:root {
    font-family:
        Inter,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        "PingFang SC",
        sans-serif;
    color: #172637;
    background: #edf1f5;
    font-synthesis: none;
    font-size: 16px;
    --muted: #647386;
    --line: #dbe2e9;
    --accent: #146557;
}
* {
    box-sizing: border-box;
}
body {
    margin: 0;
}
button,
select,
input,
.button {
    font: inherit;
    font-size: 0.875rem;
}
button,
.button,
select {
    cursor: pointer;
}
button,
.button {
    border: 1px solid var(--line);
    background: #fff;
    border-radius: 8px;
    padding: 10px 13px;
    color: inherit;
    transition:
        background 0.15s,
        box-shadow 0.15s;
}
button:hover,
.button:hover {
    background: #edf5f3;
    border-color: #9eb8b1;
}
button:focus-visible,
select:focus-visible,
input:focus-visible,
.button:focus-within {
    outline: 3px solid #35a897;
    outline-offset: 3px;
}
button:disabled {
    opacity: 0.45;
    cursor: default;
}
header {
    max-width: 1440px;
    margin: auto;
    padding: 29px 42px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.brand {
    display: flex;
    gap: 13px;
    align-items: center;
    color: inherit;
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 750;
    letter-spacing: 1.5px;
}
.brand b {
    font-weight: 400;
    color: var(--muted);
}
.brand small {
    display: block;
    font-size: 0.75rem;
    letter-spacing: 1.7px;
    font-weight: 450;
    margin-top: 5px;
    color: var(--muted);
}
.mark {
    display: grid;
    place-items: center;
    background: #173d39;
    color: #acdec6;
    border-radius: 11px;
    width: 45px;
    height: 45px;
    font-size: 2rem;
}
.badge {
    border: 1px solid #d0ded9;
    padding: 8px 12px;
    border-radius: 30px;
    color: #406b5f;
    font-size: 0.75rem;
    background: #e8f1ec;
}
main {
    max-width: 1440px;
    margin: auto;
    padding: 13px 42px 28px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 350px;
    gap: 28px;
}
.workspace {
    min-width: 0;
    width: 100%;
}
aside {
    min-width: 0;
}
.board-heading {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 0 0 20px;
    gap: 12px;
}
.eyebrow {
    font-size: 0.7rem;
    font-weight: 750;
    letter-spacing: 2.7px;
    color: var(--accent);
}
h1 {
    font-size: 1.65rem;
    letter-spacing: -0.5px;
    margin: 8px 0 0;
    font-weight: 650;
}
.board-actions {
    display: flex;
    gap: 7px;
}
.board-shell {
    background: #263b48;
    padding: 18px;
    border-radius: 15px;
    box-shadow: 0 15px 35px #142c3d12;
}
#board {
    width: 100%;
    max-width: 720px;
    min-width: 0;
    margin: auto;
    touch-action: manipulation;
}
#board svg {
    display: block;
    width: 100%;
    height: auto;
    border-radius: 3px;
    overflow: visible;
}
.board-foot {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    margin-top: 15px;
    font-size: 0.875rem;
    color: var(--muted);
    min-height: 20px;
}
.file-actions {
    display: flex;
    gap: 8px;
    align-items: center;
    margin-top: 19px;
}
.file-actions span {
    font-size: 0.75rem;
    color: var(--muted);
    margin-left: auto;
}
aside {
    padding-top: 0;
}
.panel {
    background: #fff;
    border: 1px solid #e0e5ea;
    border-radius: 13px;
    padding: 22px;
    margin-bottom: 18px;
}
.panel-title {
    display: flex;
    align-items: center;
    gap: 9px;
    margin-bottom: 20px;
}
.panel-title h2 {
    font-size: 1rem;
    margin: 0;
    font-weight: 650;
}
.panel-title select {
    margin-left: auto;
    max-width: 120px;
    font-size: 0.75rem;
    padding: 7px;
}
.number {
    font-size: 0.75rem;
    letter-spacing: 1px;
    color: var(--muted);
    border: 1px solid var(--line);
    border-radius: 5px;
    padding: 4px 5px;
}
select,
input {
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 7px;
    background: #fff;
    color: inherit;
    min-width: 0;
}
.tools {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 7px;
}
.tool {
    padding: 10px 4px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    align-items: center;
    font-size: 0.75rem;
}
.tool.wide {
    grid-column: span 2;
    flex-direction: row;
    padding: 10px;
    justify-content: center;
    font-size: 0.875rem;
}
.tool.active {
    border-color: var(--accent);
    background: #eaf4ef;
    box-shadow: 0 0 0 1px var(--accent);
}
.swatch {
    width: 19px;
    height: 19px;
    border-radius: 6px;
    background: var(--color);
    border: 1px solid #0002;
}
.target-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 18px;
    font-size: 0.875rem;
}
.target-row select {
    width: 58%;
}
.fine,
.note {
    font-size: 0.75rem;
    line-height: 1.8;
    color: var(--muted);
    margin: 16px 0 0;
}
.note {
    padding: 0 10px;
}
.settings {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 13px;
}
.settings label {
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 0.875rem;
    position: relative;
}
.settings label span {
    position: absolute;
    right: 0;
    color: var(--muted);
    font-size: 0.75rem;
}
.primary {
    background: var(--accent);
    color: #fff;
    width: 100%;
    font-weight: 600;
    margin-top: 18px;
    border: 0;
    padding: 14px 16px;
    display: flex;
    justify-content: space-between;
}
.primary:hover {
    background: #104e44;
}
.primary.running {
    background: #80522d;
}
.result {
    border-top: 1px solid var(--line);
    margin-top: 20px;
    padding-top: 20px;
    color: var(--muted);
    font-size: 0.875rem;
    line-height: 1.8;
}
.result strong {
    font-size: 2.8rem;
    line-height: 1.1;
    letter-spacing: -2px;
    color: #173d39;
    margin-right: 8px;
}
.result .optimal {
    color: #146557;
    font-weight: 650;
}
.result small {
    display: block;
    color: var(--muted);
    font-size: 0.75rem;
}
.status-dot {
    display: inline-block;
    width: 7px;
    height: 7px;
    background: #8b9aab;
    border-radius: 50%;
    margin-right: 7px;
}

.replay-controls {
    display: flex;
    gap: 8px;
    align-items: center;
    border-top: 1px solid var(--line);
    margin-top: 18px;
    padding-top: 17px;
}
.replay-controls span {
    font-size: 0.875rem;
    flex: 1;
    text-align: center;
}
.replay-controls button {
    padding: 7px 9px;
    font-size: 0.75rem;
}
#moves {
    padding: 0;
    list-style: none;
    max-height: 230px;
    overflow: auto;
    margin: 14px 0 0;
}
#moves button {
    width: 100%;
    display: flex;
    gap: 10px;
    align-items: center;
    border: none;
    text-align: left;
    margin: 3px 0;
    font-size: 0.875rem;
}
#moves button.selected {
    background: #eaf4ef;
}
#moves .swatch {
    width: 12px;
    height: 12px;
    border-radius: 4px;
}
#moves small {
    margin-left: auto;
    color: var(--muted);
}
footer {
    max-width: 1440px;
    margin: auto;
    padding: 20px 42px 30px;
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--muted);
    border-top: 1px solid var(--line);
}
footer a {
    color: inherit;
}
#toast {
    position: fixed;
    bottom: 25px;
    left: 50%;
    transform: translateX(-50%);
    max-width: 90vw;
    padding: 14px 20px;
    border-radius: 9px;
    background: #243746;
    color: #fff;
    box-shadow: 0 5px 30px #0003;
    font-size: 0.875rem;
    z-index: 5;
}
svg [role="gridcell"]:focus {
    outline: none;
    stroke: #10a68c;
    stroke-width: 3;
}
svg .wall-hit {
    cursor: crosshair;
}
.board-actions button {
    white-space: nowrap;
}
@media (min-width: 1250px) {
    main {
        grid-template-columns: minmax(0, 1fr) 370px;
    }
    .board-shell {
        padding: 23px;
    }
    aside {
        padding-top: 6px;
    }
}
@media (max-width: 950px) {
    header {
        padding: 22px;
    }
    main {
        padding: 10px 22px 24px;
        grid-template-columns: minmax(0, 1fr);
        gap: 18px;
    }
    .panel {
        padding: 17px;
    }
    .board-heading {
        align-items: start;
        flex-direction: column;
    }
    h1 {
        font-size: 1.4rem;
    }
    .board-shell {
        padding: 12px;
    }
    .board-foot {
        flex-direction: column;
        gap: 5px;
    }
    footer {
        padding: 18px 22px;
    }
}
@media (max-width: 730px) {
    header {
        padding: 20px 16px;
    }
    .badge {
        display: none;
    }
    main {
        padding: 5px 12px 24px;
    }
    .board-heading {
        flex-direction: row;
        align-items: center;
    }
    .board-actions {
        flex-direction: column;
    }
    .board-actions button {
        font-size: 0.75rem;
        padding: 7px 9px;
    }
    h1 {
        font-size: 1.35rem;
    }
    .board-shell {
        padding: 10px;
    }
    .board-foot {
        font-size: 0.75rem;
        min-height: 34px;
    }
    .file-actions {
        margin-top: 10px;
    }
    .panel {
        padding: 20px;
    }
    .tools {
        grid-template-columns: repeat(5, minmax(0, 1fr));
    }
    .tool {
        padding: 10px 4px;
    }
    footer {
        padding: 16px;
        gap: 15px;
        line-height: 1.7;
        flex-direction: column;
    }
    .note {
        margin-bottom: 0;
    }
}
@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
    }
}
dialog {
    border: 1px solid var(--line);
    border-radius: 16px;
    padding: 26px;
    width: min(860px, 94vw);
    max-height: 90vh;
    color: #172637;
    background: #f5f8fa;
    box-shadow: 0 25px 80px #0004;
}
dialog::backdrop {
    background: #12263599;
    backdrop-filter: blur(3px);
}
.dialog-heading,
.assembly-toolbar,
.dialog-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}
.dialog-heading h2 {
    font-size: 1.25rem;
    margin: 8px 0;
}
.assembly-help {
    font-size: 0.875rem;
    color: var(--muted);
    line-height: 1.7;
}
.assembly-slots {
    width: 310px;
    max-width: 100%;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 6px;
    margin: 18px auto;
}
.assembly-slot {
    padding: 8px;
    border: 2px solid var(--line);
    border-radius: 8px;
}
.assembly-slot span {
    display: block;
    font-size: 0.75rem;
    margin-bottom: 7px;
}
.assembly-slot svg,
.tile-option svg {
    width: 100%;
    display: block;
}
.assembly-slot.selected,
.tile-option.selected {
    border-color: var(--accent);
    box-shadow: 0 0 0 1px var(--accent);
    background: #e8f3ef;
}
.assembly-toolbar {
    font-size: 0.875rem;
    padding: 14px 0;
    border-top: 1px solid var(--line);
}
.assembly-toolbar span {
    margin-right: auto;
}
#tile-catalog {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
}
.tile-group h3 {
    font-size: 0.875rem;
    margin: 8px 0;
}
.tile-options {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 8px;
}
.tile-option {
    padding: 7px;
    border: 2px solid var(--line);
}
.tile-option span {
    display: block;
    font-size: 0.75rem;
    margin-top: 7px;
}
.dialog-footer {
    position: sticky;
    bottom: -26px;
    background: #f5f8fa;
    padding: 15px 0;
}
.dialog-footer .primary {
    width: auto;
    margin: 0;
}
.goal-picker {
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 0.875rem;
    margin-top: 18px;
}
.goal-picker[hidden] {
    display: none;
}
.rule-toggle {
    display: flex;
    align-items: center;
    gap: 7px;
    font-size: 0.75rem;
    line-height: 1.6;
    margin-top: 16px;
}
.rule-toggle input {
    accent-color: var(--accent);
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}
.board-actions {
    flex-wrap: wrap;
    justify-content: flex-end;
}
@media (max-width: 730px) {
    dialog {
        padding: 18px;
    }
    .assembly-toolbar {
        flex-wrap: wrap;
    }
    .assembly-toolbar span {
        width: 100%;
    }
    .dialog-footer {
        bottom: -18px;
    }
    #tile-catalog {
        gap: 10px;
    }
    .tile-options {
        gap: 4px;
    }
    .tile-option {
        padding: 3px;
    }
    .board-actions {
        flex-direction: column;
    }
    .board-heading {
        align-items: center;
    }
}

header .site-title {
    margin: 0;
    font-size: 1.5rem;
    font-weight: 650;
    letter-spacing: 0;
}
.setup-group {
    border-top: 1px solid var(--line);
    padding-top: 15px;
    margin-top: 15px;
}
.setup-group h3 {
    font-size: 0.875rem;
    font-weight: 650;
    margin: 0 0 11px;
}
.setup-group:first-of-type {
    border-top: 0;
    padding-top: 0;
    margin-top: 0;
}
.control-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 7px;
}
.control-grid button {
    padding: 9px 7px;
}
.control-grid button.active {
    border-color: var(--accent);
    background: #eaf4ef;
    box-shadow: 0 0 0 1px var(--accent);
}
.group-heading {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    margin-bottom: 11px;
}
.group-heading h3 {
    margin: 0;
}
.group-heading select {
    font-size: 0.75rem;
    padding: 7px;
}
.full-control {
    width: 100%;
    margin-top: 9px;
    padding: 8px;
}
.setup-group .goal-picker {
    margin-top: 12px;
}
.setup-group .target-row {
    margin-top: 12px;
}
.workspace {
    align-self: start;
    position: sticky;
    top: 18px;
}
footer {
    justify-content: flex-end;
}
.replay-controls {
    flex-wrap: wrap;
}
@media (max-width: 950px), (max-height: 760px) {
    .workspace {
        position: static;
    }
}
@media (max-width: 480px) {
    .board-shell {
        padding: 6px;
        border-radius: 10px;
    }
    .panel {
        padding: 16px;
    }
    header .site-title {
        font-size: clamp(1.1rem, 5vw, 1.5rem);
    }
    #tile-catalog {
        grid-template-columns: minmax(0, 1fr);
    }
    .dialog-heading {
        align-items: flex-start;
    }
    .dialog-heading h2 {
        font-size: 1.05rem;
    }
}
.file-actions {
    flex-wrap: wrap;
}
.settings label,
.tool,
.assembly-slot,
.tile-option {
    min-width: 0;
}
.settings input,
.settings select {
    width: 100%;
}

/* Keep the board beside settings when both columns have usable space. */
@media (min-width: 860px) and (max-width: 950px),
    (min-width: 740px) and (max-width: 950px) and (min-aspect-ratio: 6/5) {
    main {
        grid-template-columns: minmax(0, 1fr) 310px;
    }
}
.goal-color-row {
    display: grid;
    grid-template-columns: 28px minmax(0, 1fr);
    align-items: center;
    gap: 6px;
    margin-top: 7px;
    font-size: 0.75rem;
}
.goal-buttons {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 4px;
}
.goal-buttons button {
    min-width: 0;
    padding: 7px 2px;
    color: var(--goal-color);
}
.goal-buttons b,
.goal-buttons small {
    display: block;
}
.goal-buttons b {
    font-size: 1.2rem;
}
.goal-buttons small {
    font-size: 0.65rem;
    color: var(--muted);
}
.goal-buttons button.active {
    border-color: var(--goal-color);
    box-shadow: inset 0 0 0 1px var(--goal-color);
    background: #edf5f3;
}
[hidden] {
    display: none !important;
}

.control-grid .button {
    padding: 9px 7px;
    text-align: center;
}
/* Compact workspace: persistent solving controls and one setup group at a time. */
header {
    padding: 16px 24px;
}
main {
    padding: 0 24px 16px;
    gap: 20px;
}
aside {
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.panel {
    padding: 16px;
    margin-bottom: 0;
}
.solve-panel {
    order: -1;
}
.panel-title {
    margin-bottom: 12px;
}
.solve-bar {
    display: flex;
    align-items: flex-end;
    gap: 10px;
}
.solve-bar .settings {
    flex: 0 0 100px;
}
.solve-bar .settings label {
    font-size: 0.75rem;
    gap: 4px;
}
.solve-bar .primary {
    margin: 0;
    flex: 1;
    min-width: 0;
}
.result {
    margin-top: 12px;
    padding-top: 10px;
}
.result strong {
    font-size: 2rem;
}
.replay-controls {
    margin-top: 10px;
    padding-top: 10px;
}
#replay .fine {
    display: none;
}
.move-details {
    margin-top: 10px;
}
summary {
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 600;
    padding: 10px 0;
}
summary:focus-visible {
    outline: 3px solid #35a897;
    outline-offset: 2px;
}
.setup-group {
    padding-top: 0;
    margin-top: 5px;
}
.setup-group[open] > summary {
    margin-bottom: 8px;
}
.setup-group .group-heading {
    font-size: 0.875rem;
}
.rule-toggle {
    margin-top: 12px;
}
.board-foot {
    min-height: 0;
    margin-top: 8px;
}
.board-foot:has(#hint[hidden]) {
    display: none;
}
.goal-buttons button {
    padding: 4px 2px;
}
.goal-buttons b {
    font-size: 1rem;
}
footer {
    padding: 8px 24px;
}
@media (min-width: 860px), (min-width: 740px) and (min-aspect-ratio: 6/5) {
    main {
        grid-template-columns: minmax(0, 1fr) clamp(310px, 34vw, 430px);
        align-items: start;
    }
    .workspace {
        position: sticky;
        top: 12px;
    }
    .board-shell {
        width: min(100%, max(280px, calc(100dvh - 120px)));
        margin-inline: auto;
        padding: 12px;
    }
    .control-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}
@media (max-width: 859px) and (max-aspect-ratio: 6/5), (max-width: 739px) {
    header {
        padding: 12px;
    }
    main {
        padding: 0 12px 100px;
        gap: 12px;
    }
    .workspace {
        position: static;
    }
    .board-shell {
        padding: 6px;
    }
    .solve-bar {
        position: fixed;
        left: 0;
        right: 0;
        bottom: 0;
        z-index: 4;
        background: #fff;
        padding: 10px 12px calc(10px + env(safe-area-inset-bottom));
        border-top: 1px solid var(--line);
        box-shadow: 0 -4px 20px #142c3d12;
    }
    .solve-panel .panel-title {
        display: none;
    }
    .solve-panel .result {
        border: 0;
        margin: 0;
        padding: 0;
    }
    footer {
        padding-bottom: 100px;
    }
    #toast {
        bottom: 100px;
    }
}
/* Shared controls and predictable spacing across both layouts. */
button,
.button,
select {
    min-height: 40px;
}
.panel-title .compact {
    margin-left: auto;
    padding: 5px 10px;
    min-height: 32px;
}
.quick-actions {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 10px;
}
.quick-actions span {
    font-size: 0.75rem;
    color: var(--muted);
}
#new-round {
    background: #eaf4ef;
    border-color: #9eb8b1;
    color: var(--accent);
    font-weight: 600;
}
#step-range {
    width: 100%;
    padding: 0;
    margin: 12px 0 0;
    accent-color: var(--accent);
    cursor: pointer;
}
.setup-group > summary {
    min-height: 40px;
}
.tool {
    flex-direction: row;
    justify-content: center;
    gap: 4px;
    padding: 7px 3px;
}
.swatch {
    width: 15px;
    height: 15px;
    border-radius: 5px;
}
.goal-buttons button {
    min-height: 42px;
}
.goal-buttons small {
    font-size: 0.7rem;
}
#current-target {
    margin-top: 8px;
    color: #344b5b;
}
#moves {
    max-height: 160px;
}
@media (min-width: 860px), (min-width: 740px) and (min-aspect-ratio: 6/5) {
    main {
        grid-template-columns: minmax(0, 1fr) clamp(330px, 37vw, 470px);
    }
    aside {
        max-height: calc(100dvh - 84px);
        overflow-y: auto;
        scrollbar-gutter: stable;
        padding: 0 3px 3px;
    }
    .solve-panel {
        position: sticky;
        top: 0;
        z-index: 2;
        box-shadow: 0 4px 10px #142c3d0a;
        flex-shrink: 0;
    }
    .board-shell {
        width: min(100%, max(240px, calc(100dvh - 170px)));
    }
    .control-grid {
        gap: 6px;
    }
}
@media (max-width: 859px) and (max-aspect-ratio: 6/5), (max-width: 739px) {
    button,
    .button,
    select {
        min-height: 44px;
    }
    .quick-actions span {
        font-size: 0.7rem;
    }
    .panel {
        padding: 12px;
    }
    footer {
        padding-bottom: 100px;
    }
}
.setup-group .group-heading {
    margin-top: 12px;
}
.setup-panel .panel-title {
    margin-bottom: 4px;
}
.goal-buttons b,
.goal-buttons small {
    display: inline;
}
.goal-buttons b {
    margin-right: 3px;
}
.goal-buttons button {
    padding: 3px 1px;
}
.goal-color-row {
    margin-top: 4px;
}
.setup-group[open] > summary {
    margin-bottom: 2px;
}
.solve-panel .panel-title {
    margin-bottom: 8px;
}
@media (min-width: 860px), (min-width: 740px) and (min-aspect-ratio: 6/5) {
    .goal-buttons button {
        min-height: 34px;
    }
    .panel {
        padding: 12px;
    }
    .setup-group .goal-picker {
        margin-top: 6px;
    }
    .result {
        margin-top: 8px;
        padding-top: 8px;
    }
    footer {
        border: 0;
        padding-block: 2px;
    }
}
.result-line {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}
.result-line small {
    margin-left: auto;
}
.result-line strong {
    font-size: 1.8rem;
}
#step-range {
    border: 0;
    background: transparent;
    box-shadow: none;
}
@media (min-width: 860px), (min-width: 740px) and (min-aspect-ratio: 6/5) {
    .setup-panel .full-control {
        margin-top: 5px;
    }
    .setup-group {
        margin-top: 2px;
    }
    .setup-group > summary {
        min-height: 32px;
        padding: 7px 0;
    }
    .solve-panel .panel-title {
        display: none;
    }
    main {
        padding-bottom: 4px;
    }
    aside {
        max-height: calc(100dvh - 100px);
    }
}
.next-round {
    background: #eaf4ef;
    color: var(--accent);
    border-color: #9eb8b1;
    font-weight: 600;
}