/* §9 breakpoints and §10's single 48px control floor (L3) -- never 44px.
   The full-viewport-height unit that ignores mobile browser chrome is never
   used here; the dynamic/small variants are used instead. */

:root {
    --control-floor: 48px;
    --board-width: min(70dvh, 640px);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100dvh;
    background: var(--bg-page);
    color: var(--fg-body);
}

.control {
    min-inline-size: var(--control-floor);
    min-block-size: var(--control-floor);
}

.board {
    inline-size: var(--board-width);
    block-size: var(--board-width);
    aspect-ratio: 1;
}

.digit-bar {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    block-size: 60px; /* L2: row 60 = button 48 + 6px padding on each side */
    gap: 0;
    padding-bottom: env(safe-area-inset-bottom, 0px);
}

.digit-bar button {
    inline-size: calc(var(--board-width) / 9);
    block-size: 48px;
}

.app-shell {
    display: flex;
    flex-direction: column;
    min-height: 100dvh;
}

.notes-rail {
    inline-size: 280px;
}

/* wide: side-by-side board and notes rail, board can shrink but never overlays. */
@media (min-width: 1024px) {
    :root {
        --board-width: min(70dvh, 640px);
    }

    .app-shell {
        flex-direction: row;
    }
}

/* medium: portrait stacks the board over controls; landscape puts them side by
   side; notes live in a bottom sheet rather than a fixed rail. */
@media (min-width: 600px) and (max-width: 1023px) {
    :root {
        --board-width: min(80dvh, 90vw);
    }

    .notes-rail {
        inline-size: auto;
        block-size: auto;
    }
}

/* narrow: board fills the viewport width minus a small margin; digit targets
   are exactly board-width/9 with no inter-button gap. */
@media (max-width: 599px) {
    :root {
        --board-width: calc(100vw - 16px);
    }

    .digit-bar {
        gap: 0;
    }
}