/* ============================================================
   Leonard Chow — Portfolio design system
   "Engineer-founder editorial": warm paper, ink, one ember accent.
   No framework. Mobile-first. Print-friendly. Works without JS.
   ============================================================ */

/* ---------- Design tokens ---------- */
:root {
  /* palette */
  --paper:       #FBFAF7;
  --paper-2:     #F3F1EA;   /* sunken panels */
  --card:        #FFFFFF;
  --ink:         #1A1815;   /* near-black, warm */
  --ink-2:       #514B43;   /* secondary text */
  --ink-3:       #8A8276;   /* muted / captions */
  --line:        #E4E0D6;   /* hairlines */
  --line-2:      #D2CCBE;
  --ember:       #CE4B22;   /* primary accent */
  --ember-deep:  #A93A18;
  --ember-soft:  #F6E7DF;   /* accent tint bg */
  --gold:        #B8862F;   /* secondary accent for "live" etc. */
  --good:        #2E7D5B;

  /* type */
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans:  "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono:  "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  /* rhythm */
  --maxw: 1140px;
  --gut: clamp(1.1rem, 4vw, 2.6rem);
  --r: 14px;          /* card radius */
  --r-sm: 9px;
  --shadow: 0 1px 2px rgba(26,24,21,.04), 0 8px 24px -12px rgba(26,24,21,.14);
  --shadow-lift: 0 2px 4px rgba(26,24,21,.05), 0 18px 40px -16px rgba(26,24,21,.22);

  --ease: cubic-bezier(.22,.61,.36,1);
}

/* ---------- Reset-ish ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 86px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { animation: none !important; transition: none !important; } }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: clamp(1rem, .55vw + .9rem, 1.075rem);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { margin: 0; padding: 0; list-style: none; }
:focus-visible { outline: 2.5px solid var(--ember); outline-offset: 3px; border-radius: 4px; }

/* ---------- Typography ---------- */
h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.08; letter-spacing: -0.01em; margin: 0; }
.display { font-size: clamp(2.4rem, 6.4vw, 4.4rem); font-weight: 700; letter-spacing: -0.025em; }
h2.section-title { font-size: clamp(1.6rem, 3.4vw, 2.3rem); }
.eyebrow {
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 0 0 .9rem;
  display: flex; align-items: center; gap: .6rem;
}
.eyebrow::before { content:""; width: 26px; height: 1px; background: var(--line-2); }
.lead { font-size: clamp(1.1rem, 1.4vw, 1.35rem); color: var(--ink-2); line-height: 1.55; }
.mono { font-family: var(--mono); }
strong { font-weight: 650; color: var(--ink); }
mark { background: var(--ember-soft); color: var(--ember-deep); padding: 0 .18em; border-radius: 3px; }

/* ---------- Layout ---------- */
.wrap { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: var(--gut); }
section { padding-block: clamp(3.4rem, 8vw, 6rem); border-top: 1px solid var(--line); }
section:first-of-type { border-top: 0; }
.section-head { max-width: 60ch; margin-bottom: clamp(1.8rem, 4vw, 3rem); }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap { display: flex; align-items: center; gap: 1rem; min-height: 64px; }
.brand { display: flex; align-items: baseline; gap: .55rem; font-family: var(--serif); }
.brand .name { font-weight: 700; font-size: 1.18rem; letter-spacing: -.01em; }
.brand .role { font-family: var(--mono); font-size: .68rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); }
.nav { margin-left: auto; display: flex; align-items: center; gap: clamp(.6rem,1.6vw,1.4rem); }
.nav a.navlink { font-size: .92rem; color: var(--ink-2); padding: .35rem .1rem; border-bottom: 2px solid transparent; transition: color .2s; }
.nav a.navlink:hover { color: var(--ink); border-color: var(--ember); }
@media (max-width: 720px){ .nav .navlink { display: none; } }

/* lang toggle */
.lang-toggle {
  font-family: var(--mono); font-size: .76rem; letter-spacing: .06em;
  background: var(--card); color: var(--ink-2);
  border: 1px solid var(--line-2); border-radius: 100px;
  padding: .32rem .7rem; cursor: pointer; transition: all .2s;
}
.lang-toggle:hover { border-color: var(--ink-3); color: var(--ink); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: .5rem;
  font-family: var(--sans); font-weight: 550; font-size: .95rem;
  padding: .7rem 1.15rem; border-radius: 100px; cursor: pointer;
  border: 1px solid transparent; transition: all .2s var(--ease);
}
.btn .arr { transition: transform .25s var(--ease); }
.btn:hover .arr { transform: translateX(3px); }
.btn-primary { background: var(--ember); color: #fff; box-shadow: 0 8px 20px -10px var(--ember); }
.btn-primary:hover { background: var(--ember-deep); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line-2); }
.btn-ghost:hover { border-color: var(--ink); }

/* ---------- Hero ---------- */
.hero { padding-top: clamp(2.6rem, 6vw, 4.6rem); }
.hero .display { max-width: 16ch; }
.hero .display .accent { color: var(--ember); }
.hero-sub { margin-top: 1.4rem; max-width: 62ch; }
.hero-cta { margin-top: 2rem; display: flex; flex-wrap: wrap; gap: .8rem; }

/* role switcher */
.role-switch { margin-top: 2.4rem; }
.role-switch .switch-label { font-family: var(--mono); font-size: .7rem; letter-spacing: .2em; text-transform: uppercase; color: var(--ink-3); margin-bottom: .7rem; }
.switch-row { display: inline-flex; flex-wrap: wrap; gap: .4rem; background: var(--paper-2); padding: .35rem; border-radius: 100px; border: 1px solid var(--line); }
.role-btn {
  font-family: var(--sans); font-size: .9rem; font-weight: 550;
  border: 0; background: transparent; color: var(--ink-2);
  padding: .5rem 1rem; border-radius: 100px; cursor: pointer; transition: all .2s var(--ease);
}
.role-btn[aria-pressed="true"] { background: var(--ink); color: var(--paper); box-shadow: var(--shadow); }
.role-pitch {
  margin-top: 1.5rem; max-width: 64ch; font-family: var(--serif);
  font-size: clamp(1.15rem,1.7vw,1.45rem); line-height: 1.5; color: var(--ink);
}
.role-pitch b { color: var(--ember-deep); font-weight: 600; }

/* stat strip */
.stats { margin-top: 2.8rem; display: grid; grid-template-columns: repeat(auto-fit,minmax(150px,1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: var(--r); overflow: hidden; }
.stat { background: var(--paper); padding: 1.2rem 1.3rem; }
.stat .num { font-family: var(--serif); font-weight: 700; font-size: clamp(1.5rem,2.4vw,2rem); color: var(--ink); letter-spacing: -.02em; }
.stat .lbl { font-size: .82rem; color: var(--ink-2); margin-top: .15rem; }

/* ---------- Project grid ---------- */
.proj-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(330px,1fr)); gap: 1.2rem; }
.card {
  position: relative; background: var(--card); border: 1px solid var(--line);
  border-radius: var(--r); padding: 1.4rem 1.45rem 1.5rem; box-shadow: var(--shadow);
  display: flex; flex-direction: column; transition: transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lift); border-color: var(--line-2); }
.card .card-top { display: flex; align-items: center; gap: .6rem; margin-bottom: .85rem; }
.tag { font-family: var(--mono); font-size: .64rem; letter-spacing: .12em; text-transform: uppercase; padding: .22rem .5rem; border-radius: 100px; border: 1px solid var(--line-2); color: var(--ink-3); white-space: nowrap; }
.tag.flagship { color: var(--ember-deep); border-color: color-mix(in srgb, var(--ember) 35%, var(--line-2)); background: var(--ember-soft); }
.badge-live { margin-left: auto; font-family: var(--mono); font-size: .66rem; letter-spacing: .1em; color: var(--good); display: inline-flex; align-items: center; gap: .35rem; }
.badge-live::before { content:""; width: 7px; height: 7px; border-radius: 50%; background: var(--good); box-shadow: 0 0 0 0 color-mix(in srgb,var(--good) 60%,transparent); animation: pulse 2.4s infinite; }
.badge-live.internal { color: var(--ink-3); } .badge-live.internal::before { background: var(--ink-3); animation: none; }
@keyframes pulse { 0%{box-shadow:0 0 0 0 color-mix(in srgb,var(--good) 50%,transparent)} 70%{box-shadow:0 0 0 7px transparent} 100%{box-shadow:0 0 0 0 transparent} }
.card h3 { font-size: 1.28rem; margin-bottom: .15rem; }
.card .one { color: var(--ink-2); font-size: .96rem; line-height: 1.5; margin: .5rem 0 .9rem; }
.card .metrics { display: flex; flex-wrap: wrap; gap: .4rem; margin-bottom: 1rem; }
.metric { font-family: var(--mono); font-size: .72rem; color: var(--ink-2); background: var(--paper-2); border: 1px solid var(--line); border-radius: 7px; padding: .26rem .5rem; }
.metric b { color: var(--ember-deep); font-weight: 600; }
.card .stack { font-family: var(--mono); font-size: .73rem; color: var(--ink-3); line-height: 1.7; margin-bottom: 1.1rem; }
.card .links { margin-top: auto; display: flex; gap: 1rem; align-items: center; padding-top: .3rem; }
.card .links a { font-size: .85rem; font-weight: 550; color: var(--ink); display: inline-flex; align-items: center; gap: .3rem; border-bottom: 1.5px solid transparent; padding-bottom: 1px; transition: border-color .2s; }
.card .links a:hover { border-color: var(--ember); }
.card .links a.live { color: var(--ember-deep); }
.card .links .priv { font-family: var(--mono); font-size: .73rem; color: var(--ink-3); display: inline-flex; align-items: center; gap: .3rem; }
.card .links .priv::before { content: "🔒"; font-size: .8em; filter: grayscale(1); opacity: .7; }
/* role dimming */
body[data-role-filter="on"] .card[data-roles]:not(.role-match) { opacity: .34; filter: grayscale(.4); }
.card { } /* default */

/* ---------- Skills ---------- */
.skills-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(260px,1fr)); gap: 1.4rem 2rem; }
.skill-group h3 { font-family: var(--sans); font-weight: 650; font-size: .82rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ember-deep); margin-bottom: .8rem; padding-bottom: .5rem; border-bottom: 1px solid var(--line); }
.chips { display: flex; flex-wrap: wrap; gap: .45rem; }
.chip { font-size: .85rem; padding: .3rem .65rem; border-radius: 8px; background: var(--card); border: 1px solid var(--line); color: var(--ink-2); }
.chip.strong { border-color: var(--line-2); color: var(--ink); font-weight: 500; }
.chip.strong::after { content: "●"; color: var(--ember); font-size: .5em; vertical-align: middle; margin-left: .4em; }

/* ---------- Experience timeline ---------- */
.timeline { position: relative; margin-left: .4rem; }
.tl-item { position: relative; padding: 0 0 1.9rem 1.9rem; border-left: 2px solid var(--line); }
.tl-item:last-child { border-left-color: transparent; padding-bottom: 0; }
.tl-item::before { content:""; position: absolute; left: -7px; top: .3rem; width: 12px; height: 12px; border-radius: 50%; background: var(--paper); border: 2.5px solid var(--ember); }
.tl-item.current::before { background: var(--ember); }
.tl-when { font-family: var(--mono); font-size: .74rem; letter-spacing: .04em; color: var(--ink-3); }
.tl-role { font-family: var(--serif); font-size: 1.2rem; font-weight: 600; margin: .2rem 0 .05rem; }
.tl-co { font-weight: 600; color: var(--ember-deep); }
.tl-desc { color: var(--ink-2); font-size: .95rem; margin-top: .45rem; max-width: 64ch; }

/* ---------- About ---------- */
.about-grid { display: grid; grid-template-columns: 1.6fr 1fr; gap: clamp(1.6rem,4vw,3.4rem); align-items: start; }
@media (max-width: 820px){ .about-grid { grid-template-columns: 1fr; } }
.about-body p { margin: 0 0 1.1rem; color: var(--ink-2); }
.about-body p:first-child { font-size: 1.12rem; color: var(--ink); }
.about-card { background: var(--paper-2); border: 1px solid var(--line); border-radius: var(--r); padding: 1.4rem; font-size: .92rem; }
.about-card dt { font-family: var(--mono); font-size: .68rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); margin-top: 1rem; }
.about-card dt:first-child { margin-top: 0; }
.about-card dd { margin: .2rem 0 0; color: var(--ink); }

/* ---------- Contact ---------- */
.contact { text-align: center; background: var(--paper-2); }
.contact .display { margin-inline: auto; max-width: 18ch; }
.contact-links { margin-top: 2rem; display: flex; flex-wrap: wrap; gap: .8rem; justify-content: center; }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--line); padding-block: 2.2rem; }
.site-footer .wrap { display: flex; flex-wrap: wrap; gap: 1rem; align-items: center; justify-content: space-between; color: var(--ink-3); font-size: .85rem; }
.site-footer .mono { font-family: var(--mono); font-size: .76rem; }

/* ---------- Lang visibility ---------- */
[lang="zh"] { display: none; }
html[data-lang="zh"] [lang="en"] { display: none; }
html[data-lang="zh"] [lang="zh"] { display: revert; }
/* inline spans */
span[lang]{ }

/* reveal on scroll */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s var(--ease), transform .6s var(--ease); animation: lc-reveal-failsafe .01s linear 2.2s forwards; }
.reveal.in { opacity: 1; transform: none; animation: none; }
/* failsafe: 即使 JS 未能加 .in(IO 未触发/脚本中断),内容也在 2.2s 后强制显形,永不白屏 */
@keyframes lc-reveal-failsafe { to { opacity: 1; transform: none; } }

/* ---------- Print (one-pager friendly) ---------- */
@media print {
  .site-header, .role-switch, .hero-cta, .site-footer, .lang-toggle, .badge-live::before { display: none !important; }
  body { font-size: 10.5pt; background: #fff; }
  section { padding-block: .6rem; border-top: 1px solid #ccc; }
  .card { box-shadow: none; break-inside: avoid; border-color: #ccc; }
  a { color: #000; }
}