/* ===== Tokens ===== */
:root {
  --orange: #f37021;
  --orange-deep: #d65a0e;
  --orange-soft: #fff2e6;
  --black: #111111;
  --black-soft: #1f1f1f;
  --ink: #2a2a2a;
  --gray-line: #e5e5e5;
  --gray-bg: #f6f6f6;
  --gray-mid: #6b6b6b;
  --white: #ffffff;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
body {
  margin: 0;
  font-family: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei",
    -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: var(--ink); text-decoration: none; transition: color 0.15s; }
a:hover { color: var(--orange); }
h1, h2, h3, h4, h5 { margin: 0 0 12px; line-height: 1.3; color: var(--black); font-weight: 700; }
h1 { font-size: clamp(2.2rem, 4.5vw + 0.6rem, 3.4rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.3rem, 2vw + 0.5rem, 1.8rem); font-weight: 500; color: var(--gray-mid); }
h3 { font-size: 1.7rem; }
h4 { font-size: 1.05rem; }
h5 { font-size: 1rem; letter-spacing: 0.04em; }
p { margin: 0 0 14px; }
ul, ol { margin: 0; padding: 0; }

/* ===== Top nav ===== */
.topnav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(17, 17, 17, 0.96);
  backdrop-filter: saturate(160%) blur(8px);
  border-bottom: 1px solid var(--black-soft);
}
.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}
.brand {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--white);
  letter-spacing: 0.02em;
}
.brand::before {
  content: "";
  display: inline-block;
  width: 8px; height: 8px;
  margin-right: 10px;
  background: var(--orange);
  vertical-align: middle;
  transform: rotate(45deg);
}
.brand:hover { color: var(--orange); }
.nav-links {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 6px 22px;
  flex-wrap: wrap;
}
.nav-links a {
  display: inline-block;
  padding: 6px 0;
  font-size: 0.95rem;
  color: #cccccc;
  font-weight: 500;
  border-bottom: 2px solid transparent;
}
.nav-links a:hover { color: var(--white); }
.nav-links a.active {
  color: var(--orange);
  border-bottom-color: var(--orange);
}
.nav-links .has-subs {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.subs {
  font-size: 0.85rem;
  color: #888888;
  letter-spacing: 0.05em;
}
.subs a {
  display: inline-block;
  padding: 0 4px;
  margin: 0 1px;
  color: #aaaaaa;
  font-size: 0.85rem;
  border-bottom: 1px solid transparent;
}
.subs a:hover {
  color: var(--orange);
  border-bottom-color: var(--orange);
}
.nav-toggle {
  display: none;
  background: transparent;
  border: 0;
  width: 40px; height: 40px;
  padding: 8px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 100%; height: 2px;
  margin: 5px 0;
  background: var(--white);
  transition: transform 0.25s, opacity 0.25s;
}

/* ===== Hero ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 100px 24px 60px;
  background: var(--black);
  color: var(--white);
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  right: -120px; top: 50%;
  width: 480px; height: 480px;
  background: var(--orange);
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.35;
  transform: translateY(-50%);
}
.hero::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 6px;
  background: var(--orange);
}
.hero-inner {
  position: relative;
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
}
.hero-eyebrow {
  display: inline-block;
  font-size: 0.9rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--orange);
  margin: 0 0 20px;
  padding-left: 36px;
  position: relative;
}
.hero-eyebrow::before {
  content: "";
  position: absolute;
  left: 0; top: 50%;
  width: 24px; height: 2px;
  background: var(--orange);
}
.hero h1 {
  color: var(--white);
  margin-bottom: 10px;
}
.hero h2 {
  color: #cccccc;
  margin-bottom: 28px;
  font-weight: 500;
}
.hero-meta {
  font-size: 1rem;
  color: #999999;
  margin: 0;
  border-top: 1px solid #333333;
  padding-top: 18px;
  max-width: 600px;
}

/* ===== Container ===== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}
.page-top { padding-top: 120px; }

/* ===== Section ===== */
.section {
  padding: 72px 0;
}
.section-head {
  margin-bottom: 36px;
}
.section-head h3 {
  display: inline-block;
  position: relative;
  padding: 0 0 10px 18px;
  border-left: 5px solid var(--orange);
}
.section-head h3::after {
  content: "";
  display: block;
  width: 56px; height: 3px;
  background: var(--black);
  margin-top: 10px;
  margin-left: -18px;
}

/* ===== Cards ===== */
.card {
  background: var(--white);
  border: 1px solid var(--gray-line);
  border-radius: 4px;
  padding: 24px 28px;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.card:hover {
  border-color: var(--orange);
  box-shadow: 0 8px 20px rgba(243, 112, 33, 0.08);
}
.card.mini { padding: 18px 20px; }
.card.highlight {
  background: var(--black);
  border-color: var(--black);
  color: var(--white);
}
.card.highlight h4,
.card.highlight p { color: var(--white); }
.card h4 {
  position: relative;
  padding-bottom: 8px;
  margin-bottom: 10px;
}
.card h4::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 24px; height: 2px;
  background: var(--orange);
}
.card.highlight h4::after { background: var(--white); }

.card-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: 1fr 1fr;
}
.card-grid > .card { grid-column: 1; }
.card-grid > .card-row { grid-column: 2; }

.card-row {
  display: grid;
  gap: 14px;
  margin-top: 18px;
}
.card-row.two { grid-template-columns: 1fr 1fr; }
.card-row.three { grid-template-columns: repeat(3, 1fr); }

/* ===== Image box ===== */
.image-box {
  margin: 0;
  text-align: center;
}
.image-placeholder {
  background: var(--gray-bg);
  color: var(--gray-mid);
  border: 1px dashed #c4c4c4;
  border-radius: 4px;
  padding: 70px 20px;
  font-size: 0.95rem;
  letter-spacing: 0.05em;
  position: relative;
}
.image-placeholder::before {
  content: "";
  position: absolute;
  top: 12px; left: 12px;
  width: 24px; height: 24px;
  border-top: 3px solid var(--orange);
  border-left: 3px solid var(--orange);
}
.image-placeholder::after {
  content: "";
  position: absolute;
  bottom: 12px; right: 12px;
  width: 24px; height: 24px;
  border-bottom: 3px solid var(--orange);
  border-right: 3px solid var(--orange);
}
.image-box img {
  width: 100%;
  max-height: 360px;
  object-fit: cover;
  border-radius: 4px;
  border: 1px solid var(--gray-line);
}
.image-box figcaption {
  margin-top: 10px;
  font-size: 0.9rem;
  color: var(--gray-mid);
}

/* ===== Index list (landing — staircase layout) ===== */
.index-list {
  display: flex;
  flex-direction: column;
  gap: 56px;
  padding: 30px 0;
}
.index-box {
  display: flex;
  align-items: center;
  gap: 40px;
}
.index-box:nth-child(even) {
  margin-left: 22vw;
}
.index-blob {
  position: relative;
  flex-shrink: 0;
  width: 200px;
  height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--black);
  border-radius: 4px;
  overflow: hidden;
  transition: background 0.3s, transform 0.3s, box-shadow 0.3s;
}
.index-blob::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 50%, var(--orange) 50%);
  opacity: 0.18;
  transition: opacity 0.3s;
}
.index-blob::after {
  content: "";
  position: absolute;
  bottom: 0; left: 0;
  width: 100%; height: 6px;
  background: var(--orange);
}
.index-blob:hover {
  background: var(--orange);
  transform: translateY(-6px);
  box-shadow: 0 10px 24px rgba(243, 112, 33, 0.3);
}
.index-blob:hover::before { opacity: 0; }
.index-blob:hover::after { background: var(--black); }
.index-blob h4 {
  position: relative;
  z-index: 1;
  margin: 0;
  font-size: 1.5rem;
  color: var(--white);
  letter-spacing: 0.06em;
}
.index-text {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.index-text a {
  display: inline-block;
  padding: 6px 0;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--ink);
  border-bottom: 1px solid transparent;
  transition: color 0.2s, border-color 0.2s, padding 0.2s;
}
.index-text a::before {
  content: "›";
  margin-right: 10px;
  color: var(--orange);
  font-weight: 700;
}
.index-text a:hover {
  color: var(--orange);
  padding-left: 4px;
}

/* ===== Custom numbered list (work page) ===== */
.custom-list {
  list-style: none;
  position: relative;
  padding-left: 56px;
  max-width: 760px;
  margin: 0 auto;
  counter-reset: custom-counter;
}
.custom-list::before {
  content: "";
  position: absolute;
  left: 18px; top: 8px; bottom: 8px;
  width: 2px;
  background: var(--gray-line);
}
.custom-list li {
  counter-increment: custom-counter;
  position: relative;
  margin-bottom: 22px;
  padding: 6px 0 6px 18px;
}
.custom-list li::before {
  content: counter(custom-counter, decimal-leading-zero);
  position: absolute;
  left: -56px; top: 4px;
  width: 38px; height: 38px;
  background: var(--black);
  color: var(--orange);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
  font-family: "Courier New", monospace;
}

/* ===== Split section (title + body, alternating) ===== */
.section.split {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 48px;
  align-items: center;
  min-height: 60vh;
}
.section.split.reverse { grid-template-columns: 2fr 1fr; }
.split-title { display: flex; justify-content: center; }
.title-blob {
  position: relative;
  width: 100%;
  max-width: 260px;
  aspect-ratio: 1 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--black);
  border-radius: 4px;
  color: var(--white);
  overflow: hidden;
}
.title-blob::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 50%, var(--orange) 50%);
  opacity: 0.15;
}
.title-blob::after {
  content: "";
  position: absolute;
  bottom: 0; left: 0;
  width: 100%; height: 6px;
  background: var(--orange);
}
.title-blob.alt { background: var(--orange); }
.title-blob.alt::before {
  background: linear-gradient(135deg, transparent 50%, var(--black) 50%);
  opacity: 0.18;
}
.title-blob.alt::after { background: var(--black); }
.title-blob h3 {
  position: relative;
  z-index: 1;
  margin: 0;
  font-size: 1.5rem;
  color: var(--white);
  letter-spacing: 0.05em;
}
.split-body p { margin-bottom: 16px; }

/* ===== Skill grid (learning page) ===== */
.skill-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}
.skill-card {
  position: relative;
  border-radius: 4px;
  padding: 26px 26px 26px 30px;
  border: 1px solid var(--gray-line);
  transition: transform 0.2s, box-shadow 0.2s;
}
.skill-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; bottom: 0;
  width: 4px;
  background: var(--orange);
}
.skill-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 22px rgba(17, 17, 17, 0.08);
}
.skill-card.tech {
  background: var(--black);
  border-color: var(--black);
  color: #e0e0e0;
}
.skill-card.tech h4 {
  color: var(--white);
  position: relative;
  padding-bottom: 8px;
  margin-bottom: 10px;
}
.skill-card.tech h4::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 24px; height: 2px;
  background: var(--orange);
}
.skill-card.soft {
  background: var(--white);
  color: var(--ink);
}
.skill-card.soft h4 {
  color: var(--black);
  position: relative;
  padding-bottom: 8px;
  margin-bottom: 10px;
}
.skill-card.soft h4::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 24px; height: 2px;
  background: var(--orange);
}

/* ===== Scroll-to-top ===== */
.scroll-top {
  position: fixed;
  right: 24px; bottom: 24px;
  width: 48px; height: 48px;
  border: 0;
  border-radius: 4px;
  background: var(--black);
  color: var(--orange);
  font-size: 1.4rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 6px 16px rgba(17, 17, 17, 0.3);
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 0.25s, transform 0.25s, background 0.2s;
  z-index: 90;
}
.scroll-top.show { opacity: 1; transform: translateY(0); }
.scroll-top:hover { background: var(--orange); color: var(--white); }

/* ===== Footer ===== */
.footer {
  margin-top: 72px;
  background: var(--black);
  padding: 48px 24px 32px;
  color: #cccccc;
  border-top: 4px solid var(--orange);
}
.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}
.footer h5 {
  color: var(--orange);
  margin-bottom: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-size: 0.85rem;
}
.footer p { margin: 0; color: #cccccc; }
.footer a { color: var(--white); text-decoration: underline; text-decoration-color: var(--orange); }
.footer a:hover { color: var(--orange); }
.footer-bottom {
  max-width: 1100px;
  margin: 32px auto 0;
  padding-top: 18px;
  border-top: 1px solid #2a2a2a;
  text-align: center;
}
.footer-bottom p {
  margin: 0;
  font-size: 0.85rem;
  color: #888888;
  letter-spacing: 0.04em;
}

/* ===== Animations ===== */
.from-bottom { opacity: 0; transform: translateY(40px); transition: opacity 0.7s ease-out, transform 0.7s ease-out; }
.from-bottom.show { opacity: 1; transform: translateY(0); }
.from-left { opacity: 0; transform: translateX(-60px); transition: opacity 0.7s ease-out, transform 0.7s ease-out; }
.from-left.show { opacity: 1; transform: translateX(0); }
.from-right { opacity: 0; transform: translateX(60px); transition: opacity 0.7s ease-out, transform 0.7s ease-out; }
.from-right.show { opacity: 1; transform: translateX(0); }
.from-center { opacity: 0; transition: opacity 1.2s ease-out; }
.from-center.show { opacity: 1; }

@media (prefers-reduced-motion: reduce) {
  .from-bottom, .from-left, .from-right, .from-center {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
  html { scroll-behavior: auto; }
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .card-grid { grid-template-columns: 1fr; }
  .card-grid > .card,
  .card-grid > .card-row { grid-column: auto; }
  .card-row.three { grid-template-columns: 1fr 1fr; }
  .section.split,
  .section.split.reverse { grid-template-columns: 1fr; gap: 28px; }
  .section.split.reverse .split-title { order: -1; }
  .index-box:nth-child(even) { margin-left: 12vw; }
  .index-blob { width: 160px; height: 160px; }
  .index-blob h4 { font-size: 1.3rem; }
}

@media (max-width: 720px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: 0;
    padding: 8px 0 12px;
    border-top: 1px solid var(--black-soft);
    margin-top: 10px;
  }
  .nav-links.open { display: flex; }
  .nav-links li { width: 100%; }
  .nav-links a {
    display: block;
    padding: 12px 4px;
    border-bottom: 2px solid var(--black-soft);
  }
  .nav-links a.active { border-bottom-color: var(--orange); }
  .nav-links .has-subs { display: block; width: 100%; }
  .nav-links .subs { display: none; }

  .hero { padding: 100px 20px 40px; }
  .section { padding: 56px 0; }
  .card-row.two,
  .card-row.three { grid-template-columns: 1fr; }
  .index-list { gap: 32px; }
  .index-box,
  .index-box:nth-child(even) {
    flex-direction: column;
    align-items: stretch;
    margin-left: 0;
    gap: 16px;
  }
  .index-blob {
    width: 100%;
    height: 90px;
  }
  .index-blob h4 { font-size: 1.2rem; }
  .footer-inner { grid-template-columns: 1fr; }
  .custom-list { padding-left: 48px; }
  .custom-list li::before { left: -48px; width: 32px; height: 32px; }
}

/* ===== Print friendly ===== */
@media print {
  .topnav, .scroll-top, .nav-toggle { display: none !important; }
  .hero, .section { min-height: auto; padding: 24px 0; }
  .hero { background: var(--white); color: var(--black); border-bottom: 4px solid var(--orange); }
  .hero h1, .hero h2 { color: var(--black); }
  .hero-meta { color: var(--gray-mid); border-top-color: var(--gray-line); }
  body { background: var(--white); color: var(--black); }
  .from-bottom, .from-left, .from-right, .from-center { opacity: 1 !important; transform: none !important; }
  .footer { background: var(--white); color: var(--black); border-top: 4px solid var(--orange); }
  .footer p, .footer h5 { color: var(--black); }
}