:root {
    --ink: #10212b;
    --paper: #f4efe4;
    --gold: #d9a441;
    --mint: #7dcaa5;
    --rose: #e07a6a;
    --line: rgba(16, 33, 43, 0.18);
    --thick: rgba(16, 33, 43, 0.62);
}

html, body {
    margin: 0;
    min-height: 100%;
    background:
        radial-gradient(1200px 600px at 10% -10%, rgba(217, 164, 65, 0.18), transparent 55%),
        radial-gradient(900px 500px at 100% 0%, rgba(125, 202, 165, 0.12), transparent 50%),
        var(--ink);
    color: var(--paper);
    font-family: "Source Serif 4", "Iowan Old Style", Georgia, serif;
}

.wrap {
    max-width: 980px;
    margin: 0 auto;
    padding: 24px 16px 48px;
    outline: none;
}

.top {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    align-items: end;
    margin-bottom: 18px;
}

.eyebrow {
    margin: 0;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    font-size: 12px;
    color: var(--gold);
}

h1, h2 {
    margin: 4px 0 0;
    font-weight: 600;
}

.top-meta {
    display: flex;
    gap: 14px;
    font-variant-numeric: tabular-nums;
    opacity: 0.85;
}

.picker {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 10px;
    margin-top: 28px;
}

.kind, .chip, .go, .digit, .actions button {
    font: inherit;
    cursor: pointer;
    border: 1px solid rgba(244, 239, 228, 0.16);
    background: rgba(244, 239, 228, 0.06);
    color: inherit;
    border-radius: 14px;
}

.kind {
    text-align: left;
    padding: 12px;
    display: grid;
    gap: 4px;
}

.kind small {
    opacity: 0.72;
    font-size: 12px;
}

.kind .badge {
    color: var(--gold);
    font-size: 12px;
}

.kind.active, .chip.active, .actions .on {
    background: rgba(217, 164, 65, 0.2);
    border-color: var(--gold);
}

.kind:disabled {
    opacity: 0.55;
    cursor: wait;
}

.diff {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 18px;
}

.chip, .go, .actions button {
    padding: 8px 14px;
}

.go {
    margin-left: auto;
    background: var(--gold);
    color: var(--ink);
    border: none;
    font-weight: 600;
}

.go:disabled {
    opacity: 0.6;
    cursor: wait;
}

.error {
    color: var(--rose);
}

.stage {
    position: relative;
    margin: 0 auto 18px;
    width: min(100%, 560px);
}

.size-16 {
    width: min(100%, 720px);
}

.board {
    --n: 9;
    position: relative;
    display: grid;
    grid-template-columns: repeat(var(--n), 1fr);
    aspect-ratio: 1;
    background: var(--paper);
    color: var(--ink);
    overflow: hidden;
    box-shadow: 0 24px 60px rgba(0, 0, 0, 0.28);
}

.cell {
    position: relative;
    border: 1px solid var(--line);
    background: transparent;
    color: inherit;
    font: inherit;
    padding: 0;
    min-width: 0;
    min-height: 0;
    display: grid;
    place-items: center;
    cursor: pointer;
}

.cell .val {
    font-size: clamp(14px, 4.2vw, 28px);
    font-weight: 650;
}

.size-16 .cell .val {
    font-size: clamp(11px, 2.4vw, 18px);
}

.cell.given .val {
    color: #1b2a33;
}

.cell:not(.given) .val {
    color: #1d5c7a;
}

.cell.peer {
    background: rgba(16, 33, 43, 0.06);
}

.cell.same .val {
    color: #8a4b12;
}

.cell.selected {
    background: rgba(217, 164, 65, 0.34);
    z-index: 1;
}

.cell.conflict, .cell.wrong {
    background: rgba(224, 122, 106, 0.28);
}

.cell.edge-n { border-top: 2px solid var(--thick); }
.cell.edge-s { border-bottom: 2px solid var(--thick); }
.cell.edge-w { border-left: 2px solid var(--thick); }
.cell.edge-e { border-right: 2px solid var(--thick); }
.cell.box-w { border-left: 2px solid var(--thick); }
.cell.box-n { border-top: 2px solid var(--thick); }

.r0 { background-color: rgba(217, 164, 65, 0.08); }
.r1 { background-color: rgba(125, 202, 165, 0.10); }
.r2 { background-color: rgba(110, 158, 201, 0.10); }
.r3 { background-color: rgba(196, 132, 186, 0.10); }
.r4 { background-color: rgba(232, 176, 107, 0.12); }
.r5 { background-color: rgba(143, 188, 143, 0.10); }
.r6 { background-color: rgba(180, 150, 120, 0.12); }
.r7 { background-color: rgba(120, 170, 190, 0.10); }
.r8 { background-color: rgba(210, 140, 140, 0.10); }

.stage.diagonal .cell.diag {
    background-color: rgba(217, 164, 65, 0.22);
}

.stage.diagonal .cell.selected {
    background-color: rgba(217, 164, 65, 0.46);
}

.stage.star {
    width: min(100%, 620px);
}

.astra-board {
    width: 100%;
    display: block;
    overflow: visible;
}

.acell {
    stroke: rgba(16, 33, 43, 0.55);
    stroke-width: 0.012;
    cursor: pointer;
}

.acell.chk0 { fill: #f7f1e6; }
.acell.chk1 { fill: #efcfc4; }
.acell.peer { fill: #d9e4d6; }
.acell.selected { fill: #e8c36a; }
.acell.conflict, .acell.wrong { fill: #e7a599; }

.aval, .anotes {
    pointer-events: none;
    text-anchor: middle;
    dominant-baseline: middle;
    font-weight: 650;
    font-family: "Source Serif 4", "Iowan Old Style", Georgia, serif;
}

.aval {
    fill: #1d5c7a;
}

.aval.given { fill: #1b2a33; }
.aval.same { fill: #8a4b12; }

.anotes {
    fill: #5d6b73;
}

.notes {
    display: grid;
    grid-template-columns: repeat(var(--notes, 3), 1fr);
    width: 92%;
    height: 92%;
    font-size: 9px;
    line-height: 1;
    color: #5d6b73;
}

.pad {
    display: grid;
    gap: 10px;
}

.digits {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(42px, 1fr));
    gap: 8px;
}

.digit {
    min-height: 48px;
    font-size: 20px;
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.overlay {
    position: fixed;
    inset: 0;
    background: rgba(10, 16, 20, 0.55);
    display: grid;
    place-items: center;
    z-index: 5;
}

.overlay .card {
    background: var(--paper);
    color: var(--ink);
    padding: 28px 32px;
    border-radius: 18px;
    text-align: center;
    min-width: min(90vw, 320px);
}

.overlay.win .go {
    margin: 16px 0 0;
}

@media (max-width: 720px) {
    .go { margin-left: 0; }
    .top { flex-direction: column; align-items: start; }
}