/* ============================================================
   基础层：重置、排版、氛围背景、焦点与降级动效
   ============================================================ */
* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.75;
  letter-spacing: .02em;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

/* 氛围层：纸面晕染（左上淡绿、右下暖赭）+ 横向信纸格线 */
body::before {
  content: "";
  position: fixed; inset: 0;
  pointer-events: none;
  z-index: 0;
  background:
    radial-gradient(56rem 40rem at 8% -12%, rgba(29, 91, 69, .10), transparent 58%),
    radial-gradient(48rem 36rem at 102% 108%, rgba(191, 66, 38, .07), transparent 55%),
    repeating-linear-gradient(0deg, transparent 0 31px, rgba(42, 36, 27, .045) 31px 32px);
}

/* 颗粒：SVG feTurbulence 噪点，模拟纸张纤维 */
body::after {
  content: "";
  position: fixed; inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: .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");
}

main { position: relative; z-index: 1; }

h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: -.01em;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 4px; }

/* 键盘焦点：2px 朱红描边 + 偏移，纸上像盖章 */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

::selection { background: rgba(29, 91, 69, .22); }

/* 等宽数字：日期、编号 */
.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0;
}

/* 入场编排：错峰显现 */
.reveal { opacity: 0; transform: translateY(24px); }
.reveal.in {
  opacity: 1; transform: none;
  transition: opacity var(--dur-base) var(--ease-out),
              transform var(--dur-base) var(--ease-out);
}
/* 邮戳类元素：从盖下落到落定 */
.reveal.stamp-in { transform: scale(1.7) rotate(-14deg); opacity: 0; }
.reveal.stamp-in.in {
  transform: scale(1) rotate(var(--stamp-tilt, -6deg));
  transition: transform var(--dur-slow) var(--ease-out), opacity var(--dur-slow) var(--ease-out);
}

/* 降级：偏好减少动效时，全部直接呈现 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal, .reveal.stamp-in { opacity: 1 !important; transform: none !important; transition: none !important; }
  .stamp-in.in { transform: rotate(var(--stamp-tilt, -6deg)) !important; }
  * { animation: none !important; transition: none !important; }
}