/* =====================================================================
   AI 依搭官网 · 基础样式
   包含：重置、排版、布局容器、区块节奏、通用工具类、滚动动效
   ===================================================================== */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 24px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--c-ink);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* 轻微的纸张颗粒，增强杂志质感（不影响交互） */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--c-ink);
  letter-spacing: -0.01em;
  text-wrap: balance;
}

p {
  margin: 0;
}

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

a {
  color: inherit;
  text-decoration: none;
}

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

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

button {
  cursor: pointer;
}

::selection {
  color: #fff;
  background: var(--c-accent);
}

:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 布局 ---------- */
.container {
  width: min(var(--container), 100% - var(--gutter) * 2);
  margin-inline: auto;
}

.section {
  padding-block: var(--section-y);
}

.section--tight {
  padding-block: clamp(48px, 6vw, 80px);
}

.section--deep {
  background: var(--c-bg-deep);
}

.section--line {
  border-top: 1px solid var(--c-line);
}

/* ---------- 通用文本 ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 18px;
  font-family: var(--font-body);
  font-size: 11px;
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--c-accent);
}

.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: currentColor;
}

.section-head {
  max-width: 780px;
  margin-bottom: clamp(36px, 5vw, 56px);
}

.section-head h2 {
  margin-bottom: 18px;
  font-size: clamp(30px, 4vw, 46px);
  line-height: 1.25;
}

.section-head p {
  max-width: 640px;
  font-size: 17px;
  line-height: 1.85;
  color: var(--c-sub);
}

.section-head--center {
  margin-inline: auto;
  text-align: center;
}

.section-head--center .eyebrow {
  justify-content: center;
}

.section-head--center p {
  margin-inline: auto;
}

.text-accent {
  color: var(--c-accent);
}

.text-muted {
  color: var(--c-sub);
}

.serif {
  font-family: var(--font-display);
}

/* ---------- 跳转链接（无障碍） ---------- */
.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1000;
  padding: 10px 18px;
  color: var(--c-bg);
  background: var(--c-ink);
  border-radius: var(--radius-pill);
  transform: translateY(-160%);
  transition: transform 0.25s var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
}

/* ---------- 滚动进场动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.8s var(--ease), transform 0.8s var(--ease);
  transition-delay: var(--d, 0s);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  :root {
    --header-h: 68px;
  }

  body {
    font-size: 15.5px;
  }
}