:root {
            /* Fourier Theme Colors */
            --color-fundamental: #38bdf8; /* Cyan */
            --color-fundamental-glow: rgba(56, 189, 248, 0.35);
            --color-harmonics: #a855f7;    /* Purple */
            --color-harmonics-glow: rgba(168, 85, 247, 0.35);
            --color-composite: #ff2a85;    /* Rose (composite wave) */
            --color-composite-glow: rgba(255, 42, 133, 0.35);
            --color-accent: #ffb000;       /* Amber */
            --color-accent-glow: rgba(255, 176, 0, 0.35);
        }

        .btn-sound {
            background: var(--color-accent);
            color: var(--bg-color);
            font-weight: 600;
            border: none;
            padding: 10px 18px;
            border-radius: 10px;
            font-size: 0.9rem;
            cursor: pointer;
            display: flex;
            align-items: center;
            gap: 8px;
            box-shadow: 0 4px 12px var(--color-accent-glow);
            transition: all var(--transition-speed) ease;
        }

        .btn-sound:hover {
            transform: translateY(-1px);
            box-shadow: 0 6px 18px rgba(255, 176, 0, 0.4);
        }

        .btn-sound.playing {
            background: #ef4444;
            color: white;
            box-shadow: 0 4px 12px rgba(239, 68, 68, 0.35);
        }

        /* Sliders layout */
        .harmonic-sliders {
            display: grid;
            grid-template-columns: 1fr;
            gap: 0.75rem;
            margin-top: 1rem;
        }

        .control-row {
            display: flex;
            align-items: center;
            gap: 12px;
        }

        .control-label {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.8rem;
            color: var(--text-muted);
            width: 140px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .control-val-display {
            background: rgba(255, 255, 255, 0.05);
            color: var(--text-color);
            font-size: 0.75rem;
            padding: 1px 5px;
            border-radius: 4px;
        }

        .harm-slider-even::-webkit-slider-thumb { background: var(--color-harmonics) !important; }

        /* Formula viewer styling */
        .formula-box {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.95rem;
            line-height: 1.6;
            color: var(--text-color);
            padding: 0.75rem;
            background: rgba(0, 0, 0, 0.2);
            border-radius: 8px;
            border: 1px solid rgba(255, 255, 255, 0.03);
            overflow-x: auto;
            white-space: pre-wrap;
            word-break: break-all;
        }

        .coeff-val { color: var(--color-accent); font-weight: 600; }
        .sin-term { color: var(--color-fundamental); }

        /* Code reference styling */
        .code-container {
            position: relative;
        }

        .code-tabs {
            display: flex;
            gap: 4px;
            margin-bottom: 6px;
        }

        .code-tab {
            background: rgba(255, 255, 255, 0.02);
            border: 1px solid var(--card-border);
            color: var(--text-muted);
            padding: 4px 10px;
            border-radius: 6px 6px 0 0;
            font-family: 'Outfit', sans-serif;
            font-size: 0.75rem;
            font-weight: 500;
            cursor: pointer;
            transition: all var(--transition-speed) ease;
        }

        .code-tab.active {
            color: var(--text-color);
            background: rgba(10, 12, 20, 0.9);
            border-bottom-color: transparent;
        }

        .code-panel {
            background: rgba(10, 12, 20, 0.9);
            border: 1px solid var(--card-border);
            border-radius: 0 10px 10px 10px;
            padding: 1.25rem;
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.8rem;
            color: #d1d5db;
            overflow-x: auto;
            line-height: 1.5;
        }

        /* Keyword colors for code display */
        .kw { color: #f43f5e; } /* keywords */
        .func { color: #38bdf8; } /* functions */
        .num { color: #a855f7; } /* numbers */
        .comment { color: #6b7c93; font-style: italic; }