/* ==========================================================
   GridRule — single-page interactive write-up
   Theme: violet / aubergine (same palette as CausaLab).
   ========================================================== */

:root {
  --bg:        #fbfaff;
  --bg-tint:   #f2eefc;
  --bg-dark:   #160f2b;
  --bg-dark-2: #1f1640;
  --ink:       #1c1730;
  --ink-soft:  #443a5c;
  --ink-quiet: #6c6385;
  --rule:      #e0d8f2;

  --accent:    #7c3aed;
  --accent-deep:#6024c0;
  --accent-soft:#a472f0;
  --accent-2:  #2563c9;
  --accent-3:  #149a73;
  --good:      #1b9d5b;
  --bad:       #c2356b;
  --code-bg:   #efeafb;

  --serif: "Source Serif 4", Charter, Georgia, "Iowan Old Style", serif;
  --sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono:  "JetBrains Mono", "SF Mono", Menlo, monospace;

  --container: 1100px;
  --narrow: 740px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--serif);
  font-size: 19px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  font-feature-settings: "kern" 1, "liga" 1, "onum" 1;
}

a { color: var(--accent-deep); text-decoration: none; border-bottom: 1px solid rgba(124,58,237,.3); }
a:hover { border-bottom-color: var(--accent); }

h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink);
}
h2 { font-size: 2rem; line-height: 1.18; margin: 0 0 1.2rem; }
h3 { font-size: 1.35rem; line-height: 1.25; margin: 0 0 .6rem; }
h4 { font-size: 1.1rem; margin: 0 0 .4rem; }

p { margin: 0 0 1.1em; }
em { font-style: italic; }
strong { font-weight: 700; }

code {
  font-family: var(--mono);
  font-size: .86em;
  background: var(--code-bg);
  color: var(--accent-deep);
  padding: 1px 6px;
  border-radius: 5px;
  white-space: nowrap;
}
.band-dark code { background: rgba(164,114,240,.18); color: #d9c8fa; }

.container        { max-width: var(--container); margin: 0 auto; padding: 0 28px; }
.container.narrow { max-width: var(--narrow); }

/* ===================== TOP NAV ===================== */
.topnav {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(150%) blur(14px);
  -webkit-backdrop-filter: saturate(150%) blur(14px);
  background: rgba(251, 250, 255, .82);
  border-bottom: 1px solid var(--rule);
}
.topnav-inner {
  max-width: var(--container); margin: 0 auto; padding: 12px 28px;
  display: flex; align-items: center; justify-content: space-between;
  font-family: var(--sans); font-size: 14px;
}
.topnav-brand {
  font-weight: 700; color: var(--ink);
  letter-spacing: -.01em; border-bottom: none;
  display: inline-flex; align-items: center; gap: 9px;
}
.topnav-brand .brand-dot {
  width: 11px; height: 11px; border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, var(--accent-soft), var(--accent-deep));
  box-shadow: 0 0 0 3px rgba(124,58,237,.16);
}
.topnav-brand:hover { color: var(--accent); }
.topnav-links {
  list-style: none; margin: 0; padding: 0;
  display: flex; gap: 18px; flex-wrap: wrap;
}
.topnav-links a { color: var(--ink-soft); border-bottom: none; font-size: 13px; }
.topnav-links a:hover { color: var(--accent); }

@media (max-width: 860px) {
  .topnav-links { display: none; }
}

/* ===================== HERO ===================== */
.hero {
  position: relative;
  padding: 110px 28px 88px;
  border-bottom: 1px solid var(--rule);
  overflow: hidden;
  background:
    radial-gradient(circle at 18% -10%, rgba(124,58,237,.16), transparent 46%),
    radial-gradient(circle at 90% 8%,  rgba(37,99,201,.10), transparent 42%),
    radial-gradient(circle at 65% 110%, rgba(20,154,115,.09), transparent 46%);
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background-image: radial-gradient(rgba(124,58,237,.12) 1.4px, transparent 1.6px);
  background-size: 30px 30px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,.45), transparent 72%);
          mask-image: linear-gradient(180deg, rgba(0,0,0,.45), transparent 72%);
  pointer-events: none;
}
.hero-inner { position: relative; max-width: 900px; margin: 0 auto; }
.hero-eyebrow {
  font-family: var(--sans);
  font-size: 13px; font-weight: 600;
  letter-spacing: .14em; text-transform: uppercase;
  color: var(--accent-deep);
  margin: 0 0 1rem;
}
.hero-title {
  font-size: clamp(2rem, 5vw, 3.2rem);
  line-height: 1.1;
  letter-spacing: -.03em;
  margin: 0 0 1.4rem;
  max-width: 820px;
}
.hero-title .accent { color: var(--accent); }
.hero-sub {
  font-size: 1.18rem;
  line-height: 1.62;
  color: var(--ink-soft);
  max-width: 680px;
  margin: 0 0 1.4rem;
}
.hero-joint {
  font-size: .97rem;
  color: var(--ink-quiet);
  margin: 0 0 2rem;
  max-width: 700px;
}

/* disclaimer */
.disclaimer {
  background: var(--bg-tint);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent-soft);
  border-radius: 10px;
  padding: 18px 22px;
  margin: 0 0 2rem;
  max-width: 680px;
}
.disclaimer-label {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}
.disclaimer p { font-size: .96rem; color: var(--ink-soft); margin: 0; }

.hero-links {
  display: flex; flex-wrap: wrap; gap: 10px;
  margin-top: 2rem;
}
.pill {
  display: inline-flex; align-items: center; gap: 7px;
  font-family: var(--sans); font-size: 14px; font-weight: 600;
  padding: 9px 18px; border-radius: 99px;
  background: var(--accent); color: #fff;
  border-bottom: none; transition: background .15s, transform .1s;
}
.pill:hover { background: var(--accent-deep); transform: translateY(-1px); }
.pill-ghost {
  background: transparent;
  color: var(--accent-deep);
  border: 1.5px solid rgba(124,58,237,.35);
}
.pill-ghost:hover { background: rgba(124,58,237,.06); border-color: var(--accent); }

.hero-scroll {
  position: absolute; bottom: 22px; left: 50%; transform: translateX(-50%);
  font-family: var(--sans); font-size: 12px; letter-spacing: .08em;
  color: var(--ink-quiet); text-transform: uppercase;
}

/* ===================== BANDS ===================== */
.band { padding: 72px 0; }
.band + .band { border-top: 1px solid var(--rule); }
.band-tint { background: var(--bg-tint); }
.band-dark {
  background: var(--bg-dark);
  color: #e2d9f8;
}
.band-dark h2, .band-dark h3, .band-dark h4 { color: #f0eaff; }
.band-dark p { color: #c8bde8; }
.band-dark .kicker { color: var(--accent-soft); }
.band-dark a { color: var(--accent-soft); border-bottom-color: rgba(164,114,240,.35); }

.kicker {
  font-family: var(--sans);
  font-size: 12px; font-weight: 700;
  letter-spacing: .15em; text-transform: uppercase;
  color: var(--accent-deep);
  margin: 0 0 .9rem;
}

/* ===================== TL;DR ===================== */
.tldr-card {
  background: var(--bg-dark);
  color: #e2d9f8;
  border-radius: 16px;
  padding: 36px 40px;
  box-shadow: 0 8px 48px rgba(96,36,192,.18);
}
.tldr-label {
  font-family: var(--sans); font-size: 12px; font-weight: 700;
  letter-spacing: .18em; text-transform: uppercase;
  color: var(--accent-soft);
  margin-bottom: 14px;
}
.tldr-list {
  list-style: none; margin: 0; padding: 0;
  display: flex; flex-direction: column; gap: 14px;
}
.tldr-list li {
  padding-left: 26px; position: relative;
  font-size: 1rem; line-height: 1.6; color: #d5c8f2;
}
.tldr-list li::before {
  content: "★";
  position: absolute; left: 0; top: 1px;
  color: var(--accent-soft); font-size: .85rem;
}
.tldr-list strong { color: #f0eaff; }
.tldr-list code { background: rgba(164,114,240,.18); color: #d9c8fa; }

/* ===================== RESULT CARDS ===================== */
.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 2rem;
}
.result-card {
  background: var(--bg);
  border: 1px solid var(--rule);
  border-radius: 14px;
  padding: 24px 28px;
  box-shadow: 0 2px 12px rgba(124,58,237,.07);
}
.result-card .rc-label {
  font-family: var(--sans); font-size: 11px; font-weight: 700;
  letter-spacing: .14em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 8px;
}
.result-card .rc-num {
  font-size: 2.6rem; font-weight: 700; color: var(--accent-deep);
  letter-spacing: -.04em; line-height: 1; margin-bottom: 4px;
}
.result-card .rc-desc {
  font-size: .94rem; color: var(--ink-soft); margin: 0;
}
.rc-good { border-left: 3px solid var(--good); }
.rc-accent { border-left: 3px solid var(--accent); }
.rc-blue  { border-left: 3px solid var(--accent-2); }

/* ===================== TABLE ===================== */
.tbl-wrap { overflow-x: auto; margin: 1.6rem 0; }
table {
  width: 100%;
  border-collapse: collapse;
  font-size: .95rem;
  font-family: var(--sans);
}
th {
  background: var(--bg-tint);
  color: var(--ink-soft);
  font-weight: 700; font-size: .85rem;
  letter-spacing: .06em; text-transform: uppercase;
  padding: 10px 14px;
  border-bottom: 2px solid var(--rule);
  text-align: left;
}
td {
  padding: 9px 14px;
  border-bottom: 1px solid var(--rule);
  color: var(--ink);
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: var(--bg-tint); }
td.hi { font-weight: 700; color: var(--accent-deep); }
td.good { color: var(--good); font-weight: 700; }
.band-dark table th { background: rgba(255,255,255,.05); color: #b0a0d8; border-color: rgba(255,255,255,.1); }
.band-dark table td { border-color: rgba(255,255,255,.08); color: #d5c8f2; }
.band-dark table tr:hover td { background: rgba(255,255,255,.04); }

/* ===================== ENV DIAGRAM ===================== */
.env-diagram {
  background: var(--bg-dark);
  border-radius: 14px;
  padding: 28px 32px;
  margin: 2rem 0;
  font-family: var(--mono);
  font-size: .87rem;
  color: #c8bde8;
  overflow-x: auto;
  line-height: 1.55;
  box-shadow: 0 4px 24px rgba(96,36,192,.18);
}
.env-diagram .room { color: #a472f0; font-weight: 600; }
.env-diagram .gate { color: #2563c9; }
.env-diagram .agent { color: #f0b429; font-weight: 700; }
.env-diagram .key   { color: #56cfad; }
.env-diagram .exit  { color: var(--good); font-weight: 700; }
.env-diagram .comment { color: #6c6385; font-size: .82rem; }

/* ===================== CALLOUT ===================== */
.callout {
  border-left: 3px solid var(--accent);
  background: var(--bg-tint);
  border-radius: 0 10px 10px 0;
  padding: 16px 22px;
  margin: 1.6rem 0;
}
.callout.good { border-color: var(--good); }
.callout.blue { border-color: var(--accent-2); }
.callout p { margin: 0; font-size: 1rem; color: var(--ink-soft); }
.callout strong { color: var(--ink); }

/* ===================== STEPS ===================== */
.steps {
  list-style: none; margin: 1.4rem 0; padding: 0;
  display: flex; flex-direction: column; gap: 16px;
}
.steps li {
  display: flex; gap: 16px; align-items: flex-start;
}
.step-num {
  flex-shrink: 0;
  width: 32px; height: 32px;
  background: var(--accent); color: #fff;
  border-radius: 50%;
  font-family: var(--sans); font-size: 13px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.step-body { flex: 1; }
.step-body strong { color: var(--ink); }
.step-body p { margin: 0; font-size: 1rem; color: var(--ink-soft); }

/* ===================== FINDING BOXES ===================== */
.finding {
  background: var(--bg-dark);
  color: #e2d9f8;
  border-radius: 12px;
  padding: 24px 28px;
  margin: 2rem 0;
}
.finding-label {
  font-family: var(--sans); font-size: 11px; font-weight: 700;
  letter-spacing: .14em; text-transform: uppercase;
  color: var(--accent-soft); margin-bottom: 10px;
}
.finding p { color: #d5c8f2; font-size: 1rem; margin-bottom: 0; }
.finding strong { color: #f0eaff; }

/* ===================== MECHANISM DIAGRAM ===================== */
.mech-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 1.8rem 0;
}
@media (max-width: 640px) { .mech-row { grid-template-columns: 1fr; } }
.mech-box {
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 20px 22px;
}
.mech-box h4 { color: var(--accent-deep); margin-bottom: 6px; }
.mech-box p { font-size: .95rem; color: var(--ink-soft); margin: 0; }
.mech-box.good { border-color: rgba(27,157,91,.4); background: rgba(27,157,91,.04); }
.mech-box.bad  { border-color: rgba(194,53,107,.4); background: rgba(194,53,107,.04); }

/* ===================== FOOTER ===================== */
.footer {
  background: var(--bg-dark);
  padding: 48px 28px;
  text-align: center;
  border-top: 1px solid rgba(255,255,255,.06);
}
.footer p {
  font-family: var(--sans); font-size: .92rem;
  color: #8476a8;
  margin: 0 auto; max-width: 600px;
}
.footer a { color: var(--accent-soft); border-bottom-color: rgba(164,114,240,.3); }

/* ===================== UTILITY ===================== */
.narrow { max-width: var(--narrow); margin-left: auto; margin-right: auto; }
.mt { margin-top: 2.4rem; }
.tag {
  font-family: var(--sans); font-size: 11px; font-weight: 700;
  letter-spacing: .1em; text-transform: uppercase;
  padding: 3px 10px; border-radius: 99px;
}
.tag-violet { background: rgba(124,58,237,.12); color: var(--accent); }
.tag-green  { background: rgba(27,157,91,.12);  color: var(--good); }
.tag-blue   { background: rgba(37,99,201,.12);  color: var(--accent-2); }
.tag-amber  { background: rgba(240,180,41,.15); color: #7a5300; }

/* ===================== FIGURES ===================== */
.fig {
  margin: 2.2rem 0;
  opacity: 0;
  transform: translateY(10px);
  transition: opacity .5s ease, transform .5s ease;
}
.fig.is-visible { opacity: 1; transform: none; }
.fig img {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--rule);
  box-shadow: 0 4px 24px rgba(96,36,192,.10);
  display: block;
}
.fig figcaption {
  font-family: var(--sans);
  font-size: .84rem;
  color: var(--ink-quiet);
  margin-top: 8px;
  text-align: center;
  line-height: 1.4;
}
.fig figcaption strong { color: var(--ink-soft); }
.band-dark .fig img { border-color: rgba(255,255,255,.12); }
.band-dark .fig figcaption { color: #9484c2; }

/* ===================== DEMO ===================== */
#demo-container {
  background: var(--bg-dark);
  border-radius: 16px;
  padding: 24px;
  box-shadow: 0 8px 48px rgba(96,36,192,.22);
  outline: none;
  margin-top: 2rem;
}
#demo-container:focus-within { box-shadow: 0 8px 48px rgba(124,58,237,.38); }

/* level picker */
.demo-lvl-row {
  display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 18px;
}
.demo-lvl-btn {
  font-family: var(--sans); font-size: 13px; font-weight: 600;
  padding: 6px 14px; border-radius: 99px; cursor: pointer;
  background: rgba(255,255,255,.08); color: #c8bde8;
  border: 1px solid rgba(255,255,255,.12);
  transition: background .15s, border-color .15s;
}
.demo-lvl-btn:hover { background: rgba(124,58,237,.25); border-color: var(--accent-soft); }
.dlb-active { background: var(--accent) !important; color: #fff !important; border-color: var(--accent) !important; }

/* desc */
#demo-desc {
  font-size: .95rem; color: #b0a0d8;
  margin-bottom: 14px; min-height: 1.4em;
  font-family: var(--sans);
}

/* grid */
#demo-grid-wrap {
  width: 100%; overflow-x: auto;
  margin-bottom: 16px;
}
#demo-grid-inner {
  outline: none;
  margin: 0 auto;
}

/* cells */
.dc {
  display: flex; align-items: center; justify-content: center;
  position: relative;
  font-family: var(--mono);
  font-weight: 700;
  border-radius: 3px;
  transition: background .12s, transform .1s, box-shadow .1s;
  user-select: none;
}
.dc-wall {
  background: #0e0a1e;
  border: 1px solid #1e1640;
}
.dc-floor {
  background: #1e1640;
  border: 1px solid #251e4a;
}
.dc-agent {
  background: radial-gradient(circle at 40% 35%, #a472f0, #6024c0);
  color: #fff;
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(164,114,240,.45), 0 4px 14px rgba(96,36,192,.6);
  z-index: 2;
}
.dc-agent.dc-anim {
  transform: scale(1.18);
  box-shadow: 0 0 0 5px rgba(164,114,240,.55), 0 6px 20px rgba(96,36,192,.7);
}
.dc-exit {
  background: radial-gradient(circle at 40% 30%, #1de0a0, #1b9d5b);
  color: #fff;
  border-radius: 50%;
  box-shadow: 0 0 0 2px rgba(27,157,91,.5), 0 4px 14px rgba(27,157,91,.4);
  font-size: .9em !important;
}
.dc-key {
  background: #2a1e4a;
  color: #f0b429;
  border: 1.5px solid #f0b42966;
  box-shadow: 0 0 10px rgba(240,180,41,.3);
}
.dc-door {
  background: #7c3aed;
  color: rgba(255,255,255,.8);
  border-radius: 2px 2px 2px 2px;
  box-shadow: inset 0 0 0 2px rgba(255,255,255,.15);
}
.dc-door-open {
  background: #2a2050;
  border: 1px dashed #4a3880;
}
.dc-gate {
  background: #1a4a8a;
  color: #82b4f4;
  border: 1.5px solid #2563c9aa;
}
.dc-sw {
  background: #1e2a40;
  color: #82b4f4;
  border: 1.5px solid #2563c966;
}
.dc-sw-on {
  background: radial-gradient(circle, #1a7a58, #1b4a3a);
  color: #1de0a0;
  border: 1.5px solid #1de0a066;
  box-shadow: 0 0 10px rgba(29,224,160,.3);
}
.dc-subgoal-cell {
  background: rgba(240,180,41,.18) !important;
  border: 2px solid #f0b429 !important;
  color: #f0b429 !important;
  box-shadow: 0 0 14px rgba(240,180,41,.4) !important;
  animation: subgoal-pulse 1s infinite alternate;
}
@keyframes subgoal-pulse {
  from { box-shadow: 0 0 8px rgba(240,180,41,.3); }
  to   { box-shadow: 0 0 20px rgba(240,180,41,.6); }
}
.dc-has-label::after {
  content: attr(data-label);
  position: absolute;
  top: 3px; left: 50%;
  transform: translateX(-50%);
  font-family: var(--sans);
  font-size: 9px; font-weight: 700;
  color: rgba(164,114,240,.7);
  letter-spacing: .06em;
  white-space: nowrap;
  pointer-events: none;
}

/* HUD */
#demo-hud {
  display: flex; flex-wrap: wrap; gap: 8px;
  margin-bottom: 12px;
}
.hb {
  font-family: var(--sans); font-size: 12px;
  padding: 4px 10px; border-radius: 99px;
  background: rgba(255,255,255,.07);
  color: #9080c0;
  border: 1px solid rgba(255,255,255,.1);
}
.hb strong { color: #d9c8fa; }
.hb-ok { background: rgba(27,157,91,.18); color: #56d49a; border-color: rgba(27,157,91,.3); }
.hb-win { background: rgba(240,180,41,.2); color: #f0c060; border-color: rgba(240,180,41,.4); font-weight: 700; }

/* Log */
#demo-log {
  min-height: 80px;
  background: rgba(0,0,0,.25);
  border-radius: 8px;
  padding: 10px 14px;
  margin-bottom: 16px;
  overflow: hidden;
}
.dl-entry {
  font-family: var(--mono); font-size: 12px;
  color: #b0a0d8; line-height: 1.55;
  border-bottom: 1px solid rgba(255,255,255,.04);
  padding: 2px 0;
}
.dl-hint {
  font-family: var(--sans); font-size: 12px;
  color: #7060a0; font-style: italic;
}

/* controls discovered */
.demo-bottom {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 16px;
  align-items: start;
}
@media (max-width: 600px) { .demo-bottom { grid-template-columns: 1fr; } }

/* d-pad */
.dpad {
  display: grid;
  grid-template-columns: repeat(3, 44px);
  grid-template-rows: repeat(3, 44px);
  gap: 4px;
}
.dpad-btn {
  width: 44px; height: 44px;
  border-radius: 8px;
  background: rgba(124,58,237,.25);
  border: 1px solid rgba(124,58,237,.4);
  color: #d9c8fa;
  font-size: 18px; font-weight: 700;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background .1s, transform .08s;
  user-select: none;
}
.dpad-btn:hover { background: rgba(124,58,237,.45); }
.dpad-btn:active { transform: scale(.92); }
.dpad-empty { background: transparent; border: none; cursor: default; }

/* ctrl table */
.demo-ctrl {
  background: rgba(0,0,0,.2);
  border-radius: 10px;
  padding: 12px 16px;
  min-width: 180px;
}
.demo-ctrl-title {
  font-family: var(--sans); font-size: 11px; font-weight: 700;
  letter-spacing: .12em; text-transform: uppercase;
  color: var(--accent-soft); margin-bottom: 8px;
}
.demo-ctrl table { width: 100%; font-family: var(--mono); font-size: 13px; }
.demo-ctrl td { padding: 4px 8px; color: #9080c0; }
.ck { color: #d9c8fa !important; font-size: 16px !important; }
.ca { color: #5a4880 !important; }
.cv { color: #5a4880 !important; }
.cf { color: #56d49a !important; }

/* action buttons */
.demo-actions {
  display: flex; gap: 8px; flex-wrap: wrap; margin-top: 16px;
}
.demo-btn {
  font-family: var(--sans); font-size: 13px; font-weight: 600;
  padding: 8px 16px; border-radius: 99px; cursor: pointer;
  border: 1px solid rgba(124,58,237,.4);
  background: rgba(124,58,237,.18); color: #d9c8fa;
  transition: background .15s;
}
.demo-btn:hover { background: rgba(124,58,237,.35); }
.demo-btn.btn-stop { background: rgba(194,53,107,.25); border-color: rgba(194,53,107,.4); color: #f0a0b8; }
.demo-btn-reveal { background: rgba(37,99,201,.18); border-color: rgba(37,99,201,.4); }

/* ===================== RESPONSIVE ===================== */
@media (max-width: 640px) {
  .hero { padding: 72px 20px 60px; }
  .band { padding: 52px 0; }
  .container { padding: 0 18px; }
  .tldr-card { padding: 24px 22px; }
  h2 { font-size: 1.55rem; }
}