/* ============================================================
   Yijia (Jya) Li — Portfolio
   Design: Minimal / Editorial / Dark
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

/* ── Design Tokens ──────────────────────────────────────── */
:root {
  --bg:        #0c0c0c;
  --surface:   #141414;
  --surface-2: #1c1c1c;
  --text:      #eeebe5;
  --muted:     #555;
  --muted-2:   #888;
  --border:    #222;
  --accent:    #c2ff4d;

  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --nav-h: 60px;
  --max-w: 1080px;
  --pad: clamp(1.25rem, 4vw, 2.5rem);
  --radius: 8px;
}

/* ── Reset ──────────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  font-size: 16px;
  scroll-behavior: smooth;
}
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img, video, iframe {
  display: block;
  max-width: 100%;
}
a {
  color: inherit;
  text-decoration: none;
}
ul { list-style: none; }

/* ── Navigation ─────────────────────────────────────────── */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--pad);
  background: rgba(12, 12, 12, 0.8);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
}
.nav-logo {
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--text);
  transition: opacity 0.2s;
}
.nav-logo:hover { opacity: 0.65; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}
.nav-links a {
  font-size: 0.825rem;
  color: var(--muted-2);
  transition: color 0.2s;
}
.nav-links a:hover,
.nav-links a.active { color: var(--text); }
.nav-resume {
  color: var(--accent) !important;
  font-weight: 500;
}
.nav-resume:hover { color: var(--text) !important; }

/* ── Layout ─────────────────────────────────────────────── */
.wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--pad);
}

/* ── Buttons ────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.6rem 1.25rem;
  font-size: 0.825rem;
  font-weight: 500;
  font-family: var(--font);
  border-radius: 100px;
  border: 1px solid var(--border);
  color: var(--text);
  background: transparent;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
  white-space: nowrap;
}
.btn:hover {
  background: var(--surface);
  border-color: var(--muted-2);
}
.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #0c0c0c;
  font-weight: 600;
}
.btn-primary:hover {
  background: #cfff6a;
  border-color: #cfff6a;
  color: #0c0c0c;
}

/* ── Tags ───────────────────────────────────────────────── */
.tag {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  border: 1px solid var(--border);
  border-radius: 100px;
  color: var(--muted-2);
}

/* ── Label ──────────────────────────────────────────────── */
.label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.accent { color: var(--accent); }

/* ── Scroll Reveal ──────────────────────────────────────── */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible { opacity: 1; transform: none; }
.reveal-d1 { transition-delay: 0.08s; }
.reveal-d2 { transition-delay: 0.16s; }
.reveal-d3 { transition-delay: 0.24s; }

/* ============================================================
   HOME
   ============================================================ */

.hero {
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-top: calc(var(--nav-h) + 2rem);
  padding-bottom: clamp(2rem, 5vh, 4rem);
  position: relative;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 65% 55% at 15% 65%, rgba(194,255,77,0.04) 0%, transparent 65%);
  pointer-events: none;
}
.hero-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--pad);
  width: 100%;
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 3rem;
  align-items: flex-end;
}
.hero-label { margin-bottom: 1.25rem; }
.hero-name {
  font-size: clamp(3rem, 9.5vw, 8rem);
  font-weight: 800;
  line-height: 0.92;
  letter-spacing: -0.03em;
}
.hero-sub {
  margin-top: 1.5rem;
  font-size: clamp(0.875rem, 1.8vw, 1rem);
  color: var(--muted-2);
  max-width: 420px;
  line-height: 1.65;
}
.hero-cta {
  margin-top: 2.25rem;
  display: flex;
  gap: 0.625rem;
  flex-wrap: wrap;
}
.hero-media {
  aspect-ratio: 4 / 3;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  flex-shrink: 0;
  align-self: flex-end;
}
.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Work section */
.work-section { padding: 6rem 0 8rem; }
.work-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 2.5rem;
}
.section-title {
  font-size: clamp(0.9rem, 2vw, 1.05rem);
  font-weight: 600;
  letter-spacing: -0.01em;
}
.work-count { font-size: 0.75rem; color: var(--muted); }
.work-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.work-card {
  background: var(--bg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  position: relative;
  transition: background 0.2s;
}
.work-card:hover { background: var(--surface); }
.work-card-thumb {
  width: 100%;
  aspect-ratio: 16 / 9;
  border-radius: 5px;
  overflow: hidden;
  background: var(--surface-2);
}
.work-card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.45s ease;
}
.work-card:hover .work-card-thumb img { transform: scale(1.04); }
.work-card-thumb.empty {
  display: flex;
  align-items: center;
  justify-content: center;
}
.work-card-thumb.empty span {
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--border);
}
.work-card-tags { display: flex; gap: 0.375rem; flex-wrap: wrap; }
.work-card-title {
  font-size: 1.075rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.work-card-desc {
  font-size: 0.825rem;
  color: var(--muted-2);
  line-height: 1.55;
}
.work-card-arrow {
  position: absolute;
  top: 1.75rem;
  right: 1.75rem;
  font-size: 0.9rem;
  color: var(--muted);
  transition: color 0.2s, transform 0.2s;
}
.work-card:hover .work-card-arrow {
  color: var(--accent);
  transform: translate(2px, -2px);
}

/* ============================================================
   PROJECTS PAGE
   ============================================================ */

.projects-top {
  padding-top: calc(var(--nav-h) + 5rem);
  padding-bottom: 3rem;
  border-bottom: 1px solid var(--border);
}
.page-heading {
  font-size: clamp(2.25rem, 6vw, 4.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1;
  margin-top: 1rem;
}
.project-list { padding-bottom: 6rem; }
.project-item {
  padding: 3.5rem 0;
  border-bottom: 1px solid var(--border);
}
.project-num {
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--muted);
  margin-bottom: 1.5rem;
}
.project-top-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 2rem;
  margin-bottom: 2.25rem;
  flex-wrap: wrap;
}
.project-title {
  font-size: clamp(1.4rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
}
.project-title-wip {
  font-size: 0.75em;
  font-weight: 400;
  color: var(--muted-2);
  margin-left: 0.4rem;
}
.project-role {
  font-size: 0.825rem;
  color: var(--muted-2);
  margin-top: 0.35rem;
}
.project-tags {
  display: flex;
  gap: 0.375rem;
  flex-wrap: wrap;
  padding-top: 0.2rem;
  flex-shrink: 0;
}
.project-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3.5rem;
  align-items: start;
}
.project-body.single {
  grid-template-columns: 1fr;
  max-width: 600px;
}
.project-desc {
  font-size: 0.875rem;
  color: var(--muted-2);
  line-height: 1.75;
  margin-bottom: 0.75rem;
}
.project-goal {
  font-size: 0.825rem;
  color: var(--muted-2);
  line-height: 1.7;
  font-style: italic;
  border-left: 2px solid var(--accent);
  padding-left: 1rem;
  margin: 1.25rem 0;
}
.project-feats {
  margin-top: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}
.feat {
  font-size: 0.825rem;
  color: var(--muted-2);
  display: flex;
  gap: 0.6rem;
  line-height: 1.55;
}
.feat::before {
  content: '—';
  color: var(--accent);
  flex-shrink: 0;
}
.project-links {
  margin-top: 1.75rem;
  display: flex;
  gap: 0.625rem;
  flex-wrap: wrap;
}
.media-box {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}
.media-box iframe {
  width: 100%;
  aspect-ratio: 16 / 9;
  border: none;
}
.media-box img { width: 100%; height: auto; }
.media-2col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 0.75rem;
}
.media-caption {
  font-size: 0.68rem;
  color: var(--muted);
  margin-top: 0.4rem;
  letter-spacing: 0.03em;
  line-height: 1.4;
}

/* ============================================================
   ABOUT PAGE
   ============================================================ */

.about-page {
  padding-top: calc(var(--nav-h) + 5rem);
  padding-bottom: 8rem;
}
.about-grid {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 6rem;
  align-items: start;
}
.about-photo {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  filter: grayscale(10%) contrast(1.04);
  display: block;
}
.about-headline {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.1;
  margin-top: 1.25rem;
  margin-bottom: 2rem;
}
.about-bio {
  font-size: 0.9rem;
  color: var(--muted-2);
  line-height: 1.8;
  margin-bottom: 0.75rem;
}
.section-hr { border: none; border-top: 1px solid var(--border); margin: 2.25rem 0; }
.skills-label { margin-bottom: 0.875rem; }
.skills-list { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.about-contact { margin-top: 2.5rem; }
.contact-label { margin-bottom: 0.875rem; }
.contact-row { display: flex; gap: 0.625rem; flex-wrap: wrap; }

/* ============================================================
   FOOTER
   ============================================================ */

footer { border-top: 1px solid var(--border); }
.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 1.75rem var(--pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.775rem;
  color: var(--muted);
}
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a { color: var(--muted); transition: color 0.2s; }
.footer-links a:hover { color: var(--text); }

/* ============================================================
   RESPONSIVE
   ============================================================ */

@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-media { display: none; }
  .about-grid { grid-template-columns: 1fr; gap: 3rem; }
  .about-photo { max-width: 240px; aspect-ratio: 1; }
}

@media (max-width: 720px) {
  .work-grid { grid-template-columns: 1fr; }
  .project-body { grid-template-columns: 1fr; gap: 2rem; }
  .project-top-row { flex-direction: column; gap: 1rem; }
  .media-2col { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .nav-links { gap: 1.25rem; }
  .hero-cta { gap: 0.5rem; }
}