/* ============================================================
   原构工坊 设计系统 — Base（重置 / 排版 / 布局工具）
   ============================================================ */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: 1.7;
  color: var(--ink-1);
  background: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  letter-spacing: 0.01em;
  overflow-x: hidden;
}

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

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

ul,
ol {
  list-style: none;
}

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

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

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

::selection {
  background: rgba(97, 92, 237, 0.16);
}

/* ---------- 排版层级 ---------- */
h1, h2, h3, h4 {
  line-height: 1.22;
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--ink-1);
}

.display {
  font-size: var(--fs-display);
  line-height: 1.12;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.h1 { font-size: var(--fs-h1); }
.h2 { font-size: var(--fs-h2); }
.h3 { font-size: var(--fs-h3); }

.lead {
  font-size: clamp(16px, 1.6vw, 19px);
  color: var(--ink-2);
  line-height: 1.75;
  font-weight: 400;
}

.text-secondary { color: var(--ink-2); }
.text-tertiary { color: var(--ink-3); }
.text-accent { color: var(--accent); }

.text-gradient {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* ---------- 布局工具 ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: 24px;
}

.container--wide {
  max-width: var(--container-wide);
}

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

.section--tint {
  background: var(--bg-secondary);
}

.section-head {
  max-width: 720px;
  margin-bottom: var(--sp-16);
}

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

.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: var(--fs-small);
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.04em;
  margin-bottom: var(--sp-4);
}

.section-eyebrow::before {
  content: "";
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: var(--gradient-text);
}

.section-head--center .section-eyebrow::before { display: none; }

.section-title {
  font-size: var(--fs-h2);
  margin-bottom: var(--sp-4);
}

.section-title em {
  font-style: normal;
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-sub {
  color: var(--ink-2);
  font-size: clamp(15px, 1.4vw, 17px);
}

/* 标题装饰符号：参照站的 "_" 下划线点缀 */
.deco-underscore {
  display: inline-block;
  width: 0.62em;
  height: 0.1em;
  border-radius: 3px;
  background: var(--accent);
  margin-inline: 0.08em;
  transform: translateY(-0.06em);
}

/* ---------- 滚动渐入动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s var(--ease-standard), transform 0.7s var(--ease-standard);
  transition-delay: var(--reveal-delay, 0ms);
}

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

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ---------- 响应式工具 ---------- */
@media (max-width: 768px) {
  .section { padding-block: clamp(56px, 12vw, 80px); }
  .section-head { margin-bottom: var(--sp-10); }
}