/* ============================================
   Hunter Wang — Personal Site v2.1
   Light theme · Performance-first · Hand-crafted
   ============================================ */

/* ----- CSS Custom Properties ----- */
:root {
  --bg:            #faf8f5;
  --surface:       #f3f0eb;
  --surface-hover: #ebe6de;
  --border:        #e0dbd3;
  --border-light:  #d4cec4;
  --text-primary:  #1a1714;
  --text-secondary:#5c5852;
  --text-muted:    #969088;
  --accent:        #8b5e3c;
  --accent-dim:    #b8957a;
  --accent-light:  #e8d5c0;
  --font-heading:  'Songti SC', 'STSong', 'SimSun', 'Noto Serif SC', '华文宋体', '宋体', serif;
  --font-body:     'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', 'Noto Sans SC', '微软雅黑', sans-serif;
  --max-width:     1200px;
  --gap:           clamp(1rem, 3vw, 2.5rem);
  --section-pad:   clamp(3rem, 6vw, 5rem);
}

/* ----- Reset & Base ----- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-weight: 350;
  font-size: clamp(0.95rem, 1.5vw, 1.05rem);
  line-height: 1.7;
  letter-spacing: 0.01em;
  overflow-x: hidden;
}

::selection { background: var(--accent-light); color: var(--text-primary); }

h1, h2, h3 { font-family: var(--font-heading); font-weight: 600; line-height: 1.15; }
h3 { font-weight: 500; }

a { color: inherit; text-decoration: none; transition: color 0.25s ease; }
a:hover, a:focus-visible { color: var(--accent); }
img { max-width: 100%; display: block; }
button { font: inherit; cursor: pointer; border: none; background: none; }

/* ---- Performance: lazy-render off-screen sections ---- */
.research,
.experience,
.contact,
.happy-moments,
.footer { content-visibility: auto; contain-intrinsic-size: 500px; }

/* GPU 硬件加速：让浏览器预合成动画元素 */
.reveal,
.reveal-stagger > * { will-change: transform, opacity; }
.reveal.visible,
.reveal-stagger > *.visible { will-change: auto; }

/* 让滚动手感更丝滑 */
main { contain: layout style; }

/* ============================================
   Orb Background — CSS only, no JS
   缩小尺寸 + 降低模糊 = 性能安全
   ============================================ */
.orb {
  position: fixed;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.05;
}

.orb--1 {
  width: 400px; height: 400px;
  background: #c8956a;
  top: -10%; left: -8%;
  animation: orb-drift-1 30s ease-in-out infinite;
}

.orb--2 {
  width: 350px; height: 350px;
  background: #a08060;
  bottom: -8%; right: -10%;
  animation: orb-drift-2 35s ease-in-out infinite;
  opacity: 0.04;
}

@keyframes orb-drift-1 {
  0%, 100% { transform: translate(0, 0); }
  25%      { transform: translate(60px, 30px); }
  50%      { transform: translate(15px, -25px); }
  75%      { transform: translate(-30px, 15px); }
}

@keyframes orb-drift-2 {
  0%, 100% { transform: translate(0, 0); }
  33%      { transform: translate(-50px, -40px); }
  66%      { transform: translate(25px, 50px); }
}

@media (max-width: 767px), (prefers-reduced-motion: reduce) {
  .orb { display: none; }
}

/* ============================================
   Navigation
   ============================================ */
.nav-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 1.1rem var(--gap);
  transition: transform 0.4s cubic-bezier(0.22, 0.61, 0.36, 1),
              background-color 0.4s ease, box-shadow 0.4s ease;
}
.nav-header.hidden { transform: translateY(-100%); }
.nav-header.scrolled {
  background-color: rgba(250, 248, 245, 0.85);
  border-bottom: 1px solid var(--border);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 rgba(0,0,0,0.03);
}

.nav-inner {
  max-width: var(--max-width); margin: 0 auto;
  display: flex; justify-content: space-between; align-items: center;
}

.nav-logo {
  font-family: var(--font-heading); font-size: 1.35rem; font-weight: 700;
  letter-spacing: 0.04em; color: var(--text-primary);
}
.nav-logo:hover { color: var(--accent); }

.nav-updated {
  font-size: 0.7rem; color: var(--text-muted);
  letter-spacing: 0.04em; white-space: nowrap;
  margin-right: auto; margin-left: 1rem;
}
.nav-links { display: flex; gap: clamp(1.2rem, 3.5vw, 2.5rem); list-style: none; }
.nav-links a {
  font-size: 0.82rem; font-weight: 450; letter-spacing: 0.06em;
  color: var(--text-secondary); position: relative; padding: 0.3em 0;
}
.nav-links a::after {
  content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 1.5px;
  background: var(--accent);
  transition: width 0.3s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.nav-links a:hover::after,
.nav-links a:focus-visible::after,
.nav-links a.active::after { width: 100%; }
.nav-links a:hover,
.nav-links a:focus-visible,
.nav-links a.active { color: var(--text-primary); }

/* ============================================
   Hero
   ============================================ */
.hero {
  padding-top: clamp(4.5rem, 8vw, 6rem);
  padding-bottom: clamp(1.5rem, 3vw, 2.5rem);
  padding-left: var(--gap); padding-right: var(--gap);
  position: relative; z-index: 1;
}

.hero-grid {
  max-width: var(--max-width); margin: 0 auto;
  display: grid; grid-template-columns: 1fr;
  gap: clamp(2rem, 5vw, 4rem); align-items: start;
}

/* Portrait */
.hero-portrait { display: flex; justify-content: center; }
.portrait-frame {
  width: clamp(180px, 35vw, 260px); aspect-ratio: 3 / 4;
  background: var(--surface); border: 1px solid var(--border);
  position: relative; overflow: hidden;
}
.portrait-frame--empty .portrait-placeholder { display: flex; }
.portrait-img { width: 100%; height: 100%; object-fit: cover; position: relative; z-index: 1; }
.portrait-placeholder {
  display: none; position: absolute; inset: 0;
  align-items: center; justify-content: center;
  background: var(--surface); z-index: 0;
}
.portrait-placeholder-text {
  font-family: var(--font-heading); font-size: 1rem;
  font-style: italic; color: var(--text-muted); letter-spacing: 0.06em;
}

/* Hero Info */
.hero-info { display: flex; flex-direction: column; gap: 1rem; }
.hero-rule {
  width: clamp(40px, 8vw, 80px); height: 1.5px;
  background: var(--accent); margin-bottom: 0.25rem;
}
.hero-name {
  font-size: clamp(2rem, 5.4vw, 3.24rem); font-weight: 700;
  line-height: 1.1; color: var(--text-primary);
}
.hero-line { display: block; }
.hero-line:last-child { color: var(--accent-dim); font-weight: 500; }
.hero-role { font-size: clamp(0.95rem, 1.8vw, 1.1rem); color: var(--text-secondary); line-height: 1.7; font-weight: 450; }
.hero-bio { font-size: 0.92rem; color: var(--text-muted); line-height: 1.8; max-width: 74ch; margin-top: 0.25rem; text-align: justify; }

/* Hero links — monochrome icons */
.hero-links { display: flex; gap: 1.5rem; margin-top: 0.5rem; }
.hero-link {
  display: inline-flex; align-items: center; gap: 0.4rem;
  font-size: 0.85rem; font-weight: 500; color: var(--accent);
  letter-spacing: 0.03em; transition: color 0.25s ease, transform 0.25s ease;
}
.hero-link:hover { color: var(--text-primary); transform: translateX(2px); }
.hero-link-icon {
  width: 16px; height: 16px;
  /* 原版品牌色，不做任何着色处理 */
}

/* ---- Education Horizontal Timeline ---- */
.edu-horizontal {
  max-width: var(--max-width);
  margin: clamp(2rem, 4vw, 3.5rem) auto 0;
  padding: 0 var(--gap);
  position: relative;
}

.edu-axis {
  position: absolute;
  top: 0.35rem;
  left: var(--gap);
  right: var(--gap);
  height: 1px;
  background: var(--border);
}

.edu-track {
  display: flex;
  justify-content: space-around;
  gap: 1rem;
  position: relative;
  z-index: 1;
}

.edu-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  flex: 1;
  min-width: 0;
}

.edu-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent-dim);
  border: 2px solid var(--bg);
  margin-bottom: 0.6rem;
  flex-shrink: 0;
}

.edu-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  font-size: 0.78rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.edu-period {
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

.edu-school {
  font-weight: 550;
  color: var(--text-primary);
}

.edu-major {
  color: var(--text-secondary);
}

.edu-note {
  font-size: 0.7rem;
  color: var(--text-muted);
  font-style: italic;
  margin-top: 0.1rem;
}

/* ============================================
   Section Head
   ============================================ */
.section-head {
  display: flex; align-items: baseline; gap: 0.75rem;
  margin-bottom: clamp(2rem, 4vw, 3rem); padding-top: var(--section-pad);
}
.section-num {
  font-family: var(--font-heading); font-size: clamp(2rem, 4.5vw, 3.2rem);
  font-weight: 650; letter-spacing: -0.01em; color: var(--accent-dim);
}
.section-title {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 650; letter-spacing: -0.015em; color: var(--text-primary);
}

/* ============================================
   幸福时刻 — Irregular masonry grid
   ============================================ */
.happy-moments { max-width: var(--max-width); margin: 0 auto; padding: 0; }

.happy-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}

.happy-card {
  background: var(--bg);
  transition: background-color 0.35s ease;
  display: flex;
  flex-direction: column;
}
.happy-card:hover { background: var(--surface-hover); }
.happy-card a { display: flex; flex-direction: column; height: 100%; color: inherit; }
.happy-card a:hover { color: inherit; }

.happy-card-media {
  overflow: hidden; flex-shrink: 0;
  /* 不同尺寸卡的媒体区高度不同 */
}
.happy-card--small  .happy-card-media { aspect-ratio: 3 / 2; }
.happy-card--medium .happy-card-media { aspect-ratio: 16 / 10; }
.happy-card--wide   .happy-card-media { aspect-ratio: 21 / 9; }

.happy-card-placeholder {
  width: 100%; height: 100%;
  background: var(--surface);
  display: flex; align-items: center; justify-content: center;
  transition: background-color 0.35s ease;
}
.happy-card:hover .happy-card-placeholder { background: var(--accent-light); }
.happy-card-placeholder-text {
  font-family: var(--font-heading);
  font-size: clamp(0.9rem, 2vw, 1.25rem);
  font-style: italic; color: var(--text-muted);
  letter-spacing: 0.03em; text-align: center; padding: 0.75rem;
}

.happy-card-body {
  padding: clamp(0.9rem, 2vw, 1.35rem);
  display: flex; flex-direction: column; gap: 0.3rem; flex: 1;
}
.happy-card-tag {
  font-size: 0.68rem; font-weight: 550; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--accent-dim);
}
.happy-card-title {
  font-size: clamp(0.95rem, 1.8vw, 1.2rem);
  font-weight: 600; line-height: 1.25; color: var(--text-primary);
}
.happy-card-desc {
  font-size: 0.82rem; color: var(--text-secondary); line-height: 1.55;
}

/* 移动端教育经历垂直堆叠 */
@media (max-width: 767px) {
  .edu-track { flex-direction: column; align-items: flex-start; gap: 1rem; }
  .edu-axis  { display: none; }
  .edu-node  { flex-direction: row; align-items: flex-start; text-align: left; gap: 0.65rem; }
  .edu-dot   { margin-bottom: 0; margin-top: 0.3rem; flex-shrink: 0; }
  .edu-content { align-items: flex-start; }
}

/* Tablet+: 2-column irregular */
@media (min-width: 768px) {
  /* Hero — 照片左，信息右 */
  .hero-grid {
    grid-template-columns: auto 1fr;
    align-items: start;
  }
  .hero-portrait { justify-content: flex-start; }

  .happy-grid {
    grid-template-columns: 1fr 1fr;
    grid-auto-flow: dense;
  }
  .happy-card--wide { grid-column: 1 / -1; }
}

/* Desktop: 3-column irregular */
@media (min-width: 1024px) {
  .hero-grid {
    grid-template-columns: 280px 1fr;
    gap: clamp(3rem, 6vw, 5rem);
  }
  .hero-name { font-size: clamp(2.16rem, 4.5vw, 3.42rem); }

  .happy-grid { grid-template-columns: 1fr 1fr 1fr; }
  .happy-card--wide { grid-column: span 2; }
  .happy-card--medium { grid-column: span 1; }
}

/* ============================================
   科研工作 — Horizontal cards
   ============================================ */
.research { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--gap); }
.research-list { display: flex; flex-direction: column; gap: 1.5rem; }

.research-card {
  display: grid; grid-template-columns: 1fr;
  border: 1px solid var(--border); background: var(--bg);
  border-radius: 8px; overflow: hidden;
  transition: background-color 0.35s ease, border-color 0.35s ease;
  cursor: pointer;
}
.research-card:hover { background: var(--surface-hover); border-color: var(--border-light); }

.research-card-media {
  overflow: hidden; border-bottom: 1px solid var(--border);
}
.research-placeholder {
  aspect-ratio: 16 / 9; background: var(--surface);
  display: flex; align-items: center; justify-content: center;
  transition: background-color 0.35s ease;
}
.research-card:hover .research-placeholder { background: var(--accent-light); }
.research-placeholder-label {
  font-family: var(--font-heading);
  font-size: clamp(1.1rem, 2.8vw, 1.6rem);
  font-style: italic; color: var(--text-muted); letter-spacing: 0.03em;
}
.research-placeholder-img {
  width: 100%; height: 100%;
  object-fit: cover;
}

.research-card-body {
  padding: clamp(0.7rem, 1.5vw, 1rem);
  display: flex; flex-direction: column; gap: 0.3rem;
  min-height: 0; overflow: hidden;
}
.research-card-tag {
  font-size: 0.7rem; font-weight: 550; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--accent-dim);
}
.research-card-title {
  font-family: var(--font-heading);
  font-size: clamp(1.15rem, 2.2vw, 1.45rem);
  font-weight: 650; line-height: 1.25; color: var(--text-primary);
  display: -webkit-box; -webkit-line-clamp: 2; line-clamp: 2;
  -webkit-box-orient: vertical; overflow: hidden;
}
.research-card-authors {
  font-size: 0.85rem; color: var(--text-muted); font-weight: 400; font-style: italic;
  display: -webkit-box; -webkit-line-clamp: 2; line-clamp: 2;
  -webkit-box-orient: vertical; overflow: hidden;
}
.research-card-abstract {
  font-size: 0.88rem; color: var(--text-secondary); line-height: 1.65;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* 论文按钮 — 保持原色 */
.research-card-links { display: flex; gap: 0.6rem; margin-top: 0.4rem; }
.pill-link {
  display: inline-flex; align-items: center; gap: 0.35em;
  padding: 0.35em 0.8em;
  font-size: 0.75rem; font-weight: 500; letter-spacing: 0.04em;
  color: var(--text-secondary);
  border: 1px solid var(--border-light);
  transition: all 0.25s ease;
}
.pill-link:hover { border-color: var(--text-muted); color: var(--text-primary); }
.pill-link-icon { width: 14px; height: 14px; flex-shrink: 0; }
/* 品牌图标保持原色 — 不加 filter */

@media (min-width: 768px) {
  .research-card { grid-template-columns: 280px 1fr; }
  .research-card-media { border-bottom: none; border-right: 1px solid var(--border); }
  .research-placeholder { height: 100%; aspect-ratio: auto; }
}
@media (min-width: 1024px) {
  .research-card { grid-template-columns: 340px 1fr; }
}

/* "更多工作" 链接 */
.more-work-link {
  display: inline-block; text-align: left;
  padding: 1.2rem 0 0.5rem;
  font-size: 0.85rem; font-weight: 500; letter-spacing: 0.05em;
  color: var(--text-muted);
  transition: color 0.25s ease;
}
.more-work-link:hover {
  color: var(--text-primary);
}

/* ============================================
   个人经历 — Card grid
   ============================================ */
.experience { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--gap); }
.exp-grid {
  display: grid; grid-template-columns: 1fr;
  gap: 1px; background: var(--border); border: 1px solid var(--border);
}
.exp-card {
  background: var(--bg); padding: clamp(1.25rem, 3vw, 2rem);
  display: flex; flex-direction: column; gap: 0.5rem;
  transition: background-color 0.35s ease;
}
.exp-card:hover { background: var(--surface-hover); }
.exp-card-top {
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 0.5rem;
}
.exp-card-tag {
  font-size: 0.7rem; font-weight: 550; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--accent-dim);
}
.exp-card-date { font-size: 0.75rem; color: var(--text-muted); letter-spacing: 0.03em; }
.exp-card-title {
  font-family: var(--font-heading);
  font-size: clamp(1.1rem, 2vw, 1.35rem);
  font-weight: 650; line-height: 1.25; color: var(--text-primary);
}
.exp-card-desc { font-size: 0.88rem; color: var(--text-secondary); line-height: 1.6; max-width: 52ch; }

@media (min-width: 768px) {
  .exp-grid { grid-template-columns: 1fr 1fr; }
}

/* ============================================
   联系我 — 每行一个，明文显示
   ============================================ */
.contact { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--gap); }
.contact-rows {
  display: flex; flex-direction: column;
  border-top: 1px solid var(--border);
}

.contact-row-item {
  display: flex; align-items: baseline; gap: 0.6rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: color 0.25s ease, background-color 0.25s ease;
}
.contact-row-item:hover { color: var(--text-primary); background-color: var(--surface); }
a.contact-row-item:hover { color: var(--accent); }

.contact-row-label {
  font-weight: 500; min-width: 5em; flex-shrink: 0;
  color: var(--text-primary);
  display: flex; align-items: center; gap: 0.35em;
}
.contact-row-icon { font-size: 0.9em; opacity: 0.6; }
.contact-row-icon-img {
  width: 18px; height: 18px; flex-shrink: 0;
  vertical-align: middle;
}
.contact-row-value { word-break: break-all; }

/* WeChat 按钮样式 */
.contact-row-item--wechat { cursor: pointer; }
.contact-row-item--wechat:hover { color: var(--accent); }

/* ============================================
   WeChat QR Modal
   ============================================ */
.modal-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(26, 23, 20, 0.55);
  display: flex; align-items: center; justify-content: center; padding: 1.5rem;
  opacity: 0; pointer-events: none;
  transition: opacity 0.3s ease;
  -webkit-backdrop-filter: blur(4px);
  backdrop-filter: blur(4px);
}
.modal-overlay.open { opacity: 1; pointer-events: auto; }
.modal-card {
  background: var(--bg); padding: 2.5rem 2rem 2rem; text-align: center;
  position: relative; border: 1px solid var(--border);
  max-width: 360px; width: 100%;
}
.modal-close {
  position: absolute; top: 0.6rem; right: 0.8rem;
  font-size: 1.4rem; color: var(--text-muted);
  line-height: 1; padding: 0.3rem; transition: color 0.2s ease;
}
.modal-close:hover { color: var(--text-primary); }
.modal-title {
  font-family: var(--font-heading); font-size: 1.2rem;
  font-weight: 600; margin-bottom: 1.25rem; color: var(--text-primary);
}
.modal-qr {
  width: 200px; height: 200px; margin: 0 auto 1rem;
  background: var(--surface); border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center; overflow: hidden;
}
.modal-qr-img { width: 100%; height: 100%; object-fit: contain; }
.modal-qr-placeholder { font-size: 0.78rem; color: var(--text-muted); line-height: 1.6; padding: 1rem; }
.modal-hint { font-size: 0.8rem; color: var(--text-muted); letter-spacing: 0.03em; }

/* ============================================
   Footer — 居中
   ============================================ */
.footer {
  max-width: var(--max-width); margin: 0 auto;
  padding: clamp(2rem, 4vw, 3rem) var(--gap);
  border-top: 1px solid var(--border);
  margin-top: var(--section-pad);
  text-align: center;
}
.footer-inner {
  display: flex; align-items: center; justify-content: center;
  gap: 0.5rem; flex-wrap: wrap;
  font-size: 0.76rem; color: var(--text-muted); letter-spacing: 0.03em;
}
.footer-sep { color: var(--border-light); user-select: none; }
.footer-icp { color: var(--text-muted); transition: color 0.25s ease; }
.footer-icp:hover { color: var(--accent); }

/* ============================================
   Scroll Reveal
   ============================================ */
.reveal {
  opacity: 0; transform: translateY(20px);
  transition: opacity 0.65s cubic-bezier(0.22, 0.61, 0.36, 1),
              transform 0.65s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.reveal.visible { opacity: 1; transform: translateY(0); }

.reveal-stagger > * {
  opacity: 0; transform: translateY(14px);
  transition: opacity 0.5s cubic-bezier(0.22, 0.61, 0.36, 1),
              transform 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.reveal-stagger > *.visible { opacity: 1; transform: translateY(0); }

/* ----- Focus ----- */
:focus-visible { outline: 2px solid var(--accent-dim); outline-offset: 3px; border-radius: 1px; }

/* ----- Reduced Motion ----- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}

/* ----- Print ----- */
@media print {
  .nav-header, .orb, .modal-overlay { display: none !important; }
  body { background: #fff; color: #111; }
  .hero-name, .section-title, .happy-card-title, .research-card-title { color: #111; }
  .hero-role, .hero-bio, .happy-card-desc, .research-card-abstract { color: #333; }
}