.history-timeline {
    flex-shrink: 0;
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-xs) 0;
}

.history-timeline.is-idle {
    visibility: hidden;
    pointer-events: none;
    height: 0;
    padding: 0;
    overflow: hidden;
}

.history-timeline__nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    width: 100%;
    max-width: 520px;
    margin: 0 auto;
}

.history-timeline__step-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    padding: 0;
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-full);
    background: var(--surface-dark);
    color: var(--text-light);
    font-size: 22px;
    line-height: 1;
    cursor: pointer;
    transition:
        background var(--transition-fast),
        border-color var(--transition-fast),
        opacity var(--transition-fast);
}

.history-timeline__step-btn:hover:not(:disabled) {
    background: var(--surface-hover);
    border-color: rgba(255, 255, 255, 0.2);
}

.history-timeline__step-btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

.history-timeline__track-area {
    position: relative;
    flex: 1;
    min-width: 0;
    height: 28px;
    display: flex;
    align-items: center;
}

.history-timeline__track {
    position: absolute;
    left: 7px;
    right: 7px;
    height: 4px;
    border-radius: var(--radius-full);
    background: rgba(255, 255, 255, 0.12);
    pointer-events: none;
}

.history-timeline__fill {
    position: absolute;
    left: 7px;
    top: 0;
    height: 100%;
    border-radius: var(--radius-full);
    background: rgba(59, 130, 246, 0.55);
    pointer-events: none;
    transition: width 0.2s ease;
}

.history-timeline__markers {
    position: absolute;
    left: 7px;
    right: 7px;
    top: 50%;
    height: 0;
    pointer-events: none;
}

.history-timeline__marker {
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 6px;
    height: 6px;
    padding: 0;
    border: none;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.45);
    cursor: pointer;
    pointer-events: auto;
    transition:
        transform var(--transition-fast),
        background var(--transition-fast);
}

.history-timeline__marker::before {
    content: '';
    position: absolute;
    inset: -10px;
}

.history-timeline__marker:hover {
    transform: translate(-50%, -50%) scale(1.2);
    background: rgba(255, 255, 255, 0.75);
}

.history-timeline__marker.is-original {
    background: rgba(147, 197, 253, 0.55);
}

.history-timeline__marker.is-original:hover {
    background: rgba(147, 197, 253, 0.85);
}

.history-timeline__scrubber {
    position: relative;
    z-index: 2;
    width: 100%;
    height: 28px;
    margin: 0;
    background: transparent;
    cursor: pointer;
    -webkit-appearance: none;
    appearance: none;
}

.history-timeline__scrubber:focus-visible {
    outline: none;
}

.history-timeline__scrubber:focus-visible::-webkit-slider-thumb {
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.45);
}

.history-timeline__scrubber::-webkit-slider-runnable-track {
    height: 4px;
    border-radius: var(--radius-full);
    background: transparent;
}

.history-timeline__scrubber::-moz-range-track {
    height: 4px;
    border-radius: var(--radius-full);
    background: transparent;
}

.history-timeline__scrubber::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    margin-top: -6px;
    border: 2px solid #fff;
    border-radius: 50%;
    background: var(--accent-blue);
    box-shadow:
        0 1px 4px rgba(0, 0, 0, 0.45),
        0 0 0 3px rgba(59, 130, 246, 0.35);
    cursor: grab;
}

.history-timeline__scrubber:active::-webkit-slider-thumb {
    cursor: grabbing;
}

.history-timeline__scrubber::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border: 2px solid #fff;
    border-radius: 50%;
    background: var(--accent-blue);
    box-shadow:
        0 1px 4px rgba(0, 0, 0, 0.45),
        0 0 0 3px rgba(59, 130, 246, 0.35);
    cursor: grab;
}

.history-timeline__caption {
    margin: var(--spacing-xs) 0 0;
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    text-align: center;
    letter-spacing: 0.02em;
}

@media (max-width: 480px) {
    .history-timeline__step-btn {
        width: 44px;
        height: 44px;
    }

    .history-timeline__nav {
        gap: var(--spacing-xs);
    }
}