/* 干皓丞 · Portfolio — Precision Lab */
:root {
  --ink: #121a1f;
  --ink-soft: #2c3a44;
  --muted: #5c6b75;
  --paper: #e8eef1;
  --paper-2: #f4f7f8;
  --line: rgba(18, 26, 31, 0.12);
  --accent: #b85a2a;
  --accent-deep: #8f3f18;
  --steel: #1f5f6b;
  --steel-soft: #3a7f8c;
  --hero-veil: linear-gradient(
    105deg,
    rgba(10, 18, 22, 0.78) 0%,
    rgba(10, 18, 22, 0.55) 42%,
    rgba(10, 18, 22, 0.28) 70%,
    rgba(10, 18, 22, 0.15) 100%
  );
  --font-display: "Syne", "Noto Serif TC", sans-serif;
  --font-zh: "Noto Serif TC", "Songti TC", serif;
  --font-body: "Instrument Sans", "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", system-ui, sans-serif;
  --space: clamp(1rem, 2.5vw, 2rem);
  --section: clamp(4.5rem, 10vw, 8rem);
  --max: 1120px;
  --header-h: 4.25rem;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  line-height: 1.65;
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(31, 95, 107, 0.12), transparent 55%),
    radial-gradient(900px 500px at 100% 20%, rgba(184, 90, 42, 0.08), transparent 50%),
    linear-gradient(180deg, var(--paper-2) 0%, var(--paper) 40%, #dde5e9 100%);
  background-attachment: fixed;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--steel);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--accent-deep);
}

h1, h2, h3 {
  font-family: var(--font-display);
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 0 0 0.6em;
}

p { margin: 0 0 1em; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--ink);
  color: #fff;
  padding: 0.5rem 1rem;
  z-index: 1000;
}

.skip-link:focus { left: 0; }

/* Header */
.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 50;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0 clamp(1rem, 3vw, 2.5rem);
  transition: background 0.35s var(--ease), backdrop-filter 0.35s var(--ease), box-shadow 0.35s var(--ease);
}

.site-header.is-scrolled {
  background: rgba(244, 247, 248, 0.88);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--line);
}

.site-header.is-scrolled .logo,
.site-header.is-scrolled .nav a,
.site-header.is-scrolled .lang-toggle,
.site-header.is-scrolled .nav-toggle {
  color: var(--ink);
}

.logo {
  display: flex;
  align-items: baseline;
  gap: 0.55rem;
  color: #f4f7f8;
  text-decoration: none;
}

.logo-zh {
  font-family: var(--font-zh);
  font-weight: 700;
  font-size: 1.25rem;
}

.logo-en {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  opacity: 0.75;
}

.nav {
  display: none;
  gap: 1.35rem;
}

.nav a {
  color: rgba(244, 247, 248, 0.9);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
}

.nav a:hover { color: #fff; }

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.lang-toggle {
  border: 1px solid currentColor;
  background: transparent;
  color: rgba(244, 247, 248, 0.95);
  font: inherit;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  padding: 0.35rem 0.65rem;
  cursor: pointer;
}

.nav-toggle {
  width: 2.4rem;
  height: 2.4rem;
  border: 0;
  background: transparent;
  display: grid;
  place-content: center;
  gap: 6px;
  cursor: pointer;
  color: rgba(244, 247, 248, 0.95);
  padding: 0;
}

.nav-toggle span {
  display: block;
  width: 1.35rem;
  height: 2px;
  background: currentColor;
  transition: transform 0.3s var(--ease);
}

.nav-toggle[aria-expanded="true"] span:first-child {
  transform: translateY(4px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:last-child {
  transform: translateY(-4px) rotate(-45deg);
}

.mobile-nav {
  position: fixed;
  inset: var(--header-h) 0 auto;
  z-index: 49;
  display: grid;
  gap: 0.25rem;
  padding: 1rem 1.25rem 1.5rem;
  background: rgba(244, 247, 248, 0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}

.mobile-nav[hidden] { display: none; }

.mobile-nav a {
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-display);
  font-size: 1.35rem;
  padding: 0.55rem 0;
}

@media (min-width: 900px) {
  .nav { display: flex; }
  .nav-toggle { display: none; }
  .mobile-nav { display: none !important; }
}

/* Hero */
.hero {
  position: relative;
  min-height: 100svh;
  display: grid;
  align-items: end;
  overflow: hidden;
  color: #f4f7f8;
}

.hero-media {
  position: absolute;
  inset: 0;
}

.hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 40%;
  transform: scale(1.06);
  animation: hero-drift 18s var(--ease) infinite alternate;
}

@keyframes hero-drift {
  from { transform: scale(1.06) translate3d(0, 0, 0); }
  to { transform: scale(1.12) translate3d(-1.5%, -1%, 0); }
}

.hero-veil {
  position: absolute;
  inset: 0;
  background: var(--hero-veil);
}

.hero-content {
  position: relative;
  z-index: 1;
  width: min(100% - 2rem, var(--max));
  margin: 0 auto;
  padding: calc(var(--header-h) + 2rem) 0 5.5rem;
}

.brand {
  font-family: var(--font-zh);
  font-weight: 700;
  font-size: clamp(3rem, 10vw, 6.5rem);
  line-height: 1;
  letter-spacing: 0.04em;
  margin: 0;
  opacity: 0;
  transform: translateY(28px);
  animation: rise 1s var(--ease) 0.15s forwards;
}

.brand-en {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(0.95rem, 1.6vw, 1.15rem);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin: 0.45em 0 0.85em;
  color: rgba(244, 247, 248, 0.78);
  opacity: 0;
  transform: translateY(28px);
  animation: rise 1s var(--ease) 0.25s forwards;
}

.hero h1 {
  max-width: 16ch;
  font-size: clamp(1.55rem, 3.6vw, 2.55rem);
  font-weight: 700;
  margin-bottom: 0.55em;
  opacity: 0;
  transform: translateY(28px);
  animation: rise 1s var(--ease) 0.4s forwards;
}

.lede {
  max-width: 38ch;
  font-size: clamp(1.05rem, 1.8vw, 1.25rem);
  color: rgba(244, 247, 248, 0.88);
  opacity: 0;
  transform: translateY(28px);
  animation: rise 1s var(--ease) 0.55s forwards;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
  opacity: 0;
  transform: translateY(28px);
  animation: rise 1s var(--ease) 0.7s forwards;
}

@keyframes rise {
  to { opacity: 1; transform: none; }
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.85rem;
  padding: 0.7rem 1.25rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform 0.2s var(--ease), background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.btn-primary:hover {
  background: var(--accent-deep);
  border-color: var(--accent-deep);
  color: #fff;
}

.btn-ghost {
  background: transparent;
  color: inherit;
  border-color: currentColor;
}

.hero .btn-ghost { color: #f4f7f8; }

.scroll-hint {
  position: absolute;
  left: 50%;
  bottom: 1.4rem;
  transform: translateX(-50%);
  width: 1.5rem;
  height: 2.4rem;
  border: 1px solid rgba(244, 247, 248, 0.55);
  border-radius: 999px;
  display: grid;
  justify-content: center;
  padding-top: 0.45rem;
}

.scroll-hint span {
  width: 3px;
  height: 8px;
  background: #f4f7f8;
  border-radius: 2px;
  animation: drip 1.6s var(--ease) infinite;
}

@keyframes drip {
  0% { opacity: 0; transform: translateY(0); }
  40% { opacity: 1; }
  100% { opacity: 0; transform: translateY(10px); }
}

/* Sections */
.section {
  padding: var(--section) 0;
}

.section-inner {
  width: min(100% - 2rem, var(--max));
  margin: 0 auto;
}

.section-head {
  max-width: 40rem;
  margin-bottom: clamp(2rem, 5vw, 3.5rem);
}

.eyebrow {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--steel);
  margin: 0 0 0.75rem;
}

.section-head h2 {
  font-size: clamp(1.9rem, 4vw, 3rem);
}

.section-desc {
  color: var(--ink-soft);
  max-width: 48ch;
}

.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.8s var(--ease), transform 0.8s var(--ease);
}

.reveal.is-in {
  opacity: 1;
  transform: none;
}

/* Path */
.path .timeline {
  display: grid;
  gap: 2rem;
  margin-bottom: 3rem;
}

@media (min-width: 800px) {
  .path .timeline {
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
  }
}

.timeline-block time {
  display: block;
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.timeline-block h3 {
  font-size: 1.35rem;
}

.timeline-block .tech,
.tech {
  font-size: 0.92rem;
  color: var(--muted);
  letter-spacing: 0.01em;
}

.path-visual {
  margin: 0;
  position: relative;
}

.path-visual img {
  width: 100%;
  max-height: min(520px, 58vw);
  object-fit: cover;
  object-position: center 35%;
}

.path-visual figcaption {
  margin-top: 0.75rem;
  color: var(--muted);
  font-size: 0.92rem;
}

/* Focus */
.focus-split {
  display: grid;
  gap: 1.75rem;
  margin-bottom: 3rem;
}

@media (min-width: 860px) {
  .focus-split {
    grid-template-columns: 1.4fr 1fr;
    align-items: center;
    gap: 2.5rem;
  }
}

.focus-points {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.focus-points li {
  padding-left: 1.1rem;
  border-left: 2px solid var(--accent);
}

.domain-pair {
  display: grid;
  gap: 1.5rem;
}

@media (min-width: 800px) {
  .domain-pair { grid-template-columns: 1fr 1fr; }
}

.domain-pair figure,
.exp-pair figure {
  margin: 0;
}

.domain-pair img,
.exp-pair img {
  width: 100%;
}

.domain-pair figcaption,
.exp-pair figcaption,
.project-media.trio figcaption {
  margin-top: 0.55rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
}

/* Skills */
.skills {
  background:
    linear-gradient(180deg, transparent, rgba(31, 95, 107, 0.06) 30%, transparent);
}

.skills-grid {
  display: grid;
  gap: 2.25rem;
}

@media (min-width: 860px) {
  .skills-grid { grid-template-columns: repeat(3, 1fr); gap: 2.5rem; }
}

.skill-col h3 {
  font-size: 1.2rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--line);
  margin-bottom: 1rem;
}

.skill-col ul,
.skill-col ol {
  margin: 0;
  padding-left: 1.15rem;
  color: var(--ink-soft);
}

.skill-col li + li { margin-top: 0.55rem; }

/* Projects */
.project {
  display: grid;
  gap: 1.5rem;
  padding: clamp(2rem, 5vw, 3.5rem) 0;
  border-top: 1px solid var(--line);
}

@media (min-width: 900px) {
  .project {
    grid-template-columns: 0.9fr 1.1fr;
    gap: 2.5rem;
    align-items: center;
  }

  .project-reverse .project-copy { order: 2; }
  .project-reverse .project-media { order: 1; }
}

.project-tag {
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 0.5rem;
}

.project h3 {
  font-size: clamp(1.45rem, 2.5vw, 1.9rem);
}

.project-copy p {
  color: var(--ink-soft);
}

.link-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem 1.25rem;
  margin-top: 1rem;
}

.link-row a {
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}

.project-media.pair,
.project-media.stack {
  display: grid;
  gap: 0.75rem;
}

.project-media.pair {
  grid-template-columns: 1fr 1fr;
}

.project-media.trio {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.65rem;
}

.project-media.trio figure { margin: 0; }

.project-media img,
.path-visual img,
.focus-split img,
.domain-pair img,
.research-models img,
.exp-pair img,
.pub img,
.contact-visual img {
  width: 100%;
  background: #fff;
}

/* Research */
.research-models {
  display: grid;
  gap: 1.5rem;
  margin-bottom: 3rem;
}

@media (min-width: 860px) {
  .research-models {
    grid-template-columns: 1.2fr 1fr;
    align-items: center;
    gap: 2.5rem;
  }
}

.metrics {
  margin-bottom: 3rem;
}

.metrics dl {
  display: grid;
  gap: 1.25rem;
  margin: 1rem 0 0;
}

@media (min-width: 800px) {
  .metrics dl { grid-template-columns: repeat(3, 1fr); gap: 1.75rem; }
}

.metrics dt {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.35rem;
  color: var(--steel);
}

.metrics dd {
  margin: 0.35rem 0 0;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.exp-pair {
  display: grid;
  gap: 1.5rem;
  margin-bottom: 3.5rem;
}

@media (min-width: 800px) {
  .exp-pair { grid-template-columns: 1fr 1fr; }
}

.pubs {
  display: grid;
  gap: 2.5rem;
}

.pub {
  display: grid;
  gap: 1.25rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line);
}

@media (min-width: 800px) {
  .pub {
    grid-template-columns: 1.1fr 1fr;
    gap: 2rem;
    align-items: center;
  }
}

.pub-venue {
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 0.4rem;
}

.pub h3 {
  font-size: 1.5rem;
}

.pub p:last-child {
  color: var(--ink-soft);
  margin-bottom: 0;
}

/* Contact */
.contact {
  padding-bottom: calc(var(--section) + 1rem);
}

.contact-inner {
  display: grid;
  gap: 2rem;
  align-items: center;
}

@media (min-width: 860px) {
  .contact-inner {
    grid-template-columns: 1.1fr 0.9fr;
    gap: 3rem;
  }
}

.contact-copy h2 {
  font-size: clamp(2rem, 4vw, 3.2rem);
}

.contact-visual img {
  width: 100%;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 1.5rem clamp(1rem, 3vw, 2.5rem) 2rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.site-footer p { margin: 0; }

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero-img { animation: none; transform: none; }
  .brand, .hero h1, .lede, .cta-row {
    animation: none;
    opacity: 1;
    transform: none;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .scroll-hint span { animation: none; }
}