:root {
            --bg-color: #1a1030;
            --container-bg: #241a3d;
            --card-bg: #2c2049;
            --border-color: #3f3060;
            --accent-pink: #fb7185;
            --accent-amber: #fbbf24;
            --accent-green: #4ade80;
            --accent-red: #f87171;
            --accent-cyan: #38bdf8;
            --text-primary: #f4f1fb;
            --text-secondary: #a795c9;
            --font-display: 'Baloo 2', cursive;
            --font-mono: 'Space Mono', monospace;
            --glow-color: rgba(251, 113, 133, 0.25);
            --shadow-color: rgba(0, 0, 0, 0.55);
            --panel-sunken: rgba(0, 0, 0, 0.28);
            --canvas-bg: #150c28;

            /* Shared kit mapping */
            --kit-accent: var(--accent-pink);
            --kit-accent-ink: #2a0510;
            --kit-accent-glow: var(--glow-color);
            --kit-surface: var(--card-bg);
            --kit-border: var(--border-color);
            --kit-input-bg: var(--container-bg);
            --kit-error: var(--accent-red);
        }

        /* TRUE LIGHT THEME — a bright, sunny amusement-park midday look,
           not a second dark palette. Backgrounds sit in the #f7f3fb–#ffffff
           range with dark, readable text and warmer accent tones. */
        body.light-mode {
            --bg-color: #f7f2fb;
            --container-bg: #ffffff;
            --card-bg: #fbf7ff;
            --border-color: #ddd0ef;
            --accent-pink: #db2777;
            --accent-amber: #b45309;
            --accent-green: #15803d;
            --accent-red: #dc2626;
            --accent-cyan: #0369a1;
            --text-primary: #241a3d;
            --text-secondary: #6a5a8a;
            --glow-color: rgba(219, 39, 119, 0.14);
            --shadow-color: rgba(60, 30, 80, 0.1);
            --panel-sunken: rgba(60, 30, 80, 0.05);
            --canvas-bg: #fbf7ff;

            /* Shared kit mapping (light) — redeclared in full: a custom
               property whose value is var(--other-var) does not reliably
               re-track that other var's light-mode override, so every
               --kit-* token must be restated here, not just the ink. White
               ink reads better on the deeper light-mode magenta accent
               than the dark maroon ink used in dark mode. */
            --kit-accent: var(--accent-pink);
            --kit-accent-ink: #ffffff;
            --kit-accent-glow: rgba(219, 39, 119, 0.16);
            --kit-surface: var(--card-bg);
            --kit-border: var(--border-color);
            --kit-input-bg: var(--container-bg);
            --kit-error: var(--accent-red);
        }

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            transition: background-color 0.25s ease, color 0.25s ease, border-color 0.25s ease;
        }

        body {
            background-color: var(--bg-color);
            color: var(--text-primary);
            font-family: var(--font-mono);
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            padding: 16px;
        }

        .top-controls {
            position: fixed;
            top: 18px;
            right: 22px;
            z-index: 1000;
        }

        .theme-toggle-btn {
            background: var(--container-bg);
            color: var(--text-primary);
            border: 2px solid var(--border-color);
            padding: 8px 16px;
            border-radius: 10px;
            font-family: var(--font-mono);
            font-weight: 700;
            font-size: 0.85rem;
            cursor: pointer;
            box-shadow: 0 4px 12px var(--shadow-color);
            display: flex;
            align-items: center;
            gap: 6px;
        }

        .theme-toggle-btn:hover {
            border-color: var(--accent-pink);
            color: var(--accent-pink);
        }

        .park-container {
            width: 100%;
            max-width: 1000px;
            background: var(--container-bg);
            border: 2px solid var(--border-color);
            border-top: 6px solid var(--accent-pink);
            border-radius: 16px;
            padding: 28px;
            box-shadow: 0 16px 40px var(--shadow-color);
            min-height: 600px;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
        }

        .park-title {
            font-family: var(--font-display);
            font-size: 1.9rem;
            font-weight: 800;
            color: var(--accent-pink);
            text-align: center;
            letter-spacing: 0.3px;
            margin-bottom: 4px;
        }

        .park-subtitle {
            font-family: var(--font-mono);
            text-align: center;
            color: var(--text-secondary);
            font-size: 0.85rem;
            margin-bottom: 20px;
            letter-spacing: 0.5px;
            text-transform: uppercase;
        }

        .hud-status-bar {
            display: flex;
            justify-content: space-between;
            align-items: center;
            background: var(--panel-sunken);
            border: 1px solid var(--border-color);
            padding: 12px 18px;
            margin-bottom: 20px;
            font-family: var(--font-mono);
            border-radius: 10px;
            flex-wrap: wrap;
            gap: 10px;
        }

        .hud-item {
            display: flex;
            flex-direction: column;
        }

        .hud-label {
            font-size: 0.72rem;
            color: var(--text-secondary);
            text-transform: uppercase;
        }

        .hud-value {
            font-size: 1.05rem;
            font-weight: 700;
            color: var(--accent-pink);
        }

        .meter-container {
            width: 130px;
            height: 12px;
            background: var(--border-color);
            border-radius: 6px;
            overflow: hidden;
            margin-top: 4px;
        }

        .meter-fill {
            height: 100%;
            width: 10%;
            background: var(--accent-amber);
            transition: width 0.3s ease, background-color 0.3s ease;
        }

        .arena-grid {
            display: grid;
            grid-template-columns: 420px 1fr;
            gap: 22px;
            align-items: start;
        }

        @media (max-width: 900px) {
            .arena-grid {
                grid-template-columns: 1fr;
            }
        }

        .canvas-wrapper {
            position: relative;
            width: 100%;
            max-width: 420px;
            height: 320px;
            margin: 0 auto;
            background: var(--canvas-bg);
            border: 2px solid var(--border-color);
            border-radius: 12px;
            box-shadow: inset 0 0 20px rgba(251, 113, 133, 0.06);
        }

        canvas {
            display: block;
            width: 100%;
            height: 100%;
            cursor: grab;
            border-radius: 12px;
        }

        canvas:active {
            cursor: grabbing;
        }

        .cheer-layer {
            position: absolute;
            inset: 0;
            pointer-events: none;
            overflow: hidden;
            border-radius: 12px;
        }

        .cheer-burst {
            position: absolute;
            left: 50%;
            top: 45%;
            transform: translate(-50%, -50%) scale(0.6);
            font-family: var(--font-display);
            font-weight: 800;
            font-size: 1.3rem;
            color: var(--accent-green);
            text-shadow: 0 2px 10px var(--shadow-color);
            animation: cheerPop 1.15s ease-out forwards;
            white-space: nowrap;
        }

        @keyframes cheerPop {
            0% { transform: translate(-50%, -40%) scale(0.5); opacity: 0; }
            25% { transform: translate(-50%, -60%) scale(1.15); opacity: 1; }
            75% { transform: translate(-50%, -80%) scale(1); opacity: 1; }
            100% { transform: translate(-50%, -100%) scale(0.9); opacity: 0; }
        }

        .shake-canvas {
            animation: derailShake 0.5s ease-in-out infinite;
        }

        @keyframes derailShake {
            0%, 100% { transform: translateX(0) rotate(0deg); }
            25% { transform: translateX(-3px) rotate(-0.6deg); }
            75% { transform: translateX(3px) rotate(0.6deg); }
        }

        .drag-instructions {
            background: var(--panel-sunken);
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 12px 14px;
            margin-bottom: 14px;
            font-size: 0.82rem;
            line-height: 1.6;
        }

        .drag-step {
            display: flex;
            align-items: flex-start;
            gap: 8px;
            margin-bottom: 6px;
        }

        .drag-step:last-child {
            margin-bottom: 0;
        }

        .drag-dot {
            flex: none;
            width: 12px;
            height: 12px;
            border-radius: 50%;
            margin-top: 3px;
            box-shadow: 0 0 0 2px var(--container-bg);
        }

        .vertex-dot {
            background: var(--accent-amber);
        }

        .axis-dot {
            background: var(--accent-cyan);
        }

        .guess-readout {
            display: flex;
            justify-content: space-between;
            gap: 10px;
            flex-wrap: wrap;
            font-family: var(--font-mono);
            font-size: 0.82rem;
            color: var(--text-secondary);
            background: var(--panel-sunken);
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 10px 14px;
            margin-bottom: 16px;
        }

        .guess-readout strong {
            color: var(--accent-pink);
        }

        .terminal-panel {
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            border-radius: 12px;
            padding: 20px;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
            min-height: 320px;
        }

        .equation-box {
            background: var(--panel-sunken);
            border: 1px solid var(--border-color);
            border-left: 3px solid var(--accent-pink);
            padding: 14px 18px;
            margin-bottom: 16px;
            border-radius: 8px;
        }

        .equation-title {
            font-family: var(--font-mono);
            font-size: 0.72rem;
            color: var(--accent-pink);
            text-transform: uppercase;
            letter-spacing: 1px;
            margin-bottom: 6px;
        }

        .equation-text {
            font-family: var(--font-display);
            font-size: 1.25rem;
            font-weight: 700;
            line-height: 1.5;
        }

        .fire-btn {
            background: var(--accent-pink);
            color: #2a0510;
            border: none;
            padding: 14px;
            font-family: var(--font-display);
            font-size: 1.05rem;
            font-weight: 700;
            letter-spacing: 0.5px;
            text-transform: uppercase;
            cursor: pointer;
            border-radius: 10px;
            box-shadow: 0 4px 14px var(--glow-color);
            transition: transform 0.15s ease, opacity 0.15s ease;
            width: 100%;
        }

        .fire-btn:hover {
            transform: translateY(-2px);
            opacity: 0.95;
        }

        .feedback-line {
            font-family: var(--font-mono);
            text-align: center;
            font-size: 0.95rem;
            font-weight: 700;
            min-height: 24px;
            letter-spacing: 0.3px;
            margin-top: 10px;
        }

        .text-success { color: var(--accent-green); }
        .text-error { color: var(--accent-red); }

        .screen-center {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            text-align: center;
            padding: 10px 0;
        }

        .action-btn {
            background: var(--accent-pink);
            color: #2a0510;
            border: none;
            padding: 14px 36px;
            font-family: var(--font-display);
            font-size: 1.05rem;
            font-weight: 800;
            text-transform: uppercase;
            letter-spacing: 0.5px;
            cursor: pointer;
            margin-top: 20px;
            border-radius: 10px;
            box-shadow: 0 4px 12px var(--shadow-color);
        }

        .action-btn:hover {
            opacity: 0.9;
        }

        .brief-box {
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            padding: 20px 28px;
            text-align: left;
            margin: 20px 0;
            max-width: 680px;
            line-height: 1.7;
            font-size: 0.95rem;
            border-radius: 12px;
        }

        .brief-box ul {
            padding-left: 20px;
        }

        .brief-box li {
            margin-bottom: 8px;
        }

        footer {
            margin-top: 24px;
            font-family: var(--font-mono);
            font-size: 0.8rem;
            color: var(--text-secondary);
            text-align: center;
            letter-spacing: 0.5px;
        }