:root {
  --bg: #fafaf9;
  --fg: #18181b;
  --muted: #52525b;
  --card: #ffffff;
  --border: #e4e4e7;
  --accent: #4338ca;
  --accent-soft: #eef2ff;
  --badge-bg: #fef3c7;
  --badge-fg: #92400e;
  --font-head: "Space Grotesk", "Noto Sans TC", system-ui, sans-serif;
  --font-body: "DM Sans", "Noto Sans TC", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f0f12;
    --fg: #ececf1;
    --muted: #a1a1aa;
    --card: #18181c;
    --border: #2a2a31;
    --accent: #a5b4fc;
    --accent-soft: #1e1b4b;
    --badge-bg: #422006;
    --badge-fg: #fcd34d;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { transition: none !important; } }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.65 var(--font-body);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); }
a:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }
.mono { font-family: var(--font-mono); }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 16px; }
@media (min-width: 640px) { .wrap { padding: 0 24px; } }

.skip { position: absolute; left: -9999px; }
.skip:focus { left: 16px; top: 16px; background: var(--card); padding: 8px 12px; z-index: 10; }

.top { position: sticky; top: 0; z-index: 5; background: color-mix(in srgb, var(--bg) 85%, transparent); backdrop-filter: blur(8px); border-bottom: 1px solid var(--border); }
.top-inner { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.brand { font: 600 17px var(--font-head); color: var(--fg); text-decoration: none; }
nav { display: flex; align-items: center; gap: 4px; }
nav a { color: var(--muted); text-decoration: none; font-size: 15px; padding: 10px 8px; }
nav a:hover { color: var(--fg); }
@media (max-width: 480px) { nav a { display: none; } }
.lang {
  font: 500 14px var(--font-mono); color: var(--fg); background: var(--card);
  border: 1px solid var(--border); border-radius: 8px; padding: 8px 12px; min-width: 44px; min-height: 40px; cursor: pointer; margin-left: 8px;
}
.lang:hover { border-color: var(--accent); }

.hero { padding: 72px 16px 40px; }
@media (min-width: 640px) { .hero { padding: 96px 24px 56px; } }
.eyebrow { color: var(--accent); font-size: 14px; margin: 0 0 16px; }
h1, h2, h3 { font-family: var(--font-head); line-height: 1.3; margin: 0; }
h1 { font-size: clamp(28px, 5vw, 44px); font-weight: 600; letter-spacing: -0.01em; max-width: 20em; text-wrap: balance; }
.lead { color: var(--muted); font-size: 18px; max-width: 38em; margin: 20px 0 32px; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px; min-height: 44px; padding: 0 18px;
  border: 1px solid var(--border); border-radius: 10px; background: var(--card);
  color: var(--fg); text-decoration: none; font-weight: 500; transition: border-color .2s, transform .2s;
}
.btn:hover { border-color: var(--accent); }
.btn svg { width: 18px; height: 18px; fill: currentColor; }
.btn.primary { background: var(--fg); color: var(--bg); border-color: var(--fg); }
.btn.ghost { color: var(--muted); border-style: dashed; background: transparent; }

.section { padding-top: 40px; padding-bottom: 40px; }
h2 { font-size: 24px; font-weight: 600; margin-bottom: 20px; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 24px; }
.card p { color: var(--muted); margin: 10px 0 0; }
.feature { padding: 28px; }
.feature-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 12px; }
h3 { font-size: 20px; font-weight: 600; }
.badge { flex: none; font-size: 12px; font-weight: 500; padding: 3px 10px; border-radius: 999px; background: var(--badge-bg); color: var(--badge-fg); white-space: nowrap; }

.flow { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 20px 0; font-size: 13px; }
.flow li { background: var(--accent-soft); color: var(--accent); padding: 6px 10px; border-radius: 8px; position: relative; }
.flow li:not(:last-child)::after { content: "→"; color: var(--muted); margin-left: 10px; }

.arch { margin: 20px 0; padding: 18px; border: 1px solid var(--border); border-radius: 12px; background: var(--bg); }
.arch figcaption, .side-label { font: 500 12px var(--font-mono); color: var(--muted); letter-spacing: .04em; margin: 0 0 12px; }
.arch-main, .arch-side ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 22px; grid-template-columns: 1fr; }
.node { position: relative; background: var(--card); border: 1px solid var(--border); border-radius: 10px; padding: 10px 12px; }
.node b { display: block; font: 600 14px var(--font-head); }
.node small { display: block; color: var(--muted); font-size: 13px; line-height: 1.45; margin-top: 2px; }
.node .n { position: absolute; top: -9px; left: -9px; width: 20px; height: 20px; border-radius: 50%; background: var(--accent); color: var(--bg); font: 600 11px/20px var(--font-mono); text-align: center; }
.node.dashed { border-style: dashed; background: transparent; }
.arch-main .node:not(:last-child)::after { content: "↓"; position: absolute; left: 50%; bottom: -20px; transform: translateX(-50%); color: var(--accent); font-size: 15px; }
.arch-side { margin-top: 20px; padding-top: 14px; border-top: 1px dashed var(--border); }
.arch-side ul { gap: 10px; }
@media (min-width: 760px) {
  .arch-main { grid-template-columns: repeat(6, 1fr); gap: 18px; }
  .arch-main .node:not(:last-child)::after { content: "→"; left: auto; right: -15px; top: 50%; bottom: auto; transform: translateY(-50%); }
  .arch-side ul { grid-template-columns: repeat(3, 1fr); }
}
.metrics { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 12px; margin: 8px 0 20px; }
.metrics div { border: 1px solid var(--border); border-radius: 10px; padding: 14px 16px; }
.num { display: block; font: 600 22px var(--font-head); }
.cap { display: block; color: var(--muted); font-size: 14px; }

.points { padding-left: 20px; margin: 14px 0; color: var(--fg); }
.points li { margin: 6px 0; }
.tags { list-style: none; display: flex; flex-wrap: wrap; gap: 6px; padding: 0; margin: 16px 0; font-size: 12px; }
.tags li { border: 1px solid var(--border); border-radius: 6px; padding: 2px 8px; color: var(--muted); }
.link { font-weight: 500; text-decoration: none; display: inline-block; padding: 8px 0; }
.link:hover { text-decoration: underline; }
.links { display: flex; gap: 20px; flex-wrap: wrap; }

.grid { display: grid; grid-template-columns: 1fr; gap: 16px; margin-top: 16px; }
.feature + .feature { margin-top: 16px; }
.sub { font-size: 17px; color: var(--muted); margin: 32px 0 0; }
@media (min-width: 760px) { .grid { grid-template-columns: repeat(2, 1fr); } .grid .card { display: flex; flex-direction: column; } .grid .links, .grid .card > .link { margin-top: auto; } }

.skills { display: grid; gap: 12px; margin: 0; }
.skills div { display: grid; grid-template-columns: 1fr; gap: 2px; }
@media (min-width: 640px) { .skills div { grid-template-columns: 140px 1fr; } }
.skills dt { font-weight: 700; }
.skills dd { margin: 0; color: var(--muted); }
.degrees { list-style: none; padding: 0; margin: 8px 0 0; color: var(--muted); }
.degrees li { padding: 2px 0; }

.foot { padding-top: 32px; padding-bottom: 48px; color: var(--muted); font-size: 14px; border-top: 1px solid var(--border); margin-top: 24px; }