/* ==========================================================================
   丁博文 · 个人网站
   风格：现代专业 · 金融科技编辑风（大留白、编号分节、卡片模块）
   主题：双主题 CSS 变量（:root 浅色 / [data-theme="dark"] 深色）
   依赖：零外部资源，系统字体栈
   ========================================================================== */

/* ---------- 1. 设计令牌 ---------- */
:root {
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", "Noto Sans CJK SC", "WenQuanYi Micro Hei", sans-serif;
  --mono: ui-monospace, "Cascadia Code", "SF Mono", Consolas, "Courier New", monospace;

  --bg: #ffffff;
  --bg-alt: #f6f9fa;
  --card: #ffffff;
  --border: #e2e8f0;

  --heading: #0a2540;   /* 深藏青：主色与大标题，对白底约 15.5:1 */
  --text: #4a5568;      /* 正文，约 7.5:1 */
  --muted: #5c6b7f;     /* 次要文字，对 #ffffff 约 5.4:1，对 #f6f9fa 约 5.1:1（AA） */

  --accent: #14b8a6;        /* 装饰色：仅用于大字号/非文字装饰 */
  --accent-strong: #0d9488; /* 大号数字/高亮：≥3:1（大字 AA） */
  --accent-text: #0f766e;   /* 正文级强调与链接，约 5.5:1 */

  --tag-bg: #e6f7f4;
  --tag-text: #0f766e;

  --btn-bg: #0a2540;
  --btn-text: #ffffff;

  --focus: #0f766e;
  --nav-bg: rgba(255, 255, 255, 0.92);
  --shadow-sm: 0 4px 14px -6px rgba(10, 37, 64, 0.12);
  --shadow: 0 10px 30px -12px rgba(10, 37, 64, 0.18);
}

[data-theme="dark"] {
  --bg: #0a192f;
  --bg-alt: #081527;
  --card: #112240;
  --border: #233554;

  --heading: #ccd6f6;   /* 对 #0A192F 约 12.2:1 */
  --text: #a8b2d1;      /* 约 8.3:1 */
  --muted: #8892b0;     /* 约 5.7:1 */

  --accent: #64ffda;        /* 链接/高亮/装饰，对 #0A192F 约 14:1 */
  --accent-strong: #64ffda;
  --accent-text: #64ffda;

  --tag-bg: rgba(100, 255, 218, 0.10);
  --tag-text: #64ffda;

  --btn-bg: #64ffda;
  --btn-text: #0a192f;

  --focus: #64ffda;
  --nav-bg: rgba(10, 25, 47, 0.92);
  --shadow-sm: 0 4px 14px -6px rgba(2, 8, 20, 0.55);
  --shadow: 0 10px 30px -12px rgba(2, 8, 20, 0.6);
}

/* ---------- 2. 基础与排版 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  scroll-padding-top: 88px; /* 补偿吸顶导航高度 */
  -webkit-text-size-adjust: 100%;
  color-scheme: light;
}
html[data-theme="dark"] { color-scheme: dark; }

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  color: var(--text);
  background-color: var(--bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color 0.25s ease, color 0.25s ease;
}

h1, h2, h3, h4 {
  margin: 0;
  color: var(--heading);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: 0.02em;
}

p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img { max-width: 100%; display: block; }
button { font-family: inherit; }

a { color: var(--accent-text); text-decoration: none; }
a:hover { text-decoration: underline; }

::selection { background: var(--accent); color: var(--bg); }

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

.mono { font-family: var(--mono); }

.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;
}

.skip-link {
  position: fixed;
  top: -60px; left: 16px;
  z-index: 200;
  padding: 10px 16px;
  background: var(--btn-bg);
  color: var(--btn-text);
  border-radius: 8px;
  font-weight: 700;
  transition: top 0.2s ease;
}
.skip-link:focus { top: 12px; text-decoration: none; }

/* 图标（Feather 风格：描边继承 currentColor） */
.icon {
  width: 1.25em; height: 1.25em;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  flex: none;
  vertical-align: -0.2em;
}
.icon-xs { width: 0.9em; height: 0.9em; }

/* ---------- 3. 布局工具 ---------- */
.container {
  width: min(100% - 48px, 1080px);
  margin-inline: auto;
}

.section { padding: 96px 0; }
.section--alt { background-color: var(--bg-alt); }

.section-head { margin-bottom: 48px; }
.sec-num {
  display: block;
  margin-bottom: 10px;
  font-family: var(--mono);
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--accent-text);
}
.sec-title { font-size: 1.75rem; }
.sec-desc { margin-top: 12px; color: var(--muted); max-width: 640px; }

.sec-sub {
  margin: 48px 0 20px;
  font-size: 1.2rem;
  color: var(--heading);
}

/* ---------- 4. 组件：chip / 按钮 ---------- */
.chip {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 6px;
  background: var(--tag-bg);
  color: var(--tag-text);
  font-size: 0.8125rem;
  line-height: 1.6;
  letter-spacing: 0.01em;
}
.chip--mono { font-family: var(--mono); font-size: 0.75rem; }
.chip--note { background: transparent; border: 1px dashed var(--accent-text); }
.chip--hl { font-weight: 700; }

.chips { display: flex; flex-wrap: wrap; gap: 8px; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 26px;
  border-radius: 10px;
  border: 1px solid transparent;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease,
              background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); box-shadow: var(--shadow-sm); }
.btn-primary { background: var(--btn-bg); color: var(--btn-text); }
.btn-ghost { color: var(--accent-text); border-color: var(--border); }
.btn-ghost:hover { border-color: var(--accent-text); }

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px; height: 42px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: transparent;
  color: var(--heading);
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}
.icon-btn:hover { color: var(--accent-text); border-color: var(--accent-text); }

.text-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: none;
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  font-size: 0.875rem;
  cursor: pointer;
  transition: color 0.2s ease, background-color 0.2s ease;
}
.text-btn:hover { color: var(--accent-text); background: var(--tag-bg); }

/* 主题图标：浅色显示月亮（点击转深），深色显示太阳；200ms 旋转过渡 */
.icon-moon, .icon-sun { transition: transform 0.2s ease; }
.icon-sun { display: none; }
[data-theme="dark"] .icon-sun { display: block; transform: rotate(180deg); }
[data-theme="dark"] .icon-moon { display: none; }

/* ---------- 5. 吸顶导航 ---------- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  border-bottom: 1px solid transparent;
  background: transparent;
  transition: background-color 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}
.nav.is-scrolled {
  background: var(--nav-bg);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom-color: var(--border);
  box-shadow: var(--shadow-sm);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 72px;
}
.brand {
  color: var(--heading);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: 0.02em;
}
.brand:hover { text-decoration: none; }
.brand-dot { color: var(--accent); }

.nav-list { display: flex; gap: 2px; }
.nav-link {
  position: relative;
  display: inline-flex;
  padding: 10px 12px;
  font-size: 0.9375rem;
  color: var(--muted);
  border-radius: 6px;
}
.nav-link:hover { color: var(--heading); text-decoration: none; }
.nav-link::after {
  content: "";
  position: absolute;
  left: 12px; right: 12px; bottom: 4px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}
.nav-link.is-active { color: var(--accent-text); }
.nav-link.is-active::after { transform: scaleX(1); }

.nav-actions { display: flex; align-items: center; gap: 8px; }
.nav-toggle { display: none; }
.nav-toggle .icon-close { display: none; }
.nav-toggle[aria-expanded="true"] .icon-close { display: block; }
.nav-toggle[aria-expanded="true"] .icon-menu { display: none; }

/* 移动端抽屉 */
.nav-drawer {
  position: fixed;
  top: 0; right: 0; bottom: 0;
  z-index: 120;
  width: min(78vw, 320px);
  padding: 88px 24px 24px;
  background: var(--bg);
  border-left: 1px solid var(--border);
  transform: translateX(100%);
  visibility: hidden;
  transition: transform 0.28s ease, visibility 0.28s;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.nav-drawer.is-open { transform: translateX(0); visibility: visible; }
.nav-drawer .nav-link { font-size: 1.0625rem; padding: 12px 10px; border-radius: 8px; }
.nav-drawer .nav-link::after { left: 10px; right: 10px; bottom: 6px; }

.nav-overlay {
  position: fixed;
  inset: 0;
  z-index: 110;
  background: rgba(2, 8, 20, 0.5);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}
.nav-overlay.is-show { opacity: 1; pointer-events: auto; }
body.has-drawer { overflow: hidden; }

/* ---------- 6. Hero 首屏 ---------- */
.hero {
  position: relative;
  min-height: 100vh;
  min-height: 100svh;
  display: flex;
  align-items: center;
  padding: 130px 0 88px;
}
.hero-grid { display: grid; gap: 56px; align-items: center; }

.hero-eyebrow {
  color: var(--accent-text);
  font-weight: 700;
  margin-bottom: 14px;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.2;
}
.hero-sub {
  margin-top: 14px;
  font-size: clamp(1.05rem, 2.2vw, 1.25rem);
  color: var(--heading);
}

.hero-typed {
  margin-top: 18px;
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 1.9em;
  font-size: 1.0625rem;
  color: var(--muted);
}
.typed-prompt { color: var(--accent); font-weight: 700; }
#typed { color: var(--accent-text); font-weight: 700; }
.cursor {
  display: inline-block;
  width: 2px; height: 1.15em;
  margin-left: 2px;
  background: var(--accent);
  animation: blink 1s step-end infinite;
}
@keyframes blink { 50% { opacity: 0; } }

.hero-chips { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 24px; }
.hero-cta { display: flex; flex-wrap: wrap; align-items: center; gap: 14px; margin-top: 34px; }
.gh-link { border-radius: 50%; }

.hero-photo { display: flex; justify-content: center; }
.photo-frame {
  position: relative;
  width: min(300px, 72vw);
  margin: 0 14px 14px 0;
}
.photo-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  transform: translate(14px, 14px);
  border: 2px solid var(--accent);
  border-radius: 14px;
  opacity: 0.55;
}
.photo-frame img {
  position: relative;
  z-index: 1;
  width: 100%;
  height: auto; /* 覆盖 HTML height 属性的呈现提示，否则 aspect-ratio 失效、照片被裁成竖条 */
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--bg-alt);
  box-shadow: var(--shadow);
}

.scroll-cue {
  position: absolute;
  left: 50%; bottom: 20px;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--muted);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
}
.scroll-cue:hover { color: var(--accent-text); text-decoration: none; }
.scroll-cue .icon { animation: bob 1.8s ease-in-out infinite; }
@keyframes bob { 50% { transform: translateY(6px); } }
@media (max-height: 640px) { .scroll-cue { display: none; } }

/* ---------- 7. 关于我 ---------- */
.about-lead { max-width: 640px; font-size: 1.0625rem; }

.stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 44px 0;
}
.stat {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}
.stat-num {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--accent-strong);
}
.stat-unit { font-size: 1rem; margin-left: 2px; color: var(--muted); }
.stat-label { margin-top: 8px; font-size: 0.875rem; color: var(--muted); }

.highlights { display: grid; gap: 16px; }
.hl-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
}
.hl-card h3 {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.0625rem;
}
.hl-card h3 .icon { color: var(--accent-text); width: 1.4em; height: 1.4em; }
.hl-card p { margin-top: 10px; font-size: 0.9375rem; }

/* ---------- 8. 知识体系 ---------- */
.kn-grid { display: grid; gap: 20px; }
.kn-card {
  position: relative;
  overflow: hidden;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  transition: transform 0.22s ease, border-color 0.22s ease, box-shadow 0.22s ease;
}
.kn-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--accent);
}
.kn-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-text);
  box-shadow: var(--shadow-sm);
}
.kn-head { display: flex; align-items: center; gap: 12px; margin-bottom: 10px; }
.kn-head .icon { color: var(--accent-text); width: 1.5em; height: 1.5em; }
.kn-head h3 { font-size: 1.0625rem; }
.kn-card p { font-size: 0.9375rem; }
.kn-card .chips { margin-top: 14px; }
.kn-note { margin-top: 24px; font-size: 0.875rem; color: var(--muted); }

/* ---------- 9. 产品案例 ---------- */
.proj-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 30px 26px;
  margin-bottom: 32px;
}
.proj-head { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 14px; }
.proj-head h3 { font-size: 1.3rem; }
.proj-name-sub { font-size: 0.875rem; color: var(--muted); font-weight: 400; }
.repo-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  margin-left: auto;
}
.proj-one { margin-top: 10px; color: var(--muted); max-width: 720px; }

.proj-body { display: grid; gap: 28px; margin-top: 26px; align-items: start; }

/* 截图占位（线框示意，不放虚假截图） */
.shot-frame {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-alt);
  overflow: hidden;
}
.shot-bar {
  display: flex;
  gap: 6px;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}
.shot-bar i { width: 8px; height: 8px; border-radius: 50%; background: var(--border); }
.shot-body {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 18px;
  min-height: 210px;
}
.w-line { height: 10px; border-radius: 4px; background: var(--border); }
.w-bubble {
  height: 30px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
}
.w-bubble--ai { border-style: dashed; border-color: var(--accent); opacity: 0.75; }
.w-pop {
  position: relative;
  margin-left: 20%;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 12px;
  border: 1.5px solid var(--accent);
  border-radius: 10px;
  background: var(--card);
  box-shadow: var(--shadow-sm);
}
.w-pop::before {
  content: "";
  position: absolute;
  top: -14px; left: 20px;
  width: 2px; height: 14px;
  background: var(--accent);
}
.w-tag { width: 40%; height: 8px; border-radius: 4px; background: var(--accent); opacity: 0.6; }
.shot-body--chart { gap: 12px; }
.w-row { display: flex; align-items: center; gap: 10px; }
.w-name { width: 60px; height: 10px; border-radius: 4px; background: var(--border); flex: none; }
.w-track {
  flex: 1;
  height: 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
}
.w-fill { display: block; height: 100%; background: var(--accent); opacity: 0.65; }
.w-score { width: 28px; height: 10px; border-radius: 4px; background: var(--border); flex: none; }
.shot-cap {
  margin-top: 10px;
  text-align: center;
  font-size: 0.8125rem;
  color: var(--muted);
}

/* STAR 分栏 */
.star { display: grid; gap: 18px; }
.star-item { border-left: 3px solid var(--accent); padding-left: 14px; }
.star-item h4 {
  font-family: var(--mono);
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--accent-text);
}
.star-item p { margin-top: 6px; font-size: 0.9375rem; }
.num-hl { color: var(--accent-text); font-weight: 700; } /* 正文字号：需 4.5:1，accent-text 达 5.5:1 */
.proj-tags { margin-top: 24px; }

/* ---------- 10. 工作经历（时间线） ---------- */
.timeline {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 26px;
  padding-left: 28px;
}
.timeline::before {
  content: "";
  position: absolute;
  left: 7px; top: 8px; bottom: 8px;
  width: 2px;
  background: var(--border);
}
.tl-item { position: relative; }
.tl-dot {
  position: absolute;
  left: -28px; top: 8px;
  width: 16px; height: 16px;
  border-radius: 50%;
  border: 3px solid var(--accent);
  background: var(--bg);
  transition: transform 0.2s ease;
}
.tl-item:hover .tl-dot { transform: scale(1.3); }

.tl-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.tl-card:hover { border-color: var(--accent-text); box-shadow: var(--shadow-sm); }
.tl-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; }
.tl-head h3 { font-size: 1.125rem; }
.tl-role { color: var(--accent-text); font-weight: 700; font-size: 0.9375rem; }
.tl-time { margin-left: auto; font-size: 0.8125rem; color: var(--muted); white-space: nowrap; }
.tl-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.tl-card ul:not(.tl-meta):not(.chips) { margin-top: 14px; display: grid; gap: 10px; }
.tl-card ul:not(.tl-meta):not(.chips) li {
  position: relative;
  padding-left: 18px;
  font-size: 0.9375rem;
}
.tl-card ul:not(.tl-meta):not(.chips) li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.65em;
  width: 7px; height: 7px;
  border-radius: 2px;
  background: var(--accent);
}

/* 校内与社会实践 */
.campus { display: grid; gap: 16px; }
.campus-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
}
.campus-card p { margin-top: 10px; font-size: 0.9375rem; }
.campus-card .tl-head h3 { font-size: 1rem; }

/* ---------- 11. 教育背景 / 荣誉 ---------- */
.edu-card { display: flex; flex-wrap: wrap; gap: 18px; align-items: flex-start; }
.edu-badge {
  padding: 10px 14px;
  border-radius: 10px;
  background: var(--tag-bg);
  color: var(--accent-text);
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.6;
  text-align: center;
}
.edu-body { flex: 1; min-width: 240px; }
.edu-degree { margin-top: 6px; font-size: 0.9375rem; }
.edu-body .chips { margin-top: 12px; }
.edu-master { border-color: var(--accent-text); box-shadow: var(--shadow-sm); }

.honor-grid { display: grid; gap: 16px; }
.honor-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
}
.honor-head { display: flex; align-items: flex-start; gap: 10px; }
.honor-head .icon { color: var(--accent-text); width: 1.4em; height: 1.4em; margin-top: 0.2em; }
.honor-head h3 { font-size: 1rem; }
.honor-meta { margin-top: 10px; font-size: 0.8125rem; color: var(--muted); }
.honor-card > p:not(.honor-meta) { margin-top: 10px; font-size: 0.875rem; }

.ielts { margin-top: 14px; display: grid; gap: 8px; }
.ielts-row {
  display: grid;
  grid-template-columns: 22px 1fr 44px;
  align-items: center;
  gap: 10px;
  font-family: var(--mono);
  font-size: 0.8125rem;
  color: var(--muted);
}
.ielts-track {
  display: block;
  height: 8px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-alt);
  overflow: hidden;
}
.ielts-fill { display: block; height: 100%; background: var(--accent); }
.ielts-val { color: var(--accent-text); font-weight: 700; text-align: right; }

/* ---------- 12. 联系方式 / 页脚 ---------- */
.section-contact { padding-bottom: 88px; }
.contact { text-align: center; }
.contact-head { margin-bottom: 0; }
.contact-title { font-size: clamp(1.6rem, 3.5vw, 2.25rem); }
.contact-sub { margin: 14px auto 0; max-width: 560px; color: var(--muted); }
.btn-mail { margin-top: 30px; padding: 16px 34px; font-size: 1.0625rem; }

.contact-cards {
  display: grid;
  gap: 16px;
  margin: 40px auto 0;
  max-width: 760px;
}
.contact-card {
  text-align: left;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 22px;
  display: grid;
  gap: 8px;
}
.contact-label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8125rem;
  color: var(--muted);
}
.contact-label .icon { color: var(--accent-text); }
.contact-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 16px;
  padding: 0;
  border: none;
  background: transparent;
  color: var(--heading);
  font-size: 1rem;
  cursor: pointer;
  text-align: left;
}
.contact-btn:hover { text-decoration: none; }
.contact-value {
  font-size: 1.0625rem;
  font-weight: 700;
  overflow-wrap: anywhere; /* 长邮箱在移动端可换行不断开 */
}
a.contact-btn:hover .contact-value { color: var(--accent-text); }
.copy-tip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8125rem;
  color: var(--muted);
  white-space: nowrap;
}
.contact-btn:hover .copy-tip { color: var(--accent-text); }
.contact-btn.is-copied .copy-tip { color: var(--accent-strong); }
.repo-links { font-size: 0.875rem; color: var(--muted); }

.quick-facts { margin-top: 36px; font-size: 0.9375rem; color: var(--muted); line-height: 2; }

.footer { border-top: 1px solid var(--border); padding: 26px 0; }
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
}
.footer-copy { font-size: 0.875rem; color: var(--muted); }
.footer-actions { display: flex; flex-wrap: wrap; gap: 4px; }

/* ---------- 13. 返回顶部 ---------- */
.back-top {
  position: fixed;
  right: 24px; bottom: 24px;
  z-index: 90;
  width: 46px; height: 46px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--card);
  color: var(--accent-text);
  cursor: pointer;
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  box-shadow: var(--shadow-sm);
  transition: opacity 0.25s ease, transform 0.25s ease, border-color 0.2s ease;
}
.back-top.is-show { opacity: 1; transform: none; pointer-events: auto; }
.back-top:hover { border-color: var(--accent-text); }

/* ---------- 14. 滚动渐显（含交错延迟） ---------- */
.reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.reveal.is-visible { opacity: 1; transform: none; }

[data-stagger] > *:nth-child(2).reveal { transition-delay: 60ms; }
[data-stagger] > *:nth-child(3).reveal { transition-delay: 120ms; }
[data-stagger] > *:nth-child(4).reveal { transition-delay: 180ms; }
[data-stagger] > *:nth-child(5).reveal { transition-delay: 240ms; }
[data-stagger] > *:nth-child(6).reveal { transition-delay: 300ms; }
[data-stagger] > *:nth-child(7).reveal { transition-delay: 360ms; }
[data-stagger] > *:nth-child(8).reveal { transition-delay: 420ms; }

/* ---------- 15. 响应式 ---------- */
@media (max-width: 860px) {
  .nav-list { display: none; }
  .nav-toggle { display: inline-flex; }
}
@media (min-width: 640px) {
  .stats { grid-template-columns: repeat(4, 1fr); }
  .highlights { grid-template-columns: repeat(3, 1fr); }
  .campus { grid-template-columns: repeat(2, 1fr); }
  .honor-grid { grid-template-columns: repeat(3, 1fr); }
  .contact-cards { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 768px) {
  .kn-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 861px) {
  /* 与 .nav-toggle 的显示断点保持一致，避免 768–860px 区间点开无反应 */
  .nav-drawer, .nav-overlay { display: none; }
}
@media (min-width: 900px) {
  .hero-grid { grid-template-columns: 1.25fr 0.75fr; gap: 64px; }
  .proj-body { grid-template-columns: 0.9fr 1.1fr; }
}
@media (min-width: 1024px) {
  .kn-grid { grid-template-columns: repeat(3, 1fr); } /* 2×3 网格 */
  .section { padding: 104px 0; }
}
@media (max-width: 480px) {
  .container { width: calc(100% - 40px); }
  .section { padding: 72px 0; }
  .proj-card { padding: 22px 18px; }
  .repo-link { margin-left: 0; }
  .tl-time { margin-left: 0; width: 100%; }
  .btn { padding: 13px 20px; }
  .back-top { right: 16px; bottom: 16px; }
}

/* ---------- 16. 动效克制：prefers-reduced-motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .reveal {
    opacity: 1;
    transform: none;
  }
  .cursor { display: none; }        /* 打字机降级为静态展示 */
  .scroll-cue .icon { animation: none; }
  .kn-card:hover, .btn:hover, .tl-card:hover { transform: none; } /* hover 仅保留颜色变化 */
}

/* ==========================================================================
   方向板块切换（AI 产品经理 / 金融科技 / 大模型评测）
   ========================================================================== */

/* 板块显隐：非当前方向整块隐藏 */
.board[hidden] { display: none !important; }

/* ---------- 方向切换标签条（固定原地，不随滚动吸顶） ---------- */
.board-tabs-wrap {
  position: static;
  border-bottom: 1px solid var(--border);
}

.board-tabs {
  display: flex;
  gap: 8px;
  padding: 10px 0;
  overflow-x: auto;
  scrollbar-width: none;
}
.board-tabs::-webkit-scrollbar { display: none; }

.board-tab {
  flex: 1 0 auto;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  padding: 10px 22px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
  color: var(--muted);
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
  font: inherit;
  text-align: left;
}

.board-tab:hover { border-color: var(--accent-text); color: var(--text); }

.board-tab:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.board-tab.is-active {
  border-color: var(--accent-text);
  color: var(--heading);
  box-shadow: var(--shadow-sm);
  background: var(--tag-bg);
}

.bt-name { font-weight: 700; font-size: 15px; line-height: 1.3; }
.bt-sub { font-size: 12px; line-height: 1.4; letter-spacing: 0.02em; }

/* ---------- 方向定位条 ---------- */
.board-goal { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.board-brief {
  max-width: 46em;
  margin: 0 auto;
  color: var(--text);
  font-size: 15px;
  line-height: 1.9;
  text-align: center;
}

@media (max-width: 860px) {
  .board-tab { flex: 0 0 auto; padding: 8px 16px; }
  .bt-sub { display: none; }
}

/* ---------- AIGC 视频跳转标签（链接式，非 tab） ---------- */
.board-jump {
  flex: 1 0 auto;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  padding: 10px 22px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
  color: var(--muted);
  text-decoration: none;
  transition: border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
}
.board-jump:hover {
  border-color: var(--accent-text);
  color: var(--heading);
  box-shadow: var(--shadow-sm);
  background: var(--tag-bg);
}
.board-jump .bj-arrow { color: var(--accent-text); font-size: 0.85em; margin-left: 2px; }
@media (max-width: 860px) {
  .board-jump { flex: 0 0 auto; padding: 8px 16px; }
}

/* ---------- 活动现场 · 拍立得照片墙（俏皮风） ---------- */
.ev-title-tilt { display: inline-block; transform: rotate(-1.6deg); }
.ev-title-doodle { color: var(--accent-text); font-size: 0.55em; vertical-align: 0.5em; animation: ev-spin 6s linear infinite; display: inline-block; }
@keyframes ev-spin { to { transform: rotate(360deg); } }

.ev-wall { columns: 3 280px; column-gap: 26px; }
.ev-card {
  position: relative;
  break-inside: avoid;
  margin: 0 0 26px;
  padding: 10px 10px 14px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 6px;
  box-shadow: var(--shadow);
  transform: rotate(var(--rot, 0deg));
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.3s ease, border-color 0.3s ease, z-index 0s;
}
.ev-wall .ev-card:nth-child(4n+1) { --rot: -2.4deg; }
.ev-wall .ev-card:nth-child(4n+2) { --rot: 2.2deg; }
.ev-wall .ev-card:nth-child(4n+3) { --rot: -1.2deg; }
.ev-wall .ev-card:nth-child(4n+4) { --rot: 3deg; }
.ev-card:hover {
  transform: rotate(0deg) scale(1.06) translateY(-6px);
  z-index: 6;
  border-color: var(--accent-text);
  box-shadow: 0 18px 42px rgba(0, 0, 0, 0.28), 0 0 0 4px color-mix(in srgb, var(--accent) 22%, transparent);
}
.ev-ph { overflow: hidden; border-radius: 3px; }
.ev-ph img {
  width: 100%; display: block;
  transition: transform 0.45s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.ev-card:hover .ev-ph img { transform: scale(1.1) rotate(0.6deg); }
.ev-tape {
  position: absolute; top: -11px; left: 50%;
  width: 88px; height: 22px;
  transform: translateX(-50%) rotate(-3.5deg);
  background: color-mix(in srgb, var(--accent) 55%, transparent);
  opacity: 0.75; border-radius: 2px;
  backdrop-filter: blur(2px);
}
.ev-wall .ev-card:nth-child(3n+2) .ev-tape { background: color-mix(in srgb, #ff8a5c 55%, transparent); transform: translateX(-58%) rotate(3deg); }
.ev-wall .ev-card:nth-child(3n+3) .ev-tape { background: color-mix(in srgb, #35c58f 50%, transparent); transform: translateX(-42%) rotate(-2deg); }
.ev-cap { padding: 10px 4px 0; display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.ev-cap b { font-size: 0.92rem; color: var(--heading); font-weight: 600; }
.ev-chip {
  font-size: 0.72rem; white-space: nowrap;
  color: var(--accent-text);
  background: color-mix(in srgb, var(--accent) 14%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 38%, transparent);
  border-radius: 999px; padding: 3px 10px;
  transition: transform 0.25s ease, background 0.25s ease;
}
.ev-card:hover .ev-chip { transform: rotate(-4deg) scale(1.08); background: color-mix(in srgb, var(--accent) 26%, transparent); }

@media (prefers-reduced-motion: reduce) {
  .ev-title-doodle { animation: none; }
  .ev-card, .ev-ph img, .ev-chip { transition: none; }
}

/* ---------- 语言切换按钮 ---------- */
.lang-btn {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  min-width: 34px;
  padding: 0 8px;
}

/* ---------- 治理闭环示意图 ---------- */
.gov-loop {
  margin-top: 42px;
  color: var(--accent-text);
}
.gov-loop svg { width: 100%; height: auto; display: block; }
.gov-nodes rect {
  fill: var(--card);
  stroke: currentColor;
  stroke-opacity: 0.45;
  stroke-width: 1.2;
}
.gov-nodes text {
  fill: var(--heading);
  font-size: 15px;
  font-weight: 600;
  text-anchor: middle;
}
.gov-nodes text.gov-sub {
  fill: var(--muted);
  font-size: 10.5px;
  font-weight: 400;
}
.gov-loop-cap {
  text-align: center;
  color: var(--muted);
  font-size: 0.88rem;
  margin: 10px 0 0;
}
@media (max-width: 700px) {
  .gov-nodes text { font-size: 20px; }
  .gov-nodes text.gov-sub { font-size: 15px; }
}