/* ============================================================
   基础层：重置、排版、焦点、降级动效
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: var(--fs-base);
  line-height: 1.75;
  letter-spacing: 0.02em;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* 氛围层：大地色渐变网格 + 颗粒噪点 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(56rem 36rem at 8% -8%, rgba(44, 90, 60, 0.12), transparent 60%),
    radial-gradient(48rem 36rem at 102% 4%, rgba(217, 154, 43, 0.14), transparent 55%),
    radial-gradient(40rem 30rem at 50% 110%, rgba(44, 90, 60, 0.08), transparent 60%);
}
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0.05;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.8'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
body > * { position: relative; z-index: 2; }

/* 排版 */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: 0.01em;
  color: var(--color-text);
}
h1 { font-size: var(--fs-hero); line-height: 1.05; }
h2 { font-size: var(--fs-2xl); }
h3 { font-size: var(--fs-md); }

p { max-width: 62ch; }

a {
  color: var(--color-primary);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover { color: var(--color-primary-deep); }

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

ul, ol { padding-left: 1.25em; }

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

/* 键盘焦点可见性 */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* 通用容器 */
.container {
  width: min(1120px, 92vw);
  margin-inline: auto;
}

/* 区块纵向节奏 */
.section { padding-block: var(--space-7); }
.section + .section { padding-top: 0; }

/* 眉题（编辑感标签） */
.kicker {
  font-family: var(--font-body);
  font-size: var(--fs-xs);
  font-weight: 700;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}
.kicker::before {
  content: "";
  width: 28px;
  height: 1px;
  background: var(--color-primary);
}

/* 入场序列：只动 opacity / translateY */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition:
    opacity var(--dur-base) var(--ease-out),
    transform var(--dur-base) var(--ease-out);
}
.reveal.in { opacity: 1; transform: none; }
.reveal[data-delay="1"] { transition-delay: 80ms; }
.reveal[data-delay="2"] { transition-delay: 160ms; }
.reveal[data-delay="3"] { transition-delay: 240ms; }
.reveal[data-delay="4"] { transition-delay: 320ms; }

/* 降级动效：尊重系统减弱动态设置 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* 跳转链接（可访问性） */
.skip-link {
  position: absolute;
  left: var(--space-3);
  top: -48px;
  z-index: 100;
  padding: var(--space-2) var(--space-3);
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-sm);
  transition: top var(--dur-fast) ease-out;
}
.skip-link:focus { top: var(--space-3); }