/* 基础样式：重置、排版、焦点与通用工具类 */

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

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

body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-ink);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

[hidden] {
  display: none !important;
}

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

h1,
h2,
h3 {
  margin: 0 0 var(--sp-3);
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: 0.02em;
}

p {
  margin: 0 0 var(--sp-4);
}

a {
  color: var(--c-primary-text);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

:focus-visible {
  outline: 2px solid var(--c-primary-text);
  outline-offset: 2px;
}

::selection {
  background: var(--c-primary);
  color: var(--c-on-primary);
}

.skip-link {
  position: absolute;
  left: var(--sp-4);
  top: -100px;
  z-index: 50;
  padding: var(--sp-2) var(--sp-4);
  background: var(--c-surface);
  border: 1px solid var(--c-line);
  color: var(--c-ink);
}

.skip-link:focus {
  top: var(--sp-2);
}

.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;
}

/* 用户开启「减弱动态效果」时，全站动效降到最低 */
@media (prefers-reduced-motion: reduce) {
  * {
    transition-duration: 1ms !important;
    animation-duration: 1ms !important;
    scroll-behavior: auto !important;
  }
}