.merge-page {
    --merge-blue: #4e8ed9;
    --merge-coral: #ef6458;
    --merge-yellow: #f1c84a;
    --merge-green: #c7f05a;
}

.merge-header .brand-copy strong { color: var(--merge-yellow); }

.merge-brand-mark {
    display: grid;
    grid-template-columns: 1fr 1fr;
    width: 43px;
    height: 43px;
    gap: 2px;
}

.merge-brand-mark i {
    display: grid;
    place-items: center;
    border-radius: 3px;
    color: var(--night);
    font-size: 9px;
    font-style: normal;
    font-weight: 900;
}

.merge-brand-mark i:nth-child(1) { background: var(--merge-green); }
.merge-brand-mark i:nth-child(2) { background: var(--merge-yellow); }
.merge-brand-mark i:nth-child(3) { background: var(--merge-blue); color: #fff; }
.merge-brand-mark i:nth-child(4) { background: var(--merge-coral); color: #fff; }

.game-switch-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    height: 40px;
    padding: 0 13px;
    border: 1px solid #3b423e;
    border-radius: 6px;
    color: #cfd6d2;
    font-size: 11px;
    font-weight: 800;
    text-decoration: none;
}

.game-switch-link:hover { background: #343c38; color: #fff; }

.merge-main { width: min(100%, 1420px); }

.merge-stage {
    min-height: calc(100vh - 76px);
    padding: 36px 30px 48px;
}

.merge-topline {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 24px;
    margin-bottom: 22px;
}

.merge-topline h1 {
    max-width: 700px;
    font-size: 30px;
    font-weight: 850;
    line-height: 1.15;
}

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

.new-run-button {
    min-height: 48px;
    padding: 0 17px;
    background: var(--night);
    border: 1px solid var(--night);
    border-radius: 7px;
    color: var(--merge-yellow);
    font-size: 12px;
    font-weight: 850;
    cursor: pointer;
}

.new-run-button:hover { background: #303632; }

.merge-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 270px;
    align-items: start;
    gap: 16px;
}

.merge-workbench {
    overflow: hidden;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.merge-scorebar {
    display: grid;
    grid-template-columns: 1.25fr 1fr 1fr;
    min-height: 82px;
    background: var(--night);
    color: #fff;
}

.merge-scorebar > div {
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 12px 22px;
    border-right: 1px solid #333a36;
}

.merge-scorebar > div:last-child { border: 0; }
.merge-scorebar small { margin-bottom: 4px; color: #99a39d; font-size: 9px; font-weight: 800; }
.merge-scorebar strong { color: var(--merge-yellow); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 25px; font-variant-numeric: tabular-nums; line-height: 1; }
.merge-scorebar > div:nth-child(2) strong { color: var(--merge-green); }
.merge-scorebar > div:nth-child(3) strong { color: #fff; }

.score-gain {
    position: absolute;
    right: 20px;
    bottom: 16px;
    color: var(--merge-green);
    font-family: ui-monospace, monospace;
    font-size: 13px;
    font-weight: 900;
    opacity: 0;
}

.score-gain.show { animation: score-rise 550ms ease-out; }

@keyframes score-rise {
    0% { opacity: 0; transform: translateY(5px); }
    30% { opacity: 1; }
    100% { opacity: 0; transform: translateY(-16px); }
}

.merge-board-wrap {
    display: grid;
    min-height: 570px;
    padding: 26px;
    place-items: center;
    background: #202622;
}

.merge-board {
    --gap: 10px;
    --tile-size: calc((100% - var(--gap) * 5) / 4);
    position: relative;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, 1fr);
    width: min(520px, 100%);
    aspect-ratio: 1;
    gap: var(--gap);
    padding: var(--gap);
    overflow: hidden;
    background: #0e1210;
    border: 1px solid #3c4540;
    border-radius: 7px;
    box-shadow: 0 22px 46px rgba(0, 0, 0, 0.3);
    touch-action: none;
    user-select: none;
    -webkit-user-select: none;
}

.merge-cell {
    min-width: 0;
    min-height: 0;
    background: #313834;
    border: 1px solid #414a45;
    border-radius: 5px;
}

.tile-layer {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.merge-tile {
    position: absolute;
    top: calc(var(--gap) + var(--row) * (var(--tile-size) + var(--gap)));
    left: calc(var(--gap) + var(--col) * (var(--tile-size) + var(--gap)));
    display: grid;
    width: var(--tile-size);
    height: var(--tile-size);
    place-items: center;
    background: #e6ebe7;
    border-radius: 5px;
    color: var(--ink);
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: 34px;
    font-weight: 950;
    line-height: 1;
    transition: top 115ms ease-out, left 115ms ease-out;
    will-change: top, left;
}

.merge-tile.digits-3 { font-size: 29px; }
.merge-tile.digits-4 { font-size: 24px; }
.merge-tile.digits-5 { font-size: 19px; }
.merge-tile.value-2 { background: #e9eee8; }
.merge-tile.value-4 { background: #d7e8c1; }
.merge-tile.value-8 { background: var(--merge-green); }
.merge-tile.value-16 { background: #a8db65; }
.merge-tile.value-32 { background: #6dbb84; color: #10251a; }
.merge-tile.value-64 { background: var(--merge-blue); color: #fff; }
.merge-tile.value-128 { background: #5967c2; color: #fff; }
.merge-tile.value-256 { background: #8155a8; color: #fff; }
.merge-tile.value-512 { background: var(--merge-coral); color: #fff; }
.merge-tile.value-1024 { background: #d9483c; color: #fff; }
.merge-tile.value-2048 { background: var(--merge-yellow); color: #171b19; box-shadow: inset 0 0 0 3px #fff0a9; }
.merge-tile.value-super { background: #151a17; border: 2px solid var(--merge-yellow); color: var(--merge-yellow); }
.merge-tile.new { animation: tile-appear 180ms ease-out; }
.merge-tile.merged { animation: tile-merge 220ms ease-out; }

@keyframes tile-appear {
    0% { opacity: 0; transform: scale(0.4); }
    100% { opacity: 1; transform: scale(1); }
}

@keyframes tile-merge {
    0% { transform: scale(0.88); }
    55% { transform: scale(1.14); }
    100% { transform: scale(1); }
}

.board-loading {
    position: absolute;
    inset: 0;
    z-index: 10;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    background: rgba(14, 18, 16, 0.92);
    color: #dbe2dd;
    font-size: 11px;
}

.board-loading[hidden] { display: none; }
.board-loading span { width: 28px; height: 28px; border: 3px solid #56605a; border-top-color: var(--merge-yellow); border-radius: 50%; animation: loading-spin 700ms linear infinite; }
@keyframes loading-spin { to { transform: rotate(360deg); } }

.merge-controls {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 15px;
    min-height: 66px;
    padding: 9px 14px;
    background: #edf1ed;
    border-top: 1px solid var(--line);
}

.undo-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    min-height: 38px;
    padding: 0 13px;
    background: var(--surface);
    border: 1px solid var(--line-strong);
    border-radius: 5px;
    font-size: 10px;
    font-weight: 800;
    cursor: pointer;
}

.undo-button:disabled { opacity: 0.42; cursor: not-allowed; }
.undo-button span { font-size: 18px; }

.direction-pad {
    display: flex;
    justify-content: center;
    gap: 4px;
}

.direction-pad button {
    display: grid;
    width: 38px;
    height: 38px;
    place-items: center;
    background: var(--surface);
    border: 1px solid #c6cfc8;
    border-radius: 4px;
    font-size: 17px;
    font-weight: 900;
    cursor: pointer;
}

.direction-pad button:hover { background: var(--merge-green); border-color: var(--lime-dark); }
.merge-controls p { color: var(--ink-soft); font-size: 9px; text-align: right; }
.mobile-control-copy { display: none; }

.merge-live-status {
    min-height: 31px;
    padding: 8px 14px;
    overflow: hidden;
    background: #e4e9e5;
    color: #5f6a63;
    font-size: 9px;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.merge-session-panel {
    overflow: hidden;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
}

.tile-goal { padding: 20px 18px 13px; }
.tile-goal strong { display: block; font-family: ui-monospace, monospace; font-size: 40px; line-height: 1; }
.tile-goal > span { display: block; margin-top: 7px; color: var(--ink-soft); font-size: 10px; }
.merge-progress { height: 5px; margin: 0 18px 19px; overflow: hidden; background: #e1e6e2; border-radius: 3px; }
.merge-progress span { display: block; width: 9%; height: 100%; background: var(--merge-blue); transition: width 200ms ease; }

.merge-mini-stats { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.merge-mini-stats > div { display: flex; align-items: center; justify-content: space-between; min-height: 51px; padding: 9px 18px; border-bottom: 1px solid #e6ebe7; }
.merge-mini-stats > div:last-child { border: 0; }
.merge-mini-stats dt { color: var(--ink-soft); font-size: 10px; font-weight: 750; }
.merge-mini-stats dd { font-family: ui-monospace, monospace; font-size: 18px; font-weight: 900; }

.merge-coach { margin: 15px 14px; padding: 13px; background: #eef3f9; border: 1px solid #cddbea; border-left: 3px solid var(--merge-blue); border-radius: 5px; }
.merge-coach strong { display: block; font-size: 11px; }
.merge-coach p { margin-top: 4px; color: var(--ink-soft); font-size: 9px; }
.merge-session-panel > .secondary-action { width: calc(100% - 28px); margin: 0 14px 15px; }

.merge-leaderboard {
    padding: 58px 30px 72px;
    background: var(--surface);
    border-top: 1px solid var(--line);
}

.merge-rank-list { list-style: none; }
.merge-rank-list li {
    display: grid;
    grid-template-columns: 50px minmax(0, 1fr) 145px 90px;
    align-items: center;
    min-height: 58px;
    border-bottom: 1px solid #e7ebe8;
}

.merge-rank-list li:first-child .rank-number { color: var(--merge-coral); }
.merge-rank-list li > strong { font-family: ui-monospace, monospace; font-size: 16px; text-align: right; }
.merge-rank-list li > strong small { margin-left: 3px; color: var(--ink-soft); font-size: 9px; }
.merge-rank-list li > span:last-child { color: var(--ink-soft); font-size: 10px; text-align: right; }

.merge-settings-dialog form { padding: 26px; }
.merge-settings-dialog .primary-action { width: 100%; }

.merge-rule-flow {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin: 24px 0 4px;
}

.merge-rule-flow span {
    display: grid;
    width: 52px;
    height: 52px;
    place-items: center;
    background: var(--merge-green);
    border-radius: 5px;
    font-family: ui-monospace, monospace;
    font-size: 21px;
    font-weight: 900;
}
.merge-rule-flow span:last-child { background: var(--merge-yellow); }
.merge-rule-flow b { color: var(--ink-soft); }

.milestone-dialog,
.merge-result-dialog { width: min(92vw, 450px); text-align: center; }
.milestone-tile { display: grid; width: 92px; height: 92px; margin: 0 auto 20px; place-items: center; background: var(--merge-yellow); border: 3px solid #ffe998; border-radius: 7px; font-family: ui-monospace, monospace; font-size: 23px; font-weight: 950; box-shadow: 0 10px 30px rgba(241, 200, 74, 0.28); }
.milestone-dialog h2 { margin-bottom: 7px; }
.milestone-dialog .result-content > p:not(.eyebrow) { color: var(--ink-soft); font-size: 11px; }

.merge-result-stats { display: grid; grid-template-columns: repeat(3, 1fr); margin: 24px 0 18px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.merge-result-stats span { padding: 12px 5px; border-right: 1px solid var(--line); }
.merge-result-stats span:last-child { border: 0; }
.merge-result-stats small { display: block; color: var(--ink-soft); font-size: 8px; }
.merge-result-stats strong { display: block; margin-top: 3px; font-family: ui-monospace, monospace; font-size: 17px; }

.confirm-dialog { width: min(92vw, 410px); }
.confirm-dialog > div { padding: 26px; }
.confirm-dialog h2 { margin-bottom: 7px; }
.confirm-dialog p:not(.eyebrow) { color: var(--ink-soft); font-size: 11px; }
.confirm-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 7px; margin-top: 24px; }

@media (max-width: 980px) {
    .merge-layout { grid-template-columns: minmax(0, 1fr); }
    .merge-session-panel { display: grid; grid-template-columns: 1fr 1.2fr; }
    .tile-goal { grid-column: 1; }
    .merge-progress { grid-column: 1; }
    .merge-mini-stats { grid-row: 1 / 3; grid-column: 2; border-top: 0; border-left: 1px solid var(--line); }
    .merge-coach { grid-column: 1; }
    .merge-session-panel > .secondary-action { grid-column: 2; align-self: center; }
}

@media (max-width: 700px) {
    .merge-brand-mark { width: 35px; height: 35px; }
    .game-switch-link { height: 38px; padding: 0 10px; }
    .merge-stage { min-height: calc(100vh - 62px); padding: 20px 12px 30px; }
    .merge-topline { align-items: stretch; flex-direction: column; gap: 13px; margin-bottom: 13px; }
    .merge-topline h1 { font-size: 23px; }
    .merge-top-actions { display: grid; grid-template-columns: 1fr 1fr; }
    .merge-top-actions button { min-height: 45px; }

    .merge-scorebar { min-height: 70px; }
    .merge-scorebar > div { padding: 10px 13px; }
    .merge-scorebar strong { font-size: 21px; }
    .merge-board-wrap { min-height: 390px; padding: 12px; }
    .merge-board { --gap: 7px; width: min(100%, 430px); }
    .merge-tile { font-size: 27px; }
    .merge-tile.digits-3 { font-size: 23px; }
    .merge-tile.digits-4 { font-size: 19px; }
    .merge-tile.digits-5 { font-size: 15px; }

    .merge-controls { grid-template-columns: 1fr auto; gap: 8px; padding: 9px; }
    .undo-button { justify-self: start; }
    .direction-pad { grid-row: 2; grid-column: 1 / -1; }
    .direction-pad button { width: 47px; height: 42px; }
    .merge-controls p { grid-row: 1; grid-column: 2; max-width: 150px; }
    .desktop-control-copy { display: none; }
    .mobile-control-copy { display: inline; }

    .merge-session-panel { display: block; }
    .merge-mini-stats { display: grid; grid-template-columns: repeat(3, 1fr); border-left: 0; }
    .merge-mini-stats > div { display: block; min-height: 61px; padding: 9px; border-right: 1px solid #e6ebe7; border-bottom: 0; text-align: center; }
    .merge-mini-stats > div:last-child { border: 0; }
    .merge-coach { margin: 12px; }
    .merge-session-panel > .secondary-action { width: calc(100% - 24px); margin: 0 12px 12px; }

    .merge-leaderboard { padding: 42px 16px 54px; }
    .merge-rank-list li { grid-template-columns: 34px minmax(0, 1fr) 95px 58px; }
    .merge-rank-list li > strong { font-size: 13px; }
    .merge-rank-list li > span:last-child { font-size: 8px; }
}

@media (max-width: 390px) {
    .merge-header #merge-sound { display: none; }
    .merge-board-wrap { min-height: 350px; padding: 9px; }
    .merge-controls p { display: none; }
    .merge-controls { grid-template-columns: 1fr; }
    .direction-pad { grid-row: auto; grid-column: auto; }
    .undo-button { justify-self: center; }
    .confirm-actions { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
    .merge-tile { transition: none; }
}