/* =========================
   내 수학 실험실
   메인 홈페이지 스타일
   ========================= */

:root{
  --bg:#f2f0e9;
  --paper:#fbf9f3;
  --text:#15171a;
  --muted:#6b6f74;
  --line:#d3cec3;
  --orange:#ff5a30;
  --lime:#d9f24f;
  --peach:#ffd0c4;
  --dark:#15171a;
  --deep:#101215;
  --cream:#faf5ec;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:Pretendard,"Apple SD Gothic Neo","Noto Sans KR",sans-serif;
  -webkit-font-smoothing:antialiased;
  word-break:keep-all;
}
a{color:inherit;text-decoration:none}
button,input,select{font:inherit;color:inherit}
button{cursor:pointer}
::selection{background:var(--lime)}

@keyframes hl-draw{from{transform:scaleX(0)}to{transform:scaleX(1)}}

/* ---------- header ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:60;
  background:rgba(242,240,233,.88);
  backdrop-filter:blur(16px);
  border-bottom:1px solid #ddd8cd;
}
.site-header-inner{
  width:min(1180px,calc(100% - 48px));
  height:72px;
  margin:0 auto;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:24px;
}
.brand strong{display:block;font-size:16px;font-weight:800;letter-spacing:-.035em}
.brand small{
  display:block;
  margin-top:2px;
  font-family:"IBM Plex Mono",monospace;
  font-size:9px;
  letter-spacing:.16em;
  color:#8a8d90;
}
.site-nav{display:flex;align-items:center;gap:26px;font-size:14px;font-weight:650}
.site-nav a:hover{color:var(--orange)}

.outline-pill,
.primary-pill{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  min-height:46px;
  padding:0 22px;
  border-radius:999px;
  font-weight:700;
  border:1px solid #c9c4b8;
  background:transparent;
  transition:.18s ease;
}
.outline-pill:hover{border-color:var(--text);background:#e7e3d9}
.primary-pill{color:#fff;border-color:var(--dark);background:var(--dark)}
.primary-pill:hover{background:#2b2e31}
.button-reset{font-size:inherit}

/* ---------- hero ---------- */
.hero-section{position:relative;overflow:hidden;padding:76px 0 84px}
.hero-grid-bg{
  position:absolute;
  inset:0;
  opacity:.75;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(21,23,26,.13) 1px,transparent 1px),
    linear-gradient(90deg,rgba(21,23,26,.13) 1px,transparent 1px);
  background-size:34px 34px;
  mask-image:linear-gradient(#000,rgba(0,0,0,.15));
}
.hero-square{
  position:absolute;
  width:34px;
  height:34px;
  left:max(24px,calc((100vw - 1180px)/2 - 122px));
}
.lime-square{top:40px;background:rgba(217,242,79,.62)}
.peach-square{top:74px;left:max(58px,calc((100vw - 1180px)/2 - 88px));background:rgba(255,208,196,.7)}

.hero-layout{
  position:relative;
  width:min(1180px,calc(100% - 48px));
  margin:0 auto;
  display:grid;
  grid-template-columns:minmax(0,1fr) 400px;
  gap:36px;
  align-items:center;
}
.eyebrow{
  display:flex;
  align-items:center;
  gap:10px;
  margin:0;
  color:var(--muted);
  font-size:13px;
  font-weight:650;
}
.eyebrow span{width:22px;height:2px;background:var(--orange)}
.hero-title{
  margin:22px 0 0;
  font-size:clamp(40px,6vw,70px);
  line-height:1.16;
  font-weight:800;
  letter-spacing:-.045em;
}
.highlight{position:relative;display:inline-block;font-weight:300;z-index:0}
.highlight::before{
  content:"";
  position:absolute;
  left:-.06em;
  right:-.06em;
  bottom:.1em;
  height:.34em;
  background:var(--lime);
  z-index:-1;
  transform-origin:left center;
  animation:hl-draw .75s cubic-bezier(.22,.61,.36,1) .35s both;
}
.hero-desc{
  max-width:34ch;
  margin:26px 0 0;
  color:#4b4f53;
  font-size:clamp(15px,1.4vw,18px);
  line-height:1.8;
}
.hero-desc strong{
  color:var(--text);
  font-weight:750;
  background:linear-gradient(transparent 62%,var(--lime) 0);
}
.hero-actions{display:flex;gap:10px;margin-top:30px;flex-wrap:wrap}
.link-pill{font-size:15px}
.hero-stats{
  display:flex;
  align-items:center;
  flex-wrap:wrap;
  gap:16px;
  margin-top:32px;
  color:var(--muted);
  font-size:13px;
}
.hero-stats b{
  margin-right:3px;
  color:var(--text);
  font-family:"IBM Plex Mono",monospace;
  font-size:15px;
  font-weight:500;
}
.hero-stats i{width:1px;height:12px;background:var(--line)}

.hero-art{width:400px;max-width:100%;justify-self:end}
.hero-art canvas{
  width:100%;
  aspect-ratio:500/588;
  display:block;
  mix-blend-mode:multiply;
}

/* ---------- tools ---------- */
.tools-section{padding:82px 0 94px;background:var(--paper);border-top:1px solid #e0dbd0}
.section-inner{width:min(1180px,calc(100% - 48px));margin:0 auto}
.section-heading{display:flex;flex-wrap:wrap;justify-content:space-between;gap:24px;align-items:flex-end}
.section-kicker{
  margin:0 0 10px;
  color:var(--orange);
  font-family:"IBM Plex Mono",monospace;
  font-size:10px;
  font-weight:600;
  letter-spacing:.16em;
}
.section-heading h2{margin:0;font-size:clamp(30px,3.4vw,42px);line-height:1.15;letter-spacing:-.04em}
.section-heading p:not(.section-kicker){margin:12px 0 0;color:var(--muted);font-size:15px}
.tool-number{color:#8a8d90;font-family:"IBM Plex Mono",monospace;font-size:12px;letter-spacing:.08em}
.tool-number span{color:var(--text);font-size:24px}

.finder{display:flex;flex-wrap:wrap;gap:10px;margin-top:34px}
.search-box{
  flex:1;
  min-width:240px;
  height:54px;
  display:flex;
  align-items:center;
  gap:12px;
  padding:0 18px;
  border:1px solid #e2ddd2;
  border-radius:14px;
  background:#fff;
}
.search-box span{font-size:20px;color:#9a9ea2}
.search-box input{width:100%;min-width:0;border:0;outline:0;background:transparent;font-size:15px}
.reset-btn{
  height:54px;
  flex:none;
  padding:0 26px;
  border:1px solid #e2ddd2;
  border-radius:14px;
  background:#fff;
  font-size:14px;
  font-weight:750;
  transition:.18s ease;
}
.reset-btn:hover{border-color:var(--text);background:#f4f1e9}

/* subject chips, grouped by row */
.subject-groups{display:grid;gap:14px;margin-top:26px}
.subject-row{display:grid;grid-template-columns:78px minmax(0,1fr);gap:16px;align-items:start}
.subject-row>.row-label{padding-top:9px;font-size:13px;font-weight:750;color:#3f4348}
.row-chips{display:flex;flex-wrap:wrap;gap:8px}
.subject-chip{
  display:inline-flex;
  align-items:center;
  gap:7px;
  padding:9px 16px;
  border:1px solid #e6e1d6;
  border-radius:999px;
  background:transparent;
  color:var(--muted);
  font-size:13px;
  font-weight:700;
  white-space:nowrap;
  transition:.16s ease;
}
.subject-chip .chip-count{
  font-family:"IBM Plex Mono",monospace;
  font-size:11px;
  font-weight:500;
  color:#8a8d90;
}
.subject-chip.has-items{background:#fff;border-color:#d8d3c8;color:#3f4348}
.subject-chip:hover{
  transform:translateY(-2px);
  border-color:var(--text);
  box-shadow:0 6px 14px rgba(21,23,26,.12);
}
.subject-chip.active{background:var(--text);border-color:var(--text);color:#fff}
.subject-chip.active .chip-count{color:rgba(255,255,255,.85)}

/* cards */
.tools-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(300px,1fr));
  gap:16px;
  margin-top:34px;
}
.tool-card{
  min-width:0;
  display:flex;
  flex-direction:column;
  border:1px solid #ddd8cd;
  border-radius:18px;
  background:#fff;
  overflow:hidden;
  transition:transform .2s ease,border-color .2s ease,box-shadow .2s ease;
}
.tool-card:hover{
  transform:translateY(-3px);
  border-color:#bcb5a8;
  box-shadow:0 12px 28px rgba(21,23,26,.08);
}
.card-media{
  position:relative;
  height:180px;
  display:grid;
  place-items:center;
  align-content:center;
  gap:10px;
  background:var(--card-tint);
  border-bottom:1px dashed rgba(21,23,26,.35);
}
.card-num{
  position:absolute;
  left:12px;
  top:12px;
  padding:3px 9px;
  border-radius:8px;
  background:var(--paper);
  font-family:"IBM Plex Mono",monospace;
  font-size:11px;
  font-weight:600;
}
.card-media .media-label{
  font-size:12.5px;
  font-weight:650;
  letter-spacing:-.01em;
  color:rgba(21,23,26,.66);
}
.card-body{display:flex;flex-direction:column;flex:1;padding:20px}
.subject-label{
  align-self:flex-start;
  padding:5px 11px;
  border:1px solid #ddd8cd;
  border-radius:999px;
  color:#5d6165;
  font-size:11px;
  font-weight:700;
}
.tool-card h3{margin:14px 0 8px;font-size:19px;line-height:1.35;letter-spacing:-.035em}
.tool-card p{margin:0;color:#64686c;font-size:13.5px;line-height:1.65}
.card-actions{display:flex;gap:10px;align-items:center;margin-top:auto;padding-top:22px}
.open-tool{
  flex:1;
  min-height:46px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:12px;
  background:var(--text);
  color:#fff;
  font-size:14px;
  font-weight:750;
}
.open-tool:hover{background:#2b2e31}
.qr-tool{
  width:46px;
  height:46px;
  flex:none;
  display:grid;
  place-items:center;
  border:1px solid #ddd8cd;
  border-radius:12px;
  background:#fff;
  transition:.18s ease;
}
.qr-tool:hover{border-color:var(--text)}
.qr-glyph{display:grid;grid-template-columns:repeat(3,6px);grid-template-rows:repeat(3,6px);gap:2px}
.qr-glyph i{background:#c9c4b8;border-radius:1.5px}
.qr-glyph i.on{background:var(--text)}
.empty-message{padding:36px 0;color:var(--muted);text-align:center}

/* ---------- how ---------- */
.how-section{
  position:relative;
  overflow:hidden;
  padding:clamp(26px,3vw,44px) 0 clamp(28px,3vw,40px);
  background:var(--deep);
  color:#fff;
}
.how-grid-bg{
  position:absolute;
  inset:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(255,255,255,.055) 1px,transparent 1px),
    linear-gradient(90deg,rgba(255,255,255,.055) 1px,transparent 1px);
  background-size:34px 34px;
}
.how-square{position:absolute;width:34px;height:34px}
.how-lime{top:56px;left:max(24px,calc((100vw - 1180px)/2 - 44px));background:rgba(217,242,79,.34)}
.how-orange{top:90px;left:max(58px,calc((100vw - 1180px)/2 - 10px));background:rgba(255,90,48,.32)}

.how-layout{
  position:relative;
  width:min(1180px,calc(100% - 48px));
  margin:0 auto;
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(300px,1fr));
  gap:clamp(36px,5vw,72px);
  align-items:start;
}
.how-eyebrow{
  display:flex;
  align-items:center;
  gap:10px;
  margin:0 0 20px;
  color:#c2c8cd;
  font-size:13px;
  font-weight:650;
}
.how-eyebrow span{width:26px;height:2px;background:var(--orange)}
.how-title{
  margin:0;
  font-size:clamp(34px,4vw,48px);
  line-height:1.24;
  letter-spacing:-.045em;
  font-weight:800;
  color:var(--cream);
}
.how-title em{font-style:normal;font-weight:400}
.how-desc{margin:30px 0 0;color:#b6bcc1;font-size:15.5px;line-height:2}

.steps{display:grid;gap:12px;min-width:0}
.steps article{
  display:flex;
  gap:22px;
  padding:14px 26px;
  border:1px solid #262b30;
  border-radius:14px;
  background:#1a1d21;
}
.steps article>b{
  flex:none;
  padding-top:4px;
  color:#8a9198;
  font-family:"IBM Plex Mono",monospace;
  font-size:12px;
  font-weight:500;
}
.steps strong{display:block;margin-bottom:4px;font-size:16.5px;color:var(--cream)}
.steps span{color:#b0b6bb;font-size:14px;line-height:1.7}

footer{background:var(--deep)}
footer div{
  width:min(1180px,calc(100% - 48px));
  margin:0 auto;
  padding:clamp(20px,2.5vw,32px) 0 24px;
  display:flex;
  justify-content:flex-end;
  color:#9aa1a7;
  font-size:13px;
}

/* ---------- modal ---------- */
.modal[hidden]{display:none}
.modal{position:fixed;inset:0;z-index:100}
.modal-backdrop{position:absolute;inset:0;background:rgba(21,23,26,.55);backdrop-filter:blur(4px)}
.qr-dialog{
  position:absolute;
  left:50%;
  top:50%;
  transform:translate(-50%,-50%);
  width:min(390px,calc(100% - 32px));
  padding:30px;
  border-radius:20px;
  background:var(--paper);
  text-align:center;
}
.qr-kicker{
  margin:0;
  color:#8a8d90;
  font-family:"IBM Plex Mono",monospace;
  font-size:10px;
  letter-spacing:.16em;
}
.qr-dialog h3{margin:10px 0 18px;font-size:21px}
.qr-box{
  width:220px;
  height:220px;
  margin:0 auto;
  display:grid;
  place-items:center;
  border:1px solid #ddd8cd;
  border-radius:12px;
  background:#fff;
}
.qr-box img,.qr-box canvas{max-width:190px;max-height:190px}
.qr-url{margin:16px 0;color:var(--muted);font-size:12px;line-height:1.6;word-break:break-all}
.qr-actions{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.qr-actions button{min-height:44px}

/* ---------- responsive ---------- */
@media(max-width:900px){
  .site-header-inner{width:calc(100% - 28px)}
  .site-nav{gap:8px}
  .site-nav>a{display:none}
  .hero-layout{width:calc(100% - 32px);display:flex;flex-direction:column;gap:30px;align-items:stretch}
  .hero-section{padding:46px 0 56px}
  .hero-desc{max-width:620px}
  .hero-art{width:min(78vw,390px);align-self:center;justify-self:auto}
}

@media(max-width:620px){
  .site-header-inner{height:64px}
  .brand strong{font-size:14px}
  .brand small{font-size:7px;letter-spacing:.1em}
  .site-nav .outline-pill{min-height:38px;padding:0 11px;font-size:11px}
  .hero-section{padding:38px 0 48px}
  .hero-stats{gap:9px}
  .section-inner{width:calc(100% - 32px)}
  .tools-section{padding:56px 0 64px}
  .finder{flex-direction:column}
  .reset-btn{width:100%}
  .subject-row{grid-template-columns:1fr;gap:8px}
  .subject-row>.row-label{padding-top:0}
  .how-layout{width:calc(100% - 32px)}
  footer div{width:calc(100% - 32px)}
}