/* ─────────────────────────────────────────────────────────
   海豚机械臂 · 三维模型作品集
   淡雅 / restrained editorial palette
   ───────────────────────────────────────────────────────── */
:root {
  --paper:        #f6f5f0;
  --paper-2:      #fbfaf7;
  --paper-3:      #f1f1ea;
  --ink:          #2e3632;
  --ink-soft:     #5b665f;
  --ink-faint:    #939c95;
  --line:         #e1dfd5;
  --line-soft:    #ebe9e0;
  --sage:         #7e9a8d;
  --sage-deep:    #5f7a6d;
  --sand:         #b6a68a;
  --mist:         #a8bac3;
  --serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong", "SimSun", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", Georgia, serif;
  --wrap: 1180px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
button { font: inherit; color: inherit; cursor: pointer; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
::selection { background: #dbe4dc; color: var(--ink); }

.wrap { width: min(var(--wrap), calc(100% - 96px)); margin-inline: auto; }

/* ── header ─────────────────────────────────────────────── */
.site-header {
  position: sticky; top: 0; z-index: 40;
  background: rgba(246, 245, 240, .9);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line-soft);
}
.header-inner {
  height: 78px;
  display: flex; align-items: center; gap: 48px;
}
.brand { display: flex; align-items: center; gap: 13px; flex-shrink: 0; }
.brand-mark { width: 30px; height: 30px; color: var(--sage-deep); opacity: .85; }
.brand-text { display: flex; flex-direction: column; line-height: 1.3; }
.brand-text strong { font-family: var(--serif); font-size: 16px; font-weight: 600; letter-spacing: .22em; }
.brand-text em {
  font-style: normal; font-size: 8.5px; letter-spacing: .24em;
  color: var(--ink-faint); font-family: var(--mono);
}
.site-nav { display: flex; gap: 34px; margin-left: auto; }
.site-nav a {
  font-size: 12.5px; letter-spacing: .12em; color: var(--ink-soft);
  position: relative; padding: 6px 0; transition: color .25s;
}
.site-nav a::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: 0;
  height: 1px; background: var(--sage-deep); transition: right .3s ease;
}
.site-nav a:hover { color: var(--sage-deep); }
.site-nav a:hover::after { right: 0; }
.nav-index {
  font-family: var(--mono); font-size: 9px; letter-spacing: .18em;
  color: var(--ink-faint); white-space: nowrap;
}

/* ── hero ───────────────────────────────────────────────── */
.hero { padding: 104px 0 92px; border-bottom: 1px solid var(--line-soft); }
.hero-grid {
  display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(0, .65fr);
  gap: 72px; align-items: center;
}
.eyebrow {
  display: flex; align-items: center; gap: 14px;
  margin: 0 0 38px; font-family: var(--mono); font-size: 10px;
  letter-spacing: .2em; color: var(--sage-deep);
}
.eyebrow .rule { width: 34px; height: 1px; background: var(--sage); }
.hero h1 {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(52px, 6.6vw, 88px);
  line-height: 1.18; letter-spacing: .16em;
  margin: 0 0 16px; color: #29322d;
}
.hero h1 span { color: var(--sage-deep); }
.hero-en {
  margin: 0 0 40px; font-family: var(--mono); font-size: 10px;
  letter-spacing: .32em; color: var(--ink-faint);
}
.hero-desc {
  max-width: 540px; margin: 0 0 48px;
  color: var(--ink-soft); font-size: 14.5px; line-height: 2.15;
  letter-spacing: .025em;
}
.hero-stats { display: flex; gap: 0; margin-bottom: 46px; border-top: 1px solid var(--line); padding-top: 26px; }
.hero-stats > div {
  padding-right: 46px; margin-right: 46px; border-right: 1px solid var(--line);
  display: flex; flex-direction: column; gap: 2px;
}
.hero-stats > div:last-child { border-right: 0; margin-right: 0; }
.hero-stats b {
  font-family: var(--serif); font-size: 30px; font-weight: 500;
  line-height: 1.2; letter-spacing: .04em; color: var(--ink);
}
.hero-stats span { font-size: 10.5px; letter-spacing: .16em; color: var(--ink-faint); }
.text-link {
  display: inline-flex; align-items: center; gap: 18px;
  font-size: 12.5px; letter-spacing: .16em; color: var(--sage-deep);
  border-bottom: 1px solid var(--sage); padding-bottom: 8px;
  transition: gap .3s, border-color .3s;
}
.text-link:hover { gap: 26px; border-color: var(--sage-deep); }
.text-link span { font-size: 15px; }

.hero-aside { text-align: center; color: var(--sage); }
.hero-figure { width: 100%; max-width: 300px; margin: 0 auto; opacity: .72; }
.aside-note {
  margin: 20px 0 0; font-family: var(--mono); font-size: 9px;
  letter-spacing: .18em; color: var(--ink-faint);
}

/* ── section shell ──────────────────────────────────────── */
.section { padding: 104px 0; border-bottom: 1px solid var(--line-soft); }
.section-head {
  display: flex; align-items: baseline; gap: 24px;
  margin-bottom: 46px; padding-bottom: 20px; border-bottom: 1px solid var(--line);
}
.section-no {
  font-family: var(--mono); font-size: 11px; letter-spacing: .12em;
  color: var(--sage-deep); align-self: flex-start; padding-top: 8px;
}
.section-title { display: flex; align-items: baseline; gap: 20px; flex-wrap: wrap; }
.section-title h2 {
  font-family: var(--serif); font-weight: 500; font-size: 27px;
  letter-spacing: .2em; margin: 0;
}
.section-title p {
  margin: 0; font-family: var(--mono); font-size: 9.5px;
  letter-spacing: .24em; color: var(--ink-faint);
}
.section-note {
  margin: 0 0 0 auto; font-size: 11.5px; letter-spacing: .1em;
  color: var(--ink-faint); text-align: right;
}

/* ── viewer ─────────────────────────────────────────────── */
.viewer-shell {
  display: grid; grid-template-columns: minmax(0, 1fr) 272px;
  border: 1px solid var(--line); background: var(--paper-2);
}
.viewer-stage {
  position: relative; min-height: 610px;
  background:
    radial-gradient(ellipse 74% 62% at 50% 44%, #fdfcfa 0%, #f2f3ed 58%, #e9ece5 100%);
  border-right: 1px solid var(--line);
  overflow: hidden;
}
.viewer-stage::before {
  content: ""; position: absolute; inset: 20px; pointer-events: none;
  border: 1px solid rgba(126, 154, 141, .14); z-index: 2;
}
#scene { position: absolute; inset: 0; width: 100%; height: 100%; display: block; z-index: 1; }
.viewer-topbar, .viewer-bottombar {
  position: absolute; left: 0; right: 0; z-index: 3;
  display: flex; align-items: center; justify-content: space-between;
  padding: 26px 34px; pointer-events: none;
}
.viewer-topbar { top: 0; }
.viewer-bottombar { bottom: 0; align-items: flex-end; }
.viewer-topbar > *, .viewer-bottombar > * { pointer-events: auto; }

.current-model { display: flex; align-items: center; gap: 14px; }
.cm-no {
  font-family: var(--mono); font-size: 10px; color: var(--sage-deep);
  border: 1px solid rgba(126, 154, 141, .5); border-radius: 50%;
  width: 30px; height: 30px; display: grid; place-items: center;
  background: rgba(251, 250, 247, .7);
}
.current-model div { display: flex; flex-direction: column; line-height: 1.4; }
.current-model strong { font-family: var(--serif); font-size: 16px; font-weight: 500; letter-spacing: .12em; }
.current-model span { font-family: var(--mono); font-size: 9px; letter-spacing: .12em; color: var(--ink-faint); }

.view-tools, .toggle-tools { display: flex; gap: 0; background: rgba(251, 250, 247, .78); border: 1px solid var(--line); }
.view-tools button, .toggle-tools button {
  border: 0; border-right: 1px solid var(--line); background: transparent;
  font-size: 11px; letter-spacing: .1em; color: var(--ink-soft);
  padding: 8px 13px; transition: background .2s, color .2s;
  white-space: nowrap;
}
.view-tools button:last-child, .toggle-tools button:last-child { border-right: 0; }
.view-tools button:hover, .toggle-tools button:hover { background: #eef1eb; color: var(--sage-deep); }
.view-tools button.is-active, .toggle-tools button[aria-pressed="true"] {
  background: var(--sage-deep); color: #fbfaf7;
}
.hint { font-size: 10.5px; letter-spacing: .1em; color: var(--ink-faint); }
.loader {
  position: absolute; inset: 0; z-index: 5; display: grid; place-content: center;
  gap: 16px; justify-items: center; background: rgba(246, 245, 240, .86);
  transition: opacity .45s ease, visibility .45s ease;
}
.loader.is-hidden { opacity: 0; visibility: hidden; }
.loader em { font-style: normal; font-size: 11px; letter-spacing: .2em; color: var(--ink-faint); }
.loader-bar { width: 92px; height: 1px; background: var(--line); position: relative; overflow: hidden; }
.loader-bar::after {
  content: ""; position: absolute; inset: 0; width: 40%; background: var(--sage-deep);
  animation: slide 1.35s ease-in-out infinite;
}
@keyframes slide { 0% { transform: translateX(-100%); } 100% { transform: translateX(250%); } }
.viewer-fallback {
  position: absolute; inset: 0; z-index: 6; display: grid; place-content: center;
  font-size: 12px; letter-spacing: .1em; color: var(--ink-faint); text-align: center;
}
.viewer-fallback[hidden] { display: none; }

.model-desc { padding: 34px 28px; display: flex; flex-direction: column; }
.md-kicker {
  display: flex; justify-content: space-between; margin: 0 0 42px;
  font-family: var(--mono); font-size: 9px; letter-spacing: .16em;
  color: var(--ink-faint);
}
.md-group {
  display: inline-block; align-self: flex-start; margin: 0 0 16px;
  font-size: 10px; letter-spacing: .18em; color: var(--sage-deep);
  border: 1px solid rgba(126, 154, 141, .4); padding: 3px 10px;
}
.model-desc h3, .drawing-notes h3 {
  font-family: var(--serif); font-size: 24px; font-weight: 500;
  letter-spacing: .14em; margin: 0 0 4px;
}
.md-en, .sc-en {
  margin: 0 0 26px; font-family: var(--mono); font-size: 9.5px;
  letter-spacing: .18em; color: var(--ink-faint);
}
.md-desc { font-size: 12.5px; line-height: 2.05; color: var(--ink-soft); margin: 0 0 26px; }
.md-specs { list-style: none; padding: 0; margin: 0 0 34px; }
.md-specs li {
  font-size: 11.5px; color: var(--ink-soft); padding: 8px 0 8px 16px;
  border-bottom: 1px solid var(--line-soft); position: relative;
}
.md-specs li::before {
  content: ""; position: absolute; left: 0; top: 17px;
  width: 5px; height: 1px; background: var(--sage);
}
.md-facts { margin: auto 0 0; border-top: 1px solid var(--line); }
.md-facts div { display: flex; justify-content: space-between; padding: 9px 0; border-bottom: 1px solid var(--line-soft); }
.md-facts dt { font-size: 11px; color: var(--ink-faint); letter-spacing: .08em; }
.md-facts dd { margin: 0; font-family: var(--mono); font-size: 11px; color: var(--ink); }

/* ── gallery ────────────────────────────────────────────── */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 34px; }
.filters button {
  border: 1px solid var(--line); background: transparent;
  font-size: 11px; letter-spacing: .12em; color: var(--ink-soft);
  padding: 7px 17px; transition: all .25s;
}
.filters button:hover { border-color: var(--sage); color: var(--sage-deep); }
.filters button.is-active { background: var(--sage-deep); border-color: var(--sage-deep); color: #fbfaf7; }
.gallery {
  display: grid; grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0; background: var(--paper-2); border: 1px solid var(--line);
}
.card {
  position: relative; display: flex; flex-direction: column;
  background: var(--paper-2); padding: 26px 26px 24px;
  min-height: 216px; text-align: left;
  border: 0; border-right: 1px solid var(--line-soft); border-bottom: 1px solid var(--line-soft);
  transition: background .3s ease;
  animation: cardIn .55s cubic-bezier(.2, .7, .3, 1) both;
}
.card:nth-child(3n) { border-right: 0; }
@keyframes cardIn {
  from { opacity: 0; transform: translateY(9px); }
  to   { opacity: 1; transform: none; }
}
@media (prefers-reduced-motion: reduce) { .card { animation: none; } }
.card::after {
  content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 2px;
  background: var(--sage-deep); transform: scaleY(0); transform-origin: top;
  transition: transform .35s ease;
}
.card:hover, .card.is-active { background: #fdfdfa; }
.card:hover::after, .card.is-active::after { transform: scaleY(1); }
.card-top { display: flex; align-items: flex-start; justify-content: space-between; margin-bottom: 26px; }
.card-no { font-family: var(--mono); font-size: 10px; letter-spacing: .1em; color: var(--ink-faint); }
.card-icon { width: 34px; height: 34px; color: var(--sage); opacity: .8; }
.card h3 { font-family: var(--serif); font-size: 17px; font-weight: 500; letter-spacing: .13em; margin: 0 0 3px; }
.card-en { font-family: var(--mono); font-size: 8.5px; letter-spacing: .12em; color: var(--ink-faint); margin: 0 0 14px; }
.card-desc { font-size: 11.5px; line-height: 1.9; color: var(--ink-soft); margin: 0 0 18px; }
.card-foot { margin-top: auto; display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.card-spec { font-size: 10px; color: var(--ink-faint); letter-spacing: .05em; }
.card-arrow { font-size: 13px; color: var(--sage-deep); transition: transform .3s; }
.card:hover .card-arrow { transform: translateX(4px); }

/* ── anatomy ────────────────────────────────────────────── */
.structure-section { background: var(--paper-3); }
.struct-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.struct-card { background: var(--paper-2); padding: 32px 30px 28px; min-height: 252px; display: flex; flex-direction: column; }
.sc-no { font-family: var(--mono); font-size: 9.5px; letter-spacing: .16em; color: var(--sage); margin: 0 0 24px; }
.struct-card h3 { font-family: var(--serif); font-size: 19px; font-weight: 500; letter-spacing: .16em; margin: 0 0 2px; }
.struct-card .sc-en { margin: 0 0 18px; letter-spacing: .2em; }
.struct-card > p:not(.sc-no):not(.sc-en) { font-size: 12px; line-height: 2; color: var(--ink-soft); margin: 0 0 22px; }
.tags { list-style: none; display: flex; flex-wrap: wrap; gap: 6px; padding: 0; margin: auto 0 0; }
.tags li {
  font-family: var(--mono); font-size: 9px; letter-spacing: .08em;
  color: var(--sage-deep); border: 1px solid rgba(126, 154, 141, .35);
  padding: 3px 8px;
}

/* ── drawing ────────────────────────────────────────────── */
.drawing-grid { display: grid; grid-template-columns: minmax(0, 1.45fr) minmax(0, .75fr); gap: 54px; align-items: start; }
.drawing-figure { margin: 0; }
.drawing-zoom {
  display: block; position: relative; padding: 0; border: 1px solid var(--line);
  background: #fff; width: 100%; overflow: hidden;
}
.drawing-zoom img { width: 100%; transition: transform .6s ease; }
.drawing-zoom:hover img { transform: scale(1.018); }
.zoom-hint {
  position: absolute; right: 14px; bottom: 14px; background: rgba(251, 250, 247, .92);
  border: 1px solid var(--line); padding: 5px 11px; font-size: 10px;
  letter-spacing: .1em; color: var(--sage-deep);
}
.drawing-figure figcaption {
  margin-top: 12px; font-family: var(--mono); font-size: 9.5px;
  letter-spacing: .14em; color: var(--ink-faint);
}
.drawing-notes .md-group { margin-bottom: 20px; }
.dn-lead { font-size: 12.5px; line-height: 2.05; color: var(--ink-soft); margin: 0 0 30px; }
.spec-table { margin: 0; border-top: 1px solid var(--line); }
.spec-table div { display: grid; grid-template-columns: 96px 1fr; gap: 12px; padding: 11px 0; border-bottom: 1px solid var(--line-soft); }
.spec-table dt { font-size: 11px; color: var(--ink-faint); letter-spacing: .06em; }
.spec-table dd { margin: 0; font-size: 11.5px; color: var(--ink); line-height: 1.8; }

/* ── footer / lightbox ──────────────────────────────────── */
.site-footer { padding: 40px 0; }
.footer-inner {
  display: flex; justify-content: space-between; gap: 20px;
  font-size: 10.5px; letter-spacing: .12em; color: var(--ink-faint);
}
.lightbox {
  position: fixed; inset: 0; z-index: 90; background: rgba(38, 44, 40, .9);
  display: grid; place-items: center; padding: 4vh 4vw; cursor: zoom-out;
}
.lightbox[hidden] { display: none; }
.lightbox img { max-height: 92vh; max-width: 100%; object-fit: contain; background: #fff; }
.lightbox-close {
  position: absolute; top: 24px; right: 32px; border: 1px solid rgba(255,255,255,.4);
  background: transparent; color: #fff; width: 40px; height: 40px; font-size: 22px; line-height: 1;
}

/* ── reveal ─────────────────────────────────────────────── */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .7s ease, transform .7s ease; }
.reveal.is-visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .loader-bar::after { animation: none; }
}

/* ── responsive ─────────────────────────────────────────── */
@media (max-width: 1080px) {
  .wrap { width: min(var(--wrap), calc(100% - 56px)); }
  .hero-grid { gap: 40px; }
  .viewer-shell { grid-template-columns: minmax(0, 1fr) 240px; }
  .viewer-stage { min-height: 540px; }
  .gallery { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .card:nth-child(3n) { border-right: 1px solid var(--line-soft); }
  .card:nth-child(2n) { border-right: 0; }
  .struct-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 780px) {
  .wrap { width: calc(100% - 40px); }
  .header-inner { height: 66px; gap: 16px; }
  .site-nav { gap: 16px; overflow-x: auto; }
  .site-nav a { font-size: 11px; white-space: nowrap; }
  .nav-index { display: none; }
  .hero { padding: 66px 0 58px; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-aside { display: none; }
  .hero h1 { font-size: clamp(42px, 11vw, 62px); }
  .hero-stats > div { padding-right: 24px; margin-right: 24px; }
  .hero-stats b { font-size: 24px; }
  .section { padding: 66px 0; }
  .section-head { flex-wrap: wrap; gap: 12px; }
  .section-note { margin-left: 0; text-align: left; width: 100%; }
  .viewer-shell { grid-template-columns: 1fr; }
  .viewer-stage { min-height: 430px; border-right: 0; border-bottom: 1px solid var(--line); }
  .viewer-topbar, .viewer-bottombar { padding: 18px; flex-direction: column; align-items: flex-start; gap: 12px; }
  .viewer-bottombar { align-items: flex-start; }
  .view-tools button, .toggle-tools button { padding: 7px 10px; font-size: 10px; }
  .model-desc { padding: 26px 22px; }
  .md-kicker { margin-bottom: 24px; }
  .gallery, .struct-grid { grid-template-columns: 1fr; }
  .card, .card:nth-child(3n), .card:nth-child(2n) { border-right: 0; }
  .drawing-grid { grid-template-columns: 1fr; gap: 34px; }
  .footer-inner { flex-direction: column; gap: 6px; }
}