/* ==========================================================================
   Common Stylesheet
   Shared tokens, reset, navigation, footer and accessibility
   ========================================================================== */

:root {
  color-scheme: light;

  --ink: #1d1d1f;
  --muted: #6e6e73;
  --soft: #f5f5f7;
  --paper: #ffffff;
  --white: #ffffff;
  --black: #000000;

  --blue: #0071e3;
  --blue-strong: #005fcc;
  --green: #008c5a;
  --red: #ff3b30;
  --purple: #8b5cf6;

  --line: rgba(29, 29, 31, 0.12);
  --ink-08: rgba(29, 29, 31, 0.08);
  --ink-12: rgba(29, 29, 31, 0.12);
  --ink-68: rgba(29, 29, 31, 0.68);
  --ink-82: rgba(29, 29, 31, 0.82);

  --shadow-sm: 0 1px 2px rgba(29, 29, 31, 0.04);
  --shadow-md: 0 18px 54px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 34px 90px rgba(0, 0, 0, 0.12);

  --radius: 8px;
  --radius-md: 18px;
  --radius-lg: 28px;
  --radius-xl: 36px;
  --max: 980px;
  --wide: 1440px;

  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --duration-fast: 180ms;
  --duration: 260ms;
  --duration-slow: 320ms;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background: var(--soft);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

button {
  font: inherit;
}

button,
a,
[role="link"],
[tabindex] {
  -webkit-tap-highlight-color: rgba(0, 113, 227, 0.16);
}

a:focus-visible,
button:focus-visible,
[role="link"]:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid var(--blue-strong);
  outline-offset: 4px;
}

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

h1,
h2,
h3,
p {
  margin-top: 0;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1000;
  border-radius: 999px;
  padding: 10px 16px;
  color: var(--white);
  background: var(--blue-strong);
  font-weight: 700;
  transform: translateY(-140%);
  transition: transform var(--duration-fast) var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  clip-path: inset(50%);
}

.liquid-glass-filter {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
  pointer-events: none;
}

[data-glass] {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.82);
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.72), rgba(255, 255, 255, 0.28)),
    linear-gradient(315deg, rgba(0, 113, 227, 0.08), rgba(255, 255, 255, 0.12));
  box-shadow:
    var(--shadow-md),
    inset 0 1px 0 rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(22px) saturate(1.25);
  -webkit-backdrop-filter: blur(22px) saturate(1.25);
}

[data-glass]::before,
[data-glass]::after {
  content: none;
}

[data-glass] > * {
  position: relative;
  z-index: 1;
}

.site-shell {
  overflow: hidden;
}

.topbar {
  position: fixed;
  z-index: 20;
  top: 0;
  left: 0;
  display: flex;
  width: 100%;
  height: 44px;
  align-items: center;
  justify-content: flex-start;
  padding: 0 18px;
  border-bottom: 1px solid var(--ink-08);
  background: rgba(255, 255, 255, 0.78);
  box-shadow: 0 1px 12px rgba(0, 0, 0, 0.02);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  overflow: visible;
}

.brand,
.nav-links {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
}

.brand {
  gap: 8px;
  font-size: 0.82rem;
  font-weight: 600;
}

.brand-mark {
  display: grid;
  width: 24px;
  height: 24px;
  place-items: center;
  border-radius: 7px;
  color: var(--white);
  background: linear-gradient(135deg, var(--ink), var(--blue));
  font-size: 0.64rem;
}

.nav-links {
  gap: 30px;
  margin-left: auto;
  justify-content: flex-end;
}

.nav-links a,
.contact-toggle {
  display: flex;
  height: 44px;
  align-items: center;
  border: 0;
  padding: 0;
  color: rgba(29, 29, 31, 0.78);
  background: transparent;
  font: inherit;
  font-size: 0.78rem;
  line-height: 1;
  cursor: pointer;
  transition:
    color var(--duration-fast) var(--ease),
    background var(--duration-fast) var(--ease);
}

.nav-links a:hover,
.contact-toggle:hover,
.contact-toggle[aria-expanded="true"] {
  color: var(--ink);
}

.menu-toggle {
  display: none;
}

.contact-popover {
  position: absolute;
  z-index: 30;
  top: 52px;
  right: 18px;
  display: grid;
  width: min(292px, calc(100vw - 36px));
  gap: 8px;
  border-radius: var(--radius-md);
  padding: 8px;
  opacity: 0;
  transform: translateY(-10px) scale(0.98);
  transform-origin: top right;
  pointer-events: none;
  transition:
    opacity var(--duration-fast) var(--ease),
    transform var(--duration-fast) var(--ease);
}

.contact-popover.is-open {
  opacity: 1;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.mail-card {
  display: grid;
  grid-template-columns: 36px minmax(0, 1fr);
  gap: 10px;
  align-items: center;
  border: 1px solid rgba(255, 255, 255, 0.62);
  border-radius: 14px;
  padding: 11px 12px;
  background: rgba(255, 255, 255, 0.78);
  box-shadow: var(--shadow-md);
  text-decoration: none;
  transition:
    transform var(--duration-fast) var(--ease),
    box-shadow var(--duration-fast) var(--ease);
}

.mail-card:hover,
.mail-card:focus-visible {
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.mail-logo {
  display: grid;
  width: 36px;
  height: 36px;
  place-items: center;
}

.mail-logo svg {
  width: 30px;
  height: 30px;
}

.linkedin-logo svg {
  width: 28px;
  height: 28px;
}

.mail-card strong,
.mail-card small {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mail-card strong {
  color: var(--ink);
  font-size: 0.9rem;
  font-weight: 700;
}

.mail-card small {
  margin-top: 2px;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 600;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--blue);
  font-size: 0.86rem;
  font-weight: 700;
  text-transform: uppercase;
}

.button,
.contact-actions a {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 10px 22px;
  font-weight: 500;
  transition:
    transform var(--duration-fast) var(--ease),
    box-shadow var(--duration-fast) var(--ease),
    background var(--duration-fast) var(--ease);
}

.button:hover,
.contact-actions a:hover {
  transform: translateY(-2px);
}

.primary {
  color: var(--white);
  background: var(--blue);
}

.secondary,
.contact-actions a {
  color: var(--blue);
  border: 1px solid var(--blue);
  background: transparent;
}

.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition:
    opacity 700ms var(--ease),
    transform 700ms var(--ease);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.delay-1 { transition-delay: 100ms; }
.delay-2 { transition-delay: 200ms; }
.delay-3 { transition-delay: 300ms; }

.site-footer {
  display: grid;
  min-height: 56px;
  grid-template-columns: max-content 1fr max-content;
  align-items: center;
  column-gap: 16px;
  padding: 10px 28px;
  color: var(--black);
  background: var(--white);
}

.footer-powered {
  display: flex;
  min-width: 0;
  align-items: center;
  justify-self: start;
  gap: 12px;
  white-space: nowrap;
}

.footer-credit {
  grid-column: 3;
  justify-self: end;
  color: var(--black);
  font-size: 0.95rem;
  font-weight: 600;
}

.footer-brand {
  display: inline-flex;
  flex-shrink: 0;
  align-items: center;
  gap: 6px;
  color: inherit;
  text-decoration: none;
}

.footer-brand svg {
  display: block;
  width: 20px;
  height: 20px;
  color: currentColor;
  fill: currentColor;
  stroke: none;
}

main:focus {
  outline: none;
}

@media (max-width: 960px) {
  .topbar {
    min-height: 44px;
    height: 44px;
    align-items: center;
    flex-wrap: wrap;
    align-content: flex-start;
    padding: 0 max(16px, env(safe-area-inset-right)) 0 max(16px, env(safe-area-inset-left));
    background: rgba(255, 255, 255, 0.86);
    overflow: hidden;
    transition:
      height var(--duration) var(--ease),
      background var(--duration) var(--ease);
  }

  .topbar.is-menu-open {
    height: 88px;
    background: rgba(255, 255, 255, 0.94);
  }

  .topbar.is-contact-open {
    overflow: visible;
  }

  .topbar .brand {
    height: 44px;
  }

  .menu-toggle {
    position: relative;
    z-index: 2;
    display: inline-grid;
    width: 44px;
    height: 44px;
    place-items: center;
    margin-left: auto;
    border: 0;
    background: transparent;
    cursor: pointer;
  }

  .menu-toggle span {
    position: absolute;
    width: 16px;
    height: 2px;
    border-radius: 999px;
    background: rgba(29, 29, 31, 0.86);
    transition: transform 220ms var(--ease);
  }

  .menu-toggle span:first-child { transform: translateY(-4px); }
  .menu-toggle span:last-child { transform: translateY(4px); }

  .topbar.is-menu-open .menu-toggle span:first-child { transform: rotate(45deg); }
  .topbar.is-menu-open .menu-toggle span:last-child { transform: rotate(-45deg); }

  .topbar .nav-links {
    order: 3;
    display: grid;
    width: 100%;
    height: 44px;
    max-height: 0;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 0;
    overflow: hidden;
    margin: 0;
    padding: 0;
    border-top: 1px solid var(--ink-08);
    opacity: 0;
    transform: translateY(-4px);
    transition:
      max-height var(--duration) var(--ease),
      opacity 220ms var(--ease),
      transform 220ms var(--ease);
  }

  .topbar.is-menu-open .nav-links {
    max-height: 44px;
    opacity: 1;
    transform: translateY(0);
  }

  .topbar .nav-links a,
  .topbar .contact-toggle {
    min-height: 44px;
    height: 44px;
    justify-content: center;
    font-size: 0.76rem;
    font-weight: 500;
  }

  .topbar .contact-popover {
    z-index: 80;
    top: 88px;
    right: max(16px, env(safe-area-inset-right));
    width: min(320px, calc(100vw - 32px));
  }

  .topbar:not(.is-menu-open) .contact-popover {
    opacity: 0;
    transform: translateY(-10px) scale(0.98);
    pointer-events: none;
  }
}

@media (max-width: 720px) {
  .site-footer {
    grid-template-columns: 1fr;
    row-gap: 10px;
    min-height: auto;
    padding: 16px 22px calc(16px + env(safe-area-inset-bottom));
    overflow: hidden;
    text-align: center;
  }

  .footer-credit {
    grid-column: 1;
    justify-self: center;
  }

  .footer-powered {
    width: 100%;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px 10px;
    white-space: normal;
    line-height: 1.35;
  }

  .footer-powered > span,
  .footer-brand {
    white-space: nowrap;
  }

  .footer-brand svg {
    width: 18px;
    height: 18px;
  }
}

@media (max-width: 520px) {
  .topbar .nav-links a,
  .topbar .contact-toggle {
    font-size: 0.74rem;
  }
}

@media (prefers-contrast: more) {
  :root {
    --ink: #000000;
    --muted: #3a3a3c;
    --line: rgba(0, 0, 0, 0.32);
    --blue: #005fcc;
    --green: #006c47;
  }
}

@media (prefers-reduced-transparency: reduce) {
  [data-glass],
  .github-link {
    background: rgba(255, 255, 255, 0.96) !important;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
  }
}

@media (inverted-colors: inverted) {
  img,
  svg {
    filter: invert(1);
  }
}

@media (forced-colors: active) {
  * {
    forced-color-adjust: auto;
  }

  [data-glass] {
    border: 1px solid CanvasText;
    background: Canvas;
    box-shadow: none;
  }

  a:focus-visible,
  button:focus-visible,
  [role="link"]:focus-visible,
  [tabindex]:focus-visible {
    outline: 3px solid Highlight;
  }
}

@media (pointer: coarse) {
  button,
  a,
  [role="link"],
  [tabindex] {
    min-height: 44px;
  }

  .footer-brand,
  .mail-card {
    touch-action: manipulation;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 1ms !important;
  }

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

/* 这是多语言切换按钮样式：无导航页面会显示为右上角玻璃按钮。 */
.language-switch {
  display: inline-flex;
  width: 38px;
  height: 28px;
  align-items: center;
  justify-content: center;
  border: 0;
  border-radius: 10px;
  color: rgba(29, 29, 31, 0.78);
  background: rgba(255, 255, 255, 0.52);
  box-shadow: inset 0 0 0 1px rgba(29, 29, 31, 0.08);
  font: inherit;
  font-size: 0.76rem;
  font-weight: 800;
  cursor: pointer;
}

.language-switch.is-floating {
  position: fixed;
  z-index: 80;
  top: 14px;
  right: 14px;
  backdrop-filter: blur(18px) saturate(1.2);
  -webkit-backdrop-filter: blur(18px) saturate(1.2);
}