/* ===== Elements of Civilization — manuscript / cosmology aesthetic ===== */
:root{
  --paper: #f3ecdb;
  --paper-2: #ebe3cf;
  --paper-deep: #ddd3b8;
  --ink: #2c2418;
  --ink-soft: #5a4d34;
  --rule: #b8a877;
  --rule-2: #9e8c5a;
  --gold: #a87a23;
  --gold-2: #c89b3c;
  /* Five canonical elemental colours */
  --wood:  #4a8a4a;
  --fire:  #c8513e;
  --earth: #c89b3c;
  --metal: #8a99a8;
  --water: #2a4a8a;
  --aether:#6a4a8a;
}
[data-theme="dark"]{
  --paper: #16130b;
  --paper-2: #1f1a10;
  --paper-deep: #2a2317;
  --ink: #f3ecdb;
  --ink-soft: #b8a877;
  --rule: #5a4d34;
  --rule-2: #7a6c4d;
  --gold: #d8b14a;
  --gold-2: #e8c266;
  --wood:  #6abf6a;
  --fire:  #e0735c;
  --earth: #e8b95c;
  --metal: #b3bac0;
  --water: #5c8aae;
  --aether:#a07ad6;
}

*{box-sizing: border-box}
html, body{margin:0; padding:0}
html{scroll-behavior: smooth; scroll-padding-top: 72px}
body{
  font-family: "Source Serif 4", Georgia, serif;
  font-size: 17px; line-height: 1.65;
  color: var(--ink); background: var(--paper);
  background-image:
    radial-gradient(900px 500px at 18% -8%, rgba(74,138,74,0.08), transparent 60%),
    radial-gradient(800px 600px at 105% 25%, rgba(200,81,62,0.07), transparent 60%),
    radial-gradient(700px 500px at 50% 110%, rgba(42,74,138,0.06), transparent 60%);
}
[data-theme="dark"] body{
  background-image:
    radial-gradient(900px 500px at 18% -8%, rgba(106,191,106,0.08), transparent 60%),
    radial-gradient(800px 600px at 105% 25%, rgba(224,115,92,0.06), transparent 60%),
    radial-gradient(700px 500px at 50% 110%, rgba(92,138,174,0.06), transparent 60%);
}

a{color: var(--ink); text-decoration: underline; text-decoration-color: var(--rule); text-underline-offset: 3px}
a:hover{text-decoration-color: var(--gold)}
em{font-style: italic; color: var(--gold)}
code, .mono{font-family: "JetBrains Mono", ui-monospace, monospace}

/* Bilingual */
[lang="zh"]{display:none}
html[data-lang="zh"] [lang="en"]{display:none}
html[data-lang="zh"] [lang="zh"]{display:initial}
html svg [lang="zh"]{display:none}
html[data-lang="zh"] svg [lang="zh"]{display:inline}
html[data-lang="zh"] svg [lang="en"]{display:none}
html[data-lang="zh"]{ font-family: "Noto Serif SC", "Source Han Serif SC", "Source Serif 4", Georgia, serif; }

/* Topbar */
.topbar{
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--paper) 90%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
}
.topbar-inner{
  max-width: 1320px; margin: 0 auto;
  padding: 12px 24px;
  display: flex; align-items: center; gap: 18px;
}
.brand{
  display: flex; align-items: center; gap: 12px;
  font-family: "Cormorant Garamond", serif;
  font-size: 22px; font-weight: 600; letter-spacing: .005em;
  text-decoration: none; color: var(--ink);
}
.brand .seal{
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 50%;
  background: var(--paper);
  border: 1.5px solid var(--ink);
  position: relative;
  flex-shrink: 0;
}
.brand .seal svg{width: 28px; height: 28px; display: block}
.brand em{color: var(--gold); font-style: italic}
.nav{display: flex; gap: 14px; flex-wrap: wrap; margin-left: 8px}
.nav a{
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; letter-spacing: .06em;
  text-transform: uppercase; text-decoration: none;
  color: var(--ink-soft);
  padding: 6px 0; border-bottom: 1px solid transparent;
}
.nav a:hover{color: var(--ink); border-bottom-color: var(--gold)}
.toolbar{margin-left: auto; display: flex; gap: 10px}
.lang-toggle, .theme-toggle{
  display: inline-flex; gap: 0;
  border: 1px solid var(--rule); border-radius: 4px; overflow: hidden;
}
.lang-toggle button, .theme-toggle button{
  font-family: "JetBrains Mono", monospace; font-size: 11px;
  background: transparent; color: var(--ink-soft);
  border: none; border-right: 1px solid var(--rule);
  padding: 5px 10px; cursor: pointer; letter-spacing: .04em;
}
.lang-toggle button:last-child, .theme-toggle button:last-child{border-right: none}
.lang-toggle button.active, .theme-toggle button.active{background: var(--ink); color: var(--paper)}

/* Hero */
.hero{ max-width: 1320px; margin: 0 auto; padding: 90px 24px 60px; position: relative; }
.hero-eyebrow{
  font-family: "JetBrains Mono", monospace;
  font-size: 12px; letter-spacing: .18em;
  color: var(--gold); text-transform: uppercase;
  margin-bottom: 24px;
}
.hero h1{
  font-family: "Cormorant Garamond", serif; font-weight: 600;
  font-size: clamp(40px, 6vw, 78px);
  line-height: 1.05; letter-spacing: -.005em;
  margin: 0 0 20px; max-width: 18ch;
}
.hero h1 em{
  font-style: italic;
  background: linear-gradient(120deg, var(--wood), var(--fire), var(--earth), var(--metal), var(--water), var(--aether));
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-sub{
  font-family: "Cormorant Garamond", serif;
  font-size: 24px; line-height: 1.35;
  color: var(--ink-soft); font-style: italic;
  font-weight: 400; max-width: 60ch;
  margin: 0 0 24px;
}
.hero-lede{
  font-size: 19px; line-height: 1.6;
  max-width: 64ch; color: var(--ink-soft);
  margin: 0 0 28px;
}
.hero-thesis{
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px; margin-top: 40px;
}
.hero-thesis div{
  border-left: 3px solid var(--rule);
  padding: 8px 0 8px 16px;
  position: relative;
}
.hero-thesis div:nth-child(1){border-left-color: var(--wood)}
.hero-thesis div:nth-child(2){border-left-color: var(--fire)}
.hero-thesis div:nth-child(3){border-left-color: var(--metal)}
.hero-thesis div:nth-child(4){border-left-color: var(--water)}
.hero-thesis strong{
  font-family: "JetBrains Mono", monospace; font-weight: 500;
  font-size: 11px; letter-spacing: .12em;
  color: var(--gold); text-transform: uppercase;
  display: block; margin-bottom: 6px;
}

/* Sections */
section{ max-width: 1320px; margin: 0 auto; padding: 72px 24px; border-top: 1px solid var(--rule); }
section.no-rule{border-top: none}
.section-eyebrow{
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; letter-spacing: .18em;
  color: var(--gold); text-transform: uppercase;
  margin: 0 0 14px;
}
.section-title{
  font-family: "Cormorant Garamond", serif; font-weight: 500;
  font-size: clamp(30px, 3.6vw, 46px);
  line-height: 1.15; margin: 0 0 16px;
  letter-spacing: -.005em;
}
.section-lede{
  font-size: 18px; line-height: 1.6; color: var(--ink-soft);
  max-width: 72ch; margin: 0 0 32px;
}

/* Comparative engine grid */
.systems-grid{
  display: grid; gap: 16px;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}
.system{
  border: 1px solid var(--rule);
  background: color-mix(in oklab, var(--paper-2) 70%, var(--paper));
  border-radius: 6px;
  padding: 22px;
  position: relative; cursor: pointer;
  transition: border-color .15s, transform .15s;
}
.system:hover{border-color: var(--ink); transform: translateY(-2px)}
.system .swatch{
  position: absolute; top: 22px; right: 22px;
  width: 28px; height: 28px; border-radius: 50%;
  border: 1.5px solid var(--ink);
}
.system h3{
  font-family: "Cormorant Garamond", serif; font-weight: 600;
  font-size: 22px; line-height: 1.2;
  margin: 0 0 4px; padding-right: 40px;
}
.system .origin{
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; letter-spacing: .06em;
  color: var(--gold); text-transform: uppercase;
  margin-bottom: 12px;
}
.system .elements{
  display: flex; flex-wrap: wrap; gap: 6px;
  margin-bottom: 12px;
}
.system .elements span{
  background: var(--paper-deep); border: 1px solid var(--rule);
  font-family: "JetBrains Mono", monospace; font-size: 11px;
  padding: 3px 8px; border-radius: 3px;
}
.system .logic{
  font-family: "JetBrains Mono", monospace; font-size: 12px;
  color: var(--ink-soft); margin-bottom: 12px; line-height: 1.5;
}
.system p{margin: 0; line-height: 1.55; font-size: 15px}

/* Wu Xing diagram */
.wuxing-wrap{
  display: grid; grid-template-columns: 460px 1fr;
  gap: 32px; align-items: start;
}
.wuxing-svg{
  border: 1px solid var(--rule); border-radius: 6px;
  background: color-mix(in oklab, var(--paper-2) 70%, var(--paper));
  padding: 12px;
}
.wuxing-svg svg{display: block; width: 100%; height: auto}
.wuxing-info{
  display: flex; flex-direction: column; gap: 12px;
}
.wuxing-row{
  border: 1px solid var(--rule); border-radius: 4px;
  background: var(--paper); padding: 16px 18px;
  display: grid; grid-template-columns: 80px 1fr;
  gap: 14px; align-items: center;
}
.wuxing-row .glyph{
  width: 60px; height: 60px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-family: "Cormorant Garamond", serif;
  font-size: 38px; font-weight: 600; color: white;
  border: 2px solid var(--ink);
  flex-shrink: 0;
}
.wuxing-row .body h4{
  font-family: "Cormorant Garamond", serif;
  font-size: 22px; font-weight: 600; margin: 0 0 4px; line-height: 1.1;
}
.wuxing-row .body .meta{
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; color: var(--ink-soft); letter-spacing: .04em;
  margin-bottom: 6px;
}
.wuxing-row .body p{margin: 0; font-size: 14px; line-height: 1.5; font-style: italic; color: var(--ink-soft)}

/* Cards */
.grid{ display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid.two{grid-template-columns: repeat(auto-fit, minmax(380px, 1fr))}
.card{
  border: 1px solid var(--rule);
  background: color-mix(in oklab, var(--paper-2) 70%, var(--paper));
  border-radius: 6px; padding: 22px;
  position: relative;
}
.card.wood{border-top: 3px solid var(--wood)}
.card.fire{border-top: 3px solid var(--fire)}
.card.earth{border-top: 3px solid var(--earth)}
.card.metal{border-top: 3px solid var(--metal)}
.card.water{border-top: 3px solid var(--water)}
.card.aether{border-top: 3px solid var(--aether)}
.card h3{
  font-family: "Cormorant Garamond", serif; font-weight: 600;
  font-size: 22px; margin: 0 0 8px; line-height: 1.2;
}
.card .meta{
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; letter-spacing: .08em;
  color: var(--gold); text-transform: uppercase;
  margin-bottom: 10px;
}
.card p{margin: 0 0 10px; line-height: 1.55}
.card .extra{
  margin-top: 10px; padding-top: 10px;
  border-top: 1px dashed var(--rule);
  font-size: 14px; color: var(--ink-soft);
  font-style: italic;
}

/* Tables */
.table-wrap{
  border: 1px solid var(--rule); border-radius: 6px; overflow: hidden;
}
table{
  width: 100%; border-collapse: collapse; font-size: 14px;
}
th, td{
  text-align: left; vertical-align: top;
  padding: 14px 16px; border-bottom: 1px solid var(--rule);
}
th{
  background: var(--paper-deep);
  font-family: "JetBrains Mono", monospace; font-weight: 500;
  font-size: 10px; letter-spacing: .14em; text-transform: uppercase;
  color: var(--gold);
}
td:first-child{
  font-family: "Cormorant Garamond", serif;
  font-size: 18px; font-weight: 600;
}

/* Modern science contrast */
.modern-grid{
  display: grid; gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(420px, 1fr));
}
.modern-card{
  border: 1px solid var(--rule); border-radius: 6px;
  background: color-mix(in oklab, var(--paper-2) 70%, var(--paper));
  padding: 22px;
}
.modern-card h3{
  font-family: "Cormorant Garamond", serif; font-weight: 600;
  font-size: 22px; margin: 0 0 14px; line-height: 1.2;
}
.modern-card .col{
  display: grid; grid-template-columns: 90px 1fr;
  gap: 14px; padding: 10px 0; border-top: 1px dashed var(--rule);
  font-size: 14px; line-height: 1.55;
}
.modern-card .col strong{
  font-family: "JetBrains Mono", monospace; font-weight: 500;
  font-size: 10px; letter-spacing: .12em;
  text-transform: uppercase; color: var(--gold);
  align-self: start; padding-top: 2px;
}
.modern-card .link{
  margin-top: 10px; padding-top: 12px; border-top: 1px solid var(--rule);
  font-style: italic; color: var(--ink-soft); font-size: 14px;
}

/* Simulator */
.sim{
  display: grid; grid-template-columns: 320px 1fr; gap: 24px;
  border: 1px solid var(--rule); border-radius: 6px;
  background: color-mix(in oklab, var(--paper-2) 70%, var(--paper));
  padding: 24px;
}
.sim-controls .ctrl{margin-bottom: 18px}
.sim-controls label{
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; letter-spacing: .1em; text-transform: uppercase;
  color: var(--ink-soft); display: block; margin-bottom: 6px;
}
.sim-controls input[type="range"]{ width: 100%; accent-color: var(--gold); }
.sim-controls .val{
  font-family: "JetBrains Mono", monospace; font-size: 12px;
  color: var(--gold); float: right;
}
.sim-output{display: flex; flex-direction: column; gap: 16px}
.sim-meter{
  display: grid; grid-template-columns: 160px 1fr 60px;
  gap: 12px; align-items: center;
  font-family: "JetBrains Mono", monospace; font-size: 12px;
}
.sim-meter .bar{ height: 8px; background: var(--paper-deep); border-radius: 4px; overflow: hidden; }
.sim-meter .bar-fill{
  height: 100%;
  background: linear-gradient(90deg, var(--wood), var(--fire), var(--earth), var(--metal), var(--water), var(--aether));
  transition: width .25s ease;
}
.sim-meter .num{text-align: right; color: var(--gold)}
.sim-summary{
  margin-top: 8px; padding: 16px;
  background: var(--paper); border: 1px dashed var(--rule); border-radius: 4px;
  font-style: italic; color: var(--ink-soft); font-size: 15px; line-height: 1.55;
}

/* AI Q&A */
.ai-panel{
  border: 1px solid var(--rule); border-radius: 6px;
  background: color-mix(in oklab, var(--paper-2) 70%, var(--paper));
  padding: 24px;
}
.ai-q{
  font-family: "Cormorant Garamond", serif;
  font-size: 22px; font-weight: 500; margin: 0 0 8px;
}
.ai-q::before{content: "❧ "; color: var(--gold)}
.ai-a{
  margin: 0 0 24px;
  padding-left: 22px; border-left: 2px solid var(--rule);
  font-size: 16px; line-height: 1.65; color: var(--ink-soft);
}
.ai-a:last-child{margin-bottom: 0}

/* Footer */
footer{
  max-width: 1320px; margin: 0 auto; padding: 48px 24px 64px;
  border-top: 1px solid var(--rule);
  font-size: 14px; color: var(--ink-soft);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px;
}
footer a{color: var(--ink-soft)}

/* Responsive */
@media (max-width: 900px){
  .nav{display: none}
  .sim{grid-template-columns: 1fr}
  .wuxing-wrap{grid-template-columns: 1fr}
}
@media (max-width: 600px){
  .topbar-inner{padding: 10px 16px; gap: 10px}
  .hero{padding: 56px 16px 36px}
  section{padding: 56px 16px}
  .modern-grid{grid-template-columns: 1fr}
  .modern-card .col{grid-template-columns: 1fr; gap: 4px}
}