/* ============================================================
   base.css — 重置、排版、焦点、动效降级
   ============================================================ */

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

* {
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.7;
  letter-spacing: 0.01em;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  overflow-x: hidden;
}

/* 工业风等宽数字：所有时间、统计、编号字段都必须齐宽 */
.num,
time,
.tabular {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

h1,
h2,
h3,
h4 {
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

h1 {
  font-size: clamp(38px, 5.6vw, 68px);
  letter-spacing: -0.035em;
  line-height: 0.98;
}

h2 {
  font-size: var(--text-2xl);
}

h3 {
  font-size: var(--text-lg);
  line-height: 1.25;
}

a {
  color: var(--color-accent);
  text-underline-offset: 3px;
}

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

button {
  cursor: pointer;
  background: none;
  border: none;
}

ul,
ol {
  list-style: none;
}

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

/* ---------- 键盘可达：焦点圈必须可见 ---------- */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ---------- 屏幕阅读器专用 ---------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 滚动条：与工业风统一 ---------- */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--color-surface-2);
}

::-webkit-scrollbar-thumb {
  background: var(--color-border-strong);
  border: 2px solid var(--color-surface-2);
  border-radius: 6px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-muted);
}

/* ============================================================
   氛围层：网格线 + 双径向渐变 + 噪点
   工业风不铺纯色底，靠这三层建立「仪表盘」质感
   ============================================================ */

.atmosphere::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(52rem 34rem at 6% -8%, rgba(184, 65, 15, 0.12), transparent 62%),
    radial-gradient(46rem 32rem at 102% 4%, rgba(28, 79, 134, 0.1), transparent 58%);
}

.atmosphere::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.5;
  background-image:
    linear-gradient(var(--color-border) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-border) 1px, transparent 1px);
  background-size: 72px 72px;
  mask-image: radial-gradient(ellipse 100% 70% at 50% 0%, #000 10%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 100% 70% at 50% 0%, #000 10%, transparent 78%);
}

.grain {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0.045;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ============================================================
   入场序列：3–6 组错峰，间隔 80ms
   ============================================================ */

.reveal {
  opacity: 0;
  transform: translateY(20px);
}

.reveal.in {
  opacity: 1;
  transform: none;
  transition:
    opacity var(--dur-slow) var(--ease-out),
    transform var(--dur-slow) var(--ease-out);
}

.reveal:nth-child(1) { transition-delay: 0ms; }
.reveal:nth-child(2) { transition-delay: 80ms; }
.reveal:nth-child(3) { transition-delay: 160ms; }
.reveal:nth-child(4) { transition-delay: 240ms; }
.reveal:nth-child(5) { transition-delay: 320ms; }

/* ---------- 动效降级：必须验证过 ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal,
  .reveal.in {
    opacity: 1;
    transform: none;
    transition: none;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}