/* 基础重置与版式骨架 */

/* Inter 自托管，只用拉丁字符集，中文继续走系统字体栈 */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('/Static/fonts/inter-latin-400.woff2') format('woff2');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('/Static/fonts/inter-latin-500.woff2') format('woff2');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url('/Static/fonts/inter-latin-600.woff2') format('woff2');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url('/Static/fonts/inter-latin-700.woff2') format('woff2');
}

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

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

body {
  margin: 0;
  background: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  color: var(--color-ink);
  font-weight: 700;
}

h1 {
  font-size: var(--fs-h1);
  line-height: 1.2;
}

h2 {
  font-size: var(--fs-h2);
  line-height: var(--lh-heading);
  font-weight: 600;
}

h3 {
  font-size: var(--fs-h3);
  line-height: 1.3;
  font-weight: 600;
}

p {
  margin: 0 0 var(--space-3);
}

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

a {
  color: var(--color-brand);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color var(--duration) var(--ease);
}

a:hover {
  color: var(--color-brand-dark);
}

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

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

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

/* 版式容器 */

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding-left: var(--page-x);
  padding-right: var(--page-x);
}

/* 区块。垂直间距固定，不允许逐页微调 */

.section {
  padding-top: var(--space-7);
  padding-bottom: var(--space-7);
}

@media (min-width: 1200px) {
  .section {
    padding-top: var(--space-8);
    padding-bottom: var(--space-8);
  }
}

.section--alt {
  background: var(--color-surface-alt);
}

.section--tight {
  padding-top: var(--space-6);
  padding-bottom: var(--space-6);
}

/* 章节头 */

.section-head {
  margin-bottom: var(--space-5);
}

.section-head__title {
  font-size: var(--fs-h2);
}

.section-head__lead {
  margin-top: var(--space-2);
  font-size: var(--fs-lead);
  line-height: 1.6;
  color: var(--color-text-secondary);
  max-width: 60ch;
}

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

@media (prefers-reduced-motion: reduce) {
  * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}