:root {
  --bg: #f7f7f4;
  --fg: #11110f;
  --line: rgba(17, 17, 15, .17);
  --line-strong: rgba(17, 17, 15, .72);
  --muted: #7d7d76;
  --panel: rgba(250, 250, 247, .93);
}

* { box-sizing: border-box; }
html, body, #app { width: 100%; height: 100%; margin: 0; }
body {
  overflow: hidden;
  background: var(--bg);
  color: var(--fg);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: geometricPrecision;
}
button { font: inherit; color: inherit; }
.screen { display: none; width: 100%; height: 100%; }
.screen.active { display: block; }

/* Home remains deliberately quiet: only the mathematical choices. */
#home { position: relative; overflow-y: auto; }
.selector {
  width: min(1180px, calc(100% - 48px));
  min-height: 100%;
  margin: 0 auto;
  padding: 28px 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  align-content: center;
  gap: 12px;
}
.choice {
  appearance: none;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, .08);
  min-height: 176px;
  padding: 32px 26px 28px;
  cursor: pointer;
  transition: background 150ms ease, border-color 150ms ease, transform 150ms ease;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: flex-start;
  text-align: left;
}
.choice.loading { cursor: progress; opacity: .62; }
.choice.load-error { border-color: rgba(181, 55, 55, .72); }
.choice.choice-special {
  background: rgba(227, 232, 255, .72);
  border-color: rgba(75, 88, 168, .58);
}
.choice.choice-special .choice-prime,
.choice.choice-special .choice-count {
  color: rgba(48, 56, 122, .88);
}
.choice.choice-special .choice-count { display: inline; }
.choice.choice-special:hover, .choice.choice-special:focus-visible {
  background: rgba(220, 227, 255, .94);
  border-color: rgba(58, 70, 151, .78);
}
.choice:hover, .choice:focus-visible {
  background: rgba(255,255,255,.72);
  border-color: rgba(17,17,15,.62);
  outline: none;
  transform: translateY(-2px);
}
.choice-eq {
  font-size: clamp(21px, 2.1vw, 33px);
  line-height: 1;
  letter-spacing: -0.035em;
  font-weight: 520;
}
.choice-meta {
  margin-top: 50px;
  width: 100%;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
}
.choice-stat {
  width: 100%;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
}
.choice-meta-stats {
  flex-direction: column;
  align-items: stretch;
  gap: 6px;
}
.choice-meta-stats .choice-prime { margin-top: 0; }
.choice-prime {
  font-size: 12px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  letter-spacing: .015em;
}
.choice-count {
  font-size: 14px;
  line-height: 1;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  letter-spacing: .01em;
  white-space: nowrap;
}

#viewer { position: relative; background: var(--bg); }
.stage {
  position: absolute;
  inset: 0;
  overflow: hidden;
  cursor: grab;
  touch-action: none;
  user-select: none;
}
.stage.dragging { cursor: grabbing; }
.stage > canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
#overlay { pointer-events: none; }

.icon-btn {
  width: 34px;
  height: 34px;
  border: 1px solid var(--line);
  background: rgba(247,247,244,.86);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: grid;
  place-items: center;
  cursor: pointer;
  font-size: 18px;
  line-height: 1;
  padding: 0 0 2px;
  transition: background 120ms ease, border-color 120ms ease;
}
.icon-btn:hover, .icon-btn:focus-visible {
  border-color: var(--line-strong);
  outline: none;
  background: rgba(255,255,255,.96);
}
.back {
  position: static;
}
.zoom-controls {
  position: absolute;
  z-index: 6;
  right: 14px;
  bottom: 14px;
  display: flex;
  gap: 5px;
}

.detail {
  position: absolute;
  z-index: 10;
  top: calc(var(--top-chrome-bottom, 48px) + 8px);
  right: 14px;
  width: max-content;
  max-width: min(960px, calc(100vw - 82px));
  padding: 17px 42px 16px 17px;
  background: var(--panel);
  border: 1px solid rgba(17,17,15,.36);
  box-shadow: 0 9px 30px rgba(17,17,15,.055);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  opacity: 0;
  transform: translateY(-5px);
  pointer-events: none;
  transition: opacity 120ms ease, transform 120ms ease;
}
.detail.show {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.detail-close {
  position: absolute;
  top: 7px;
  right: 8px;
  width: 27px;
  height: 27px;
  border: 0;
  background: transparent;
  cursor: pointer;
  display: grid;
  place-items: center;
  padding: 0 0 2px;
  font-size: 20px;
  line-height: 1;
  color: rgba(17,17,15,.55);
}
.detail-close:hover, .detail-close:focus-visible { color: var(--fg); outline: none; }
.detail-expression,
.detail-factor {
  white-space: normal;
  overflow: visible;
  overflow-wrap: anywhere;
  font-variant-numeric: tabular-nums lining-nums;
  letter-spacing: -.018em;
}
.detail-expression {
  font-size: 15px;
  line-height: 1.35;
  font-weight: 530;
}
.detail-factor {
  margin-top: 7px;
  font-size: 13px;
  line-height: 1.42;
  color: rgba(17,17,15,.68);
}
.detail-factor sup {
  font-size: .68em;
  line-height: 0;
  vertical-align: .5em;
}

@media (max-width: 760px) {
  .selector {
    grid-template-columns: 1fr;
    align-content: center;
    gap: 8px;
    width: min(520px, calc(100% - 28px));
  }
  .choice { min-height: 126px; padding: 22px 20px 18px; }
  .choice-prime { margin-top: 26px; }
  .choice-meta-stats { margin-top: 26px; }
  .zoom-controls { right: 10px; bottom: 10px; }
  .solution-count { top: 10px; right: 10px; font-size: 15px; }
  .detail { right: 10px; width: max-content; max-width: calc(100vw - 66px); }
}

.solution-count {
  position: absolute;
  z-index: 8;
  top: 14px;
  right: 14px;
  min-height: 34px;
  padding: 7px 10px 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  background: rgba(247,247,244,.86);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  font-size: 16px;
  line-height: 1;
  font-variant-numeric: tabular-nums lining-nums;
  white-space: nowrap;
}

.tools {
  position: absolute;
  z-index: 9;
  top: 14px;
  left: 14px;
  width: min(570px, calc(100vw - 28px));
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 7px;
  pointer-events: none;
  max-height: calc(100vh - 70px);
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  padding-bottom: 3px;
}
.tool-buttons {
  --top-button-size: clamp(28px, calc(16.6667vw - 8.8333px), 34px);
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  width: max-content;
  max-width: 100%;
  pointer-events: auto;
}
.tool-buttons .icon-btn {
  width: var(--top-button-size);
  height: var(--top-button-size);
  flex: 0 0 var(--top-button-size);
}
.tool-buttons .icon-btn.active { border-color: var(--line-strong); background: rgba(255,255,255,.98); }
.tool-panel {
  display: none;
  pointer-events: auto;
  background: var(--panel);
  border: 1px solid rgba(17,17,15,.30);
  box-shadow: 0 8px 25px rgba(17,17,15,.045);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}
.tool-panel.show { display: block; }
.prime-panel { padding: 9px; max-width: 100%; }
.prime-actions { display: flex; gap: 5px; margin-bottom: 8px; }
.mini-btn {
  width: 31px;
  height: 27px;
  border: 1px solid var(--line);
  background: transparent;
  padding: 0;
  display: grid;
  place-items: center;
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
}
.mini-btn:hover, .mini-btn:focus-visible { border-color: var(--line-strong); background: rgba(255,255,255,.82); outline: none; }
.prime-options { display: flex; flex-wrap: wrap; gap: 5px 7px; }
.prime-option {
  min-width: 48px;
  height: 29px;
  padding: 0 7px 0 6px;
  border: 1px solid var(--line);
  display: inline-flex;
  align-items: center;
  justify-content: flex-start;
  gap: 6px;
  cursor: pointer;
  background: rgba(255,255,255,.24);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
}
.prime-option input { margin: 0; width: 13px; height: 13px; accent-color: var(--fg); }
.power-panel { width: min(570px, calc(100vw - 28px)); max-width: 100%; padding: 9px; }
.power-options {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(83px, 1fr));
  gap: 5px 7px;
  max-height: min(345px, calc(100vh - 155px));
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
}
.power-option { min-width: 0; white-space: nowrap; }

.search-panel { width: min(570px, calc(100vw - 28px)); padding: 9px; }
.search-input-row { display: flex; align-items: center; gap: 7px; }
.search-input {
  display: block;
  width: 100%;
  min-width: 0;
  height: 34px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,.55);
  color: var(--fg);
  outline: none;
  padding: 5px 9px;
  font: inherit;
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}
.search-input:focus { border-color: var(--line-strong); }
.search-plus {
  flex: 0 0 34px;
  width: 34px;
  height: 34px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,.42);
  color: var(--muted);
  padding: 0;
  font: inherit;
  font-size: 20px;
  line-height: 30px;
  cursor: pointer;
  transition: background .14s ease, border-color .14s ease, color .14s ease, transform .14s ease;
}
.search-plus:hover, .search-plus:focus-visible { border-color: var(--line-strong); color: var(--fg); outline: none; }
.search-plus.active { background: var(--fg); border-color: var(--fg); color: var(--bg); }
.search-plus.loading { animation: search-plus-pulse .8s ease-in-out infinite alternate; }
@keyframes search-plus-pulse { from { opacity: .48; } to { opacity: 1; } }
.search-results {
  max-height: 288px;
  overflow-y: auto;
  overscroll-behavior: contain;
  margin-top: 7px;
}
.search-results:empty { display: none; }
.search-result {
  display: block;
  width: 100%;
  min-height: 34px;
  border: 0;
  border-top: 1px solid rgba(17,17,15,.10);
  background: transparent;
  color: var(--fg);
  cursor: pointer;
  text-align: left;
  padding: 7px 5px;
  font-size: 12px;
  line-height: 1.35;
  font-variant-numeric: tabular-nums;
  overflow-wrap: anywhere;
}
.search-result:first-child { border-top: 0; }
.search-result-enhanced { font-weight: 500; }
.search-result:hover, .search-result:focus-visible { background: rgba(255,255,255,.66); outline: none; }

@media (max-width: 760px) {
  .tools { top: 10px; left: 10px; width: calc(100vw - 20px); }
  .search-panel { width: calc(100vw - 20px); }
  .search-results { max-height: 272px; }
}

@media (max-width: 360px) {
  .solution-count { top: calc(var(--tool-buttons-bottom, 44px) + 8px); }
}

.range-panel {
  width: min(270px, calc(100vw - 28px));
  padding: 9px;
  align-items: center;
  gap: 7px;
}
.range-panel.show { display: flex; }
.range-sign {
  flex: 0 0 auto;
  font-size: 18px;
  line-height: 1;
}
.range-input {
  min-width: 0;
  width: 100%;
  height: 34px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,.55);
  color: var(--fg);
  outline: none;
  padding: 5px 9px;
  font: inherit;
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}
.range-input:focus { border-color: var(--line-strong); }
@media (max-width: 760px) {
  .range-panel { width: min(270px, calc(100vw - 20px)); }
}
.icon-btn.loading { opacity: .46; }