/* ═══════════════════════════════════════════════════════════
   assets/css/global.css — 全局样式 v2
   排版基础 + 网格系统 + 工具类 + Section节奏系统
   ═══════════════════════════════════════════════════════════ */

/* ── Reset ── */
*, *::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-body);
  font-size: var(--text-body);
  line-height: 1.75;
  color: var(--color-text-body);
  background: var(--color-bg-page);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── 排版基础 ── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--color-text-primary);
  font-weight: var(--fw-bold);
}

h1 { font-size: var(--text-hero); line-height: var(--lh-tight); letter-spacing: 0; }
h2 { font-size: var(--text-section-title); line-height: 1.2; letter-spacing: 0; }
h3 { font-size: var(--text-subtitle); line-height: 1.35; }
h4 { font-size: var(--text-body-lg); line-height: var(--lh-snug); }

p { margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

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

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

/* ── 响应式图片增强 ── */
.img-cover {
  width: 100%; height: 100%; object-fit: cover;
}
.img-contain {
  width: 100%; height: 100%; object-fit: contain;
}
.img-ratio-1-1 { aspect-ratio: 1/1; }
.img-ratio-4-3 { aspect-ratio: 4/3; }
.img-ratio-16-10 { aspect-ratio: 16/10; }
.img-ratio-16-9 { aspect-ratio: 16/9; }
.img-ratio-2-1 { aspect-ratio: 2/1; }

/* 图片悬停缩放 */
.img-hover-zoom {
  overflow: hidden;
}
.img-hover-zoom img {
  transition: transform 0.6s var(--ease-out-expo);
}
.img-hover-zoom:hover img {
  transform: scale(1.06);
}

/* ── 列表 ── */
ul, ol { padding-left: 1.25rem; }
li { margin-bottom: 0.375rem; }

/* ── 主内容区域：为固定 header 留出空间 ── */
main {
  padding-top: 72px;
}

/* ── 容器 ── */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}
.container-narrow {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* ── Section 节奏系统 ── */
.section { padding: var(--space-section) 0; }
.section-sm { padding: var(--space-section-sm) 0; }

/* Section背景交替 */
.section-alt { background: var(--color-surface-alt); }
.section-dark { background: var(--color-text-primary); color: var(--color-text-inverse); }
.section-dark h2, .section-dark h3 { color: var(--color-white); }
.section-dark .section-subtitle { color: rgba(255,255,255,0.78); }
.section-dark .text-muted { color: rgba(255,255,255,0.65); }
.section-primary { background: var(--color-primary-dark); color: var(--color-text-inverse); }
.section-primary h2, .section-primary h3 { color: var(--color-white); }

/* Section装饰分隔线 */
.section-divider {
  height: 1px;
  background: var(--color-divider);
  margin: 0;
  border: 0;
}
.section-divider-thick {
  height: 4px;
  background: var(--gradient-primary);
  border: 0;
  margin: 0;
  width: 80px;
}
.section-divider-center {
  margin: 0 auto;
}

/* ── 网格系统 ── */
.grid-2  { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-block); align-items: start; }
.grid-3  { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-block); }
.grid-4  { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; }
.grid-5  { display: grid; grid-template-columns: repeat(5, 1fr); gap: 1.5rem; }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--space-block); }

@media (max-width: 1024px) {
  .grid-3, .grid-4, .grid-5 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .grid-2, .grid-3, .grid-4, .grid-5 { grid-template-columns: 1fr; }
}

/* ── 超小屏 (375px) 额外收紧 ── */
@media (max-width: 400px) {
  :root {
    --container-padding: 1rem;
    --space-section: 3rem;
    --space-block: 1.5rem;
  }
  .section { padding: var(--space-section) 0; }
  .section-sm { padding: 2rem 0; }
}

/* ── 工具类 ── */
.text-center { text-align: center; }
.text-left   { text-align: left; }
.text-muted  { color: var(--color-text-muted); }
.text-primary { color: var(--color-primary); }
.text-accent  { color: var(--color-accent); }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap;
}
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-auto { margin-top: auto; }

/* ── Section装饰元素 ── */
.deco-dot-grid {
  position: absolute;
  width: 100%; height: 100%;
  background-image: radial-gradient(circle, var(--color-primary-200) 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: 0.4;
  pointer-events: none;
}
.deco-line-left {
  position: relative;
}
.deco-line-left::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 4px;
  background: var(--gradient-primary);
  border-radius: 2px;
}

/* ── 图片占位符增强 ── */
.img-placeholder {
  background: linear-gradient(135deg, var(--color-primary-100) 0%, var(--color-surface-alt) 50%, var(--color-accent-100) 100%);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-primary-400);
  font-size: var(--text-sm);
  font-weight: var(--fw-medium);
}

/* ── 滚动动画 ── */
.animate {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s var(--ease-out-expo), transform 0.6s var(--ease-out-expo);
}
.animate.visible {
  opacity: 1;
  transform: translateY(0);
}

/* 延迟动画变体 */
.animate-delay-1 { transition-delay: 100ms; }
.animate-delay-2 { transition-delay: 200ms; }
.animate-delay-3 { transition-delay: 300ms; }
.animate-delay-4 { transition-delay: 400ms; }

/* ── 键盘焦点样式 ── */
/* 全局默认焦点环 (所有可交互元素) */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}
/* 交互元素焦点微调 —— 增加偏移量避免裁切 */
.btn:focus-visible,
.tag:focus-visible,
.nav-link:focus-visible,
a:focus-visible,
input:focus-visible,
textarea:focus-visible,
button:focus-visible,
.menu-toggle:focus-visible,
.card-tag:focus-visible,
.ip-chip-link:focus-visible,
.case-card-link:focus-visible,
select:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
}
/* 深色背景下的焦点环使用白色，以保证对比度 */
.section-dark a:focus-visible,
.section-dark .btn:focus-visible,
.section-dark button:focus-visible,
.site-footer a:focus-visible,
.site-footer button:focus-visible,
.cta-section a:focus-visible,
.cta-section .btn:focus-visible {
  outline-color: var(--color-white);
}
/* 表单元素在获得焦点时由自身规则处理（含 box-shadow），移除默认 outline */
.form-input:focus-visible,
.form-textarea:focus-visible {
  outline: none;
}

/* ── 减弱动画偏好 ── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0s !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0s !important;
    scroll-behavior: auto !important;
  }
  /* 禁用滚动触发的动画 */
  .animate {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .animate.visible {
    opacity: 1;
    transform: none;
  }
  /* 禁用所有 hover 变换 */
  .card:hover,
  .card-elevated:hover,
  .card-interactive:hover,
  .service-card:hover,
  .case-feature-card:hover,
  .ip-card:hover,
  .team-card:hover,
  .value-card:hover,
  .btn:hover {
    transform: none;
  }
  /* 禁用图片 hover 缩放 */
  .img-hover-zoom:hover img,
  .case-card:hover .case-card-image img,
  .ip-card:hover .ip-image img,
  .case-feature-card:hover .case-feature-image img,
  .evidence-card:hover .evidence-image img {
    transform: none;
  }
  /* 保留 hover 颜色/阴影变化（非动画），它们仍有用 */
}

/* ── 全局响应式 ── */
@media (max-width: 768px) {
  body { line-height: 1.7; }
  main { padding-top: 64px; }
  .hide-mobile { display: none !important; }
}
@media (min-width: 769px) {
  .hide-desktop { display: none !important; }
}