.m3m-page {
    min-height: 100vh;
    background: var(--bg);
    color: var(--text);
}

.m3m-shell {
    width: min(100%, 1040px);
    margin: 0 auto;
    padding: calc(var(--header-h) + 24px) var(--sp-4) var(--sp-8);
}

.m3m-topbar {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: var(--sp-4);
    align-items: end;
    margin-bottom: var(--sp-4);
}

.m3m-kicker {
    margin-bottom: 6px;
    color: var(--green);
    font-size: var(--fs-xs);
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.m3m-title {
    margin: 0;
    font-size: clamp(2rem, 5vw, 3.2rem);
    line-height: 1;
    letter-spacing: 0;
    text-transform: uppercase;
}

.m3m-copy {
    max-width: 680px;
    margin-top: var(--sp-2);
    color: var(--text-2);
    font-size: var(--fs-sm);
    line-height: 1.6;
}

.m3m-tier-tabs {
    display: flex;
    gap: 6px;
    padding: 4px;
    border: 1px solid var(--b1);
    border-radius: var(--r);
    background: var(--surface);
}

.m3m-tier {
    min-height: 38px;
    padding: 0 12px;
    border: 1px solid transparent;
    border-radius: var(--r-sm);
    color: var(--text-3);
    font-size: var(--fs-xs);
    font-weight: 800;
    text-transform: uppercase;
}

.m3m-tier.active {
    color: var(--text);
    border-color: var(--border-active);
    background: var(--green-bg);
}

.m3m-layout {
    display: grid;
    grid-template-columns: minmax(340px, 0.95fr) minmax(360px, 1.05fr);
    gap: var(--sp-4);
    align-items: start;
}

.m3m-board-panel,
.m3m-controls {
    border: 1px solid var(--b1);
    border-radius: var(--r-lg);
    background: var(--panel-bg, var(--panel));
    box-shadow: var(--sh);
}

.m3m-board-panel {
    padding: var(--sp-4);
}

.m3m-card {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    grid-template-areas:
        ". top ."
        "left target right"
        ". bottom .";
    gap: 12px;
    align-items: center;
    justify-items: center;
    min-height: 390px;
    padding: clamp(14px, 4vw, 28px);
    border: 1px solid var(--b1);
    border-radius: var(--r-lg);
    background:
        repeating-linear-gradient(135deg, rgba(255,255,255,.035) 0 1px, transparent 1px 14px),
        var(--surface);
}

.m3m-cell {
    display: grid;
    place-items: center;
    min-width: clamp(76px, 18vw, 112px);
    min-height: clamp(60px, 15vw, 88px);
    padding: 8px 10px;
    border: 2px solid var(--accent, var(--b2));
    border-radius: var(--r);
    background: rgba(255,255,255,.04);
    font-family: var(--f-mono);
    font-size: clamp(1.3rem, 5vw, 2rem);
    font-weight: 900;
}

.m3m-cell--top { grid-area: top; --accent: #9b7cff; }
.m3m-cell--right { grid-area: right; --accent: #fa7d6d; }
.m3m-cell--bottom { grid-area: bottom; --accent: #5dade2; }
.m3m-cell--left { grid-area: left; --accent: #55d6c2; }

.m3m-target {
    grid-area: target;
    display: grid;
    place-items: center;
    width: clamp(108px, 24vw, 150px);
    aspect-ratio: 1;
    border: 4px solid var(--green);
    border-radius: 50%;
    background: var(--green-bg);
    color: var(--text);
    font-family: var(--f-mono);
    font-size: clamp(2rem, 7vw, 3rem);
    font-weight: 900;
    box-shadow: inset 0 0 0 1px rgba(255,255,255,.16), 0 18px 48px rgba(0,0,0,.28);
}

.m3m-board-meta {
    display: flex;
    justify-content: space-between;
    gap: var(--sp-3);
    margin-top: var(--sp-3);
    color: var(--text-3);
    font-size: var(--fs-xs);
}

.m3m-controls {
    display: grid;
    gap: var(--sp-3);
    padding: var(--sp-4);
}

.m3m-expression-wrap,
.m3m-palette,
.m3m-actions,
.m3m-feedback,
.m3m-solution,
.m3m-session {
    border: 1px solid var(--b1);
    border-radius: var(--r);
    background: rgba(255,255,255,.035);
}

.m3m-expression-wrap {
    padding: var(--sp-3);
}

.m3m-label-row,
.m3m-session {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--sp-2);
}

.m3m-label {
    color: var(--text-3);
    font-size: var(--fs-xs);
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.m3m-used {
    color: var(--green);
    font-family: var(--f-mono);
    font-weight: 800;
}

.m3m-expression {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px;
    min-height: 56px;
    margin-top: var(--sp-2);
    padding: 10px;
    border: 1px solid var(--b1);
    border-radius: var(--r-sm);
    background: var(--bg);
    font-family: var(--f-mono);
    font-size: 1.05rem;
}

.m3m-empty {
    color: var(--text-4);
    font-family: var(--f-sans);
    font-size: var(--fs-sm);
}

.m3m-token {
    display: inline-flex;
    align-items: center;
    min-height: 30px;
    padding: 2px 8px;
    border-radius: var(--r-sm);
    background: var(--surface);
    font-weight: 800;
}

.m3m-token--num {
    color: var(--green);
    background: var(--green-bg);
}

.m3m-token--op,
.m3m-token--slash {
    color: var(--cyan);
}

.m3m-token--pending {
    color: var(--amber);
    border: 1px dashed rgba(232,169,62,.42);
    background: var(--amber-bg);
}

.m3m-cursor {
    width: 8px;
    height: 24px;
    border-radius: 2px;
    background: var(--amber);
    animation: m3mBlink 1s steps(2, start) infinite;
}

@keyframes m3mBlink {
    50% { opacity: 0; }
}

.m3m-palette {
    display: grid;
    gap: var(--sp-3);
    padding: var(--sp-3);
}

.m3m-chip-row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
}

.m3m-chip-row--ops {
    grid-template-columns: repeat(7, 1fr);
}

.m3m-chip-row--tools {
    grid-template-columns: repeat(4, 1fr);
}

.m3m-chip,
.m3m-btn {
    min-height: 46px;
    border: 1px solid var(--b1);
    border-radius: var(--r);
    background: var(--surface);
    color: var(--text);
    font-weight: 800;
    transition: background var(--dur), border-color var(--dur), transform var(--dur), opacity var(--dur);
}

.m3m-chip:hover:not(:disabled),
.m3m-btn:hover:not(:disabled) {
    border-color: var(--b2);
    background: var(--surface-h);
}

.m3m-chip:active:not(:disabled),
.m3m-btn:active:not(:disabled) {
    transform: translateY(1px);
}

.m3m-chip--number {
    min-height: 58px;
    color: var(--green);
    font-family: var(--f-mono);
    font-size: 1.25rem;
}

.m3m-chip:disabled {
    opacity: .35;
    cursor: default;
    text-decoration: line-through;
}

.m3m-actions {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: var(--sp-3);
    align-items: center;
    padding: var(--sp-3);
}

.m3m-btn--primary {
    min-height: 54px;
    padding: 0 22px;
    background: var(--green);
    color: #183000;
}

.m3m-btn--primary:hover:not(:disabled) {
    background: color-mix(in srgb, var(--green) 82%, white);
}

.m3m-btn--primary:disabled {
    opacity: .38;
}

.m3m-next {
    min-width: 124px;
}

.m3m-feedback,
.m3m-solution,
.m3m-session {
    min-height: 44px;
    padding: 11px 12px;
    color: var(--text-3);
    font-size: var(--fs-sm);
}

.m3m-feedback.success {
    color: var(--green);
    border-color: rgba(129,182,76,.45);
    background: var(--green-bg);
}

.m3m-feedback.error {
    color: var(--red);
    border-color: rgba(250,65,45,.38);
    background: var(--red-bg);
}

.m3m-feedback.hint,
.m3m-solution {
    color: var(--amber);
    border-color: rgba(232,169,62,.34);
    background: var(--amber-bg);
}

.m3m-stat {
    color: var(--text-3);
    font-size: var(--fs-xs);
    font-weight: 700;
}

.m3m-stat strong {
    color: var(--text);
    font-family: var(--f-mono);
}

@media (max-width: 820px) {
    .m3m-topbar,
    .m3m-layout {
        grid-template-columns: 1fr;
    }

    .m3m-tier-tabs {
        width: 100%;
    }

    .m3m-tier {
        flex: 1;
    }
}

@media (max-width: 520px) {
    .m3m-shell {
        padding-left: 10px;
        padding-right: 10px;
    }

    .m3m-board-panel,
    .m3m-controls {
        padding: 10px;
    }

    .m3m-card {
        min-height: 330px;
        gap: 8px;
        padding: 10px;
    }

    .m3m-cell {
        min-width: 72px;
        min-height: 58px;
    }

    .m3m-target {
        width: 104px;
    }

    .m3m-chip-row,
    .m3m-chip-row--tools {
        grid-template-columns: repeat(2, 1fr);
    }

    .m3m-chip-row--ops {
        grid-template-columns: repeat(4, 1fr);
    }

    .m3m-actions {
        grid-template-columns: 1fr;
    }

    .m3m-next {
        min-width: 0;
    }
}