.tool-main-area.red-outline {
    border: 2px solid red;
    border-radius: 10px;
    padding: 2rem;
    background: #fff;
    margin: 2rem 0;
    box-shadow: 0 2px 12px rgba(0,0,0,0.04);
}
.audio-joiner-tool {
    margin-bottom: 2rem;
}
#audio-joiner-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1rem;
}
#audio-files {
    padding: 0.5rem;
    border: 1px solid #ccc;
    border-radius: 6px;
    font-size: 1rem;
    background: #fafbfc;
}
.audio-file-list {
    margin: 1rem 0;
    min-height: 2rem;
}
.audio-file-item {
    display: flex;
    align-items: center;
    background: #f7f7fa;
    border: 1px solid #e0e0e0;
    border-radius: 6px;
    margin-bottom: 0.5rem;
    padding: 0.5rem 1rem;
    gap: 1rem;
    cursor: grab;
    transition: background 0.2s;
}
.audio-file-item.dragging {
    opacity: 0.5;
}
.audio-file-item.drag-over {
    background: #ffeaea;
    border-color: #ff4d4d;
}
.file-name {
    flex: 1 1 auto;
    font-weight: 500;
    color: #333;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.preview-btn, .remove-btn {
    background: #fff;
    border: 1px solid #ccc;
    border-radius: 4px;
    padding: 0.25rem 0.75rem;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s, border 0.2s;
}
.preview-btn:hover {
    background: #e6f7ff;
    border-color: #1890ff;
}
.remove-btn {
    color: #ff4d4d;
    border-color: #ff4d4d;
    font-weight: bold;
}
.remove-btn:hover {
    background: #ffeaea;
}
.drag-handle {
    cursor: grab;
    font-size: 1.3rem;
    color: #888;
    margin-left: 0.5rem;
}
.primary-btn {
    background: #ff4d4d;
    color: #fff;
    border: none;
    border-radius: 6px;
    padding: 0.75rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 1rem;
    transition: background 0.2s;
}
.primary-btn:disabled {
    background: #ffd6d6;
    color: #aaa;
    cursor: not-allowed;
}
.primary-btn:hover:not(:disabled) {
    background: #d93636;
}
.feedback {
    margin: 1rem 0;
    color: #d93636;
    font-weight: 500;
    min-height: 1.5rem;
}
.merged-audio-section {
    margin-top: 2rem;
    background: #f7f7fa;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    padding: 1.5rem;
    text-align: center;
}
.download-btn {
    display: inline-block;
    margin-top: 1rem;
    background: #1890ff;
    color: #fff;
    padding: 0.75rem 2rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: background 0.2s;
}
.download-btn:hover {
    background: #1464b0;
}
.instructions ul {
    margin: 0.5rem 0 0 1.5rem;
    padding: 0;
    color: #555;
    font-size: 1rem;
}
.tool-faq {
    margin-top: 2rem;
}
.faq-list details {
    margin-bottom: 1rem;
    background: #fafbfc;
    border-radius: 6px;
    padding: 0.75rem 1rem;
    border: 1px solid #e0e0e0;
}
.faq-list summary {
    font-weight: 600;
    cursor: pointer;
}
.tool-seo {
    margin-top: 2.5rem;
    color: #222;
    font-size: 1.08rem;
    line-height: 1.7;
}
.tool-seo h2, .tool-seo h3 {
    margin-top: 1.5rem;
    font-size: 1.2rem;
    color: #d93636;
}
@media (max-width: 900px) {
    .tool-main-area.red-outline {
        padding: 1rem;
    }
    .merged-audio-section {
        padding: 1rem;
    }
}
@media (max-width: 600px) {
    .tool-main-area.red-outline {
        margin: 1rem 0;
        padding: 0.5rem;
    }
    .audio-file-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
        padding: 0.5rem;
    }
    .download-btn {
        width: 100%;
    }
}