:root {
  color-scheme: dark;
  --bg: #151822;
  --panel: #1d2130;
  --edge: #353a4b;
  --text: #f5f2fb;
  --muted: #b8bacb;
  --lavender: #c8b8fc;
  --pink: #ffb4c2;
  --mint: #a8e4cd;
  font-family: system-ui, sans-serif;
  font-synthesis: none;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: radial-gradient(ellipse at 50% 0, #2b2641 0, var(--bg) 570px);
  color: var(--text);
}

main {
  width: min(54rem, 100% - 2.5rem);
  margin: 0 auto;
  padding: clamp(2rem, 6vw, 4.5rem) 0 3rem;
}

.intro {
  text-align: center;
  margin-bottom: clamp(1.75rem, 4vw, 2.75rem);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  border: 1px solid #504665;
  border-radius: 999px;
  background: #30283f;
  padding: .45rem .85rem;
  color: #e0d5ff;
  font-size: .7rem;
  font-weight: 750;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.brand svg { width: .85rem; height: .85rem; fill: var(--lavender); }

h1 {
  margin: .55rem 0 .45rem;
  font-size: clamp(2.5rem, 7.1vw, 4.7rem);
  line-height: 1.05;
  letter-spacing: -.064em;
  font-weight: 800;
}

h1 span { color: var(--lavender); }

.intro p, .rules > p {
  margin: 0;
  color: var(--muted);
  line-height: 1.55;
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, .78fr) minmax(0, 1.22fr);
  gap: 1.1rem;
  align-items: start;
}

.panel {
  min-width: 0;
  border: 1px solid var(--edge);
  border-radius: 1.25rem;
  background: var(--panel);
  padding: clamp(1rem, 3.2vw, 1.85rem);
  box-shadow: 0 14px 35px #10111b50;
}

h2 {
  margin: 0;
  font-size: 1.25rem;
  line-height: 1.3;
  letter-spacing: -.025em;
}

.rules > p { margin-top: .5rem; font-size: .9rem; }

.rule-list {
  list-style: none;
  padding: 0;
  margin: 1.2rem 0 0;
}

.rule {
  display: flex;
  align-items: center;
  gap: .7rem;
  min-height: 3.5rem;
  padding: .6rem 0;
  border-top: 1px solid var(--edge);
}

.rule svg {
  width: 1.45rem;
  flex: none;
  fill: none;
  stroke: #76758e;
  stroke-width: 1.35;
  stroke-linecap: round;
}

.rule svg .accent { stroke: var(--lavender); stroke-width: 1.7; }
.rule strong, .rule small { display: block; }
.rule strong { font-size: .88rem; font-weight: 700; }
.rule small { color: var(--muted); font-size: .76rem; margin-top: .12rem; }
.rule-result { margin-left: auto; text-align: right; font-size: .72rem; }
.rule[data-result="error"] .rule-result { color: var(--pink); }
.rule[data-result="success"] .rule-result { color: var(--mint); }

.puzzle-heading {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: .5rem;
  margin-bottom: 1rem;
}

.count {
  flex: none;
  color: var(--muted);
  background: #282d3e;
  border: 1px solid var(--edge);
  border-radius: 999px;
  padding: .33rem .65rem;
  font-size: .74rem;
  font-weight: 650;
  font-variant-numeric: tabular-nums;
}

.target-settings, .target-entry, .puzzle-tools, .total-control, #selection-info:not([hidden]) {
  display: flex;
  align-items: center;
  gap: .45rem;
}

.target-settings, .puzzle-tools, #selection-info:not([hidden]) { flex-wrap: wrap; }
.target-settings, .puzzle-tools { justify-content: space-between; }

.target, .target-entry label, .total-control label {
  margin: 0;
  color: var(--muted);
  font-size: .82rem;
}

.target strong {
  margin-left: .3rem;
  color: var(--lavender);
  font-size: 1.15rem;
  font-variant-numeric: tabular-nums;
}

#new-target, #total-mode, #share-link {
  min-height: 2.25rem;
  padding: .35rem .5rem;
  border: 1px solid #41465a;
  border-radius: .55rem;
  background: #282d3e;
  color: var(--text);
  font: inherit;
}

#new-target { width: 4.3rem; font-size: 1rem; }
#total-mode { font-size: .82rem; }
#new-target[aria-invalid="true"] { border-color: var(--pink); }
#new-target:focus-visible, #total-mode:focus-visible, #share-link:focus-visible {
  outline: 2px solid var(--lavender);
  outline-offset: 2px;
}

#target-help, #target-feedback, #share-feedback {
  margin: .4rem 0 0;
  color: var(--muted);
  font-size: .76rem;
  line-height: 1.4;
}

#target-feedback:empty { margin: 0; }
#share-feedback { margin: 0 0 .65rem; }
#share-feedback:empty { margin: 0; }
#share-link { width: 100%; margin-bottom: .65rem; font-size: .85rem; }
#target-form:has([aria-invalid="true"]) #target-feedback { color: var(--pink); }
.puzzle-tools { margin: .85rem 0 .55rem; }
#selection-info { margin-bottom: .55rem; color: var(--mint); font-size: .83rem; }

.board {
  --board-tracks: repeat(2, minmax(0, 1fr)) .3rem repeat(2, minmax(0, 1fr));
  --board-rows: repeat(2, auto) .3rem repeat(2, auto);
  display: grid;
  grid-template-columns: var(--board-tracks);
  grid-template-rows: var(--board-rows);
  gap: .38rem;
  padding: .6rem;
  border: 1px solid #34384c;
  border-radius: .9rem;
  background: #161a27;
}

.board[data-totals] {
  grid-template-columns: var(--board-tracks) 2.6rem;
  grid-template-rows: var(--board-rows) 1.65rem;
}

.line-total {
  align-self: center;
  padding: .25rem 0;
  border-radius: .4rem;
  background: #25293a;
  color: var(--muted);
  text-align: center;
  font-size: .76rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.line-total[data-result="met"] { background: #29443f; color: var(--mint); }
.line-total[data-result="wrong"] { background: #4c293b; color: var(--pink); }

.cell {
  position: relative;
  display: grid;
  min-width: 0;
  aspect-ratio: 1;
}

.cell:nth-child(4n + 1) { grid-column: 1; }
.cell:nth-child(4n + 2) { grid-column: 2; }
.cell:nth-child(4n + 3) { grid-column: 4; }
.cell:nth-child(4n + 4) { grid-column: 5; }
.cell:nth-child(-n + 4) { grid-row: 1; }
.cell:nth-child(n + 5):nth-child(-n + 8) { grid-row: 2; }
.cell:nth-child(n + 9):nth-child(-n + 12) { grid-row: 4; }
.cell:nth-child(n + 13) { grid-row: 5; }

.cell > :is(input, button) {
  position: absolute;
  inset: 0;
  width: 100%;
  min-height: 0;
  padding: 0;
  border: 1px solid #41465e;
  border-radius: .5rem;
  background: #262c3e;
  color: var(--text);
  text-align: center;
  font: 750 clamp(1rem, 5.5vw, 2rem) / 1 system-ui, sans-serif;
  font-variant-numeric: tabular-nums;
  caret-color: var(--lavender);
  appearance: none;
}

.cell.alternate > :is(input, button) { background: #2d2b44; border-color: #4c4563; }
.cell:has(input[readonly]) > :is(input, button) { background: #3a3053; border-color: #675782; color: var(--lavender); }
.cell[data-selected] > :is(input, button) { box-shadow: inset 0 0 0 2px var(--mint); }
.cell[data-hint] > :is(input, button) { background: #29443f; border-color: var(--mint); color: var(--mint); }

.cell input::placeholder { color: #8f91a9; opacity: 1; }
.cell input:hover { border-color: #8580a2; }
.cell input[aria-invalid="true"] { border-color: var(--pink); background: #4c293b; }
.cell input:focus { outline: 2px solid var(--lavender); outline-offset: 1px; z-index: 1; }
.board[data-solved] input { border-color: #65ad96; }

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: .6rem;
  margin-top: .9rem;
}

button, .download-project {
  min-height: 2.85rem;
  padding: .55rem .9rem;
  border: 1px solid transparent;
  border-radius: .65rem;
  cursor: pointer;
  font: 700 .9rem / 1.2 system-ui, sans-serif;
}

:is(button, .download-project):focus-visible { outline: 2px solid var(--lavender); outline-offset: 3px; }

.check {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: .45rem;
  background: var(--lavender);
  color: #251d38;
}

.check:hover { background: #ded2ff; }
.check svg { width: 1.05rem; fill: none; stroke: currentColor; stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }
.reset { background: #282d3e; border-color: #41465a; color: var(--text); }
.reset:hover { background: #353b50; }
:is(button, .download-project).tool { min-height: 2.25rem; padding: .38rem .58rem; font-size: .82rem; }
.download-project { display: inline-flex; align-items: center; margin-top: .85rem; text-decoration: none; }
.tool[aria-pressed="true"] { background: #29443f; border-color: #74bca7; color: var(--mint); }

#feedback { margin: .8rem 0 0; font-size: .85rem; line-height: 1.5; }
#feedback:empty { margin: 0; }
#feedback[data-result="error"] { color: var(--pink); }
#feedback[data-result="success"] { color: var(--mint); }

@media (max-width: 42rem) {
  main { width: min(29rem, 100% - 1.5rem); }
  .layout { grid-template-columns: minmax(0, 1fr); }
  .puzzle { grid-row: 1; }
}