/* Nova Product Site — OpenAI dark tech tokens (single source) */
:root {
  --bg: #0a0a0a;
  --bg-elevated: #141414;
  --bg-soft: #111111;
  --text: #ececec;
  --text-body: #c8c8c8;
  --text-muted: #6b6b6b;
  --line: rgba(255, 255, 255, 0.1);
  --line-subtle: rgba(255, 255, 255, 0.06);
  --accent: #10a37f;
  --accent-hover: #19c37d;
  --accent-soft: rgba(16, 163, 127, 0.12);
  --danger: #ef4444;

  --font-sans: "Segoe UI Variable Display", "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: ui-monospace, "SF Mono", Consolas, monospace;

  --site-top-h: 64px;
  --site-top-h-compact: 56px;
  --content-max: 1120px;
  --doc-max: 740px;
  --toc-w: 220px;
  --form-max: 560px;
  --page-pad: clamp(24px, 5vw, 48px);

  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 16px;
  --radius-pill: 999px;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --dur-fast: 180ms;
  --dur: 280ms;
  --dur-slow: 420ms;
  --dur-panel: 480ms;

  --shadow-float: 0 8px 32px rgba(0, 0, 0, 0.45);

  color-scheme: dark;
}

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

html {
  scroll-behavior: smooth;
  overflow-x: clip;
  max-width: 100%;
}

body {
  margin: 0;
  min-height: 100%;
  min-width: 0;
  max-width: 100%;
  overflow-x: clip;
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.65;
  color: var(--text-body);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  /* PWA / 刘海屏安全区 */
  padding:
    env(safe-area-inset-top, 0)
    env(safe-area-inset-right, 0)
    env(safe-area-inset-bottom, 0)
    env(safe-area-inset-left, 0);
}

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

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

button,
input,
textarea,
select {
  font: inherit;
  color: inherit;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

::selection {
  background: var(--accent-soft);
  color: var(--text);
}