/* =========================================================
   吴俊东 Jundong Wu — personal site
   Design language: BotLearn "Academic Vermilion" editorial
   Primary spine: vermilion #E93B36 on paper #FAF7F2
   Brand cameos: Aibrary cyan→mint, contained to its block
   ========================================================= */

:root {
  --paper: #faf7f2;
  --paper-2: #f4efe6;
  --ink: #1a1a1a;
  --warm: #6b6660;
  --warm-2: #a8a29a;
  --hair: rgba(26, 26, 26, 0.14);
  --hair-strong: rgba(26, 26, 26, 0.28);
  --vermilion: #e93b36;
  --vermilion-ink: #fff7ef;
  --ghost-no: #ddd8ce; /* giant faint index numbers */
  --aib-1: #00d5f1;
  --aib-2: #00f2bf;

  --ff-serif: "Playfair Display", Georgia, serif;
  --ff-zh-title: "ZCOOL XiaoWei", "Songti SC", serif;
  --ff-sans: "Space Grotesk", "Noto Sans SC", system-ui, sans-serif;
  --ff-zh: "Noto Sans SC", system-ui, sans-serif;
  --ff-mono: "IBM Plex Mono", ui-monospace, monospace;

  --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
  --ease-io: cubic-bezier(0.77, 0, 0.175, 1);

  --wrap: 1200px;
  --pad: clamp(1.25rem, 5vw, 4.5rem);
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #14110f;
    --paper-2: #1c1815;
    --ink: #f3ede3;
    --warm: #a49c90;
    --warm-2: #6f675d;
    --hair: rgba(243, 237, 227, 0.16);
    --hair-strong: rgba(243, 237, 227, 0.3);
    --vermilion: #ff5a4d;
    --vermilion-ink: #14110f;
    --ghost-no: #2b2621;
  }
}

/* ---------- reset-ish ---------- */
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--ff-zh);
  font-weight: 400;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

::selection { background: var(--vermilion); color: var(--vermilion-ink); }

/* fixed subtle paper texture / frame */
.page-frame {
  position: fixed;
  inset: 0;
  z-index: 60;
  pointer-events: none;
  background-image: radial-gradient(rgba(26, 26, 26, 0.025) 1px, transparent 1px);
  background-size: 3px 3px;
  mix-blend-mode: multiply;
  opacity: 0.6;
}
@media (prefers-color-scheme: dark) {
  .page-frame { mix-blend-mode: screen; background-image: radial-gradient(rgba(243,237,227,0.03) 1px, transparent 1px); }
}

/* ---------- the seal motif (crest / wax stamp echo) ---------- */
.seal {
  display: inline-block;
  width: 26px; height: 26px;
  border: 1.5px solid var(--vermilion);
  transform: rotate(45deg);
  flex: none;
}
.seal--sm { width: 15px; height: 15px; border-width: 1.5px; }

/* ---------- shared type ---------- */
.eyebrow {
  font-family: var(--ff-mono);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--vermilion);
  margin: 0 0 1.5rem;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
}
.eyebrow__dot { width: 6px; height: 6px; background: var(--vermilion); transform: rotate(45deg); }

/* ================= NAV ================= */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  padding: 0 var(--pad);
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--hair);
}
.nav__brand { display: inline-flex; align-items: center; gap: 0.7rem; }
.nav__mark { width: 28px; height: 28px; flex: none; }
.nav__mark path { fill: none; stroke-width: 8; stroke-linecap: round; stroke-linejoin: round; }
.nav__mark .ink { stroke: var(--ink); }
.nav__mark .acc { stroke: var(--vermilion); }
.nav__name { display: inline-flex; flex-direction: column; gap: 2px; line-height: 1.04; }
.nav__name-cn { font-family: var(--ff-zh-title); font-size: 1.22rem; letter-spacing: 0.1em; color: var(--ink); }
.nav__name-en { font-family: var(--ff-serif); font-weight: 500; font-size: 0.78rem; letter-spacing: 0.02em; color: var(--warm); }
.nav__name-en i { font-style: italic; font-weight: 400; font-size: 0.88em; color: var(--warm-2); letter-spacing: 0.01em; }
.nav__links { display: flex; align-items: center; gap: clamp(1rem, 2.4vw, 2.4rem); font-family: var(--ff-zh); font-size: 0.9rem; }
.nav__links a { color: var(--warm); transition: color 0.25s var(--ease-out); position: relative; }
.nav__links a:hover { color: var(--ink); }
.nav__cta {
  color: var(--ink) !important;
  border: 1px solid var(--hair-strong);
  padding: 0.42rem 1rem;
  border-radius: 999px;
  transition: border-color 0.25s var(--ease-out), color 0.25s;
}
.nav__cta:hover { border-color: var(--vermilion); color: var(--vermilion) !important; }
@media (max-width: 560px) {
  .nav__name-en { display: none; }
  .nav__links { gap: 0.95rem; font-size: 0.82rem; }
}

/* ================= HERO ================= */
.hero { padding: clamp(3rem, 9vh, 6.5rem) var(--pad) clamp(3.5rem, 7vh, 5rem); max-width: var(--wrap); margin: 0 auto; min-height: calc(100dvh - 68px); display: flex; flex-direction: column; justify-content: center; }
.hero__grid { display: grid; grid-template-columns: minmax(0, 1fr) 17rem; gap: clamp(2rem, 5vw, 5rem); align-items: start; }
.hero__title {
  font-family: var(--ff-serif);
  font-weight: 700;
  font-size: clamp(3.3rem, 11vw, 8.4rem);
  line-height: 0.94;
  letter-spacing: -0.02em;
  margin: 0 0 1.8rem;
}
.hero__title-en { display: block; }
.hero__title em { font-style: italic; font-weight: 700; color: var(--vermilion); line-height: 1.1; padding-bottom: 0.04em; }
.hero__title-zh { display: block; font-family: var(--ff-zh-title); font-weight: 400; font-size: clamp(1.35rem, 4vw, 2.4rem); letter-spacing: 0.08em; color: var(--warm); margin-top: 1.1rem; line-height: 1.2; }
.hero__lede { font-family: var(--ff-zh); font-weight: 300; font-size: clamp(1rem, 1.6vw, 1.2rem); color: var(--ink); max-width: 30ch; margin: 0 0 2.4rem; line-height: 1.75; }
.hero__actions { display: flex; gap: 0.9rem; flex-wrap: wrap; }

.btn { display: inline-flex; align-items: center; gap: 0.55rem; font-family: var(--ff-zh); font-size: 0.96rem; padding: 0.85rem 1.5rem; border-radius: 999px; transition: transform 0.2s var(--ease-out), background 0.25s, color 0.25s, border-color 0.25s; will-change: transform; }
.btn:active { transform: translateY(1px) scale(0.99); }
.btn--primary { background: var(--vermilion); color: var(--vermilion-ink); }
.btn--primary:hover { background: color-mix(in srgb, var(--vermilion) 88%, black); }
.btn--primary .btn__arw { transition: transform 0.25s var(--ease-out); }
.btn--primary:hover .btn__arw { transform: translateX(4px); }
.btn--ghost { border: 1px solid var(--hair-strong); color: var(--ink); }
.btn--ghost:hover { border-color: var(--vermilion); color: var(--vermilion); }

.hero__meta { padding-top: 0.35rem; }
.hero__portrait { margin: 0 0 1.6rem; border-radius: 6px; overflow: hidden; border: 1px solid var(--hair); background: var(--paper-2); box-shadow: 0 18px 44px rgba(26, 26, 26, 0.13); }
.hero__portrait img { width: 100%; height: auto; display: block; aspect-ratio: 780 / 1212; object-fit: cover; object-position: 50% 10%; }
.hero__rule { display: block; width: 42px; height: 2px; background: var(--vermilion); margin-bottom: 1.4rem; }
.meta-list { margin: 0; display: grid; gap: 1.05rem; }
.meta-list div { display: grid; gap: 0.15rem; }
.meta-list dt { font-family: var(--ff-mono); font-size: 0.66rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--warm-2); }
.meta-list dd { margin: 0; font-family: var(--ff-zh); font-size: 0.98rem; color: var(--ink); }
.meta-sub { display: block; font-family: var(--ff-mono); font-size: 0.66rem; letter-spacing: 0.03em; color: var(--warm-2); margin-top: 3px; text-transform: none; }

.hero__foot { margin-top: clamp(2.5rem, 6vh, 4rem); font-family: var(--ff-mono); font-size: 0.68rem; letter-spacing: 0.14em; color: var(--warm-2); text-transform: uppercase; }

@media (max-width: 820px) {
  .hero__grid { grid-template-columns: 1fr; gap: 2.6rem; align-items: start; }
  .hero__meta { border-top: 1px solid var(--hair); padding-top: 1.8rem; }
  .hero__portrait { max-width: 260px; }
  .hero__rule { display: none; }
  .meta-list { grid-template-columns: repeat(2, 1fr); gap: 1.4rem 1rem; }
}
@media (max-width: 480px) { .meta-list { grid-template-columns: 1fr; } }

/* ================= SECTIONS ================= */
.section { max-width: var(--wrap); margin: 0 auto; padding: clamp(4.5rem, 11vh, 9rem) var(--pad); }
.section__head { margin-bottom: clamp(3rem, 6vw, 5rem); }
.section__title { font-family: var(--ff-serif); margin: 0; font-weight: 700; display: flex; flex-direction: column; gap: 0.6rem; }
.section__title .zh { font-family: var(--ff-zh-title); font-weight: 400; font-size: clamp(2rem, 5.5vw, 3.4rem); letter-spacing: 0.06em; }
.section__title .en { font-family: var(--ff-serif); font-style: italic; font-weight: 500; font-size: clamp(1.05rem, 2vw, 1.5rem); color: var(--warm); letter-spacing: 0; }
.section__sub { font-family: var(--ff-zh); font-weight: 300; color: var(--warm); max-width: 44ch; margin: 1.4rem 0 0; }
.section__lead { font-family: var(--ff-zh); font-weight: 300; font-size: clamp(1.02rem, 1.5vw, 1.18rem); color: var(--ink); max-width: 56ch; margin: 1.8rem 0 0; line-height: 1.85; }
.section__lead strong { font-weight: 500; color: var(--vermilion); }

/* ---------- professional projects ---------- */
.proj { display: grid; grid-template-columns: 0.85fr 1.15fr; gap: clamp(2rem, 5vw, 4.5rem); align-items: start; padding: clamp(2.5rem, 5vw, 4rem) 0; border-top: 1px solid var(--hair); }
.proj:last-child { border-bottom: 1px solid var(--hair); }
.proj--rev .proj__panel { order: 2; }

.proj__panel {
  position: relative;
  aspect-ratio: 4 / 3;
  border-radius: 4px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: clamp(1.6rem, 3vw, 2.4rem);
  overflow: hidden;
}
.proj__panel--aibrary { background: linear-gradient(135deg, var(--aib-1), var(--aib-2)); }
.proj__panel--botlearn { background: var(--vermilion); }
.proj__no { font-family: var(--ff-serif); font-weight: 900; font-size: clamp(3rem, 8vw, 5.5rem); line-height: 1; color: rgba(255, 255, 255, 0.42); }
.proj__panel--aibrary .proj__no { color: rgba(20, 30, 30, 0.28); }
/* white capsule lockup — brand rule: logos on brand-color fields sit on white */
.proj__logo { width: min(74%, 300px); height: auto; align-self: flex-start; background: #fff; padding: 0.85rem 1.15rem; border-radius: 7px; box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1); }
.proj__tag { font-family: var(--ff-mono); font-size: 0.68rem; letter-spacing: 0.1em; color: rgba(255, 255, 255, 0.9); text-transform: uppercase; }
.proj__panel--aibrary .proj__tag { color: rgba(15, 40, 40, 0.72); }

.proj__name { font-family: var(--ff-serif); font-weight: 700; font-size: clamp(2rem, 4.5vw, 3rem); margin: 0 0 0.3rem; letter-spacing: -0.01em; }
.proj__role { font-family: var(--ff-zh-title); font-size: clamp(1rem, 1.7vw, 1.2rem); color: var(--vermilion); margin: 0 0 1.3rem; letter-spacing: 0.03em; }
.proj--aibrary .proj__role { color: #00a89b; }
.proj__desc { font-family: var(--ff-zh); font-weight: 300; color: var(--ink); max-width: 46ch; margin: 0 0 1.8rem; line-height: 1.8; }

.hair-list { list-style: none; margin: 0; padding: 0; }
.hair-list li { display: grid; grid-template-columns: 6.5rem 1fr; gap: 1rem; padding: 0.85rem 0; border-top: 1px solid var(--hair); align-items: baseline; }
.hair-list li:last-child { border-bottom: 1px solid var(--hair); }
.hair-list__k { font-family: var(--ff-mono); font-size: 0.7rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--warm-2); }
.hair-list__v { font-family: var(--ff-zh); font-size: 0.98rem; color: var(--ink); }

.proj__link { display: inline-block; margin-top: 1.6rem; font-family: var(--ff-mono); font-size: 0.82rem; letter-spacing: 0.06em; color: var(--ink); border-bottom: 1px solid var(--vermilion); padding-bottom: 2px; transition: color 0.25s, letter-spacing 0.25s var(--ease-out); }
.proj__link:hover { color: var(--vermilion); letter-spacing: 0.1em; }

@media (max-width: 780px) {
  .proj { grid-template-columns: 1fr; gap: 2rem; }
  .proj--rev .proj__panel { order: 0; }
  .proj__panel { aspect-ratio: 16 / 9; }
}

/* ================= ETHOS ================= */
.ethos { text-align: center; max-width: 980px; }
.ethos__inner { display: flex; flex-direction: column; align-items: center; }
.ethos .seal { margin-bottom: 2.4rem; width: 30px; height: 30px; }
.ethos__quote { font-family: var(--ff-zh-title); font-weight: 400; font-size: clamp(1.6rem, 4.2vw, 2.9rem); line-height: 1.5; letter-spacing: 0.03em; margin: 0; }
.ethos__quote em { font-family: var(--ff-serif); font-style: italic; color: var(--vermilion); }
.ethos__note { font-family: var(--ff-zh); font-weight: 300; color: var(--warm); max-width: 42ch; margin: 2.6rem auto 0; line-height: 1.85; }

/* ================= PERSONAL BUILDS ================= */
.builds { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(1.5rem, 3vw, 2.5rem); }
.build { border: 1px solid var(--hair); border-radius: 4px; overflow: hidden; display: flex; flex-direction: column; background: var(--paper-2); transition: transform 0.4s var(--ease-out), border-color 0.4s; }
.build:hover { transform: translateY(-4px); border-color: var(--hair-strong); }
.build__visual { position: relative; aspect-ratio: 16 / 10; display: flex; align-items: center; justify-content: center; overflow: hidden; }
.build__visual--nova { background: radial-gradient(120% 120% at 50% 8%, rgba(0, 213, 241, 0.16), rgba(0, 242, 191, 0.06) 55%, transparent); }
.build__visual--nova img { height: 118%; width: auto; margin-top: 8%; filter: drop-shadow(0 24px 40px rgba(0, 90, 90, 0.22)); }

.build__visual--clip { background: var(--ink); }
@media (prefers-color-scheme: dark) { .build__visual--clip { background: #0c0a09; } }
.clip-motif { display: flex; align-items: center; gap: 0.7rem; }
.clip-motif__long { width: 74px; height: 42px; border: 1.5px solid var(--vermilion); border-radius: 3px; }
.clip-motif__arw { color: var(--paper); font-family: var(--ff-mono); font-size: 1.1rem; }
.clip-motif__short { width: 15px; height: 42px; border: 1.5px solid var(--paper); border-radius: 3px; }
.clip-motif__short:nth-child(3) { border-color: var(--vermilion); }

.build__text { padding: clamp(1.5rem, 3vw, 2.2rem); }
.build__kind { font-family: var(--ff-mono); font-size: 0.68rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--warm-2); }
.build__name { font-family: var(--ff-zh-title); font-weight: 400; font-size: clamp(1.3rem, 2.5vw, 1.7rem); letter-spacing: 0.04em; margin: 0.6rem 0 0.9rem; }
.build__desc { font-family: var(--ff-zh); font-weight: 300; font-size: 0.94rem; color: var(--warm); margin: 0; line-height: 1.8; }

@media (max-width: 720px) { .builds { grid-template-columns: 1fr; } }

/* ================= CONTACT ================= */
.contact { text-align: left; }
.contact__title { font-family: var(--ff-serif); margin: 0 0 clamp(2.5rem, 5vw, 4rem); display: flex; flex-direction: column; gap: 0.6rem; }
.contact__title .en { font-style: italic; font-weight: 700; font-size: clamp(2.2rem, 6vw, 4rem); letter-spacing: -0.01em; }
.contact__title .zh { font-family: var(--ff-zh-title); font-weight: 400; font-size: clamp(1.05rem, 2.4vw, 1.5rem); color: var(--warm); letter-spacing: 0.05em; }
.contact__links { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); border-top: 1px solid var(--hair); }
.contact__links a { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; padding: 1.5rem 0.4rem; border-bottom: 1px solid var(--hair); font-family: var(--ff-serif); font-size: clamp(1.3rem, 3vw, 2rem); transition: color 0.25s, padding-left 0.3s var(--ease-out); }
.contact__links a:nth-child(odd) { padding-right: 2rem; }
.contact__links a:hover { color: var(--vermilion); padding-left: 0.9rem; }
.contact__meta { font-family: var(--ff-mono); font-size: 0.72rem; letter-spacing: 0.08em; color: var(--warm-2); text-transform: none; white-space: nowrap; }
@media (max-width: 620px) { .contact__links { grid-template-columns: 1fr; } .contact__links a:nth-child(odd) { padding-right: 0.4rem; } }

/* ================= FOOTER ================= */
.foot { max-width: var(--wrap); margin: 0 auto; padding: 2.4rem var(--pad) 3.5rem; border-top: 1px solid var(--hair); display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; font-family: var(--ff-mono); font-size: 0.72rem; letter-spacing: 0.06em; color: var(--warm-2); }
.foot__mark { width: 12px; height: 12px; border: 1.4px solid var(--vermilion); transform: rotate(45deg); }
.foot__c { color: var(--warm); }
.foot__note { margin-left: auto; }
@media (max-width: 520px) { .foot__note { margin-left: 0; width: 100%; } }

/* ================= REVEAL MOTION ================= */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out); }
.reveal.is-in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .build:hover, .btn:active { transform: none; }
}