@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&display=swap');

/* ===== 基础变量 ===== */
:root {
  --c-black: #000000;
  --c-white: #ffffff;
  --c-ink: #000000;
  --c-gray-1: #f5f5f5;
  --c-gray-2: #e0e0e0;
  --c-gray-3: #888888;
  --c-gray-4: #444444;
  --c-accent: #1a1a1a;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  --nav-h: 64px;
  --max-w: 1280px;
  --radius: 4px;
  --shadow-card: 0 2px 12px rgba(0,0,0,0.10), 0 1px 3px rgba(0,0,0,0.07);
  --transition: 0.22s ease;
}

/* ===== 重置 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body { font-family: var(--font-main); background: var(--c-white); color: var(--c-black); line-height: 1.65; -webkit-font-smoothing: antialiased; }
img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; background: none; border: none; font: inherit; }

/* ===== 包装 ===== */
.site-wrapper { display: flex; flex-direction: column; min-height: 100vh; }

/* ===== 顶部导航 ===== */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 200;
  height: var(--nav-h);
  background: var(--c-black);
  color: var(--c-white);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 0 2rem;
  border-bottom: 1px solid #222;
}

.header-brand { text-align: center; }
.brand-link { display: inline-flex; align-items: center; gap: 0.5rem; }
.logo-text {
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--c-white);
  text-transform: uppercase;
}
.logo-img { height: 36px; width: auto; }

.header-aside nav ul {
  display: flex;
  gap: 0;
  align-items: center;
}
.header-aside--left nav ul { justify-content: flex-start; }
.header-aside--right nav ul { justify-content: flex-end; }

.header-aside nav ul li a {
  display: inline-block;
  padding: 0.55rem 0.9rem;
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--c-gray-2);
  text-transform: uppercase;
  transition: color var(--transition);
  white-space: nowrap;
  min-height: 44px;
  line-height: 44px;
  padding-top: 0; padding-bottom: 0;
}
.header-aside nav ul li a:hover { color: var(--c-white); }

/* 汉堡按钮 */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 10px;
  min-height: 44px;
  min-width: 44px;
  align-items: center;
  justify-content: center;
  color: var(--c-white);
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
}
.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--c-white);
  transition: var(--transition);
}

/* ===== 全屏遮罩菜单 ===== */
.menu-overlay {
  position: fixed;
  inset: 0;
  z-index: 500;
  background: var(--c-black);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}
.menu-overlay.is-open {
  opacity: 1;
  pointer-events: all;
}
.menu-close {
  position: absolute;
  top: 1.5rem;
  right: 2rem;
  color: var(--c-white);
  font-size: 1.5rem;
  padding: 0.5rem 0.75rem;
  min-height: 44px;
  min-width: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity var(--transition);
}
.menu-close:hover { opacity: 0.6; }

.overlay-nav ul {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  text-align: center;
}
.overlay-nav ul li a {
  display: block;
  font-size: clamp(1.4rem, 4vw, 2.2rem);
  font-weight: 300;
  letter-spacing: 0.04em;
  color: var(--c-white);
  padding: 0.6rem 1.5rem;
  min-height: 56px;
  line-height: 56px;
  padding-top: 0; padding-bottom: 0;
  transition: opacity var(--transition);
  text-transform: uppercase;
}
.overlay-nav ul li a:hover { opacity: 0.55; }

/* scroll-margin-top for fixed nav */
article[id] { scroll-margin-top: calc(var(--nav-h) + 8px); }

/* ===== Hero ===== */
.hero-wrap {
  position: relative;
  margin-top: var(--nav-h);
  min-height: 70vh;
  background: var(--c-black);
  overflow: hidden;
  display: flex;
  align-items: center;
}

/* 斜切色带 */
.hero-slash {
  position: absolute;
  top: 0; right: 0;
  width: 55%;
  height: 100%;
  background: var(--c-gray-1);
  clip-path: polygon(8% 0, 100% 0, 100% 100%, 0% 100%);
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: var(--max-w);
  margin: 0 auto;
  width: 100%;
  padding: 4rem 2rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.hero-text {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  align-items: flex-start;
  justify-content: center;
}

.hero-h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--c-white);
}

.hero-desc {
  font-size: 1.05rem;
  font-weight: 300;
  color: var(--c-gray-3);
  line-height: 1.7;
  max-width: 38ch;
}

.hero-cta {
  display: inline-block;
  background: var(--c-white);
  color: var(--c-black);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.85rem 2rem;
  border: 2px solid var(--c-white);
  transition: background var(--transition), color var(--transition);
  min-height: 44px;
}
.hero-cta:hover { background: transparent; color: var(--c-white); }

.hero-image {
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.hero-image img {
  width: 100%;
  max-height: 60vh;
  object-fit: cover;
  border-radius: var(--radius);
}
.hero-image--placeholder {
  min-height: 320px;
  background: var(--c-gray-2);
  border-radius: var(--radius);
}

/* ===== 主体布局 ===== */
.body-wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  width: 100%;
  padding: 4rem 2rem;
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 4rem;
  align-items: start;
}

/* ===== main > section > article ===== */
.site-main { min-width: 0; }
.main-article { min-width: 0; }
.content-section { min-width: 0; }

/* 正文内容样式 */
.content-section h2 {
  font-size: clamp(1.35rem, 2.5vw, 1.9rem);
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.3;
  margin-top: 3.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--c-black);
}
.content-section h2:first-child { margin-top: 0; }

.content-section h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-top: 2.5rem;
  margin-bottom: 0.5rem;
  color: var(--c-accent);
}

.content-section p {
  font-size: 1rem;
  line-height: 1.75;
  margin-bottom: 1.25rem;
  color: var(--c-gray-4);
}

.content-section p:first-of-type::first-letter {
  float: left;
  font-size: 3.5em;
  line-height: 0.82;
  font-weight: 600;
  margin-right: 0.1em;
  margin-top: 0.07em;
  color: var(--c-black);
}

.content-section ul,
.content-section ol {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
}
.content-section ul { list-style: disc; }
.content-section ol { list-style: decimal; }
.content-section li {
  font-size: 1rem;
  line-height: 1.7;
  margin-bottom: 0.4rem;
  color: var(--c-gray-4);
}

.content-section blockquote {
  border-left: 4px solid var(--c-black);
  margin: 2rem 0;
  padding: 1rem 1.5rem;
  background: var(--c-gray-1);
  font-size: 1.1rem;
  font-weight: 300;
  font-style: italic;
  line-height: 1.7;
  color: var(--c-black);
}

.content-section a {
  color: var(--c-black);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: opacity var(--transition);
}
.content-section a:hover { opacity: 0.6; }

.content-section figure { margin: 2rem 0; }
.content-section figcaption {
  font-size: 0.82rem;
  color: var(--c-gray-3);
  margin-top: 0.5rem;
  text-align: center;
}

.content-section table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}
.content-section th {
  background: var(--c-black);
  color: var(--c-white);
  padding: 0.6rem 1rem;
  text-align: left;
  font-weight: 600;
  font-size: 0.82rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.content-section td {
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--c-gray-2);
  color: var(--c-gray-4);
  line-height: 1.5;
}
.content-section tr:hover td { background: var(--c-gray-1); }

/* article 分区 */
.content-section article {
  padding: 3rem 0;
  border-bottom: 1px solid var(--c-gray-2);
}
.content-section article:last-child { border-bottom: none; }

/* h2 + p.subtitle 副标题 */
.content-section h2 + .subtitle,
.content-section h2 + p.subtitle,
.content-section h2 + p.subhead,
.content-section h2 + p.desc,
.content-section h2 + p.lead {
  font-size: 1rem;
  color: var(--c-gray-3);
  font-weight: 300;
  margin-top: -0.25rem;
  margin-bottom: 1.25rem;
}

/* pull quote */
.content-section .pull-quote {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  font-weight: 300;
  font-style: italic;
  border-top: 3px solid var(--c-black);
  border-bottom: 3px solid var(--c-black);
  padding: 1.5rem 0;
  margin: 2.5rem 0;
  text-align: center;
  line-height: 1.5;
}

/* ===== 右侧 aside ===== */
.content-aside {
  position: sticky;
  top: calc(var(--nav-h) + 2rem);
  background: var(--c-gray-1);
  border-left: 3px solid var(--c-black);
  padding: 1.75rem 1.5rem;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.aside-title {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.4rem;
  border-bottom: none;
  padding-bottom: 0;
  margin-top: 0;
}

.content-aside .subtitle {
  font-size: 0.8rem;
  color: var(--c-gray-3);
  margin-bottom: 1.25rem;
  font-weight: 300;
}

.content-aside nav ul { display: flex; flex-direction: column; gap: 0.1rem; }
.content-aside nav ul li a {
  display: block;
  font-size: 0.82rem;
  font-weight: 400;
  color: var(--c-gray-4);
  padding: 0.45rem 0;
  border-bottom: 1px solid var(--c-gray-2);
  transition: color var(--transition);
  min-height: 40px;
  line-height: 40px;
  padding-top: 0; padding-bottom: 0;
}
.content-aside nav ul li:last-child a { border-bottom: none; }
.content-aside nav ul li a:hover { color: var(--c-black); }

/* ===== 页脚 ===== */
.site-footer {
  background: var(--c-black);
  color: var(--c-white);
  padding: 0 2rem;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-logo a {
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--c-white);
  white-space: nowrap;
  min-height: 40px;
  display: flex;
  align-items: center;
}

.footer-nav ul {
  display: flex;
  gap: 0;
  flex-wrap: wrap;
  align-items: center;
}
.footer-nav ul li a {
  display: block;
  font-size: 0.72rem;
  color: var(--c-gray-3);
  padding: 0.4rem 0.6rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition: color var(--transition);
  min-height: 40px;
  line-height: 40px;
  padding-top: 0; padding-bottom: 0;
  white-space: nowrap;
}
.footer-nav ul li a:hover { color: var(--c-white); }

.footer-copy small {
  font-size: 0.72rem;
  color: var(--c-gray-3);
  white-space: nowrap;
}

/* ===== 卡片（content 里可能生成） ===== */
.card {
  background: var(--c-white);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  padding: 1.5rem;
  transition: box-shadow var(--transition), transform var(--transition);
}
.card:hover { box-shadow: 0 6px 24px rgba(0,0,0,0.14); transform: translateY(-2px); }

/* ===== 分区斜切分割线 ===== */
.content-section article::before {
  content: '';
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--c-black) 60%, transparent 100%);
  margin-bottom: 2.5rem;
}
.content-section article:first-child::before { display: none; }

/* ===== 多栏文本（大屏） ===== */
@media (min-width: 1100px) {
  .content-section .multi-col {
    column-count: 2;
    column-gap: 2.5rem;
    column-rule: 1px solid var(--c-gray-2);
  }
}

/* ===== Reveal 动效 ===== */
@media (prefers-reduced-motion: no-preference) {
  .reveal-item {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.55s ease, transform 0.55s ease;
  }
  .reveal-item.revealed {
    opacity: 1;
    transform: none;
  }
  .reveal-item:nth-child(2) { transition-delay: 0.08s; }
  .reveal-item:nth-child(3) { transition-delay: 0.16s; }
  .reveal-item:nth-child(4) { transition-delay: 0.24s; }
  .reveal-item:nth-child(5) { transition-delay: 0.32s; }
}
@media (prefers-reduced-motion: reduce) {
  .reveal-item { opacity: 1; transform: none; }
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .body-wrap { grid-template-columns: 1fr; gap: 2rem; }
  .content-aside { position: static; border-left: none; border-top: 3px solid var(--c-black); border-radius: var(--radius); }
}

@media (max-width: 900px) {
  .header-aside { display: none; }
  .hamburger { display: flex; }
  .site-header { grid-template-columns: 1fr auto; }
  .header-brand { text-align: left; }
}

@media (max-width: 700px) {
  .hero-content {
    grid-template-columns: 1fr;
    padding: 3rem 1.25rem;
  }
  .hero-slash { width: 100%; clip-path: polygon(0 60%, 100% 45%, 100% 100%, 0 100%); }
  .hero-image { display: none; }
  .hero-h1 { font-size: clamp(1.6rem, 7vw, 2.4rem); }
  .body-wrap { padding: 2rem 1.25rem; }
  .site-footer { height: auto; padding: 1rem 1.25rem; flex-direction: column; align-items: flex-start; gap: 0.5rem; }
  .footer-nav ul { flex-wrap: wrap; }
  .content-section h2 { font-size: 1.25rem; }
}

@media (max-width: 480px) {
  .site-header { padding: 0 1rem; }
  .hero-wrap { min-height: 60vh; }
}

/* ===== 工具类 ===== */
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }