/* ============================================================
   基础样式 - 重置 + 基础排版
   ============================================================ */

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--color-text-body);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* 为固定导航栏预留空间 */
  padding-top: var(--header-height);
}

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

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

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input,
textarea,
select {
  font-family: inherit;
  font-size: inherit;
}

/* ---------- 标题 ---------- */
h1, h2, h3, h4, h5, h6 {
  color: var(--color-text);
  line-height: var(--lh-title);
  font-weight: 600;
}

h1 { font-size: var(--fs-h1); font-weight: 700; }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }
h4 { font-size: var(--fs-h4); }

/* ---------- 工具类 ---------- */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.text-center { text-align: center; }
.text-muted { color: var(--color-text-muted); }
.text-primary { color: var(--color-primary); }
.text-strategic { color: var(--color-strategic); }

.bg-soft { background-color: var(--color-bg-soft); }
.bg-gray { background-color: var(--color-bg-gray); }

/* 区块标题统一样式：居中、主色装饰线 */
.section {
  padding: var(--space-section) 0;
}

.section-head {
  text-align: center;
  margin-bottom: 48px;
}

.section-head .eyebrow {
  display: inline-block;
  font-size: var(--fs-small);
  color: var(--color-primary);
  letter-spacing: 2px;
  text-transform: uppercase;
  font-weight: 600;
  margin-bottom: 12px;
}

.section-head h2 {
  position: relative;
  display: inline-block;
  padding-bottom: 18px;
  margin-bottom: 16px;
}

.section-head h2::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translateX(-50%);
  width: 56px;
  height: 4px;
  border-radius: 2px;
  background: var(--gradient-primary);
}

.section-head p {
  color: var(--color-text-muted);
  max-width: 680px;
  margin: 0 auto;
  font-size: 1.0625rem;
}

/* ---------- 滚动入场动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 响应式断点 ---------- */
@media (max-width: 1024px) {
  :root {
    --fs-h1: 2rem;
    --fs-h2: 1.625rem;
    --fs-h3: 1.375rem;
    --space-section: 64px;
  }
}

@media (max-width: 768px) {
  :root {
    --fs-h1: 1.75rem;
    --fs-h2: 1.4rem;
    --fs-h3: 1.2rem;
    --space-section: 48px;
    --container-padding: 16px;
  }

  body {
    padding-top: var(--header-height);
  }

  .section-head {
    margin-bottom: 32px;
  }

  .section-head p {
    font-size: 1rem;
  }

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