:root {
  --bs-green: #0e7a5f;
  --bs-green-br: #15c79a;
  --bs-teal: #7ff0cf;
  --bs-blue: #0b5c8a;
  --bs-ink: #0f2b3d;
  --bs-ink-2: #0a1f2c;
  --bs-muted: #5b6b76;
  --bs-line: #e2e8ee;
  --bs-bg: #f4f7f9;
  --bs-card: #ffffff;
  --radius: 16px;
  --shadow: 0 18px 50px rgba(10, 31, 44, 0.12);
  --maxw: 1080px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
html, body { margin: 0; }
body { background: var(--bs-bg); color: var(--bs-ink); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 0.9em; background: rgba(14,122,95,0.1); padding: 1px 6px; border-radius: 6px; }
.dark code { background: rgba(127,240,207,0.14); color: #d6fff1; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- top bar ---------- */
.topbar {
  position: absolute; top: 0; left: 0; right: 0; z-index: 5;
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 28px;
}
.wordmark { font-weight: 800; font-size: 18px; letter-spacing: -0.02em; color: #fff; display: inline-flex; align-items: center; gap: 2px; }
.wordmark .tm { font-size: 10px; opacity: 0.7; transform: translateY(-5px); }
.wordmark .dot { color: var(--bs-teal); }
.topbar .back {
  font-size: 13px; font-weight: 600; color: rgba(255,255,255,0.75);
  border: 1px solid rgba(255,255,255,0.22); padding: 7px 13px; border-radius: 999px;
  transition: background .15s ease, color .15s ease;
}
.topbar .back:hover { background: rgba(255,255,255,0.12); color: #fff; }

.topnav { display: inline-flex; align-items: center; gap: 6px; }
.navbtn {
  display: inline-flex; align-items: center; justify-content: center;
  height: 36px; min-width: 36px; padding: 0 12px;
  border: 1px solid rgba(255,255,255,0.22); border-radius: 999px;
  color: rgba(255,255,255,0.8); font-size: 13px; font-weight: 700; letter-spacing: 0.02em;
  transition: background .15s ease, color .15s ease, border-color .15s ease;
}
.navbtn:hover { background: rgba(255,255,255,0.12); color: #fff; border-color: rgba(255,255,255,0.4); }
.navbtn.all { text-transform: uppercase; color: var(--bs-teal); border-color: rgba(127,240,207,0.4); }
.navbtn.all:hover { background: rgba(127,240,207,0.14); color: var(--bs-teal); }
.navbtn svg { width: 17px; height: 17px; display: block; }
.navbtn svg path { fill: none; stroke: currentColor; stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }

/* ---------- hero ---------- */
.hero {
  position: relative; color: #fff; overflow: hidden;
  padding: 128px 0 92px;
  background:
    radial-gradient(1200px 600px at 12% -10%, rgba(14,122,95,0.55), transparent 60%),
    radial-gradient(1000px 700px at 100% 115%, rgba(11,92,138,0.6), transparent 55%),
    linear-gradient(160deg, var(--bs-ink-2), var(--bs-ink));
}
.hero::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(900px 600px at 72% 35%, #000, transparent 75%);
}
.hero .container { position: relative; z-index: 2; display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 48px; align-items: center; }
.hero-copy { min-width: 0; }

.eyebrow { text-transform: uppercase; letter-spacing: 0.22em; font-size: 12px; font-weight: 700; color: var(--bs-teal); margin: 0 0 18px; }

h1.headline { font-size: clamp(34px, 5.4vw, 62px); line-height: 1.03; letter-spacing: -0.03em; font-weight: 800; margin: 0 0 20px; max-width: 15ch; }
p.sub { font-size: clamp(16px, 2vw, 20px); line-height: 1.5; color: rgba(255,255,255,0.84); max-width: 50ch; margin: 0 0 26px; }

ul.points { list-style: none; padding: 0; margin: 0 0 34px; gap: 11px; max-width: 52ch; }
ul.points li { position: relative; padding-left: 28px; font-size: clamp(14px, 1.7vw, 16px); color: rgba(255,255,255,0.92); line-height: 1.45; }
ul.points li::before { content: ""; position: absolute; left: 2px; top: 7px; width: 9px; height: 9px; border-radius: 3px; background: linear-gradient(135deg, var(--bs-teal), #4bbf9a); }
body.mode-tech ul.points li { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: clamp(12.5px, 1.5vw, 14px); }

.cta-row { display: flex; flex-wrap: wrap; gap: 12px; }
.btn { display: inline-flex; align-items: center; gap: 8px; font-size: 15px; font-weight: 700; padding: 13px 22px; border-radius: 999px; cursor: pointer; border: 1px solid transparent; transition: transform .12s ease, filter .12s ease, background .15s ease; }
.btn:active { transform: translateY(1px); }
.btn.primary { background: linear-gradient(135deg, var(--bs-green-br), var(--bs-green)); color: #042019; }
.btn.primary:hover { filter: brightness(1.06); }
.btn.ghost { background: transparent; border-color: rgba(255,255,255,0.28); color: #fff; }
.btn.ghost:hover { background: rgba(255,255,255,0.1); }

/* hero graphic */
.hero-art { display: flex; align-items: center; justify-content: center; }
.hero-art .art { width: 100%; max-width: 380px; color: var(--bs-teal); }
.art { color: var(--bs-green); }
.art svg, .mini { width: 100%; height: auto; display: block; }
.art .stroke, .mini .stroke { fill: none; stroke: currentColor; stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }
.art .fillt, .mini .fillt { fill: currentColor; opacity: 0.14; }
.art .accent, .mini .accent { stroke: currentColor; opacity: 0.55; fill: none; }
.art .ghost, .mini .ghost { stroke: currentColor; opacity: 0.28; fill: none; }
.art .dot, .mini .dot { fill: currentColor; stroke: none; }
.hero-art .art .muted { color: rgba(255,255,255,0.4); }

/* ---------- tag toggle ---------- */
.tagset { display: inline-flex; gap: 8px; background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.14); padding: 6px; border-radius: 999px; margin: 0 0 26px; }
.tag { border: none; background: transparent; color: rgba(255,255,255,0.7); font-size: 13px; font-weight: 700; padding: 8px 16px; border-radius: 999px; cursor: pointer; display: inline-flex; align-items: center; gap: 7px; transition: background .15s ease, color .15s ease; font-family: inherit; }
.tag .glyph { font-size: 12px; opacity: 0.8; }
.tag:hover { color: #fff; }
.tag[aria-pressed="true"] { background: #fff; color: var(--bs-ink); }
.tag[data-mode="tech"][aria-pressed="true"] { background: var(--bs-teal); color: #042019; }

/* ---------- mode visibility ---------- */
.plain, .tech { display: none; }
body.mode-plain .plain { display: revert; }
body.mode-tech  .tech  { display: revert; }
body.mode-plain ul.points.plain { display: grid; }
body.mode-tech  ul.points.tech  { display: grid; }
.swap { animation: fade .28s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ---------- sections ---------- */
section { padding: 74px 0; }
.band-oneliner { background: var(--bs-ink); color: #fff; padding: 46px 0; }
.oneliner { font-size: clamp(22px, 3.4vw, 34px); font-weight: 800; letter-spacing: -0.02em; line-height: 1.2; margin: 0; text-align: center; }
.oneliner .hl { color: var(--bs-teal); }

.sec-eyebrow { text-transform: uppercase; letter-spacing: 0.2em; font-size: 12px; font-weight: 700; color: var(--bs-green); margin: 0 0 12px; }
.sec-title { font-size: clamp(26px, 3.6vw, 38px); letter-spacing: -0.02em; line-height: 1.1; margin: 0 0 18px; font-weight: 800; }
.sec-lead { font-size: 18px; line-height: 1.6; color: var(--bs-muted); max-width: 60ch; margin: 0; }

/* analogy */
.analogy { background: var(--bs-card); }
.analogy .grid { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 54px; align-items: center; }
.analogy .art { color: var(--bs-green); max-width: 420px; }
.analogy p { font-size: 18px; line-height: 1.65; color: var(--bs-ink); margin: 0; }
body.mode-tech .analogy p.tech { font-size: 16px; }

/* comparison */
.compare { background: var(--bs-bg); }
.cmp-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 34px; }
.cmp-col { background: var(--bs-card); border: 1px solid var(--bs-line); border-radius: var(--radius); padding: 26px; box-shadow: var(--shadow); }
.cmp-col.bad { background: #fff; }
.cmp-col.good { background: linear-gradient(180deg, #ecfbf5, #ffffff); border-color: #bfe9d8; }
.cmp-col h3 { margin: 0 0 18px; font-size: 15px; letter-spacing: 0.04em; text-transform: uppercase; display: flex; align-items: center; gap: 9px; }
.cmp-col.bad h3 { color: #9aa6ad; }
.cmp-col.good h3 { color: var(--bs-green); }
.cmp-col ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 14px; }
.cmp-col li { position: relative; padding-left: 30px; font-size: 15.5px; line-height: 1.45; color: var(--bs-ink); }
.cmp-col.bad li { color: #6b7883; }
.cmp-col li .ic { position: absolute; left: 0; top: 1px; width: 20px; height: 20px; border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; font-size: 12px; font-weight: 800; }
.cmp-col.bad li .ic { background: #f1e3e2; color: #b3534c; }
.cmp-col.good li .ic { background: #15c79a; color: #042019; }

/* flow */
.flow { background: var(--bs-card); }
.flow-steps { counter-reset: step; display: grid; gap: 14px; margin-top: 34px; max-width: 760px; }
.flow-step { display: grid; grid-template-columns: 44px 1fr; gap: 18px; align-items: start; padding: 18px 20px; border: 1px solid var(--bs-line); border-radius: 14px; background: #fbfdfe; position: relative; }
.flow-step::before { counter-increment: step; content: counter(step); display: inline-flex; align-items: center; justify-content: center; width: 36px; height: 36px; border-radius: 10px; background: linear-gradient(135deg, var(--bs-green-br), var(--bs-green)); color: #042019; font-weight: 800; font-size: 16px; }
.flow-step p { margin: 6px 0 0; font-size: 16px; line-height: 1.45; color: var(--bs-ink); }

/* concept cards */
.cards { background: var(--bs-ink); color: #fff; }
.card-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin-top: 36px; }
.ccard { background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.12); border-radius: var(--radius); padding: 24px; transition: transform .14s ease, background .15s ease, border-color .15s ease; }
.ccard:hover { transform: translateY(-3px); background: rgba(255,255,255,0.09); border-color: rgba(127,240,207,0.45); }
.ccard .cglyph { font-size: 24px; color: var(--bs-teal); display: block; margin-bottom: 14px; }
.ccard h3 { margin: 0 0 8px; font-size: 18px; letter-spacing: -0.01em; }
.ccard p { margin: 0; font-size: 14.5px; line-height: 1.5; color: rgba(255,255,255,0.72); }
.cards .sec-eyebrow { color: var(--bs-teal); }
.cards .sec-title { color: #fff; }

/* glossary */
.glossary { background: var(--bs-bg); }
.gloss-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 30px; }
.gterm { background: var(--bs-card); border: 1px solid var(--bs-line); border-radius: 14px; padding: 20px 22px; }
.gterm dt { font-weight: 800; font-size: 16px; color: var(--bs-green); font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.gterm dd { margin: 8px 0 0; font-size: 14.5px; line-height: 1.5; color: var(--bs-muted); }

/* faq */
.faq { background: var(--bs-card); }
.faq-list { margin-top: 30px; max-width: 820px; display: grid; gap: 12px; }
.faq details { border: 1px solid var(--bs-line); border-radius: 14px; background: #fbfdfe; overflow: hidden; }
.faq summary { cursor: pointer; list-style: none; padding: 20px 22px; font-weight: 700; font-size: 17px; display: flex; justify-content: space-between; align-items: center; gap: 16px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--bs-green); font-size: 22px; font-weight: 400; transition: transform .2s ease; }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { margin: 0; padding: 0 22px 22px; font-size: 16px; line-height: 1.6; color: var(--bs-muted); }

/* cta */
.cta { background: linear-gradient(160deg, var(--bs-ink-2), var(--bs-green)); color: #fff; text-align: center; }
.cta h2 { font-size: clamp(28px, 4vw, 42px); letter-spacing: -0.02em; margin: 0 0 16px; }
.cta p { font-size: 18px; color: rgba(255,255,255,0.85); margin: 0 0 28px; }
.cta .cta-row { justify-content: center; }

/* pager */
.pager { background: var(--bs-ink); color: #fff; padding: 26px 0; }
.pager .container { display: flex; justify-content: space-between; align-items: center; gap: 16px; }
.pager a { font-size: 14px; font-weight: 700; color: rgba(255,255,255,0.8); border: 1px solid rgba(255,255,255,0.2); padding: 10px 16px; border-radius: 999px; }
.pager a:hover { background: rgba(255,255,255,0.1); color: #fff; }
.pager .all { color: var(--bs-teal); border-color: rgba(127,240,207,0.4); }

/* footer */
footer.site { background: var(--bs-ink-2); color: rgba(255,255,255,0.6); padding: 40px 0; font-size: 13.5px; }
footer.site .container { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; }
footer.site a { color: var(--bs-teal); }
footer.site .note { color: rgba(255,255,255,0.45); }

/* ---------- gallery ---------- */
.gallery-hero {
  position: relative; color: #fff; min-height: 100vh;
  background:
    radial-gradient(1200px 600px at 12% -6%, rgba(14,122,95,0.5), transparent 60%),
    radial-gradient(1000px 800px at 100% 108%, rgba(11,92,138,0.55), transparent 55%),
    linear-gradient(160deg, var(--bs-ink-2), var(--bs-ink));
}
.gallery-hero::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(1000px 700px at 60% 25%, #000, transparent 80%);
}
.gallery-wrap { position: relative; z-index: 2; padding: 128px 0 40px; }
.gallery-head { max-width: 760px; margin: 0 0 34px; }
.gallery-head h1 { font-size: clamp(34px, 5.5vw, 58px); letter-spacing: -0.03em; margin: 0 0 16px; line-height: 1.03; color: #fff; }
.gallery-head h1 .hl { color: var(--bs-teal); }
.gallery-head p { font-size: 18px; line-height: 1.55; color: rgba(255,255,255,0.8); margin: 0; }
.grid-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 16px; padding-bottom: 60px; position: relative; z-index: 2; }
.cardlink { display: block; background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.12); border-radius: var(--radius); padding: 24px; color: #fff; transition: transform .14s ease, background .15s ease, border-color .15s ease; min-height: 168px; }
.cardlink:hover { transform: translateY(-3px); background: rgba(255,255,255,0.09); border-color: rgba(127,240,207,0.5); }
.cardlink .num { font-size: 12px; font-weight: 700; color: var(--bs-teal); letter-spacing: 0.12em; }
.cardlink .mini { float: right; width: 54px; height: 54px; color: var(--bs-teal); opacity: 0.9; }
.cardlink .mini .stroke { stroke-width: 3; }
.cardlink .mini .ghost, .cardlink .mini .accent { opacity: 0.4; }
.cardlink h3 { font-size: 22px; line-height: 1.12; letter-spacing: -0.02em; margin: 12px 0 0; }
.cardlink .peek { font-size: 13.5px; color: rgba(255,255,255,0.62); margin: 10px 0 0; line-height: 1.45; }
body.mode-tech .cardlink h3 { font-size: 17px; }
body.mode-tech .cardlink .peek { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 12px; }
.gallery-note { position: relative; z-index: 2; text-align: center; color: rgba(255,255,255,0.45); font-size: 12.5px; padding: 0 24px 50px; }
.gallery-note kbd { background: rgba(255,255,255,0.1); border-radius: 5px; padding: 1px 7px; font-family: ui-monospace, monospace; }

/* ---------- responsive ---------- */
@media (max-width: 920px) {
  .hero .container { grid-template-columns: 1fr; gap: 30px; }
  .hero-art { order: -1; max-width: 300px; }
  .analogy .grid { grid-template-columns: 1fr; gap: 30px; }
  .analogy .art { order: -1; max-width: 320px; }
  .cmp-grid { grid-template-columns: 1fr; }
  .card-grid { grid-template-columns: repeat(2, 1fr); }
  .gloss-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .topbar { padding: 14px 18px; }
  section { padding: 56px 0; }
  .card-grid, .gloss-grid { grid-template-columns: 1fr; }
  .pager .container { flex-wrap: wrap; }
}