:root {
    --bg-dark: #0a0f1e;
    --bg-glass: rgba(10, 15, 30, 0.75);
    --acc-purple: #8b5cf6;
    --acc-cyan: #06b6d4;
    --acc-blue: #3b82f6;
    --text-primary: #f1f5f9;
    --text-muted: #94a3b8;
    --border-subtle: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(255, 255, 255, 0.18);
    --radius: 12px;
    --radius-lg: 16px;
}

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

body {
    background-color: var(--bg-dark);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--text-primary);
    overflow: hidden;
    width: 100vw;
    height: 100vh;
}

canvas { display: block; width: 100%; height: 100%; }

/* =========================================
    UI OVERLAY
   ========================================= */
#ui-overlay {
    position: absolute;
    inset: 0;
    pointer-events: none;
    display: flex;
    flex-direction: column;
}

/* ---- HEADER ---- */
header {
    padding: 18px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: linear-gradient(to bottom, rgba(10, 15, 30, 0.92), transparent);
    pointer-events: auto;
}

.title-group h1 {
    font-size: 1.35rem;
    font-weight: 700;
    letter-spacing: -0.03em;
}

.title-group h1 span {
    background: linear-gradient(135deg, var(--acc-purple), var(--acc-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.title-group p {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 2px;
}

.controls-top {
    display: flex;
    gap: 6px;
}

.btn-view {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-subtle);
    color: var(--text-primary);
    padding: 7px 14px;
    border-radius: var(--radius);
    font-size: 0.78rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.btn-view:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--acc-cyan);
    transform: translateY(-1px);
}

.btn-view.accent {
    background: linear-gradient(135deg, var(--acc-purple), #7c3aed);
    border-color: transparent;
}

.btn-view.accent:hover {
    background: linear-gradient(135deg, #9d74f7, var(--acc-purple));
}

.btn-view.active-mode {
    background: linear-gradient(135deg, var(--acc-cyan), #0891b2);
    border-color: #fff;
    box-shadow: 0 0 15px rgba(6, 182, 212, 0.6);
    animation: pulse-border 1.5s infinite;
}

@keyframes pulse-border {
    0% { box-shadow: 0 0 0 0 rgba(6, 182, 212, 0.7); }
    70% { box-shadow: 0 0 0 10px rgba(6, 182, 212, 0); }
    100% { box-shadow: 0 0 0 0 rgba(6, 182, 212, 0); }
}

/* ---- SIDEBAR ---- */
.sidebar {
    position: absolute;
    top: 90px;
    left: 20px;
    width: 250px;
    max-height: calc(100vh - 140px);
    overflow-y: auto;
    background: var(--bg-glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    pointer-events: auto;
    box-shadow: 0 12px 40px -8px rgba(0, 0, 0, 0.5);
}

.sidebar-content {
    padding: 18px;
}

.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-track { background: transparent; }
.sidebar::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.15); border-radius: 4px; }

.sidebar h2 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 14px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-subtle);
}

/* ---- ITEM GROUPS ---- */
.item-group {
    margin-bottom: 16px;
}

.item-group h3 {
    font-size: 0.68rem;
    text-transform: uppercase;
    color: var(--acc-cyan);
    margin-bottom: 8px;
    letter-spacing: 0.06em;
    font-weight: 600;
}

.add-item {
    display: flex;
    align-items: center;
    gap: 8px;
    width: 100%;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-subtle);
    color: var(--text-primary);
    padding: 8px 10px;
    border-radius: 8px;
    margin-bottom: 4px;
    text-align: left;
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.18s ease;
    font-family: inherit;
}

.add-item:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--border-hover);
    transform: translateX(3px);
}

.add-item:active {
    transform: translateX(1px) scale(0.98);
}

.item-icon {
    font-size: 1rem;
    width: 22px;
    text-align: center;
    flex-shrink: 0;
}

/* ---- SETTINGS ---- */
.settings {
    padding-top: 12px;
    border-top: 1px solid var(--border-subtle);
    margin-top: 8px;
}

.toggle-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.78rem;
    color: var(--text-muted);
    cursor: pointer;
}

.toggle-label input[type="checkbox"] {
    accent-color: var(--acc-cyan);
    width: 14px;
    height: 14px;
}

.keyboard-hint {
    margin-top: 10px;
    padding: 8px;
    background: rgba(139, 92, 246, 0.08);
    border-radius: 6px;
    text-align: center;
}

.keyboard-hint small {
    color: var(--text-muted);
    font-size: 0.7rem;
}

kbd {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 3px;
    padding: 1px 5px;
    font-size: 0.68rem;
    font-family: inherit;
}

/* ---- TOAST ---- */
.toast {
    position: absolute;
    top: 90px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, var(--acc-cyan), #0891b2);
    color: white;
    padding: 10px 24px;
    border-radius: 999px;
    font-weight: 600;
    font-size: 0.85rem;
    box-shadow: 0 6px 20px rgba(6, 182, 212, 0.35);
    transition: opacity 0.25s ease, transform 0.25s ease;
    pointer-events: none;
    z-index: 10;
}

.toast.hidden {
    opacity: 0;
    transform: translateX(-50%) translateY(-8px);
    pointer-events: none;
}

/* ---- FOOTER ---- */
footer.instructions {
    position: absolute;
    bottom: 20px;
    width: 100%;
    display: flex;
    justify-content: center;
    gap: 28px;
    color: var(--text-muted);
    font-size: 0.72rem;
    pointer-events: none;
    text-shadow: 0 1px 4px rgba(0,0,0,0.6);
}

/* ---- RESPONSIVE ---- */
@media (max-width: 768px) {
    .sidebar { width: 200px; left: 12px; top: 80px; }
    .controls-top { gap: 4px; }
    .btn-view { padding: 5px 10px; font-size: 0.7rem; }
    header { padding: 12px 16px; }
    footer.instructions { gap: 12px; font-size: 0.65rem; }
}