* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* ── Variables ────────────────────────────────────────────── */
:root {
    --accent:     #c87533;
    --accent-dim: rgba(200, 117, 51, 0.14);
    --accent-glow:rgba(200, 117, 51, 0.22);
    --red:    #e05c52;
    --green:  #35b07a;
    --amber:  #e8a84a;
    --purple: #8c72d6;
    --font:   'Syne', system-ui, sans-serif;
    --mono:   'JetBrains Mono', monospace;
    --r: 6px;

    /* Dark theme — default */
    --bg0: #060a14;
    --bg1: #0b1022;
    --bg2: #111829;
    --bg3: #182033;
    --brd: rgba(55, 78, 135, 0.32);
    --brd2:rgba(75, 105, 175, 0.5);
    --txt1: #d8e0f4;
    --txt2: #6f84b3;
    --txt3: #3a4d78;
    --color-background-primary:   #0b1022;
    --color-background-secondary: #111829;
    --color-border-secondary:  rgba(55, 78, 135, 0.38);
    --color-border-tertiary:   rgba(55, 78, 135, 0.22);
    --color-text-primary:   #d8e0f4;
    --color-text-secondary: #6f84b3;
    --color-text-tertiary:  #3a4d78;
    --panel-bg: rgba(9, 14, 30, 0.82);
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.55), 0 1px 0 rgba(255,255,255,0.03);
    --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.4);
}

:root[data-theme='light'] {
    --bg0: #eceef6;
    --bg1: #f6f7fb;
    --bg2: #eceef7;
    --bg3: #e2e5f0;
    --brd: rgba(140, 155, 210, 0.38);
    --brd2:rgba(115, 135, 195, 0.6);
    --txt1: #18223e;
    --txt2: #4a5c88;
    --txt3: #9aaace;
    --color-background-primary:   #f6f7fb;
    --color-background-secondary: #eceef7;
    --color-border-secondary:  rgba(140, 155, 210, 0.45);
    --color-border-tertiary:   rgba(140, 155, 210, 0.28);
    --color-text-primary:   #18223e;
    --color-text-secondary: #4a5c88;
    --color-text-tertiary:  #9aaace;
    --panel-bg: rgba(245, 246, 252, 0.9);
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.1), 0 1px 0 rgba(255,255,255,0.8);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
}

/* ── Base ─────────────────────────────────────────────────── */
body {
    font-family: var(--font);
    background: var(--bg0);
    color: var(--txt1);
    padding: 12px;
    min-height: 100vh;
}

/* ── App bar ──────────────────────────────────────────────── */
.app-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    margin: 0 0 12px;
    flex-wrap: wrap;
}

.app-bar .title {
    font: 700 15px/1 var(--font);
    color: var(--txt1);
    letter-spacing: 2.5px;
    text-transform: uppercase;
}

.app-bar .subtitle {
    font: 400 11px/1.2 var(--font);
    color: var(--txt3);
}

.app-bar .actions {
    display: flex;
    gap: 6px;
    align-items: center;
}

/* ── Canvas wrap ──────────────────────────────────────────── */
.wrap {
    position: relative;
}

canvas {
    display: block;
    width: 100%;
    cursor: grab;
    border-radius: 8px;
    background: var(--bg1);
    border: 1px solid var(--brd);
    box-shadow: inset 0 0 0 1px rgba(255,255,255,0.02);
    touch-action: none;
}

canvas:active {
    cursor: grabbing;
}

/* ── Tooltip ──────────────────────────────────────────────── */
#tip {
    position: absolute;
    pointer-events: none;
    padding: 7px 11px;
    border-radius: var(--r);
    background: var(--bg2);
    border: 1px solid var(--brd2);
    font: 400 12px/1.4 var(--font);
    color: var(--txt1);
    opacity: 0;
    transition: opacity .1s;
    white-space: nowrap;
    z-index: 10;
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    gap: 2px;
}

#tip .en {
    font-weight: 600;
    font-size: 12px;
    letter-spacing: .3px;
}

#tip .ed {
    font-size: 10.5px;
    color: var(--txt2);
}

/* ── Mode pill ────────────────────────────────────────────── */
#mode-pill {
    position: absolute;
    top: 10px;
    left: 10px;
    display: none;
    align-items: center;
    gap: 6px;
    padding: 4px 11px 4px 8px;
    border-radius: 4px;
    font: 600 9px/1 var(--mono);
    letter-spacing: 1.5px;
    text-transform: uppercase;
    z-index: 5;
    pointer-events: none;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

#mode-pill.vis { display: flex; }

#mode-pill .dot {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    animation: pulse 1.8s ease infinite;
}

.mp-edit {
    background: rgba(224, 92, 82, 0.12);
    color: #e05c52;
    border: 1px solid rgba(224, 92, 82, 0.22);
}
.mp-edit .dot { background: #e05c52; }

.mp-select {
    background: rgba(140, 114, 214, 0.12);
    color: var(--purple);
    border: 1px solid rgba(140, 114, 214, 0.22);
}
.mp-select .dot { background: var(--purple); }

.mp-add {
    background: rgba(53, 176, 122, 0.12);
    color: var(--green);
    border: 1px solid rgba(53, 176, 122, 0.22);
}
.mp-add .dot { background: var(--green); }

.mp-bonds {
    background: rgba(232, 168, 74, 0.12);
    color: var(--amber);
    border: 1px solid rgba(232, 168, 74, 0.22);
}
.mp-bonds .dot { background: var(--amber); }

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50%       { opacity: .3; }
}

/* ── Axis + snap indicators ───────────────────────────────── */
#axis-tip {
    position: absolute;
    pointer-events: none;
    padding: 3px 8px;
    border-radius: 4px;
    font: 600 9px/1 var(--mono);
    letter-spacing: .8px;
    background: var(--accent);
    color: #fff;
    opacity: 0;
    transition: opacity .08s;
    z-index: 10;
    white-space: nowrap;
    box-shadow: 0 2px 8px rgba(200, 117, 51, 0.35);
}

#snap-indicator {
    position: absolute;
    pointer-events: none;
    padding: 3px 8px;
    border-radius: 4px;
    font: 600 9px/1 var(--mono);
    letter-spacing: .8px;
    background: var(--green);
    color: #fff;
    opacity: 0;
    transition: opacity .1s;
    z-index: 10;
    white-space: nowrap;
    box-shadow: 0 2px 8px rgba(53, 176, 122, 0.35);
}

/* ── Buttons ──────────────────────────────────────────────── */
.btn {
    font: 500 11.5px/1 var(--font);
    letter-spacing: .2px;
    padding: 7px 12px;
    border-radius: var(--r);
    border: 1px solid var(--brd2);
    background: var(--bg2);
    color: var(--txt2);
    cursor: pointer;
    transition: background .12s, color .12s, border-color .12s, box-shadow .12s;
    white-space: nowrap;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.btn:hover:not([disabled]) {
    background: var(--bg3);
    color: var(--txt1);
    border-color: var(--brd2);
}

.btn[disabled] {
    opacity: 0.3;
    cursor: default;
}

/* Active mode states */
.btn.on.on-view {
    background: var(--bg3);
    color: var(--txt1);
    border-color: var(--brd2);
    box-shadow: inset 0 1px 3px rgba(0,0,0,.2);
}

.btn.on.on-red {
    background: rgba(224, 92, 82, 0.1);
    color: #e05c52;
    border-color: rgba(224, 92, 82, 0.3);
}

.btn.on.on-purple {
    background: rgba(140, 114, 214, 0.1);
    color: var(--purple);
    border-color: rgba(140, 114, 214, 0.3);
}

.btn.on.on-green {
    background: rgba(53, 176, 122, 0.1);
    color: var(--green);
    border-color: rgba(53, 176, 122, 0.3);
}

.btn.on.on-amber {
    background: rgba(232, 168, 74, 0.1);
    color: var(--amber);
    border-color: rgba(232, 168, 74, 0.3);
}

.btn.primary {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
    box-shadow: 0 2px 10px var(--accent-glow);
    font-weight: 600;
}

.btn.primary:hover:not([disabled]) {
    background: #b8692d;
    border-color: #b8692d;
    box-shadow: 0 3px 14px var(--accent-glow);
    color: #fff;
}

.btn.sm {
    font-size: 10.5px;
    padding: 5px 9px;
    letter-spacing: .1px;
}

/* ── Tabs ─────────────────────────────────────────────────── */
.tabs {
    display: flex;
    gap: 0;
    margin: 0;
    border-bottom: 1px solid var(--brd);
}

.tab {
    font: 500 11px/1 var(--font);
    letter-spacing: .4px;
    padding: 9px 14px;
    cursor: pointer;
    color: var(--txt3);
    border-bottom: 2px solid transparent;
    transition: color .15s, border-color .15s;
    user-select: none;
    text-transform: uppercase;
}

.tab:hover { color: var(--txt2); }

.tab.active {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

.tab-panel {
    display: none;
    padding: 12px 0 0;
}

.tab-panel.active { display: block; }

/* ── Rows, labels, sliders ────────────────────────────────── */
.row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
    margin: 0 0 10px;
}

.row:last-child { margin: 0; }

.lbl {
    font: 600 8.5px/1 var(--mono);
    color: var(--txt3);
    letter-spacing: 1.2px;
    text-transform: uppercase;
    width: 100%;
    margin: 0 0 4px;
}

.sr {
    display: flex;
    align-items: center;
    gap: 6px;
    font: 400 11.5px/1 var(--font);
    color: var(--txt2);
    min-width: 120px;
    flex: 1;
}

.sr input[type=range] {
    flex: 1;
    min-width: 36px;
    accent-color: var(--accent);
}

.sr span:last-child {
    min-width: 28px;
    text-align: right;
    font: 500 10px/1 var(--mono);
    color: var(--accent);
}

.ck {
    display: flex;
    align-items: center;
    gap: 5px;
    font: 400 11.5px/1 var(--font);
    color: var(--txt2);
    cursor: pointer;
    user-select: none;
}

.ck input { accent-color: var(--accent); }

.cr {
    display: flex;
    align-items: center;
    gap: 6px;
    font: 400 11.5px/1 var(--font);
    color: var(--txt2);
}

.cr input[type=color] {
    width: 24px;
    height: 24px;
    border: 1px solid var(--brd2);
    border-radius: 5px;
    padding: 2px;
    cursor: pointer;
    background: transparent;
}

/* ── Stats ────────────────────────────────────────────────── */
.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(85px, 1fr));
    gap: 6px;
    margin: 0;
}

.stat {
    background: transparent;
    border-radius: var(--r);
    padding: 6px 8px;
    border: none;
}

.stat .sl {
    font: 500 8px/1 var(--mono);
    color: var(--txt3);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat .sv {
    font: 600 16px/1.2 var(--mono);
    color: var(--accent);
    margin-top: 5px;
}

/* ── Context bars ─────────────────────────────────────────── */
.ctx-bar {
    font: 400 11.5px/1.3 var(--font);
    color: var(--txt2);
    padding: 7px 12px;
    background: var(--bg2);
    border-radius: var(--r);
    margin: 8px 0 0;
    display: none;
    align-items: center;
    gap: 6px;
    flex-wrap: wrap;
    border: 1px solid var(--brd);
    box-shadow: var(--shadow-sm);
}

.ctx-bar.vis { display: flex; }

.sel-chip {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 2px 8px;
    border-radius: 4px;
    font: 500 10px/1.3 var(--mono);
    border: 1px solid var(--brd2);
    background: var(--bg3);
    letter-spacing: .3px;
}

.sel-chip .dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    display: inline-block;
}

.sel-chip button {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 12px;
    color: var(--txt3);
    padding: 0 0 0 2px;
    line-height: 1;
}

/* ── Polyhedra legend ─────────────────────────────────────── */
#plegend {
    display: flex;
    flex-direction: column;
    gap: 5px;
    margin: 6px 0 0;
    font: 400 11px/1.3 var(--font);
    color: var(--txt2);
}

.pl-group {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px;
}

.pl-group .ps {
    width: 12px;
    height: 8px;
    border-radius: 2px;
    display: inline-block;
    border: 1.5px solid;
}

/* ── Status bar ───────────────────────────────────────────── */
#status-bar {
    position: absolute;
    bottom: 0; left: 0; right: 0;
    height: 24px;
    display: flex; align-items: center;
    padding: 0 12px; gap: 16px;
    background: var(--bg0);
    border-top: 1px solid var(--brd);
    font: 400 9.5px/1 var(--mono);
    letter-spacing: .5px;
    color: var(--txt3);
    z-index: 9;
    pointer-events: none;
}
#status-bar #status-sel { margin-left: auto; }

/* ── Element palette ──────────────────────────────────────── */
.elem-palette {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin: 6px 0 0;
}

.elem-btn {
    width: 44px;
    height: 44px;
    border-radius: var(--r);
    border: 1px solid var(--brd2);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: border-color .12s, background .12s, transform .1s;
    background: var(--bg2);
}

.elem-btn:hover {
    border-color: var(--accent);
    background: var(--bg3);
    transform: scale(1.06);
}

.elem-btn.selected {
    border-color: var(--accent);
    background: var(--accent-dim);
    box-shadow: 0 0 0 1px var(--accent-glow);
}

.elem-btn .sym {
    font: 700 13px/1 var(--font);
}

.elem-btn .num {
    font: 500 8.5px/1 var(--mono);
    color: var(--txt3);
    margin-top: 3px;
    letter-spacing: .5px;
}

/* ── Modal ────────────────────────────────────────────────── */
.modal-bg {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0, 0, 0, 0.65);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    z-index: 100;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 16px;
}

.modal-bg.open { display: flex; }

.mdl {
    background: var(--bg2);
    border-radius: 10px;
    border: 1px solid var(--brd2);
    box-shadow: var(--shadow);
    max-width: 420px;
    width: 100%;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.mdl-h {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 18px;
    border-bottom: 1px solid var(--brd);
}

.mdl-h h3 {
    font: 700 13px/1 var(--font);
    color: var(--txt1);
    letter-spacing: .5px;
    text-transform: uppercase;
}

.mdl-h button {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 18px;
    color: var(--txt3);
    line-height: 1;
    padding: 0;
    transition: color .1s;
}

.mdl-h button:hover { color: var(--txt1); }

.mdl-b {
    padding: 16px 18px;
}

.mdl-b p {
    font: 400 12.5px/1.55 var(--font);
    color: var(--txt2);
    margin: 0 0 12px;
}

.mdl-b input[type=text] {
    width: 100%;
    font: 400 13px/1.4 var(--font);
    color: var(--txt1);
    background: var(--bg3);
    border: 1px solid var(--brd2);
    border-radius: var(--r);
    padding: 10px 14px;
    outline: none;
    transition: border-color .12s;
}

.mdl-b input[type=text]:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 2px var(--accent-dim);
}

.mdl-f {
    display: flex;
    gap: 8px;
    justify-content: flex-end;
    padding: 12px 18px;
    border-top: 1px solid var(--brd);
}

.mdl-f .status {
    font: 400 11.5px/1 var(--font);
    color: var(--green);
    align-self: center;
    margin-right: auto;
    opacity: 0;
    transition: opacity .2s;
}

.mdl-f .status.show { opacity: 1; }

/* ── Saved items ──────────────────────────────────────────── */
.saved-list {
    max-height: 180px;
    overflow-y: auto;
    margin: 8px 0 0;
}

.saved-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 10px;
    border-radius: var(--r);
    cursor: pointer;
    transition: background .1s;
    border: 1px solid transparent;
}

.saved-item:hover {
    background: var(--bg3);
    border-color: var(--brd);
}

.saved-item .si-name {
    font: 500 12.5px/1.2 var(--font);
    color: var(--txt1);
    flex: 1;
}

.saved-item .si-date {
    font: 400 10px/1 var(--mono);
    color: var(--txt3);
    letter-spacing: .3px;
}

.saved-item .si-del {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 15px;
    color: var(--txt3);
    padding: 0;
    opacity: 0;
    transition: opacity .1s, color .1s;
}

.saved-item:hover .si-del { opacity: 1; }
.saved-item .si-del:hover { color: var(--red); }

#file-input { display: none; }

/* ── Custom element modal ─────────────────────────────────── */
.custom-row {
    display: flex;
    gap: 10px;
    margin: 8px 0 0;
}

.custom-row input {
    flex: 1;
    font: 400 12.5px/1 var(--font);
    color: var(--txt1);
    background: var(--bg3);
    border: 1px solid var(--brd2);
    border-radius: var(--r);
    padding: 8px 12px;
    outline: none;
    transition: border-color .12s;
}

.custom-row input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 2px var(--accent-dim);
}

/* ── Overlay panels ───────────────────────────────────────── */
#top-left-panel {
    position: absolute;
    top: 12px; left: 12px;
    width: auto;
    max-width: 280px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 20;
    pointer-events: none;
}

#top-left-panel > * { pointer-events: auto; }

#top-right-panel {
    position: absolute;
    top: 12px; right: 12px;
    width: 310px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 20;
    pointer-events: none;
}

#top-right-panel > * { pointer-events: auto; }

.panel-box {
    background: var(--panel-bg);
    border: 1px solid var(--brd);
    border-radius: 8px;
    padding: 12px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
}

/* ── Misc ─────────────────────────────────────────────────── */
.ui-hidden { display: none !important; }

/* Inputs / selects inside panels */
select {
    font: 400 11px/1 var(--font) !important;
    border: 1px solid var(--brd2) !important;
    border-radius: 4px !important;
    padding: 3px 6px !important;
    background: var(--bg2) !important;
    color: var(--txt1) !important;
    outline: none;
}

input[type=checkbox] { accent-color: var(--accent); }

/* Scrollbar styling */
::-webkit-scrollbar { width: 4px; height: 4px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--brd2); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--txt3); }

/* ── Body scroll lock (when modal open) ──────────────────── */
body.modal-open {
    overflow: hidden;
    /* Prevent iOS Safari from scrolling the page behind the modal */
    position: fixed;
    width: 100%;
}

/* ── Mobile stats toggle button ───────────────────────────── */
#mobile-stats-toggle {
    display: none;
    position: absolute;
    top: 12px;
    left: 12px;
    z-index: 25;
    align-items: center;
    gap: 5px;
    padding: 6px 11px;
    background: var(--panel-bg);
    border: 1px solid var(--brd);
    border-radius: var(--r);
    font: 600 9px/1 var(--mono);
    letter-spacing: 1.2px;
    color: var(--txt2);
    cursor: pointer;
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    box-shadow: var(--shadow-sm);
    text-transform: uppercase;
    transition: color .12s, border-color .12s;
}

#mobile-stats-toggle.active {
    color: var(--accent);
    border-color: var(--accent);
}

/* ── Mobile breakpoint ────────────────────────────────────── */
@media (max-width: 640px) {
    body { padding: 8px; }

    /* Compact app bar — hide undo/redo, no editing on mobile */
    #undo-redo-group { display: none !important; }

    /* Hide the entire right panel — no editing use case on mobile */
    #top-right-panel { display: none !important; }

    /* Left stats panel hidden by default; toggle reveals it */
    #top-left-panel:not(.mobile-visible) { display: none !important; }

    /* Show the toggle button */
    #mobile-stats-toggle { display: flex !important; }

    /* Context bars need room at the bottom */
    .ctx-bar {
        bottom: 10px !important;
        left: 10px !important;
        right: 10px;
        font-size: 10.5px;
    }

    /* Status bar font size */
    #status-bar { font-size: 8.5px; }

    /* Modals fill screen on mobile */
    .mdl { max-width: 100%; }
    .modal-bg { padding: 12px; align-items: flex-end; }
    .mdl { border-radius: 12px 12px 0 0; }
}