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

/* 品牌：图标 + 名称 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 640;
  letter-spacing: -.01em;
}

/* 品牌 Logo 容器（使用 icon.png 时套一层柔光底） */
.brand-logo {
  width: 30px;
  height: 30px;
  border-radius: 9px;
  object-fit: cover;
  display: block;
  background: #eef5ff;
  border: 1px solid rgba(47, 125, 246, .14);
  box-shadow: 0 4px 10px rgba(37, 99, 235, .12);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
  color: #61707d;
  font-size: 13px;
}

.nav-links a { text-decoration: none; white-space: nowrap; transition: color .18s ease; }
.nav-links a:hover { color: var(--blue); }

/* ---------- 按钮 ---------- */
.button {
  min-height: 40px;           /* 按钮高度略收，更精致 */
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 18px;
  border-radius: 999px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 540;
  transition: transform .18s ease, background .18s ease, box-shadow .18s ease;
}
.button:hover { transform: translateY(-1px); }
.button.primary {
  color: #fff;
  background: var(--blue);
  box-shadow: 0 12px 28px rgba(37, 99, 235, .18);
}
.button.primary:hover { background: #1f56cf; }
.button.secondary {
  color: var(--blue);
  background: rgba(255, 255, 255, .74);
  border: 1px solid rgba(37, 99, 235, .16);
}

/* ---------- 通用章节容器 ---------- */
.section {
  width: min(1080px, calc(100% - 36px));
  margin: 0 auto;
  padding: 72px 0;            /* 章节间距略减，更紧凑 */
}
.section + .section { border-top: 1px solid rgba(23, 32, 42, .06); }

.section-head {
  max-width: 760px;
  margin: 0 auto 36px;
  text-align: center;
}

.kicker {
  margin-bottom: 10px;
  color: #7fa093;
  font-size: 13px;
  font-weight: 640;
  letter-spacing: .01em;
}

.section h2 {
  margin: 0;
  font-size: clamp(26px, 3.6vw, 40px);
  line-height: 1.18;
  letter-spacing: -.035em;
  font-weight: 700;
}

.desc {
  max-width: 680px;
  margin: 14px auto 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.76;
}

/* ---------- 三列卡片网格 ---------- */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.card {
  min-height: 216px;
  padding: 22px;
  border-radius: var(--radius);
  background: var(--surface-solid);
  border: 1px solid var(--line);
  box-shadow: 0 12px 34px rgba(23, 32, 42, .045);
}
/* 卡片配色变体：薄荷 / 蓝 / 奶油 */
.card.soft  { background: linear-gradient(180deg, var(--mint),      rgba(255,255,255,.86)); }
.card.blue  { background: linear-gradient(180deg, var(--blue-soft), rgba(255,255,255,.86)); }
.card.cream { background: linear-gradient(180deg, var(--cream),     rgba(255,255,255,.86)); }

.card h3 {
  margin: 0;
  font-size: 19px;
  line-height: 1.26;
  letter-spacing: -.025em;
  font-weight: 660;
}
.card p,
.card li {
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.75;
}
.card p { margin: 12px 0 0; }
.card ul { margin: 13px 0 0; padding-left: 18px; }

/* ---------- 邮箱服务商网格 ---------- */
.providers {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 13px;
}
.provider {
  min-height: 124px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 18px;
  border-radius: 22px;
  background: rgba(255,255,255,.82);
  border: 1px solid var(--line);
  box-shadow: 0 12px 30px rgba(23, 32, 42, .04);
}
.provider svg { width: 36px; height: 36px; object-fit: contain; }
.provider b { font-size: 15px; letter-spacing: -.02em; }
.provider span { color: var(--muted); font-size: 12px; line-height: 1.45; }

/* ---------- 政策双栏面板 ---------- */
.policy-panel {
  display: grid;
  grid-template-columns: .9fr 1.1fr;
  gap: 18px;
  align-items: stretch;
  padding: 20px;
  border-radius: 30px;
  background: linear-gradient(145deg, #f3fbf8, #f5f9ff);
  border: 1px solid rgba(23, 32, 42, .07);
  box-shadow: var(--shadow);
}
.policy-box {
  padding: 24px;
  border-radius: 24px;
  background: rgba(255,255,255,.72);
  border: 1px solid rgba(23, 32, 42, .065);
}
.policy-box h3 { margin: 0; font-size: 19px; letter-spacing: -.025em; font-weight: 660; }
.policy-box p { margin: 12px 0 0; color: var(--muted); font-size: 13.5px; line-height: 1.75; }

.link-list { display: grid; gap: 10px; margin-top: 18px; }
.link-item {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  padding: 13px 14px;
  border-radius: 16px;
  text-decoration: none;
  color: var(--text);
  background: rgba(255,255,255,.8);
  border: 1px solid rgba(23, 32, 42, .065);
  font-size: 13.5px;
  transition: background .18s ease, transform .18s ease;
}
.link-item:hover { background: #fff; transform: translateX(2px); }
.link-item span:last-child { color: var(--blue); }

/* ---------- 首页 Hero ---------- */
.hero { padding: 72px 18px 64px; text-align: center; }
.hero-inner { width: min(980px, 100%); margin: 0 auto; }

/* 首页顶部标签（区别于文档页 .doc-hero .badge）*/
.hero .badge {
  display: inline-flex; align-items: center; gap: 8px;
  margin-bottom: 18px; padding: 6px 12px; border-radius: 999px;
  color: #3f6c5d; background: rgba(255, 255, 255, .76);
  border: 1px solid var(--line); font-size: 12.5px;
  box-shadow: 0 10px 28px rgba(23, 32, 42, .045);
}
.hero .badge::before {
  content: ""; width: 7px; height: 7px; border-radius: 50%;
  background: var(--mint-strong); box-shadow: 0 0 0 4px rgba(36, 167, 122, .12);
}

.hero h1 {
  max-width: 760px; margin: 0 auto;
  font-size: clamp(27px, 4vw, 46px);
  line-height: 1.12; letter-spacing: -.045em; font-weight: 720;
}

.hero .lead {
  max-width: 720px; margin: 20px auto 0;
  color: var(--muted);
  font-size: clamp(15px, 1.7vw, 19px);
  line-height: 1.75; letter-spacing: -.01em;
}

.actions {
  display: flex; flex-wrap: wrap; justify-content: center;
  gap: 12px; margin-top: 26px;
}

/* ---------- 海报轮播（首页展示 flymail-1/2/3.png）---------- */
.carousel {
  position: relative;
  width: min(940px, 100%);
  margin: 48px auto 0;
  border-radius: 24px;
  overflow: hidden;
  box-shadow: 0 20px 56px rgba(23, 32, 42, .1);
  background: #fff;
  /* 柔光底烘托 */
  filter: drop-shadow(0 0 40px rgba(37, 99, 235, .08));
}
/* 轮播轨道：三张横向排列，JS 控制平移 */
.carousel-track {
  display: flex;
  transition: transform .4s cubic-bezier(.4, 0, .2, 1);
}
.carousel-slide {
  width: 100%;           /* 每张占满容器宽度，一次只显示一张 */
  flex-shrink: 0;
  object-fit: contain;   /* 完整显示海报，不裁切 */
  display: block;
}

/* 左右箭头按钮 */
.carousel-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 2;
  width: 44px; height: 44px;
  border: none; border-radius: 50%;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: blur(12px);
  box-shadow: 0 4px 14px rgba(23, 32, 42, .12);
  color: var(--text);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background .18s ease, box-shadow .18s ease;
}
.carousel-arrow:hover {
  background: #fff;
  box-shadow: 0 6px 20px rgba(23, 32, 42, .16);
}
.carousel-arrow:active { transform: translateY(-50%) scale(.95); }
.carousel-prev { left: 16px; }
.carousel-next { right: 16px; }

/* 底部指示点 */
.carousel-dots {
  position: absolute;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  gap: 8px;
}
.carousel-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: rgba(23, 32, 42, .2);
  cursor: pointer;
  transition: background .2s ease, transform .2s ease;
}
.carousel-dot.active {
  background: var(--blue);
  transform: scale(1.3);
}

/* ============================================================
 * 文档页专用样式（隐私政策 / 服务条款）
 * 采用左侧目录 + 右侧内容布局，章节块使用新拟态内凹
 * ============================================================ */

/* 文档页 Hero */
.doc-hero {
  padding: 64px 18px 32px;
  text-align: center;
}
.doc-hero .badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
  padding: 6px 12px;
  border-radius: 999px;
  color: #3f6c5d;
  background: rgba(255, 255, 255, .76);
  border: 1px solid var(--line);
  font-size: 12.5px;
  box-shadow: 0 10px 28px rgba(23, 32, 42, .045);
}
.doc-hero .badge::before {
  content: "";
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--mint-strong);
  box-shadow: 0 0 0 4px rgba(36, 167, 122, .12);
}
.doc-hero h1 {
  margin: 0;
  font-size: clamp(26px, 3.4vw, 38px);
  line-height: 1.16;
  letter-spacing: -.04em;
  font-weight: 700;
}
.doc-hero .lead {
  max-width: 640px;
  margin: 16px auto 0;
  color: var(--muted);
  font-size: 14.5px;
  line-height: 1.75;
}

/* 文档主体：左目录 + 右内容 */
.doc-layout {
  width: min(1080px, calc(100% - 36px));
  margin: 0 auto;
  padding: 8px 0 72px;
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 32px;
  align-items: start;
}

/* 左侧目录（新拟态内凹容器） */
.doc-toc {
  position: sticky;
  top: 80px;
  padding: 18px 16px;
  border-radius: 20px;
  background: rgba(255,255,255,.6);
  border: 1px solid var(--line);
  box-shadow: var(--neu-inset-soft);   /* 内凹效果 */
}
.doc-toc .toc-title {
  margin: 0 0 12px;
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--subtle);
}
.doc-toc ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 4px; }
.doc-toc a {
  display: block;
  padding: 7px 12px;
  border-radius: 10px;
  text-decoration: none;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.4;
  transition: background .18s ease, color .18s ease;
}
.doc-toc a:hover { background: rgba(37, 99, 235, .06); color: var(--blue); }

/* 右侧内容区 */
.doc-content { display: grid; gap: 14px; }

/* 章节块（新拟态内凹） */
.doc-block {
  padding: 24px 26px;
  border-radius: 22px;
  background: rgba(255,255,255,.72);
  border: 1px solid rgba(23, 32, 42, .05);
  box-shadow: var(--neu-inset-soft);   /* 内凹，与目录呼应 */
  scroll-margin-top: 84px;             /* 锚点跳转留出导航高度 */
}
.doc-block h2 {
  margin: 0 0 12px;
  font-size: 17px;
  font-weight: 660;
  letter-spacing: -.02em;
  color: var(--text);
}
.doc-block p {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.78;
}
.doc-block p:last-child { margin-bottom: 0; }
.doc-block ul {
  margin: 4px 0 10px;
  padding-left: 20px;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.78;
}
.doc-block li { margin-bottom: 5px; }
.doc-block strong { color: var(--text); font-weight: 620; }
.doc-block a { color: var(--blue); text-decoration: none; }
.doc-block a:hover { text-decoration: underline; }

/* 文档页底部返回条 */
.doc-back {
  width: min(1080px, calc(100% - 36px));
  margin: 0 auto 56px;
  display: flex;
  justify-content: center;
}

/* ---------- 页脚 ---------- */
footer {
  width: min(1080px, calc(100% - 36px));
  margin: 0 auto;
  padding: 32px 0 44px;
  display: flex;
  justify-content: space-between;
  gap: 18px;
  border-top: 1px solid rgba(23, 32, 42, .07);
  color: #87939d;
  font-size: 12.5px;
}
.footer-links { display: flex; gap: 16px; flex-wrap: wrap; }
footer a { text-decoration: none; color: #697783; transition: color .18s ease; }
footer a:hover { color: var(--blue); }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .grid-3, .providers, .policy-panel { grid-template-columns: 1fr; }
  .section { padding: 60px 0; }
  /* 文档页：目录折叠到顶部横向排列 */
  .doc-layout { grid-template-columns: 1fr; gap: 18px; }
  .doc-toc { position: static; }
  .doc-toc ul { display: flex; flex-wrap: wrap; gap: 4px; }
  .doc-toc a { padding: 6px 10px; }
  footer { flex-direction: column; }
}

@media (max-width: 620px) {
  .nav-inner { align-items: flex-start; flex-direction: column; padding: 12px 0; }
  .nav-links { width: 100%; gap: 16px; overflow-x: auto; padding-bottom: 2px; }
  .hero { padding: 52px 18px 58px; }
  .hero h1 { font-size: 32px; }
  .hero .lead { font-size: 15px; }
  /* 轮播箭头在窄屏缩小 */
  .carousel-arrow { width: 36px; height: 36px; }
  .carousel-prev { left: 8px; }
  .carousel-next { right: 8px; }
  .section h2 { font-size: 26px; }
  .doc-hero { padding: 48px 18px 24px; }
}