/* ============ 设计变量（X Business 风格） ============ */
:root {
  color-scheme: dark;
  --bg: #000;
  --fg: #fff;
  --fg-secondary: #a0a0a0;
  --fg-muted: #999;
  --fg-faint: #7a7a7a;
  --divider: rgba(255, 255, 255, 0.1);
  --divider-strong: rgba(255, 255, 255, 0.2);
  --accent: #1d9bf0;
  --status-published: #4ade80;
  --status-review: #f5b942;
  --status-ongoing: #8fa3b8;
  --atom-pos: #4ade80;
  --atom-neg: #ff7a7a;
  --nav-bg: rgba(0, 0, 0, 0.85);
  --hover-bg: rgba(255, 255, 255, 0.02);
  --card-bg: rgba(255, 255, 255, 0.015);
  --chart-text: #666;
  --btn-primary-hover: #d9d9d9;
  --font-sans: "Inter", -apple-system, "SF Pro Text", "Helvetica Neue",
    "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
}

:root[data-theme="light"] {
  color-scheme: light;
  --bg: #fff;
  --fg: #0f1419;
  --fg-secondary: #536471;
  --fg-muted: #71767b;
  --fg-faint: #687680;
  --divider: rgba(0, 0, 0, 0.1);
  --divider-strong: rgba(0, 0, 0, 0.2);
  --status-published: #00a75c;
  --status-review: #b58300;
  --status-ongoing: #536471;
  --atom-pos: #00a75c;
  --atom-neg: #e0334a;
  --nav-bg: rgba(255, 255, 255, 0.85);
  --hover-bg: rgba(0, 0, 0, 0.03);
  --card-bg: rgba(0, 0, 0, 0.02);
  --chart-text: #8b98a5;
  --btn-primary-hover: #333333;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--fg);
  transition: background-color 0.3s ease, color 0.3s ease;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: rgba(29, 155, 240, 0.35); }

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

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

sub, sup { font-size: 0.7em; line-height: 0; }

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 32px;
}

/* ============ 顶部导航 ============ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--divider);
  transition: background-color 0.3s ease;
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-logo {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.2px;
  color: var(--fg);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a {
  font-size: 14px;
  color: var(--fg-secondary);
  position: relative;
  padding: 4px 0;
  transition: color 0.2s ease;
}

.nav-links a:hover { color: var(--fg); }

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--fg);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}

.nav-links a:hover::after,
.nav-links a.active::after { transform: scaleX(1); }

.nav-links a.active { color: var(--fg); }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.theme-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: none;
  border: 1px solid var(--divider-strong);
  border-radius: 50%;
  color: var(--fg-secondary);
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.theme-btn:hover { color: var(--fg); border-color: var(--fg); }

.theme-btn .icon-moon { display: none; }

:root[data-theme="light"] .theme-btn .icon-sun { display: none; }
:root[data-theme="light"] .theme-btn .icon-moon { display: block; }

.menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--divider-strong);
  border-radius: 8px;
  color: var(--fg);
  padding: 8px 10px;
  cursor: pointer;
}

.mobile-menu {
  display: none;
  flex-direction: column;
  padding: 8px 32px 20px;
  border-top: 1px solid var(--divider);
  background: var(--bg);
}

.mobile-menu a {
  padding: 14px 0;
  font-size: 15px;
  color: var(--fg-secondary);
  border-bottom: 1px solid var(--divider);
}

.mobile-menu a:last-child { border-bottom: none; }

.mobile-menu.open { display: flex; }

/* ============ 首屏 ============ */
.hero {
  min-height: 92vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 128px 0 64px;
  border-bottom: 1px solid var(--divider);
  position: relative;
  overflow: hidden;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--fg-muted);
  letter-spacing: 0.13px;
  margin-bottom: 28px;
}

.eyebrow::before {
  content: "";
  display: inline-block;
  width: 32px;
  height: 1px;
  background: var(--divider-strong);
  flex-shrink: 0;
}

.hero h1 {
  font-size: clamp(40px, 6vw, 64px);
  font-weight: 500;
  letter-spacing: -1.2px;
  line-height: 1.08;
  max-width: 15em;
}

.hero-sub {
  margin-top: 28px;
  font-size: 17px;
  color: var(--fg-secondary);
  max-width: 36em;
  line-height: 1.75;
}

/* 首屏背景：亚硝胺骨架线稿（学科签名，主题自适应，仅宽屏显示） */
:root { --mol-op: 0.15; }
:root[data-theme="light"] { --mol-op: 0.17; }

.hero-molecule {
  position: absolute;
  top: 96px;
  right: -130px;
  width: 620px;
  color: var(--fg);
  opacity: var(--mol-op);
  pointer-events: none;
  z-index: 0;
  -webkit-mask-image: linear-gradient(to bottom, #000 52%, transparent 82%);
  mask-image: linear-gradient(to bottom, #000 52%, transparent 82%);
  animation: mol-fade 1.2s ease 0.05s both;
}

.hero .container { position: relative; z-index: 1; }

@keyframes mol-fade { from { opacity: 0; } }

/* CTA 区：同款骨架线稿镜像收尾 */
.footer-cta { position: relative; overflow: hidden; }
.footer-cta .container { position: relative; z-index: 1; }

.cta-molecule {
  position: absolute;
  bottom: -70px;
  left: -150px;
  width: 540px;
  color: var(--fg);
  opacity: calc(var(--mol-op) * 0.7);
  pointer-events: none;
  transform: scaleX(-1);
  -webkit-mask-image: linear-gradient(to top, #000 55%, transparent 85%);
  mask-image: linear-gradient(to top, #000 55%, transparent 85%);
}

.hero-ctas {
  display: flex;
  gap: 14px;
  margin-top: 40px;
  flex-wrap: wrap;
}

/* 首屏一次性编排入场：标题 → 副文 → 按钮 → 研究主线图 */
@keyframes hero-rise {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: none; }
}

.hero .eyebrow { animation: hero-rise 0.55s ease both; }
.hero h1 { animation: hero-rise 0.55s ease 0.07s both; }
.hero .hero-sub { animation: hero-rise 0.55s ease 0.14s both; }
.hero .hero-ctas { animation: hero-rise 0.55s ease 0.21s both; }
.hero .figure { animation: hero-rise 0.7s ease 0.32s both; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 500;
  border-radius: 9999px;
  padding: 12px 20px;
  transition: all 0.2s ease;
  cursor: pointer;
}

.btn-primary {
  background: var(--fg);
  color: var(--bg);
}

.btn-primary:hover { background: var(--btn-primary-hover); }

.btn-ghost {
  border: 1px solid var(--divider-strong);
  color: var(--fg);
}

.btn-ghost:hover { border-color: var(--fg); }

.btn svg { transition: transform 0.2s ease; }
.btn:hover svg { transform: translateX(3px); }

/* ============ 研究示意图（通用图形卡片） ============ */
.figure {
  width: 100%;
  border: 1px solid var(--divider);
  border-radius: 12px;
  padding: 28px;
  background: var(--card-bg);
}

.hero .figure { margin-top: 72px; }

.detail .figure { margin-top: 24px; }

.figure-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 20px;
  flex-wrap: wrap;
  gap: 8px;
}

.figure-title {
  font-size: 14px;
  font-weight: 500;
  color: var(--fg-secondary);
}

.figure-meta {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-faint);
  letter-spacing: 0.1px;
}

.figure-svg { width: 100%; height: auto; display: block; }

.bond { stroke: var(--fg-faint); stroke-width: 1.5; }

.aromatic {
  fill: none;
  stroke: var(--fg-faint);
  stroke-width: 1;
  stroke-dasharray: 4 5;
  animation: spin 30s linear infinite;
  transform-box: fill-box;
  transform-origin: center;
}

@keyframes spin { to { transform: rotate(360deg); } }

.atom { fill: var(--bg); stroke: var(--fg-muted); stroke-width: 1.5; }

.atom-pos { fill: var(--atom-pos); stroke: var(--atom-pos); }
.atom-neg { fill: var(--atom-neg); stroke: var(--atom-neg); }

.atom-hot { animation: atomPulse 3.2s ease-in-out infinite; }

@keyframes atomPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.55; }
}

.contrib { font-family: var(--font-mono); font-size: 12px; }
.contrib.pos { fill: var(--atom-pos); }
.contrib.neg { fill: var(--atom-neg); }

.elem-label {
  fill: var(--bg);
  font-family: var(--font-mono);
  font-size: 10px;
}

.lg-text {
  fill: var(--fg-muted);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1px;
}

.figure-cap {
  fill: var(--fg-faint);
  font-family: var(--font-mono);
  font-size: 11px;
}

/* ============ 软件截图卡片 ============ */
.screenshot-card {
  border: 1px solid var(--divider);
  border-radius: 12px;
  padding: 20px;
  background: var(--card-bg);
}
.screenshot-card + .screenshot-card { margin-top: 20px; }
.screenshot-card .screenshot-label {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-muted);
  letter-spacing: 0.13px;
  margin-bottom: 14px;
}
.screenshot-card img {
  width: 100%;
  max-width: 680px;
  margin: 0 auto;
  height: auto;
  display: block;
  border-radius: 8px;
  border: 1px solid var(--divider);
}
.screenshot-card figcaption {
  margin-top: 14px;
  font-size: 13px;
  color: var(--fg-muted);
  line-height: 1.75;
}

/* 研究主线图（毒性核心） */
.hub { fill: none; stroke: var(--accent); stroke-width: 1.5; }
.hub-label { fill: var(--fg); font-size: 15px; font-weight: 500; text-anchor: middle; }
.hub-en { fill: var(--fg-muted); font-family: var(--font-mono); font-size: 9px; letter-spacing: 2px; text-anchor: middle; }
.branch { stroke: var(--fg-faint); stroke-width: 1; }
.branch-dot { fill: var(--accent); }
.node-icon { fill: none; stroke: var(--fg-muted); stroke-width: 1.5; }
.node-icon.alt { opacity: 0.55; }
.node-label { fill: var(--fg-secondary); font-size: 13px; text-anchor: middle; }
.node-en { fill: var(--fg-faint); font-family: var(--font-mono); font-size: 10px; letter-spacing: 1px; text-anchor: middle; }
.node-pka { fill: var(--fg); font-family: var(--font-mono); font-size: 19px; font-weight: 500; text-anchor: middle; }

/* ============ 鼠标拖影 ============ */
.trail-canvas {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 200;
  pointer-events: none;
}

/* ============ 通用区块 ============ */
section { border-bottom: 1px solid var(--divider); }

.section-pad { padding: 96px 0; }

.section-head { margin-bottom: 56px; }

.section-kicker {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--fg-muted);
  letter-spacing: 0.13px;
  margin-bottom: 16px;
}

.section-title {
  font-size: 32px;
  font-weight: 500;
  letter-spacing: -0.32px;
  line-height: 1.2;
  max-width: 20em;
}

/* ============ 项目列表（编号行） ============ */
.project-row {
  display: grid;
  grid-template-columns: 88px 1fr auto;
  gap: 32px;
  padding: 44px 0;
  border-top: 1px solid var(--divider);
  align-items: start;
  transition: background 0.25s ease;
  position: relative;
}

.project-row:last-child { border-bottom: 1px solid var(--divider); }

.project-row:hover { background: var(--hover-bg); }

.project-num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  color: var(--fg-muted);
  letter-spacing: 0.13px;
  padding-top: 8px;
}

.project-main h3 {
  font-size: 24px;
  font-weight: 500;
  letter-spacing: -0.3px;
  margin-bottom: 6px;
}

.project-en {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--fg-faint);
  letter-spacing: 0.13px;
  margin-bottom: 16px;
}

.title-link { color: inherit; }

.title-link:hover {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 5px;
}

.project-desc {
  font-size: 15px;
  color: var(--fg-secondary);
  line-height: 1.75;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.tag {
  font-size: 12px;
  font-family: var(--font-mono);
  color: var(--fg-muted);
  border: 1px solid var(--divider);
  border-radius: 9999px;
  padding: 4px 12px;
  letter-spacing: 0.1px;
}

.project-side {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 14px;
  padding-top: 8px;
  white-space: nowrap;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 13px;
  color: var(--fg-secondary);
}

.status::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
}

.status.published { color: var(--status-published); }
.status.review { color: var(--status-review); }
.status.ongoing { color: var(--status-ongoing); }

.project-year {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-faint);
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 500;
  color: var(--fg);
  margin-top: 4px;
  opacity: 0;
  transform: translateY(4px);
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.project-row:hover .project-link,
.project-row:focus-within .project-link { opacity: 1; transform: translateY(0); }

/* ============ 成果列表 ============ */
.output-row {
  display: grid;
  grid-template-columns: 110px 1fr auto;
  gap: 28px;
  padding: 26px 0;
  border-top: 1px solid var(--divider);
  align-items: baseline;
  transition: background 0.25s ease;
}

.output-row:last-child { border-bottom: 1px solid var(--divider); }
.output-row:hover { background: var(--hover-bg); }

.output-year {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--fg-muted);
}

.output-title {
  font-size: 16px;
  font-weight: 500;
  letter-spacing: -0.1px;
}

.output-venue {
  font-size: 14px;
  color: var(--fg-secondary);
  margin-top: 4px;
}

/* ============ 关于 ============ */
.about-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 64px;
  align-items: start;
}

.about-text p {
  color: var(--fg-secondary);
  margin-bottom: 20px;
  line-height: 1.8;
  max-width: 36em;
}

.about-meta {
  border-left: 1px solid var(--divider);
  padding-left: 40px;
}

.meta-item { margin-bottom: 32px; }

.meta-item dt {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-faint);
  letter-spacing: 0.13px;
  margin-bottom: 10px;
}

.meta-item dd {
  font-size: 15px;
  color: var(--fg-secondary);
  line-height: 1.7;
}

/* ============ 详情页 ============ */
.detail {
  padding: 140px 0 96px;
  min-height: 70vh;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--fg-muted);
  margin-bottom: 48px;
  transition: color 0.2s ease;
}

.back-link:hover { color: var(--fg); }

.detail-head h1 {
  font-size: clamp(30px, 4vw, 44px);
  font-weight: 500;
  letter-spacing: -0.8px;
  line-height: 1.15;
  max-width: 22em;
  margin-top: 24px;
}

.detail-en {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--fg-faint);
  letter-spacing: 0.13px;
  margin-top: 12px;
}

.detail-meta {
  display: flex;
  gap: 24px;
  align-items: center;
  margin-top: 28px;
  flex-wrap: wrap;
}

.detail-section {
  border-top: 1px solid var(--divider);
  margin-top: 48px;
  padding-top: 28px;
}

.detail-section h2 {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  color: var(--fg-muted);
  letter-spacing: 0.13px;
  margin-bottom: 18px;
}

.detail-section p {
  color: var(--fg-secondary);
  line-height: 1.85;
}

.detail-section ul { list-style: none; }

.detail-section li {
  color: var(--fg-secondary);
  line-height: 1.75;
  padding: 12px 0 12px 26px;
  position: relative;
}

.detail-section li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--fg-faint);
}

.related-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 24px;
  padding: 18px 0;
  border-top: 1px solid var(--divider);
  transition: background 0.25s ease;
}

.related-row:last-child { border-bottom: 1px solid var(--divider); }
.related-row:hover { background: var(--hover-bg); }

.related-row a {
  font-size: 15px;
  font-weight: 500;
  color: var(--fg);
}

.related-row a:hover {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.related-row .related-note {
  font-size: 13px;
  color: var(--fg-muted);
  white-space: nowrap;
  flex-shrink: 0;
}

/* ============ 底部 CTA 与页脚 ============ */
.footer-cta {
  padding: 96px 0;
  text-align: left;
  border-bottom: 1px solid var(--divider);
}

.footer-cta h2 {
  font-size: 32px;
  font-weight: 500;
  letter-spacing: -0.32px;
  margin: 16px 0 32px;
}

footer { padding: 48px 0 64px; }

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 32px;
  flex-wrap: wrap;
}

.footer-note {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--fg-faint);
  line-height: 2;
}

.footer-links {
  display: flex;
  gap: 40px;
}

.footer-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--fg-muted);
  margin-bottom: 12px;
  transition: color 0.2s ease;
}

.footer-links a:hover { color: var(--fg); }

.footer-links .col-title {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-faint);
  margin-bottom: 16px;
}

.footer-links .col {
  display: flex;
  flex-direction: column;
}

/* ============ 滚动动画 ============ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .aromatic, .atom-hot { animation: none; }
  .trail-canvas { display: none; }
  .btn svg, .project-link { transition: none; }
  .hero .eyebrow, .hero h1, .hero .hero-sub,
  .hero .hero-ctas, .hero .figure { animation: none; }
  .hero-molecule { animation: none; }
}

/* ============ 响应式 ============ */
@media (max-width: 1359px) {
  .hero-molecule, .cta-molecule { display: none; }
}

@media (max-width: 860px) {
  .nav-links { display: none; }
  .menu-btn { display: block; }
  .project-row {
    grid-template-columns: 1fr;
    gap: 14px;
  }
  .project-side {
    flex-direction: row;
    align-items: center;
    justify-content: flex-start;
    flex-wrap: wrap;
  }
  .project-link { opacity: 1; transform: none; }
  .output-row { grid-template-columns: 1fr; gap: 8px; }
  .about-grid { grid-template-columns: 1fr; }
  .about-meta {
    border-left: none;
    padding-left: 0;
    border-top: 1px solid var(--divider);
    padding-top: 32px;
  }
  .hero { min-height: auto; }
  .footer-inner { flex-direction: column; }
  .related-row { flex-direction: column; gap: 8px; }
}

/* ============ 打印 ============ */
@media print {
  :root {
    --bg: #fff;
    --fg: #000;
    --fg-secondary: #333;
    --fg-muted: #555;
    --fg-faint: #6a6a6a;
    --divider: rgba(0, 0, 0, 0.18);
    --divider-strong: rgba(0, 0, 0, 0.35);
    --nav-bg: #fff;
    --hover-bg: transparent;
    --card-bg: #fff;
    --chart-text: #6a6a6a;
  }
  :root .pka-architecture,
  :root .mixture-architecture,
  :root .nitrosamine-architecture,
  :root .at-architecture,
  :root .op-figure,
  :root .research-map {
    --pa-panel: #fff;
    --mx-panel: #fff;
    --na-panel: #fff;
    --at-panel: #fff;
    --op-panel: #fff;
  }
  .nav,
  .trail-canvas,
  .theme-btn,
  .menu-btn,
  .mobile-menu,
  .hero-ctas,
  .footer-cta,
  .hero-molecule,
  .cta-molecule,
  .back-link {
    display: none !important;
  }
  .hero { min-height: auto; padding-top: 32px; }
  .detail { padding-top: 32px; min-height: auto; }
  .hero .eyebrow, .hero h1, .hero .hero-sub,
  .hero .hero-ctas, .hero .figure { animation: none; }
  .reveal { opacity: 1 !important; transform: none !important; }
  .figure, .screenshot-card, .detail-section { break-inside: avoid; }
  footer { padding: 24px 0 32px; }
}