/* --- sidebar --- */

#controls {
    width: 260px;
    flex-shrink: 0;
    height: 100%;
    overflow-y: auto;
    background: var(--panel);
    border-right: 1px solid var(--panel-border);
    padding: 24px 20px;
    display: flex;
    flex-direction: column;
    gap: 22px;
}

.panel-header h1 {
    margin: 0;
    font-size: 1.15rem;
    letter-spacing: 0.12em;
    color: var(--teal);
}

.panel-header .tagline {
    margin: 4px 0 0;
    font-size: 0.75rem;
    color: var(--text-dim);
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group.hidden {
    display: none;
}

.control-group label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-dim);
}

.control-group label span {
    color: var(--amber);
}

.shortcuts-hint {
    margin: 0;
    font-size: 0.68rem;
    color: var(--text-dim);
    text-align: center;
}

/* --- select --- */

select {
    background: var(--bg);
    color: var(--text);
    border: 1px solid var(--panel-border);
    border-radius: 4px;
    padding: 8px 10px;
    font: inherit;
    font-size: 0.85rem;
}

select:focus-visible {
    outline: 2px solid var(--teal);
    outline-offset: 1px;
}

/* --- range sliders --- */

input[type='range'] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 4px;
    background: var(--panel-border);
    border-radius: 2px;
}

input[type='range']::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background: var(--amber);
    cursor: pointer;
    border: 2px solid var(--bg);
}

input[type='range']::-moz-range-thumb {
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background: var(--amber);
    cursor: pointer;
    border: 2px solid var(--bg);
}

input[type='range']:focus-visible {
    outline: 2px solid var(--teal);
    outline-offset: 3px;
}

/* --- range + number pairing --- */

.range-row {
    display: flex;
    align-items: center;
    gap: 10px;
}

.range-row input[type='range'] {
    flex: 1;
}

.range-row input[type='number'] {
    width: 60px;
    flex-shrink: 0;
    font: inherit;
    font-size: 0.85rem;
    background: var(--bg);
    color: var(--text);
    border: 1px solid var(--panel-border);
    border-radius: 4px;
    padding: 4px 6px;
    text-align: right;
}

.range-row input[type='number']:focus-visible {
    outline: 2px solid var(--teal);
    outline-offset: 1px;
}

.range-row input[type='number']::-webkit-inner-spin-button,
.range-row input[type='number']::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

/* --- buttons --- */

.button-row {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 6px;
}

button {
    font: inherit;
    font-size: 0.85rem;
    padding: 10px 14px;
    border-radius: 4px;
    border: 1px solid var(--panel-border);
    background: var(--bg);
    color: var(--text);
    cursor: pointer;
    transition: border-color 0.15s ease, color 0.15s ease;
}

button:hover {
    border-color: var(--teal);
    color: var(--teal);
}

button:focus-visible {
    outline: 2px solid var(--teal);
    outline-offset: 2px;
}

button:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    border-color: var(--panel-border);
    color: var(--text-dim);
}

button:disabled:hover {
    border-color: var(--panel-border);
    color: var(--text-dim);
}

button.primary {
    background: var(--teal);
    border-color: var(--teal);
    color: var(--bg);
    font-weight: 700;
}

button.primary:hover {
    background: transparent;
    color: var(--teal);
}

/* --- media queries --- */

@media (max-width: 860px) {
    #controls {
        width: 100%;
        height: auto;
        overflow-y: visible;
        border-right: none;
        border-bottom: 1px solid var(--panel-border);
        padding: 20px 16px;
    }

    .button-row {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 8px;
    }

    /* .button-row #play-pause-btn {
        grid-column: span 2;
        order: -1;
    }

    .button-row #new-array-btn { order: 1; }
    .button-row #step-btn { order: 2; }
    .button-row #benchmark-btn { order: 3; }
    .button-row #code-btn { order: 4; } */
}

@media (max-width: 480px) {
    .panel-header h1 {
        font-size: 1rem;
    }

    .range-row input[type='number'] {
        width: 52px;
        font-size: 0.78rem;
    }

    .timeline-controls button {
        font-size: 0.72rem;
        padding: 8px 2px;
    }
}