.controls {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
    flex-wrap: wrap;
    gap: 8px;
}

.controls-break {
    flex-basis: 100%;
    height: 0;
}

.clear {
    background-color: #f44336;
    color: white;
    border: none;
    padding: 3px 8px;
    border-radius: 2px;
    cursor: pointer;
    font-weight: bold;
}

.clear:hover {
    background-color: #d32f2f;
}

#brushSizeValue, #brushMixStrength {
    font-size: 12px;
    color: #a0a0a0;
    min-width: 16px;
    display: inline-block;
    text-align: right;
}

.brush-size {
    display: flex;
    align-items: center;
    gap: 2px;
}

.brush-size label {
    font-size: 12px;
    color: #ffffff;
}

.custom-range-wrap {
    position: relative;
    width: 50px;
    height: 18px;
    display: flex;
    align-items: center;
}

.brush-size input[type="range"] {
    position: absolute;
    opacity: 0;
    pointer-events: none;
    width: 100%;
}

.custom-range {
    position: absolute;
    left: 0;
    right: 0;
    height: 18px;
    display: flex;
    align-items: center;
    cursor: pointer;
    touch-action: none;
}

/* 轨道：已填充部分蓝色，未填充部分深灰 */
.custom-range::before {
    content: '';
    display: block;
    width: 100%;
    height: 3px;
    border-radius: 2px;
    background: linear-gradient(
        to right,
        #2196F3 var(--thumb-pos, 50%),
        #484848 var(--thumb-pos, 50%)
    );
}

/* 滑块 */
.custom-range::after {
    content: '';
    position: absolute;
    width: 11px;
    height: 11px;
    background: #ccc;
    border-radius: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    left: var(--thumb-pos, 50%);
    box-shadow: 0 1px 3px rgba(0,0,0,0.5);
    transition: background 0.1s, transform 0.1s;
}

.custom-range:hover::after {
    background: #fff;
}

.custom-range.dragging::after {
    background: #2196F3;
    transform: translate(-50%, -50%) scale(1.2);
}

.brush-size .unit {
    font-size: 10px;
    color: #a0a0a0;
}

.pressure-btn {
    width: 20px;
    height: 20px;
    padding: 0;
    margin-left: 2px;
    font-size: 12px;
    line-height: 20px;
    text-align: center;
    background: #3c3c3c;
    border: 1px solid #555;
    border-radius: 4px;
    color: #a0a0a0;
    cursor: pointer;
    opacity: 0.4;
    transition: opacity 0.15s, background 0.15s;
}

.pressure-btn.active {
    background: #2196F3;
    border-color: #1976D2;
    color: #fff;
    opacity: 1;
}

.brush-preview-group {
    display: flex;
    align-items: center;
    gap: 4px;
}

.brush-label {
    font-size: 12px;
    color: #ffffff;
}

.brush-preview-btn {
    width: 24px;
    height: 24px;
    border-radius: 4px;
    background-color: #3c3c3c;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border: 1px solid #4c4c4c;
}

.brush-preview-btn:hover {
    background-color: #4c4c4c;
}

.history-buttons {
    display: flex;
    gap: 4px;
}

.history-buttons button {
    width: 24px;
    height: 24px;
    border-radius: 4px;
    background-color: #3c3c3c;
    border: 1px solid #4c4c4c;
    font-size: 18px;
    cursor: pointer;
    color: #e0e0e0;
}

.history-buttons button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.history-buttons button:hover:not(:disabled) {
    background-color: #4c4c4c;
}

.tool-buttons {
    display: flex;
    gap: 3px;
    margin-left: 8px;
}

.tool-btn {
    width: 26px;
    height: 26px;
    border-radius: 4px;
    background-color: #3c3c3c;
    border: 1px solid #4c4c4c;
    cursor: pointer;
    color: #b0b0b0;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.tool-btn:hover {
    background-color: #4c4c4c;
    color: #e0e0e0;
}

.tool-btn.active {
    background-color: #2196F3;
    border-color: #1976D2;
    box-shadow: 0 0 8px rgba(33, 150, 243, 0.5);
    color: #ffffff;
}