:root {
  color-scheme: dark;
  --color-bg: #05080d;
  --color-bg-deep: #03060a;
  --color-text: #edf4ff;
  --color-text-muted: #aebdce;
  --color-text-subtle: #7f91a6;
  --color-accent: #2f8cff;
  --color-accent-bright: #69b4ff;
  --color-accent-soft: rgba(47, 140, 255, 0.1);
  --color-border-subtle: rgba(150, 181, 214, 0.16);
  --color-border-strong: rgba(150, 181, 214, 0.3);
  --font-display: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-body: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;
  --radius-sm: 0.3rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  min-width: 20rem;
  background: var(--color-bg);
}

body {
  min-width: 20rem;
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(ellipse 80% 50% at 10% -10%, rgba(47, 140, 255, 0.08), transparent 55%),
    var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

html[lang="zh-CN"] body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Noto Sans CJK SC", "Source Han Sans SC", sans-serif;
  line-height: 1.78;
  letter-spacing: 0.015em;
  overflow-wrap: anywhere;
}

a {
  color: inherit;
  text-underline-offset: 0.18em;
}

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

:focus-visible {
  outline: 3px solid var(--color-accent-bright);
  outline-offset: 4px;
}

::selection {
  background: var(--color-accent);
  color: #fff;
}

.skip-link {
  position: fixed;
  top: var(--space-3);
  left: var(--space-3);
  z-index: 100;
  padding: 0.7rem 0.9rem;
  transform: translateY(-160%);
  border-radius: var(--radius-sm);
  background: var(--color-text);
  color: var(--color-bg);
  font-weight: 750;
  text-decoration: none;
}

.skip-link:focus {
  transform: none;
}

.page {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.lang {
  display: flex;
  justify-content: flex-end;
  width: min(calc(100% - 2.5rem), 40rem);
  margin: 0 auto;
  padding-top: var(--space-5);
}

.lang a {
  color: var(--color-text-subtle);
  font-size: 0.82rem;
  font-weight: 650;
  text-decoration: none;
}

.lang a[aria-current="page"] {
  color: var(--color-text);
  pointer-events: none;
}

.lang a:not([aria-current="page"]):hover {
  color: var(--color-accent-bright);
}

.main {
  display: flex;
  flex: 1;
  align-items: center;
  width: min(calc(100% - 2.5rem), 40rem);
  margin: 0 auto;
  padding-block: var(--space-7) var(--space-8);
}

.eyebrow {
  margin: 0;
  color: var(--color-accent-bright);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 650;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

html[lang="zh-CN"] .eyebrow {
  letter-spacing: 0.08em;
  text-transform: none;
}

h1 {
  max-width: 16ch;
  margin: var(--space-4) 0 0;
  font-family: var(--font-display);
  font-size: clamp(2.15rem, 7.2vw, 3.6rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.035em;
}

html[lang="zh-CN"] h1 {
  max-width: 12em;
  letter-spacing: -0.015em;
  line-height: 1.18;
}

.intro,
.secondary {
  max-width: 38rem;
  margin: var(--space-5) 0 0;
  color: var(--color-text-muted);
  font-size: clamp(1.02rem, 2vw, 1.18rem);
  line-height: 1.6;
}

.secondary {
  margin-top: var(--space-4);
}

.cta {
  display: inline-flex;
  gap: var(--space-2);
  align-items: center;
  justify-content: center;
  min-height: 2.9rem;
  margin-top: var(--space-6);
  padding: 0.75rem 1rem;
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: #fff;
  font-size: 0.86rem;
  font-weight: 730;
  text-decoration: none;
}

.cta:hover {
  background: var(--color-accent-bright);
  color: #03101d;
}

.note {
  margin: var(--space-5) 0 0;
  color: var(--color-text-subtle);
  font-size: 0.92rem;
}

.footer {
  width: min(calc(100% - 2.5rem), 40rem);
  margin: 0 auto;
  padding-block: 0 var(--space-6);
  color: var(--color-text-subtle);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
}

@media (max-width: 430px) {
  .main {
    padding-block: var(--space-6) var(--space-7);
  }

  h1 {
    font-size: clamp(1.85rem, 9vw, 2.4rem);
  }
}