/* ============================================================
   base.css — 复位 / 全局排版 / 链接 / 滚动条
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }

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

body {
  font-family: var(--font-ui);
  font-size: var(--fs-base);
  line-height: 1.66;
  color: var(--ink);
  background: var(--paper);
  background-image: var(--paper-grad);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color var(--transition), color var(--transition);
}

h1, h2, h3, h4, h5 { line-height: 1.3; font-weight: 700; color: var(--ink); }

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

button { font-family: inherit; font-size: inherit; cursor: pointer; border: none; background: none; color: inherit; }
input, select, textarea { font-family: inherit; font-size: inherit; color: inherit; }

code, kbd, samp { font-family: var(--font-code); }

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

::selection { background: var(--brand-soft); color: var(--brand-ink); }

/* 滚动条 */
* { scrollbar-width: thin; scrollbar-color: var(--line-strong) transparent; }
*::-webkit-scrollbar { width: 10px; height: 10px; }
*::-webkit-scrollbar-thumb { background: var(--line-strong); border-radius: var(--r-full); border: 2px solid transparent; background-clip: content-box; }
*::-webkit-scrollbar-thumb:hover { background: var(--ink-mute); background-clip: content-box; }

/* 工具类 */
.muted { color: var(--ink-mute); }
.soft { color: var(--ink-soft); }
.center { text-align: center; }
.nowrap { white-space: nowrap; }
.hidden { display: none !important; }
.stack { display: flex; flex-direction: column; }
.row { display: flex; align-items: center; }
.gap1 { gap: var(--s1); } .gap2 { gap: var(--s2); } .gap3 { gap: var(--s3); } .gap4 { gap: var(--s4); }
.wrap { flex-wrap: wrap; }
.grow { flex: 1; }
.spread { display: flex; align-items: center; justify-content: space-between; gap: var(--s3); }
.mt1{margin-top:var(--s1)} .mt2{margin-top:var(--s2)} .mt3{margin-top:var(--s3)} .mt4{margin-top:var(--s4)} .mt5{margin-top:var(--s5)} .mt6{margin-top:var(--s6)}
.mb2{margin-bottom:var(--s2)} .mb3{margin-bottom:var(--s3)} .mb4{margin-bottom:var(--s4)}

.kicker {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: var(--fs-xs); font-weight: 700; letter-spacing: .08em;
  text-transform: uppercase; color: var(--brand);
}
.section-title { font-size: var(--fs-xl); font-weight: 750; letter-spacing: -.01em; }
.section-sub { color: var(--ink-soft); font-size: var(--fs-sm); }

/* 进入动画 */
@keyframes fadeUp { from { transform: translateY(9px); } to { transform: none; } }
@keyframes pop { from { opacity: 0; transform: scale(.96); } to { opacity: 1; transform: none; } }
.anim-in > * { animation: fadeUp .34s cubic-bezier(.22,.61,.36,1) backwards; }
.anim-in > *:nth-child(2){animation-delay:.03s} .anim-in > *:nth-child(3){animation-delay:.06s}
.anim-in > *:nth-child(4){animation-delay:.09s} .anim-in > *:nth-child(5){animation-delay:.12s}
.anim-in > *:nth-child(6){animation-delay:.15s} .anim-in > *:nth-child(n+7){animation-delay:.18s}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001ms !important; transition-duration: .001ms !important; }
}