/* ============================================================
   CHIHO ARCHITECTS — Design System v1.0
   Primary graphic element: the line. Grid, datum, proportion,
   alignment, hierarchy, rhythm, precision.
   ============================================================ */

:root{
  /* background */
  --bg-primary:   #F3F3F0;
  --bg-secondary: #E9EAE7;
  --bg-light:     #F7F7F4;

  /* dark */
  --dark-bg:   #1A1C1C;
  --dark-text: #ECEDEA;

  /* text */
  --text-primary:   #191B1B;
  --text-secondary: #565B5A;
  --text-muted:     #858A87;

  /* lines */
  --line-light:   rgba(25,27,27,0.10);
  --line-default: rgba(25,27,27,0.18);
  --line-strong:  rgba(25,27,27,0.38);

  /* BIM accent — 5~10% use only */
  --bim-blue:        #718792;
  --bim-blue-active: #5D88A6;
  --bim-cyan:        #88A6AA;
  --bim-green:       #84988B;
  --drawing-red:     #A36D67;

  /* radius */
  --radius-small:  2px;
  --radius-medium: 4px;

  /* spacing */
  --page-margin-desktop: 64px;
  --page-margin-tablet:  32px;
  --page-margin-mobile:  20px;

  /* width */
  --page-max-width: 1920px;
  --content-max: 1440px;

  --line-hairline: 1px;
  --line-strong-width: 2px;

  --sans: Pretendard, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SF Mono", "Roboto Mono", Menlo, Consolas, monospace;

  --header-h: 80px;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:var(--sans); background:var(--bg-primary); color:var(--text-primary);
  font-size:16px; font-weight:400; line-height:1.7; -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
button{font:inherit;color:inherit;background:none;border:none;cursor:pointer}

@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{animation-duration:.01ms !important;transition-duration:.01ms !important}
}

.wrap{max-width:var(--content-max);margin:0 auto;padding:0 var(--page-margin-desktop)}

/* ── metadata / label type ──────────────────────────────────── */
.label{
  font-family:var(--mono); font-size:12px; font-weight:500; letter-spacing:.06em;
  text-transform:uppercase; color:var(--text-muted);
}
.index-no{font-family:var(--mono);font-size:12.5px;font-weight:500;color:var(--text-secondary);letter-spacing:.04em}

/* ── Header ── default: solid light background, dark text.
   Only the hero page starts transparent/white-text (via .has-hero body class
   + JS), and only until the user scrolls — every other page is always solid,
   so nav text never sits invisible on a light background. ──────────────── */
header{
  position:fixed;top:0;left:0;right:0;z-index:100;height:var(--header-h);
  background:rgba(243,243,240,.97);border-bottom:1px solid var(--line-light);
  transition:background-color .3s ease,border-color .3s ease,color .3s ease;
}
header .wrap{height:100%;display:flex;align-items:center;gap:40px}
.brand{display:flex;flex-direction:column;line-height:1.15}
.brand .l1{font-size:14px;font-weight:600;letter-spacing:.03em;color:var(--text-primary)}
.brand .l2{font-size:10.5px;font-weight:500;letter-spacing:.14em;color:var(--text-muted)}

nav{margin-left:auto;display:flex;align-items:center;gap:32px}
nav a{
  font-family:var(--mono);font-size:11.5px;font-weight:500;letter-spacing:.08em;
  color:var(--text-secondary); position:relative;padding-bottom:3px;
}
nav a::after{content:"";position:absolute;left:0;right:0;bottom:0;height:1px;background:currentColor;
  transform:scaleX(0);transform-origin:right;transition:transform .3s ease}
nav a:hover::after{transform:scaleX(1);transform-origin:left}
nav a:hover{color:var(--text-primary)}

.mobile-menu-btn{display:none;margin-left:auto;font-family:var(--mono);font-size:11.5px;
  font-weight:500;letter-spacing:.08em;color:var(--text-primary)}

/* transparent/white variant — only while at the top of the hero page */
header.transparent{background:transparent;border-bottom-color:transparent}
header.transparent .brand .l1{color:#fff}
header.transparent .brand .l2{color:rgba(255,255,255,.68)}
header.transparent nav a{color:rgba(255,255,255,.8)}
header.transparent nav a:hover{color:#fff}
header.transparent .mobile-menu-btn{color:#fff}
header.transparent .btn-outline{border-color:rgba(255,255,255,.5);color:#fff}
header.transparent .btn-outline:hover{background:#fff;color:var(--text-primary)}

/* ── Hero ────────────────────────────────────────────────────── */
.hero{position:relative;min-height:100vh;color:#fff;overflow:hidden;background:var(--dark-bg)}
.hero .bg{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;
  opacity:.58;filter:saturate(.82) contrast(.96)}
.hero::after{content:"";position:absolute;inset:0;
  background:linear-gradient(180deg,rgba(26,28,28,.5) 0%,rgba(26,28,28,.18) 38%,rgba(26,28,28,.92) 100%)}

.hero-top{position:relative;z-index:2;padding-top:calc(var(--header-h) + 56px)}
.hero-top .wrap{display:flex;justify-content:space-between;align-items:baseline;
  padding-top:22px;border-top:1px solid rgba(255,255,255,.22)}
.hero-top .label{color:rgba(255,255,255,.62)}

.hero-body{position:relative;z-index:2;padding:64px 0 96px}
.hero-body .wrap{display:grid;grid-template-columns:repeat(12,1fr);column-gap:24px}
.hero-title{
  grid-column:1/10;
  font-size:clamp(40px,6.2vw,84px);font-weight:400;letter-spacing:-.045em;
  line-height:1.02;
}
.hero-tags{
  grid-column:10/13;display:flex;flex-direction:column;justify-content:flex-end;gap:8px;
  border-left:1px solid rgba(255,255,255,.28);padding-left:20px;
}
.hero-tags span{font-family:var(--mono);font-size:11.5px;letter-spacing:.06em;color:rgba(255,255,255,.72)}

/* ── Section scaffold ────────────────────────────────────────── */
section{border-top:1px solid var(--line-default)}
.sec-inner{padding:120px 0}
.sec-head{display:flex;align-items:baseline;gap:20px;margin-bottom:64px}
.sec-head .rule{flex:1;height:1px;background:var(--line-default)}
.sec-head h2{
  font-size:clamp(28px,3.4vw,44px);font-weight:400;letter-spacing:-.035em;white-space:nowrap;
}
.sec-lede{max-width:520px;color:var(--text-secondary);font-size:15.5px;margin-top:-40px;margin-bottom:56px}

/* ── Selected works (photography, honestly framed) ──────────── */
.works-grid{display:grid;grid-template-columns:repeat(12,1fr);column-gap:24px;row-gap:96px}
.work{grid-column:1/13;cursor:zoom-in}
.work:nth-child(2n){grid-column:1/9}
.work-frame{position:relative;overflow:hidden;background:var(--bg-secondary)}
.work-frame img{width:100%;height:100%;object-fit:cover;transition:transform .7s cubic-bezier(.2,.7,.2,1)}
.work:hover .work-frame img{transform:scale(1.015)}
.work-meta{display:flex;justify-content:space-between;align-items:baseline;
  margin-top:16px;padding-top:14px;border-top:1px solid var(--line-default)}
.work-meta .name{font-size:16px;font-weight:500}
.work-meta .idx{display:flex;gap:20px}

/* ── Practice — line index list ──────────────────────────────── */
.practice-list{border-top:1px solid var(--line-strong)}
.practice-row{
  display:grid;grid-template-columns:72px 1fr auto;gap:24px;align-items:center;
  padding:34px 0;border-bottom:1px solid var(--line-default);
  transition:background-color .25s ease;
}
.practice-row:hover{background:var(--bg-light)}
.practice-row h3{font-size:20px;font-weight:500;letter-spacing:-.01em}
.practice-row p{color:var(--text-secondary);font-size:14.5px;margin-top:4px;max-width:460px}
.practice-row .go{font-family:var(--mono);font-size:11.5px;color:var(--text-muted);
  opacity:0;transform:translateX(-6px);transition:opacity .25s ease,transform .25s ease}
.practice-row:hover .go{opacity:1;transform:translateX(0)}

/* ── BIM / Technology ─────────────────────────────────────────── */
.bim-section{background:var(--dark-bg);color:var(--dark-text);border-top:none}
.bim-grid{display:grid;grid-template-columns:repeat(12,1fr);column-gap:24px;align-items:center}
.bim-copy{grid-column:1/6}
.bim-copy .label{color:var(--bim-cyan)}
.bim-copy h2{font-size:clamp(26px,3vw,38px);font-weight:400;letter-spacing:-.03em;
  line-height:1.3;margin-top:18px}
.bim-visual{grid-column:6/13}
.bim-visual .frame{border:1px solid rgba(236,237,234,.16);aspect-ratio:16/10;
  position:relative;overflow:hidden;background:#111313}
.bim-visual img{width:100%;height:100%;object-fit:cover;opacity:.85}
.bim-tags{display:flex;gap:28px;margin-top:28px}
.bim-tags span{font-family:var(--mono);font-size:11px;letter-spacing:.05em;color:var(--bim-blue)}

/* ── Office / Contact — title-block ───────────────────────────── */
.contact-grid{display:grid;grid-template-columns:repeat(12,1fr);column-gap:24px}
.contact-info{grid-column:1/7}
.contact-info dl{display:grid;grid-template-columns:110px 1fr;border-top:1px solid var(--line-strong)}
.contact-info dt{font-family:var(--mono);font-size:11px;font-weight:500;letter-spacing:.05em;
  text-transform:uppercase;color:var(--text-muted);padding:16px 0;border-bottom:1px solid var(--line-default)}
.contact-info dd{font-size:15px;padding:16px 0;border-bottom:1px solid var(--line-default)}
.contact-side{grid-column:8/13;display:flex;flex-direction:column;justify-content:center;gap:22px}
.contact-side p{color:var(--text-secondary);font-size:14.5px;max-width:340px}

.line-btn{
  display:inline-flex;align-items:center;gap:10px;font-family:var(--mono);
  font-size:12px;font-weight:500;letter-spacing:.05em;padding-bottom:7px;
  border-bottom:1px solid var(--text-primary); width:fit-content;
}
.line-btn .arrow{transition:transform .25s ease}
.line-btn:hover .arrow{transform:translateX(4px)}

/* ── Footer — title block ─────────────────────────────────────── */
footer{border-top:1px solid var(--line-strong);padding:56px 0 40px}
.footer-top{display:grid;grid-template-columns:repeat(12,1fr);column-gap:24px;padding-bottom:40px}
.footer-brand{grid-column:1/5}
.footer-brand .l1{font-size:16px;font-weight:600;letter-spacing:.01em}
.footer-cols{grid-column:5/13;display:flex;gap:64px}
.footer-cols .col .label{margin-bottom:12px;display:block}
.footer-cols .col div{font-size:14px;color:var(--text-secondary);margin-bottom:4px}
.footer-bottom{
  display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:12px;
  padding-top:24px;border-top:1px solid var(--line-default);
}
.footer-bottom .label{font-size:11px}

/* ── Buttons ─────────────────────────────────────────────────── */
.btn-outline{
  display:inline-flex;align-items:center;gap:10px;border:1px solid rgba(255,255,255,.5);
  color:#fff;font-family:var(--mono);font-size:11.5px;font-weight:500;letter-spacing:.05em;
  padding:11px 20px;border-radius:var(--radius-small);
}
.btn-outline:hover{background:#fff;color:var(--text-primary)}

/* ── CHIHO Illustration System — DRAW motion only (see CHIHO_MOTION_SYSTEM.md
   for the deferred full grammar: MOVE/ASSEMBLE/OFFSET/REVEAL/ALIGN).
   Illustrations sit in negative space, never over content: z-index low,
   fill:none, restrained stroke. ─────────────────────────────────────── */
.sketch{width:120px;height:120px;flex-shrink:0;position:relative;z-index:5;opacity:.9}
.js-draw{fill:none;stroke:var(--text-primary);stroke-width:1.5;
  stroke-linecap:round;stroke-linejoin:round;
  transition:stroke-dashoffset 1.4s cubic-bezier(.2,.7,.2,1)}
.sketch.on-dark .js-draw{stroke:var(--dark-text)}
@media (prefers-reduced-motion: reduce){.js-draw{transition:none}}

/* ── Lightbox ────────────────────────────────────────────────── */
.lightbox{
  position:fixed;inset:0;z-index:1000;background:rgba(18,20,20,.94);
  display:none;align-items:center;justify-content:center;flex-direction:column;
  padding:56px 24px;opacity:0;transition:opacity .3s ease;
}
.lightbox.open{display:flex}
.lightbox.show{opacity:1}
.lightbox .counter{position:absolute;top:28px;left:32px;font-family:var(--mono);
  font-size:12px;letter-spacing:.05em;color:rgba(255,255,255,.7)}
.lightbox .stage{position:relative;max-width:min(90vw,1280px);max-height:74vh;width:100%;
  display:flex;justify-content:center;transform:scale(.985);transition:transform .3s ease}
.lightbox.show .stage{transform:scale(1)}
.lightbox img{max-width:100%;max-height:74vh;object-fit:contain}
.lightbox .cap{margin-top:20px;font-size:14px;color:rgba(236,237,234,.85);text-align:center;max-width:640px}
.lightbox .cap .sub{display:block;margin-top:4px;font-family:var(--mono);font-size:11.5px;
  color:rgba(236,237,234,.5);letter-spacing:.04em}
.lightbox .close{
  position:absolute;top:24px;right:28px;color:#fff;font-family:var(--mono);
  font-size:12.5px;letter-spacing:.05em;display:flex;align-items:center;gap:8px;
  border:1px solid rgba(255,255,255,.35);padding:9px 15px;border-radius:var(--radius-small);
}
.lightbox .close:hover{border-color:#fff}
.lightbox .nav-btn{
  position:absolute;top:50%;transform:translateY(-50%);color:#fff;
  border:1px solid rgba(255,255,255,.35);width:44px;height:44px;
  display:flex;align-items:center;justify-content:center;font-family:var(--mono);font-size:16px;
  border-radius:var(--radius-small);
}
.lightbox .nav-btn:hover{border-color:#fff}
.lightbox .prev{left:-62px}
.lightbox .next{right:-62px}
@media(max-width:1100px){ .lightbox .prev{left:12px} .lightbox .next{right:12px} }

/* ── Focus / a11y ─────────────────────────────────────────────── */
a:focus-visible,button:focus-visible{outline:2px solid var(--bim-blue-active);outline-offset:2px}

/* ── Responsive ──────────────────────────────────────────────── */
@media(max-width:1199px){
  .wrap{padding:0 var(--page-margin-tablet)}
  .hero-title{grid-column:1/13}
  .hero-tags{grid-column:1/13;border-left:none;padding-left:0;flex-direction:row;margin-top:24px}
  .work,.work:nth-child(2n){grid-column:1/13}
  .bim-copy,.bim-visual{grid-column:1/13}
  .bim-visual{margin-top:32px}
  .contact-info,.contact-side{grid-column:1/13}
  .contact-side{padding-top:40px}
  .footer-brand,.footer-cols{grid-column:1/13}
  .footer-cols{margin-top:28px}
}
@media(max-width:767px){
  :root{--header-h:64px}
  .wrap{padding:0 var(--page-margin-mobile)}
  nav{display:none}
  .mobile-menu-btn{display:block}
  .hero-title{font-size:clamp(36px,10vw,52px)}
  .sec-inner{padding:80px 0}
  .sec-head h2{font-size:clamp(28px,7vw,34px)}
  .practice-row{grid-template-columns:40px 1fr}
  .practice-row .go{display:none}
  .footer-cols{flex-direction:column;gap:24px}
}