/* ------- page background + overlays ------- */
html, body {
    height: 100%;
    margin: 0;
}

body {
    background: #000;
    color: #e6e6e6;
    font-family: ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
    overflow: hidden;
}

/* canvas as full-screen background */
.sim {
    position: fixed;
    inset: 0; /* top:0 right:0 bottom:0 left:0 */
    width: 100vw;
    height: 100vh;
    display: block;
    z-index: 0;
}

/* floating toolbar */
.toolbar {
    position: fixed;
    top: 12px;
    left: 12px;
    right: 12px;
    z-index: 20;
    display: flex;
    gap: 1rem;
    align-items: center;
    padding: .6rem .75rem;
    background: rgba(15,15,15,.65);
    border: 1px solid #2a2a2a;
    border-radius: 10px;
    backdrop-filter: blur(6px);
}

/* collapse/expand toolbar */
.toolbar .spacer {
    flex: 1 1 auto;
}

#toggleToolbar {
    padding: .35rem .5rem;
    border-radius: .4rem;
}

.toolbar.collapsed {
    padding: .35rem .5rem;
    gap: .5rem;
}

.toolbar.collapsed .group,
.toolbar.collapsed #restart,
.toolbar.collapsed #permalink,
.toolbar.collapsed .spacer {
    display: none;
}

/* floating rules panel (details) */
.rulepanel {
    position: fixed;
    left: 12px;
    right: 12px;
    bottom: 12px;
    z-index: 20;
    background: rgba(11,11,11,.65);
    border: 1px solid #1a1a1a;
    border-radius: 10px;
    backdrop-filter: blur(6px);
    overflow: hidden; /* collapsed state shows only summary */
    max-height: 42vh; /* when open, content scrolls inside */
}

.rulepanel[open] {
    overflow: auto;
}

.rulepanel > summary {
    cursor: pointer;
    font-weight: 600;
    list-style: none;
    user-select: none;
    padding: .6rem .75rem;
    margin: 0;
    position: sticky;
    top: 0;
    background: transparent;
    display: flex;
    align-items: center;
    gap: .5rem;
    border-bottom: 1px solid #1a1a1a;
}

.rulepanel > summary::-webkit-details-marker {
    display: none;
}

.rulepanel > summary::after {
    content: "▾";
    margin-left: auto;
    opacity: .8;
}

.rulepanel:not([open]) > summary::after {
    content: "▸";
}

.rules-body {
    padding: .75rem 1rem 1rem;
    display: grid;
    gap: .75rem;
}

.rule-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px,1fr));
    gap: .5rem 1rem;
}

.rule-item {
    align-items: center;
    gap: .5rem;
}

/* buttons + inputs (keep your existing styles, just a few tweaks) */
button {
    background: #1f1f1f;
    border: 1px solid #2a2a2a;
    color: #e6e6e6;
    padding: .4rem .7rem;
    border-radius: .5rem;
    cursor: pointer;
}

button:hover {
    background: #2a2a2a;
}

/* range styling (from your sheet; leave as-is) */
:root {
    --slider-track: #444;
    --slider-fill: #4cafef;
    --slider-thumb: #ff5722;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    background: transparent;
    width: 100%;
}

input[type="range"]::-webkit-slider-runnable-track {
    height: 6px;
    background: var(--slider-track);
    border-radius: 3px;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    border: 2px solid #222;
    margin-top: -6px;
    cursor: pointer;
    background: var(--slider-thumb);
}

input[type="range"]::-moz-range-track {
    height: 6px;
    background: var(--slider-track);
    border-radius: 3px;
}

input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    border: 2px solid #222;
    cursor: pointer;
    background: var(--thumb-color, var(--slider-thumb));
}

input[type="range"]::-moz-range-progress {
    background: var(--slider-fill);
    height: 6px;
    border-radius: 3px;
}

/* container no longer controls layout; keep for semantics */
.container {
    position: relative;
    height: 100vh;
}

/* Canvas already full screen; nothing to change there */

/* --- Toolbar square when collapsed --- */
.toolbar {
    position: fixed;
    top: 12px;
    left: 12px;
    right: 12px;
    z-index: 20;
    background: rgba(15,15,15,.65);
    border: 1px solid #2a2a2a;
    border-radius: 10px;
    backdrop-filter: blur(6px);
}

.toolbar.collapsed {
    left: 12px;
    right: auto; /* stop spanning full width */
    width: 44px;
    height: 44px;
    padding: 0;
    gap: 0;
    display: grid;
    place-items: center;
}

.toolbar.collapsed .group,
.toolbar.collapsed #restart,
.toolbar.collapsed #permalink,
.toolbar.collapsed .spacer {
    display: none;
}

.toolbar.collapsed #toggleToolbar {
    width: 100%;
    height: 100%;
    padding: 0;
    border-radius: 8px;
    font-size: 0; /* hide the word "Toolbar" */
}

.toolbar.collapsed #toggleToolbar::before {
    content: "☰"; /* icon only */
    font-size: 18px;
}

/* --- Rules panel as a floating card; tiny square when closed --- */
.rulepanel {
    position: fixed;
    left: 12px;
    right: 12px;
    bottom: 12px;
    z-index: 20;
    background: rgba(11,11,11,.65);
    border: 1px solid #1a1a1a;
    border-radius: 10px;
    backdrop-filter: blur(6px);
    max-height: 42vh;
    overflow: auto;
}

.rulepanel[open] {
    max-height: calc(100dvh - 24px - 60px);
    overflow: auto;
    scrollbar-gutter: stable both-edges; /* avoids layout jump */
    overscroll-behavior: contain;
}

.rulepanel[open] {
    scrollbar-width: none;
}
/* Firefox */
.rulepanel[open]::-webkit-scrollbar {
    width: 0;
    height: 0;
}
/* WebKit */

.rulepanel > summary {
    position: sticky;
    top: 0;
    padding: .6rem .75rem;
    margin: 0;
    cursor: pointer;
    font-weight: 600;
    border-bottom: 1px solid #1a1a1a;
    display: flex;
    align-items: center;
    gap: .5rem;
}

.rulepanel > summary::-webkit-details-marker {
    display: none;
}

.rulepanel[open] > summary::after {
    content: "▾";
    margin-left: auto;
    opacity: .8;
}

/* closed => tiny square pinned bottom-right */
.rulepanel:not([open]) {
    left: 12px;
    right: auto; /* stop spanning full width */
    width: 44px;
    height: 44px;
    padding: 0;
    gap: 0;
    display: grid;
    place-items: center;
}

.rulepanel:not([open]) > summary {
    border: 0;
    padding: 0;
    margin: 0;
    width: 100%;
    height: 100%;
    display: grid;
    place-items: center;
    font-size: 0; /* hide label text */
}

.rulepanel:not([open]) > summary::after {
    content: "";
}
/* no caret */
.rulepanel:not([open]) > summary::before {
    content: "Rules"; /* icon only */
    font-size: 18px;
}

/* Keep sliders/layout rules you already have */

@media (max-width: 640px) {
    /* Default to FAB */
    .toolbar {
        top: 12px;
        left: 12px;
        width: 44px;
        height: 44px;
        padding: 0;
        gap: 0;
        display: grid;
        place-items: center;
    }

    .toolbar .group, .toolbar #restart, .toolbar #permalink, .toolbar .spacer {
        display: none;
    }

    /* FAB button icon */
    #toggleToolbar {
        width: 100%;
        height: 44px;
        padding: 0;
        border-radius: 8px;
        font-size: 18px;
    }

    #toggleToolbar::before {
        width: 44px;
        font-size: 18px;
    }

    /* Expanded drawer */
    .toolbar.mobile.open {
        left: 12px;
        width: min(85vw, 420px);
        height: 70vh; /* scroll within drawer if needed */
        padding: .6rem .75rem;
        display: flex;
        flex-direction: column;
        gap: .65rem;
        overflow: auto;
    }

    .toolbar.mobile.open .group,
    .toolbar.mobile.open #restart,
    .toolbar.mobile.open #permalink {
        display: inline-flex;
    }

    .toolbar.mobile.open .group {
        flex-wrap: wrap;
        gap: .5rem;
    }

    .toolbar.mobile.open input[type="number"],
    .toolbar.mobile.open input[type="range"] {
        width: 100%;
        min-width: 0;
    }

    .toolbar.mobile.open label {
        white-space: nowrap;
    }
}