/**
 * Base · reset, type, utilities, reveal
 */

@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url("../fonts/ibm-plex-mono-latin-400-normal.woff2") format("woff2");
}

@font-face {
  font-family: "IBM Plex Mono";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("../fonts/ibm-plex-mono-latin-500-normal.woff2") format("woff2");
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 1rem);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection {
  background: rgba(29, 85, 165, 0.18);
}

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

a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

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

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

.skip-link {
  position: absolute;
  left: 0.75rem;
  top: 0.75rem;
  z-index: 100;
  padding: 0.55rem 0.9rem;
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: #fff;
  font-size: var(--text-small);
  font-weight: 600;
  text-decoration: none;
  transform: translateY(-150%);
  transition: transform var(--duration-ui) var(--ease-out);
}

.skip-link:focus,
.skip-link:focus-visible {
  transform: translateY(0);
  outline: 2px solid #fff;
  outline-offset: 2px;
  color: #fff;
}

h1,
h2,
h3,
h4 {
  margin: 0 0 var(--space-4);
  font-weight: 600;
  line-height: var(--leading-heading);
  color: inherit;
  text-wrap: balance;
}

h1 {
  font-size: var(--text-h1);
  line-height: var(--leading-display);
  letter-spacing: var(--tracking-display);
}

h2 {
  font-size: var(--text-h2);
}

h3 {
  font-size: var(--text-h3);
  line-height: 1.4;
}

p {
  margin: 0 0 var(--space-4);
  max-width: 40rem;
}

p:last-child {
  margin-bottom: 0;
}

.wrap {
  width: var(--wrap);
  margin-inline: auto;
}

.muted {
  color: var(--color-muted);
}

.mono {
  font-family: var(--font-mono);
  font-feature-settings: "zero" 0;
}

/*
 * Eyebrow: mono index + label, e.g. "01 — 业务".
 * Latin/digits render in Plex Mono; CJK falls back to the sans stack.
 */
.eyebrow {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 0 0 1.1rem;
  font-family: var(--font-mono), var(--font-sans);
  font-size: var(--text-label);
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: var(--tracking-label);
  text-transform: uppercase;
  color: var(--color-accent);
}

.eyebrow__index {
  color: var(--color-faint);
}

.eyebrow::before {
  content: "";
  width: 1.5rem;
  height: 1px;
  background: currentColor;
  opacity: 0.6;
  order: 1;
}

.eyebrow__index + .eyebrow__label {
  order: 2;
}

.lead {
  font-size: var(--text-lead);
  line-height: 1.7;
  color: var(--color-muted);
  max-width: 38rem;
}

.sr-only,
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Reveal: once, opacity + short rise; static under reduced motion */
.reveal {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: no-preference) {
  .reveal.is-reveal-ready {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity var(--duration-reveal) var(--ease-out),
      transform var(--duration-reveal) var(--ease-out);
  }

  .reveal.is-reveal-ready.is-in {
    opacity: 1;
    transform: none;
  }

  html.is-motion .eyebrow::before {
    transform: scaleX(0);
    transform-origin: left center;
  }

  html.is-motion .reveal.is-in .eyebrow::before,
  html.is-motion .is-hero-in .eyebrow::before {
    transform: scaleX(1);
    transition: transform var(--duration-reveal) var(--ease-out);
  }

  html.is-motion .lines > li.reveal.is-in:nth-child(2) { transition-delay: 80ms; }
  html.is-motion .lines > li.reveal.is-in:nth-child(3) { transition-delay: 160ms; }
}