/* killer-math store pages — shared styles. Pure CSS, no build step. */
:root {
  --bg: #0f1115;
  --surface: #171a21;
  --surface-2: #1f232c;
  --text: #e8eaed;
  --muted: #9aa0aa;
  --accent: #5b8cff;
  --accent-2: #7c5cff;
  --border: #2a2f3a;
  --max: 880px;
  --radius: 14px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Apple SD Gothic Neo",
    "Noto Sans KR", "Malgun Gothic", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* Header / nav */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: rgba(15, 17, 21, 0.85);
  backdrop-filter: saturate(150%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.site-header .wrap {
  display: flex; align-items: center; justify-content: space-between;
  min-height: 58px; gap: 16px; flex-wrap: wrap;
}
.brand { font-weight: 700; font-size: 1.05rem; letter-spacing: -0.02em; color: var(--text); }
.brand span { color: var(--accent); }
.nav { display: flex; gap: 18px; flex-wrap: wrap; }
.nav a { color: var(--muted); font-size: 0.92rem; }
.nav a:hover, .nav a.active { color: var(--text); text-decoration: none; }

/* Hero (landing) */
.hero { padding: 72px 0 48px; text-align: center; }
.hero h1 { font-size: clamp(1.8rem, 5vw, 2.8rem); line-height: 1.2; margin: 0 0 16px; letter-spacing: -0.03em; }
.hero p.lede { font-size: 1.12rem; color: var(--muted); max-width: 620px; margin: 0 auto 28px; }
.badges { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-top: 8px; }
.badge-store {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--surface-2); border: 1px solid var(--border);
  padding: 12px 18px; border-radius: 10px; color: var(--text);
  font-size: 0.9rem; min-width: 180px; justify-content: center;
}
.badge-store small { display: block; color: var(--muted); font-size: 0.72rem; }

/* Feature grid */
.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; margin: 36px 0; }
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 22px;
}
.card h3 { margin: 0 0 8px; font-size: 1.05rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; }

/* Screenshot placeholders */
.shots { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 16px; margin: 28px 0; }
.shot {
  aspect-ratio: 9 / 19; border: 1px dashed var(--border); border-radius: 18px;
  background: var(--surface-2); display: flex; align-items: center; justify-content: center;
  color: var(--muted); font-size: 0.82rem; text-align: center; padding: 12px;
}

/* Document pages */
main.doc { padding: 40px 0 64px; }
.doc h1 { font-size: 1.8rem; letter-spacing: -0.02em; margin: 0 0 6px; }
.doc h2 { font-size: 1.25rem; margin: 38px 0 10px; padding-top: 8px; border-top: 1px solid var(--border); }
.doc h2:first-of-type { border-top: 0; }
.doc h3 { font-size: 1.05rem; margin: 22px 0 8px; }
.doc p, .doc li { color: #d4d7dd; }
.doc ul, .doc ol { padding-left: 22px; }
.doc li { margin: 4px 0; }
.meta { color: var(--muted); font-size: 0.9rem; margin: 0 0 8px; }

.callout {
  background: var(--surface); border: 1px solid var(--border);
  border-left: 3px solid var(--accent-2);
  border-radius: 10px; padding: 14px 18px; margin: 18px 0;
  font-size: 0.92rem; color: var(--muted);
}
.placeholder {
  background: rgba(124, 92, 255, 0.14);
  border-bottom: 1px dashed var(--accent-2);
  padding: 0 4px; border-radius: 3px; color: #cfc4ff; white-space: nowrap;
}

table { border-collapse: collapse; width: 100%; margin: 16px 0; font-size: 0.92rem; }
th, td { border: 1px solid var(--border); padding: 9px 12px; text-align: left; vertical-align: top; }
th { background: var(--surface-2); }

details { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 12px 16px; margin: 10px 0; }
summary { cursor: pointer; font-weight: 600; }
details[open] summary { margin-bottom: 8px; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 28px 0 48px; color: var(--muted); font-size: 0.85rem; }
.site-footer .wrap { display: flex; flex-direction: column; gap: 8px; }
.site-footer .nav a { font-size: 0.85rem; }
.disclaimer { font-size: 0.8rem; color: #6f7682; }

.shot--img { padding: 0; border-style: solid; overflow: hidden; }
.shot--img img { width: 100%; height: 100%; object-fit: cover; display: block; }