/* Wenli Xie — personal site
   Warm, calm, considered. A person's homepage, not a hire-me page.
   --------------------------------------------------------------- */

:root {
  /* Palette — slightly warm light theme */
  --bg:        #F6F3EA;       /* warm cream */
  --bg-soft:   #EFEBDF;
  --paper:     #FBFAF5;
  --ink:       #1B1B17;
  --ink-soft:  #3F3F39;
  --muted:     #797971;
  --border:    #E5E1D4;
  --border-strong: #CDC8B7;
  --accent:    #345E7E;       /* muted slate-blue (less cobalt) */
  --accent-2:  #1F3F5C;
  --accent-soft: #E0E8EF;
  --shadow-1:  0 1px 0 rgba(27,27,23,0.03);
  --shadow-2:  0 1px 1px rgba(27,27,23,0.04),
               0 8px 22px -10px rgba(27,27,23,0.10);

  --ff-sans:   -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
               "Inter", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --ff-mono:   "Geist Mono", ui-monospace, "SFMono-Regular", "SF Mono", Menlo, monospace;

  --max:       70rem;
  --pad:       clamp(1.25rem, 0.5rem + 2vw, 2.25rem);
  --radius:    12px;
  --easing:    cubic-bezier(0.22, 0.61, 0.36, 1);
}

*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }

html { scroll-behavior: smooth; background: var(--bg); }
body {
  font-family: var(--ff-sans);
  font-size: 17px;
  line-height: 1.55;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-feature-settings: "ss01", "cv11";
  letter-spacing: -0.005em;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
::selection { background: var(--accent); color: var(--paper); }

.muted { color: var(--muted); }
em { font-style: italic; }

/* ─────────────  Nav  ───────────── */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklab, var(--bg) 82%, transparent);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
}
.nav-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.85rem var(--pad);
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 1.25rem;
  align-items: center;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
}
.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 26px; height: 26px;
  border-radius: 6px;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--ff-mono);
  font-size: 10px;
  font-weight: 600;
}
.brand-name {
  font-size: 0.92rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.nav nav { display: flex; gap: 1.5rem; justify-content: center; }
.nav nav a {
  font-size: 0.88rem;
  color: var(--ink-soft);
  position: relative;
  padding: 0.3rem 0;
  transition: color 150ms var(--easing);
}
.nav nav a:hover { color: var(--ink); }
.nav nav a::after {
  content: "";
  position: absolute;
  left: 50%; right: 50%;
  bottom: 0.05rem;
  height: 1px;
  background: var(--ink);
  transition: left 220ms var(--easing), right 220ms var(--easing);
}
.nav nav a:hover::after { left: 0; right: 0; }

.nav-link {
  font-size: 0.88rem;
  color: var(--ink-soft);
  border-bottom: 1px solid color-mix(in oklab, var(--ink-soft) 30%, transparent);
  padding-bottom: 1px;
  transition: color 150ms var(--easing), border-color 150ms var(--easing);
}
.nav-link:hover { color: var(--ink); border-bottom-color: var(--ink); }

/* ─────────────  Hero  ───────────── */

.hero {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(3rem, 5vw + 1rem, 5.5rem) var(--pad) 4rem;
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  column-gap: clamp(2rem, 1rem + 4vw, 4.5rem);
  align-items: center;
}
.hero-text { grid-column: 1; min-width: 0; }

.kicker {
  margin: 0 0 0.4rem;
  font-family: var(--ff-mono);
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  color: var(--accent);
}

.hero-name {
  margin: 0;
  font-family: var(--ff-sans);
  font-weight: 600;
  font-size: clamp(2.6rem, 1.6rem + 4.2vw, 4.6rem);
  line-height: 1.02;
  letter-spacing: -0.045em;
  color: var(--ink);
}

.hero-role {
  margin: 1rem 0 1.5rem;
  font-size: 1.15rem;
  font-weight: 500;
  letter-spacing: -0.012em;
  color: var(--ink-soft);
  line-height: 1.4;
}
.hero-role .at {
  font-weight: 400;
  color: var(--muted);
  margin: 0 0.05em;
}

.hero-prose {
  max-width: 56ch;
  display: grid;
  gap: 0.85rem;
}
.hero-prose p {
  font-size: 1.05rem;
  line-height: 1.6;
  color: var(--ink-soft);
  margin: 0;
  letter-spacing: -0.005em;
}

/* Social links — Apple-style pills with inline SVG glyphs */
.social {
  list-style: none;
  display: flex;
  gap: 0.5rem;
  padding: 0;
  margin: 1.75rem 0 0;
  flex-wrap: wrap;
}
.social-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 0.85rem 0.5rem 0.7rem;
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--ink-soft);
  font-size: 0.88rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  transition:
    background-color 180ms var(--easing),
    color 180ms var(--easing),
    border-color 180ms var(--easing),
    transform 180ms var(--easing);
}
.social-link:hover {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
  transform: translateY(-1px);
}
.social-link svg {
  width: 15px;
  height: 15px;
  color: currentColor;
  flex-shrink: 0;
}

/* Portrait */
.hero-portrait {
  grid-column: 2;
  grid-row: 1;
  position: relative;
  margin: 0 0 0 auto;
  width: 100%;
  max-width: 24rem;
  aspect-ratio: 4 / 5;
  border-radius: 8px;
  overflow: hidden;
  background: var(--paper);
  border: 1px solid var(--border-strong);
  box-shadow:
    0 1px 1px rgba(27,27,23,0.04),
    0 22px 44px -20px rgba(27,27,23,0.16);
  isolation: isolate;
  transition: transform 320ms var(--easing);
}
.hero-portrait img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 16%;
  display: block;
  filter: saturate(0.96) contrast(0.98);
}
.hero-portrait::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 70%, rgba(27,27,23,0.10) 100%);
  pointer-events: none;
}
.hero-portrait-cap {
  position: absolute;
  left: 0.85rem;
  bottom: 0.85rem;
  z-index: 2;
  font-family: var(--ff-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  color: var(--paper);
  text-shadow: 0 1px 8px rgba(27,27,23,0.4);
}

/* Facts panel */
.hero-facts {
  margin: 3rem 0 0;
  padding: 1.1rem 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.85rem 2.5rem;
}
.hero-facts > div { display: grid; gap: 0.25rem; }
.hero-facts dt {
  font-family: var(--ff-mono);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  color: var(--muted);
}
.hero-facts dd { margin: 0; font-size: 0.94rem; color: var(--ink); }

/* ─────────────  Block scaffold  ───────────── */

.block {
  max-width: var(--max);
  margin: 0 auto;
  padding: 4.5rem var(--pad);
}

.sec-title {
  margin: 0 0 2rem;
  font-family: var(--ff-sans);
  font-weight: 600;
  font-size: clamp(1.6rem, 1.2rem + 1.4vw, 2.1rem);
  line-height: 1.1;
  letter-spacing: -0.028em;
  color: var(--ink);
  position: relative;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--border);
}
.sec-title::after {
  content: "";
  position: absolute;
  left: 0; bottom: -1px;
  width: 2.4rem;
  height: 1px;
  background: var(--accent);
}

/* ─────────────  About  ───────────── */

.about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  gap: 2.5rem;
}
.about-prose p {
  font-size: 1.05rem;
  line-height: 1.7;
  color: var(--ink-soft);
}
.about-prose p + p { margin-top: 1rem; }

.about-card {
  padding: 1.2rem 1.3rem;
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.card-kicker {
  font-family: var(--ff-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 0.85rem;
}
.card-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.75rem;
  font-size: 0.95rem;
  color: var(--ink-soft);
  line-height: 1.55;
}
.card-list li { position: relative; padding-left: 1.1rem; }
.card-list li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.55em;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
}
.card-list strong { color: var(--ink); font-weight: 600; }

/* ─────────────  Project cards  ───────────── */

.cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.25rem;
}
.card {
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.5rem 1.4rem;
  display: flex;
  flex-direction: column;
  transition: border-color 200ms var(--easing), transform 200ms var(--easing);
}
.card:hover {
  border-color: var(--border-strong);
  transform: translateY(-1px);
}
.card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--ff-mono);
  font-size: 0.76rem;
  letter-spacing: 0.02em;
  color: var(--muted);
  margin-bottom: 0.85rem;
}
.card-tag { color: var(--accent); }
.card h3 {
  margin: 0 0 0.6rem;
  font-family: var(--ff-sans);
  font-size: 1.2rem;
  font-weight: 600;
  letter-spacing: -0.022em;
  line-height: 1.22;
  color: var(--ink);
}
.card-lead {
  font-size: 0.98rem;
  line-height: 1.6;
  color: var(--ink-soft);
  margin: 0 0 1rem;
}
.card-lead em { font-style: italic; color: var(--ink); }
.card-points {
  list-style: none;
  padding: 0;
  margin: 0 0 1.1rem;
  display: grid;
  gap: 0.45rem;
  font-size: 0.93rem;
  line-height: 1.55;
  color: var(--ink-soft);
}
.card-points li { position: relative; padding-left: 1.1rem; }
.card-points li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.65em;
  width: 0.65rem; height: 1px;
  background: var(--accent);
}
.card-points code {
  font-family: var(--ff-mono);
  font-size: 0.86em;
  background: var(--bg-soft);
  padding: 0.05em 0.32em;
  border-radius: 4px;
  color: var(--ink);
}
.card-tags {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem 0.5rem;
  padding: 0;
  margin: auto 0 0;
}
.card-tags li {
  font-family: var(--ff-mono);
  font-size: 0.7rem;
  letter-spacing: 0.02em;
  padding: 0.18rem 0.5rem;
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 5px;
}

/* ─────────────  Experience  ───────────── */

.exp { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.75rem; }
.exp-row {
  display: grid;
  grid-template-columns: 12rem minmax(0, 1fr);
  gap: 2rem;
  padding: 1.2rem 1.4rem;
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 200ms var(--easing);
}
.exp-row:hover { border-color: var(--border-strong); }

.exp-side .exp-co { font-weight: 600; font-size: 1rem; color: var(--ink); margin: 0; }
.exp-side .exp-loc {
  margin: 0.1rem 0 0;
  font-size: 0.84rem;
  color: var(--muted);
}

.exp-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.65rem;
}
.exp-head h3 {
  margin: 0;
  font-family: var(--ff-sans);
  font-size: 1.12rem;
  font-weight: 600;
  letter-spacing: -0.018em;
  color: var(--ink);
}
.exp-head time {
  font-family: var(--ff-mono);
  font-size: 0.78rem;
  color: var(--muted);
  white-space: nowrap;
}
.exp-main ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.4rem;
  font-size: 0.95rem;
  color: var(--ink-soft);
  line-height: 1.6;
}
.exp-main ul li { position: relative; padding-left: 1.1rem; }
.exp-main ul li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.6em;
  width: 0.65rem; height: 1px;
  background: var(--accent);
}
.exp-main strong { color: var(--ink); font-weight: 600; }

/* ─────────────  Education + Skills  ───────────── */

.ed-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.25rem;
}

.panel {
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.5rem 1.6rem;
}
.panel-title {
  margin: 0 0 1.1rem;
  font-family: var(--ff-sans);
  font-size: 1.08rem;
  font-weight: 600;
  letter-spacing: -0.018em;
  color: var(--ink);
}

.ed-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 1.35rem; }
.ed-list .ed-school { font-weight: 600; font-size: 1rem; color: var(--ink); margin: 0; }
.ed-list .ed-degree { margin: 0.2rem 0 0; font-size: 0.93rem; color: var(--ink-soft); }
.ed-list .ed-meta {
  margin: 0.3rem 0 0;
  font-family: var(--ff-mono);
  font-size: 0.78rem;
  color: var(--muted);
}
.ed-list .ed-extra { margin: 0.4rem 0 0; font-size: 0.9rem; color: var(--ink-soft); line-height: 1.55; }

.badge {
  display: inline-block;
  margin-left: 0.3rem;
  padding: 0.05rem 0.42rem;
  font-family: var(--ff-mono);
  font-size: 0.66rem;
  letter-spacing: 0.06em;
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 999px;
  vertical-align: 0.18em;
}

.skill-group + .skill-group { margin-top: 1rem; }
.sk-label {
  margin: 0 0 0.5rem;
  font-family: var(--ff-mono);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--muted);
}
.chips {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem 0.4rem;
  padding: 0;
  margin: 0;
}
.chips li {
  font-size: 0.84rem;
  padding: 0.25rem 0.6rem;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  color: var(--ink-soft);
  border-radius: 6px;
  letter-spacing: -0.005em;
}

/* ─────────────  Closing note  ───────────── */

.closing {
  max-width: var(--max);
  margin: 0 auto;
  padding: 3.5rem var(--pad) 1.75rem;
  text-align: center;
}
.closing-inner {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}
.closing-mark {
  margin: 0;
  font-size: 1rem;
  color: var(--accent);
  opacity: 0.7;
  letter-spacing: 0.4em;
}
.closing-email {
  margin: 0;
  font-family: var(--ff-mono);
  font-size: 0.95rem;
  letter-spacing: -0.005em;
}
.closing-email a {
  color: var(--ink);
  border-bottom: 1px solid var(--accent);
  padding-bottom: 1px;
  transition: background 180ms var(--easing), color 180ms var(--easing);
}
.closing-email a:hover {
  color: var(--accent-2);
  background: var(--accent-soft);
}

/* ─────────────  Footer  ───────────── */

.foot {
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.25rem var(--pad) 2.5rem;
}
.foot-inner {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: var(--ff-mono);
  font-size: 0.78rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}
.foot p { margin: 0; }

/* ─────────────  Focus  ───────────── */

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

/* ─────────────  Responsive  ───────────── */

@media (max-width: 900px) {
  .nav-inner { grid-template-columns: auto 1fr; row-gap: 0.5rem; }
  .nav nav { grid-column: 1 / -1; justify-content: flex-start; gap: 1.1rem; flex-wrap: wrap; }
  .nav-link { display: none; }

  .hero-inner { grid-template-columns: 1fr; row-gap: 1.75rem; }
  .hero-text { grid-row: 2; grid-column: 1; }
  .hero-portrait {
    grid-row: 1; grid-column: 1;
    margin: 0 auto;
    max-width: 18rem;
  }
  .hero-facts { grid-template-columns: repeat(2, 1fr); gap: 0.85rem 1.5rem; }

  .about-grid { grid-template-columns: 1fr; gap: 1.5rem; }
  .cards { grid-template-columns: 1fr; }
  .ed-grid { grid-template-columns: 1fr; }
  .exp-row { grid-template-columns: 1fr; gap: 0.85rem; }
  .exp-head { flex-direction: column; align-items: flex-start; gap: 0.2rem; }
}

@media (max-width: 520px) {
  .nav nav a { font-size: 0.84rem; }
  .brand-name { display: none; }
  .hero-portrait { max-width: 15rem; }
  .hero-facts { grid-template-columns: 1fr; gap: 0.7rem; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
}