/* ==========================================================================
   Chen-Jui (Ray) Chang — portfolio
   Cool "blueprint" theme with an automatic dark mode.
   ========================================================================== */

:root {
  --bg: #f3f6fa;
  --surface: #ffffff;
  --surface-2: #e8eef5;
  --ink: #0f1729;
  --ink-2: #3c4a5e;
  --ink-3: #627189;
  --line: #d6dfea;
  --line-strong: #b5c3d4;
  --accent: #1d5bf0;
  --accent-ink: #ffffff;
  --accent-soft: #e4ecff;
  --grid: rgba(29, 91, 240, 0.06);

  --font-sans: "Instrument Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --wrap: 1160px;
  --gutter: clamp(16px, 4vw, 40px);
  --radius: 14px;
  --radius-sm: 8px;
  --shadow: 0 1px 2px rgba(22, 25, 30, 0.04), 0 8px 24px -12px rgba(22, 25, 30, 0.12);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0f1a;
    --surface: #111827;
    --surface-2: #172034;
    --ink: #eef1f4;
    --ink-2: #b4bcc6;
    --ink-3: #8a939e;
    --line: #1f2a3d;
    --line-strong: #2d3b54;
    --accent: #6b9bff;
    --accent-ink: #050a18;
    --accent-soft: #14203b;
    --grid: rgba(107, 155, 255, 0.05);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 12px 32px -16px rgba(0, 0, 0, 0.6);
  }
}

/* ---------- Base ---------- */

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; scroll-padding-top: 80px; }
@media (max-width: 720px) { html { scroll-padding-top: 116px; } }

body {
  margin: 0;
  background-color: var(--bg);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 32px 32px;
  color: var(--ink);
  font: 400 17px/1.65 var(--font-sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

a { color: inherit; text-decoration-color: var(--line-strong); text-underline-offset: 4px; text-decoration-thickness: 1px; transition: color .15s, text-decoration-color .15s; }
a:hover { color: var(--accent); text-decoration-color: currentColor; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

h1, h2, h3 { color: var(--ink); font-weight: 600; margin: 0; text-wrap: balance; }
h1 { font-size: clamp(2.4rem, 5.6vw, 4.4rem); line-height: 1.02; letter-spacing: -0.035em; }
h2 { font-size: clamp(1.6rem, 2.6vw, 2.15rem); line-height: 1.15; letter-spacing: -0.025em; }
h3 { font-size: 1.2rem; line-height: 1.3; letter-spacing: -0.01em; }
p { margin: 0 0 1em; text-wrap: pretty; }
ul { margin: 0 0 1em; padding-left: 1.2em; }
li { margin: 0.5em 0; }
li::marker { color: var(--accent); }
strong { font-weight: 600; color: var(--ink); }

.wrap { width: 100%; max-width: var(--wrap); margin-inline: auto; padding-inline: var(--gutter); }

.skip-link { position: absolute; left: -9999px; top: 8px; padding: 8px 12px; background: var(--ink); color: var(--bg); border-radius: 6px; z-index: 100; }
.skip-link:focus { left: 8px; }

.mono, .eyebrow, .label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.eyebrow { color: var(--accent); display: inline-flex; align-items: center; gap: 10px; margin-bottom: 20px; }
.eyebrow::before { content: ""; width: 22px; height: 1px; background: currentColor; }
.label { color: var(--ink-3); }
.muted { color: var(--ink-2); }

/* ---------- Header ---------- */

.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 24px; min-height: 64px; }

.brand { display: inline-flex; align-items: center; gap: 12px; text-decoration: none; font-weight: 600; font-size: 0.95rem; letter-spacing: -0.01em; white-space: nowrap; }
.brand:hover { color: var(--ink); }
.brand-mark {
  display: grid; place-items: center; width: 32px; height: 32px; border-radius: 8px;
  background: var(--ink); color: var(--bg); font: 600 0.8rem/1 var(--font-mono); letter-spacing: 0;
}

.site-nav { display: flex; align-items: center; gap: 4px; }
.site-nav a {
  text-decoration: none; color: var(--ink-2); font-size: 0.9rem; padding: 7px 12px; border-radius: 999px; white-space: nowrap;
}
.site-nav a:hover { color: var(--ink); background: var(--surface-2); }
.site-nav a[aria-current="page"] { color: var(--ink); background: var(--surface); box-shadow: inset 0 0 0 1px var(--line); }
.site-nav .nav-cta { background: var(--ink); color: var(--bg); margin-left: 8px; }
.site-nav .nav-cta:hover { background: var(--accent); color: var(--accent-ink); }

/* ---------- Buttons ---------- */

.actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 20px; border-radius: 999px; font-weight: 600; font-size: 0.95rem; text-decoration: none;
  border: 1px solid var(--line-strong); background: var(--surface); color: var(--ink);
  transition: transform .15s, background .15s, color .15s, border-color .15s;
}
.btn:hover { color: var(--ink); border-color: var(--ink); transform: translateY(-1px); }
.btn-primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { background: var(--ink); border-color: var(--ink); color: var(--bg); }
.btn .arrow { transition: transform .15s; }
.btn:hover .arrow { transform: translateX(3px); }

.text-link { font-weight: 600; text-decoration: none; display: inline-flex; align-items: center; gap: 6px; color: var(--ink); }
.text-link::after { content: "→"; transition: transform .15s; }
.text-link:hover { color: var(--accent); }
.text-link:hover::after { transform: translateX(3px); }

/* ---------- Hero ---------- */

.hero { padding-block: clamp(48px, 8vw, 96px) clamp(48px, 7vw, 88px); }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr); gap: clamp(32px, 6vw, 80px); align-items: center; }
.hero h1 { margin-bottom: 24px; }
.hero h1 .soft { color: var(--ink-3); }
.lede { font-size: clamp(1.05rem, 1.6vw, 1.2rem); line-height: 1.6; color: var(--ink-2); max-width: 36em; margin-bottom: 32px; }

.facts { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0; margin: 44px 0 0; border-top: 1px solid var(--line); }
.facts div { padding: 16px 16px 0 0; }
.facts div + div { padding-left: 16px; border-left: 1px solid var(--line); }
.facts dt { margin-bottom: 4px; }
.facts dd { margin: 0; font-size: 0.95rem; font-weight: 500; line-height: 1.4; }

.photo-frame {
  position: relative; margin: 0; border-radius: var(--radius); overflow: hidden;
  background: var(--surface); border: 1px solid var(--line); box-shadow: var(--shadow);
}
.photo-frame img { width: 100%; aspect-ratio: 4 / 5; object-fit: cover; object-position: center 30%; }
.photo-frame figcaption {
  display: flex; justify-content: space-between; gap: 12px; padding: 12px 16px;
  border-top: 1px solid var(--line); font: 0.72rem/1.4 var(--font-mono); letter-spacing: 0.03em; text-transform: uppercase; color: var(--ink-3);
}
.photo-frame .tick { position: absolute; width: 14px; height: 14px; border-color: rgba(255,255,255,.85); border-style: solid; }
.photo-frame .tick.tl { top: 14px; left: 14px; border-width: 2px 0 0 2px; }
.photo-frame .tick.tr { top: 14px; right: 14px; border-width: 2px 2px 0 0; }

/* ---------- Sections ---------- */

.section { padding-block: clamp(56px, 8vw, 96px); border-top: 1px solid var(--line); }
.section-head { display: grid; grid-template-columns: 120px minmax(0, 1fr); gap: 24px; align-items: baseline; margin-bottom: clamp(28px, 4vw, 44px); }
.section-head .index { font: 500 0.78rem var(--font-mono); color: var(--accent); letter-spacing: 0.04em; }
.section-head p { color: var(--ink-2); max-width: 40em; margin: 12px 0 0; }

/* ---------- Project cards ---------- */

.feature {
  display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow); margin-bottom: 20px;
}
.feature-media { background: var(--surface-2); min-height: 100%; }
.feature-media img { width: 100%; height: 100%; aspect-ratio: 4 / 4.2; object-fit: cover; object-position: center 25%; }
.feature-body { padding: clamp(24px, 4vw, 48px); display: flex; flex-direction: column; }
.feature-body h3 { font-size: clamp(1.5rem, 2.4vw, 2rem); letter-spacing: -0.025em; margin: 10px 0 14px; }
.feature-body > p { color: var(--ink-2); }
.feature-body .text-link { margin-top: auto; padding-top: 12px; }

.spec { display: grid; grid-template-columns: max-content 1fr; gap: 10px 20px; margin: 8px 0 28px; padding: 18px 0; border-block: 1px solid var(--line); font-size: 0.93rem; }
.spec dt { padding-top: 3px; }
.spec dd { margin: 0; color: var(--ink); }

.chips { display: flex; flex-wrap: wrap; gap: 6px; list-style: none; padding: 0; margin: 0 0 24px; }
.chips li { margin: 0; font: 0.72rem/1 var(--font-mono); padding: 6px 9px; border-radius: 999px; background: var(--surface-2); color: var(--ink-2); border: 1px solid var(--line); }

.cards { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.card {
  display: flex; flex-direction: column; background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); transition: border-color .2s, transform .2s;
}
.card:hover { border-color: var(--line-strong); transform: translateY(-2px); }
.card-media { aspect-ratio: 16 / 9; background: var(--surface-2); border-bottom: 1px solid var(--line); overflow: hidden; }
.card-media img { width: 100%; height: 100%; object-fit: cover; object-position: center 45%; }
.card-body { padding: 28px; display: flex; flex-direction: column; flex: 1; }
.card-body h3 { font-size: 1.45rem; letter-spacing: -0.02em; margin: 8px 0 10px; }
.card-body > p { color: var(--ink-2); font-size: 0.97rem; }
.card-body .role { font-size: 0.93rem; color: var(--ink-2); padding-top: 14px; border-top: 1px dashed var(--line); margin-top: 4px; }
.card-body .text-link { margin-top: auto; padding-top: 16px; }

/* Signal pipeline illustration (Audio Rate) */
.pipeline { height: 100%; display: flex; flex-direction: column; justify-content: center; gap: 12px; padding: 16px 28px; position: relative;
  background: linear-gradient(135deg, var(--surface-2), var(--surface)); }
.pipeline .wave { position: absolute; inset: auto 0 18px 0; height: 60px; opacity: .55; color: var(--accent); }
.pipeline ol { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; align-items: flex-start; gap: 18px; position: relative; }
.pipeline li { position: relative; margin: 0; font: 500 0.78rem var(--font-mono); padding: 7px 12px; background: var(--surface); border: 1px solid var(--line-strong); border-radius: 6px; }
.pipeline li + li::before { content: "↓"; position: absolute; left: 14px; top: -18px; line-height: 18px; font-size: 0.8rem; color: var(--accent); }
.pipeline li:nth-child(2) { margin-left: 24px; }
.pipeline li:nth-child(3) { margin-left: 48px; }

.card-body > p.label, .mini p.label, .feature-body > p.label { font-size: 0.72rem; color: var(--ink-3); margin: 0; }

/* ---------- Experience timeline ---------- */

.timeline { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.timeline li { display: grid; grid-template-columns: 160px minmax(0, 1fr) minmax(0, 1.3fr); gap: 24px; padding: 26px 0; margin: 0; border-bottom: 1px solid var(--line); }
.timeline .when { font: 500 0.8rem/1.6 var(--font-mono); color: var(--ink-3); padding-top: 3px; }
.timeline .when.upcoming { color: var(--accent); }
.timeline h3 { font-size: 1.1rem; }
.timeline .role { color: var(--ink-2); font-size: 0.95rem; margin: 2px 0 0; }
.timeline .what { color: var(--ink-2); font-size: 0.97rem; margin: 0; }

/* ---------- Small project cards ---------- */

.mini-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.mini { padding: 28px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); }
.mini h3 { margin: 8px 0 10px; }
.mini p { color: var(--ink-2); font-size: 0.97rem; margin: 0; }

/* ---------- Contact band ---------- */

.contact {
  display: grid; grid-template-columns: minmax(0, 1.3fr) auto; gap: 32px; align-items: center;
  padding: clamp(32px, 5vw, 56px); border-radius: calc(var(--radius) + 6px);
  background: var(--ink); color: var(--bg);
}
.contact h2 { color: var(--bg); margin-bottom: 10px; }
.contact p { color: color-mix(in srgb, var(--bg) 70%, var(--ink)); margin: 0; max-width: 34em; }
.contact .btn { background: var(--bg); color: var(--ink); border-color: var(--bg); }
.contact .btn:hover { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
.contact .email { display: block; margin-top: 10px; font: 0.8rem var(--font-mono); color: color-mix(in srgb, var(--bg) 60%, var(--ink)); text-align: center; }

/* ---------- Footer ---------- */

.site-footer { border-top: 1px solid var(--line); margin-top: clamp(56px, 8vw, 96px); }
.site-footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px 24px; padding-block: 28px; font-size: 0.88rem; color: var(--ink-3); }
.site-footer nav { display: flex; gap: 20px; }
.site-footer a { color: var(--ink-2); }

/* ==========================================================================
   Project detail pages
   ========================================================================== */

.page-hero { padding-block: clamp(36px, 6vw, 72px) clamp(40px, 6vw, 72px); }
.page-hero h1 { margin-bottom: 24px; }
.back { display: flex; width: fit-content; gap: 8px; align-items: center; font-size: 0.9rem; color: var(--ink-3); text-decoration: none; margin-bottom: 28px; }
.back:hover { color: var(--accent); }
.page-hero .lede { margin-bottom: 28px; }

.meta-strip { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 0; margin-top: 40px; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--surface); overflow: hidden; }
.meta-strip div { padding: 14px 18px; }
.meta-strip div + div { border-left: 1px solid var(--line); }
.meta-strip dt { margin-bottom: 4px; }
.meta-strip dd { margin: 0; font-size: 0.93rem; font-weight: 500; line-height: 1.4; }

.doc { display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: clamp(32px, 5vw, 64px); align-items: start; }
.prose { max-width: 42em; }
.prose h2 { margin: 0 0 18px; }
.prose h2:not(:first-child) { margin-top: 48px; }
.prose p, .prose li { color: var(--ink-2); }
.prose .lede { color: var(--ink-2); }

.aside { position: sticky; top: 88px; display: grid; gap: 16px; }
.panel { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.panel h3 { font-size: 0.75rem; font-family: var(--font-mono); text-transform: uppercase; letter-spacing: 0.05em; color: var(--ink-3); font-weight: 500; margin-bottom: 14px; }
.panel p { font-size: 0.93rem; color: var(--ink-2); }
.panel p:last-child { margin-bottom: 0; }
.panel dl { margin: 0; display: grid; gap: 12px; }
.panel dt { font: 0.72rem var(--font-mono); text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-3); }
.panel dd { margin: 2px 0 0; font-size: 0.93rem; line-height: 1.45; }

.callout { border-left: 3px solid var(--accent); background: var(--accent-soft); padding: 18px 22px; border-radius: 0 var(--radius-sm) var(--radius-sm) 0; margin: 28px 0; }
.callout strong { display: block; margin-bottom: 4px; }
.callout p { margin: 0; color: var(--ink-2); }

.note { font-size: 0.9rem; color: var(--ink-3); }

/* Flow diagram (system architecture) */
.flow { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 0; counter-reset: step; }
.flow li { position: relative; margin: 0; padding: 22px 26px 22px 22px; background: var(--surface); border: 1px solid var(--line); }
.flow li:first-child { border-radius: var(--radius) 0 0 var(--radius); }
.flow li:last-child { border-radius: 0 var(--radius) var(--radius) 0; }
.flow li + li { border-left: 0; }
.flow li:not(:last-child)::after {
  content: ""; position: absolute; right: -9px; top: 50%; width: 16px; height: 16px; z-index: 1;
  background: var(--surface); border: 1px solid var(--line); border-left: 0; border-bottom: 0; transform: translateY(-50%) rotate(45deg);
}
.flow .label { color: var(--accent); display: block; margin-bottom: 10px; }
.flow strong { display: block; font-size: 1rem; margin-bottom: 6px; }
.flow p { font-size: 0.88rem; color: var(--ink-2); margin: 0; line-height: 1.5; }

/* Figures */
.figure { margin: 0; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.figure > a, .figure > img { display: block; }
.figure img { width: 100%; }
.figure.on-white img { background: #fff; padding: clamp(12px, 3vw, 32px); }
.figure figcaption { padding: 14px 18px; border-top: 1px solid var(--line); font-size: 0.88rem; color: var(--ink-3); line-height: 1.55; }
.figure figcaption .label { display: block; margin-bottom: 4px; color: var(--accent); }

.gallery { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px; align-items: start; }
.gallery .figure img { aspect-ratio: 1 / 1.05; object-fit: contain; background: #fff; }

.badge { display: inline-block; font: 500 0.7rem/1 var(--font-mono); text-transform: uppercase; letter-spacing: 0.05em; padding: 6px 9px; border-radius: 999px; border: 1px solid var(--accent); color: var(--accent); vertical-align: middle; margin-left: 10px; }

.download { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 18px 22px; margin-top: 20px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm); text-decoration: none; }
.download span:first-child { font-weight: 600; }
.download .label { white-space: nowrap; }
.download:hover { border-color: var(--accent); color: var(--ink); }

/* ==========================================================================
   Responsive
   ========================================================================== */

@media (max-width: 960px) {
  .hero-grid, .feature, .doc { grid-template-columns: 1fr; }
  .hero-photo { max-width: 520px; }
  .feature-media img { aspect-ratio: 16 / 10; }
  .aside { position: static; }
  .flow { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
  .flow li, .flow li + li { border: 1px solid var(--line); border-radius: var(--radius-sm) !important; }
  .flow li::after { display: none; }
  .timeline li { grid-template-columns: 130px minmax(0, 1fr); }
  .timeline .what { grid-column: 2; }
  .gallery { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  body { font-size: 16px; }
  .site-header .wrap { flex-direction: column; align-items: flex-start; gap: 6px; padding-block: 12px; }
  .site-nav { width: 100%; overflow-x: auto; scrollbar-width: none; margin-inline: -12px; padding-inline: 0; }
  .site-nav::-webkit-scrollbar { display: none; }
  .site-nav .nav-cta { margin-left: 4px; }
  .section-head { grid-template-columns: 1fr; gap: 8px; }
  .facts { grid-template-columns: 1fr; }
  .facts div, .facts div + div { padding: 14px 0; border-left: 0; border-bottom: 1px solid var(--line); }
  .cards, .mini-grid, .gallery { grid-template-columns: 1fr; }
  .timeline li { grid-template-columns: 1fr; gap: 6px; }
  .timeline .what { grid-column: auto; }
  .contact { grid-template-columns: 1fr; }
  .contact .email { text-align: left; }
  .meta-strip { grid-template-columns: 1fr; }
  .meta-strip div + div { border-left: 0; border-top: 1px solid var(--line); }
  .flow { grid-template-columns: 1fr; }
  .spec { grid-template-columns: 1fr; gap: 2px; }
  .spec dd { margin-bottom: 10px; }
  .card-body, .mini { padding: 22px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}