/* UniPass 官网 — 设计系统
 * iOS 风格,品牌蓝 #0A84FF,明暗双主题(prefers-color-scheme)。
 * 调色板对齐 docs/ui-design-spec.md。纯静态,无构建。
 */

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f7;
  --bg-tertiary: #e8e8ed;
  --text-primary: #1d1d1f;
  --text-secondary: #6e6e73;
  /* tertiary 提到 AA 合规(#767676 ≈ 4.5:1 on white)：小字信息也需可读 */
  --text-tertiary: #767676;
  /* 品牌蓝(light)用 Apple 官网同款 #0071E3：白字按钮 / 正文链接达 AA 4.69:1 */
  --brand: #0071e3;
  --brand-strong: #0060c8;
  --success: #34c759;
  --warning: #ff9500;
  --danger: #ff3b30;
  --border: rgba(0, 0, 0, 0.08);
  --card: #ffffff;
  --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 8px 30px rgba(0, 0, 0, 0.05);
  --nav-bg: rgba(255, 255, 255, 0.72);
  --radius: 16px;
  --radius-sm: 10px;
  --maxw: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", system-ui,
    "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #000000;
    --bg-secondary: #1c1c1e;
    --bg-tertiary: #2c2c2e;
    --text-primary: #f5f5f7;
    --text-secondary: #98989d;
    /* dark tertiary 提到 #8e8e93(≈5:1 on dark)，小字可读 */
    --text-tertiary: #8e8e93;
    --brand: #0a84ff;
    --brand-strong: #409cff;
    --border: rgba(255, 255, 255, 0.1);
    --card: #1c1c1e;
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 8px 30px rgba(0, 0, 0, 0.3);
    --nav-bg: rgba(20, 20, 22, 0.72);
  }
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  color: var(--text-primary);
  background: var(--bg-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--brand);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

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

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

/* ---------- Nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex;
  align-items: center;
  gap: 20px;
  height: 56px;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 600;
  font-size: 17px;
  color: var(--text-primary);
}
.nav-brand:hover {
  text-decoration: none;
}
.nav-brand img {
  width: 26px;
  height: 26px;
}
.nav-links {
  display: flex;
  gap: 22px;
  margin-left: auto;
  align-items: center;
}
.nav-links a {
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
}
.nav-links a:hover {
  color: var(--text-primary);
  text-decoration: none;
}
.nav-lang {
  font-size: 13px;
  color: var(--text-tertiary);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px 10px;
}
.nav-lang:hover {
  color: var(--brand);
  text-decoration: none;
}
.nav-cta {
  padding: 7px 16px;
  font-size: 14px;
}

/* 汉堡菜单（纯 CSS，checkbox hack —— 不依赖 JS，兼容 script-src 'none' CSP） */
.nav-toggle-cb {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0; /* 视觉隐藏但保留在 tab 顺序中，键盘可切换 */
}
.nav-toggle {
  display: none; /* 桌面隐藏 */
  margin-left: auto;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 9px;
  color: var(--text-primary);
  cursor: pointer;
}
.nav-toggle:hover {
  background: var(--bg-secondary);
}
.nav-toggle .ico-close {
  display: none;
}
.nav-toggle-cb:checked ~ .nav-toggle .ico-open {
  display: none;
}
.nav-toggle-cb:checked ~ .nav-toggle .ico-close {
  display: block;
}
.nav-toggle-cb:focus-visible ~ .nav-toggle {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}

/* ---------- Accessibility ---------- */
/* 键盘可见焦点环（品牌规范要求品牌蓝 focus ring） */
a:focus-visible,
button:focus-visible,
label:focus-visible,
input:focus-visible,
.btn:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
  border-radius: 8px;
}
/* 尊重系统“减少动效” */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
  }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: inherit;
  font-size: 15px;
  font-weight: 500;
  padding: 11px 22px;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.08s ease, background 0.15s ease, opacity 0.15s ease;
}
.btn:hover {
  text-decoration: none;
}
.btn:active {
  transform: scale(0.97);
}
.btn-primary {
  /* 固定 #0071E3：白字达 AA 4.69:1，明暗两主题一致 */
  background: #0071e3;
  color: #fff;
}
.btn-primary:hover {
  background: #0060c8;
}
.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-color: var(--border);
}
.btn-secondary:hover {
  background: var(--bg-tertiary);
}
.btn-lg {
  font-size: 16px;
  padding: 14px 28px;
}

/* ---------- Hero ---------- */
.hero {
  text-align: center;
  padding: 96px 0 72px;
  background: radial-gradient(
    120% 120% at 50% 0%,
    color-mix(in srgb, var(--brand) 10%, transparent) 0%,
    transparent 55%
  );
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 13px;
  font-weight: 500;
  color: var(--brand);
  background: color-mix(in srgb, var(--brand) 12%, transparent);
  padding: 5px 14px;
  border-radius: 999px;
  margin-bottom: 22px;
}
.hero h1 {
  font-size: clamp(36px, 6vw, 60px);
  line-height: 1.06;
  letter-spacing: -0.02em;
  font-weight: 700;
  margin-bottom: 20px;
}
.hero h1 .accent {
  color: var(--brand);
}
.hero p.lead {
  font-size: clamp(17px, 2.4vw, 21px);
  color: var(--text-secondary);
  max-width: 620px;
  margin: 0 auto 32px;
}
.hero-cta {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}
.hero-note {
  margin-top: 16px;
  font-size: 13px;
  color: var(--text-tertiary);
}

/* ---------- Sections ---------- */
section.block {
  padding: 72px 0;
}
section.block.alt {
  background: var(--bg-secondary);
}
.section-head {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 48px;
}
.section-head h2 {
  font-size: clamp(28px, 4vw, 40px);
  letter-spacing: -0.02em;
  font-weight: 700;
  margin-bottom: 14px;
}
.section-head p {
  font-size: 17px;
  color: var(--text-secondary);
}

/* ---------- Feature grid ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--card-shadow);
}
.card .ico {
  width: 44px;
  height: 44px;
  border-radius: 11px;
  background: color-mix(in srgb, var(--brand) 14%, transparent);
  color: var(--brand);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}
.card h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 8px;
}
.card p {
  font-size: 14.5px;
  color: var(--text-secondary);
}

/* ---------- Steps ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  counter-reset: step;
}
.step {
  position: relative;
  padding-top: 8px;
}
.step .num {
  width: 34px;
  height: 34px;
  border-radius: 999px;
  background: var(--brand);
  color: #fff;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}
.step h3 {
  font-size: 17px;
  margin-bottom: 7px;
}
.step p {
  font-size: 14.5px;
  color: var(--text-secondary);
}

/* ---------- Security callout ---------- */
.callout {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-top: 8px;
}
.callout .row {
  display: flex;
  gap: 13px;
  align-items: flex-start;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px 20px;
}
.callout .row svg {
  flex: 0 0 auto;
  color: var(--success);
  margin-top: 2px;
}
.callout .row b {
  display: block;
  font-size: 15px;
  margin-bottom: 3px;
}
.callout .row span {
  font-size: 14px;
  color: var(--text-secondary);
}

/* ---------- CTA band ---------- */
.cta-band {
  text-align: center;
  padding: 80px 0;
}
.cta-band h2 {
  font-size: clamp(26px, 4vw, 38px);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}
.cta-band p {
  color: var(--text-secondary);
  font-size: 17px;
  margin-bottom: 28px;
}

/* ---------- Footer ---------- */
footer {
  border-top: 1px solid var(--border);
  padding: 44px 0 56px;
  background: var(--bg-secondary);
}
.foot-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 40px;
  justify-content: space-between;
}
.foot-brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 600;
  margin-bottom: 10px;
}
.foot-brand img {
  width: 24px;
  height: 24px;
}
.foot-col h4 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-tertiary);
  margin-bottom: 12px;
}
.foot-col a {
  display: block;
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 9px;
}
.foot-col a:hover {
  color: var(--text-primary);
  text-decoration: none;
}
.foot-bottom {
  margin-top: 36px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-tertiary);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- Legal / prose pages ---------- */
.prose-head {
  padding: 64px 0 28px;
  border-bottom: 1px solid var(--border);
}
.prose-head h1 {
  font-size: clamp(30px, 5vw, 44px);
  letter-spacing: -0.02em;
  margin-bottom: 10px;
}
.prose-head .meta {
  color: var(--text-tertiary);
  font-size: 14px;
}
.prose {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 24px 80px;
  font-size: 16px;
}
.prose h2 {
  font-size: 24px;
  letter-spacing: -0.01em;
  margin: 38px 0 14px;
}
.prose h3 {
  font-size: 18px;
  margin: 26px 0 10px;
}
.prose p {
  margin: 0 0 16px;
  color: var(--text-primary);
}
.prose ul,
.prose ol {
  margin: 0 0 16px 22px;
}
.prose li {
  margin-bottom: 8px;
}
.prose strong {
  font-weight: 600;
}
.prose .tldr {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-left: 3px solid var(--brand);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  margin: 0 0 28px;
}
.prose .tldr ul {
  margin-bottom: 0;
}
.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 22px;
  font-size: 14.5px;
}
.prose th,
.prose td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.prose th {
  color: var(--text-secondary);
  font-weight: 600;
  background: var(--bg-secondary);
}
.prose code {
  font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.88em;
  background: var(--bg-tertiary);
  padding: 1px 6px;
  border-radius: 5px;
}

.yes {
  color: var(--success);
  font-weight: 600;
}
.no {
  color: var(--danger);
  font-weight: 600;
}

/* ---------- Responsive ---------- */
@media (max-width: 820px) {
  .grid,
  .steps,
  .callout {
    grid-template-columns: 1fr;
  }

  /* 显示汉堡，nav-links 折叠成下拉面板 */
  .nav-toggle {
    display: inline-flex;
  }
  .nav-links {
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin-left: 0;
    padding: 8px 16px 18px;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--card-shadow);
    display: none; /* 默认收起 */
  }
  .nav-toggle-cb:checked ~ .nav-links {
    display: flex;
  }
  .nav-links a {
    padding: 12px 6px; /* 更大的触控目标 */
    font-size: 16px;
    border-bottom: 1px solid var(--border);
  }
  .nav-links .nav-lang {
    border: 1px solid var(--border);
    align-self: flex-start;
    margin-top: 12px;
    padding: 7px 14px;
  }
  .nav-links .nav-cta {
    text-align: center;
    margin-top: 12px;
    font-size: 15px;
    padding: 12px 20px;
    border-bottom: none;
  }
}
@media (max-width: 520px) {
  .hero {
    padding: 64px 0 52px;
  }
  section.block {
    padding: 56px 0;
  }
}