* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: #f5f5f5;
    color: #333;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 40px 20px;
}

.container {
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    padding: 40px;
    max-width: 600px;
    width: 100%;
}

h1 {
    font-size: 24px;
    font-weight: 600;
    text-align: center;
    margin-bottom: 8px;
}

.subtitle {
    text-align: center;
    color: #666;
    font-size: 14px;
    margin-bottom: 32px;
}

/* Upload Area */
.upload-area {
    border: 2px dashed #d0d0d0;
    border-radius: 8px;
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    background: #fafafa;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: #4a90d9;
    background: #f0f7ff;
}

.upload-icon {
    color: #999;
    margin-bottom: 12px;
}

.upload-area:hover .upload-icon,
.upload-area.dragover .upload-icon {
    color: #4a90d9;
}

.upload-text {
    font-size: 16px;
    color: #666;
    margin-bottom: 8px;
}

.upload-hint {
    font-size: 12px;
    color: #999;
}

/* File List */
.file-list {
    margin-top: 24px;
}

.file-list h3 {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 12px;
}

.file-list ul {
    list-style: none;
}

.file-list li {
    display: flex;
    align-items: center;
    padding: 10px 12px;
    background: #f9f9f9;
    border-radius: 6px;
    margin-bottom: 8px;
    font-size: 14px;
}

.file-name {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-size {
    color: #999;
    font-size: 12px;
    margin: 0 12px;
}

.btn-remove {
    background: none;
    border: none;
    color: #e74c3c;
    cursor: pointer;
    font-size: 12px;
    padding: 4px 8px;
}

.btn-remove:hover {
    text-decoration: underline;
}

/* Convert Button */
.btn-convert {
    display: block;
    width: 100%;
    padding: 12px;
    background: #4a90d9;
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    margin-top: 16px;
    transition: background 0.3s;
}

.btn-convert:hover {
    background: #357abd;
}

.btn-convert:disabled {
    background: #ccc;
    cursor: not-allowed;
}

/* Progress */
.progress {
    margin-top: 24px;
}

.progress-bar {
    height: 8px;
    background: #eee;
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: #4a90d9;
    border-radius: 4px;
    transition: width 0.3s;
}

.progress-text {
    text-align: center;
    font-size: 14px;
    color: #666;
    margin-top: 8px;
}

/* Results */
.results {
    margin-top: 24px;
}

.results h3 {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 12px;
}

.result-item {
    display: flex;
    align-items: center;
    padding: 12px;
    border-radius: 6px;
    margin-bottom: 8px;
    font-size: 14px;
}

.result-item.success {
    background: #f0fff0;
    border: 1px solid #d4edda;
}

.result-item.error {
    background: #fff5f5;
    border: 1px solid #f5c6cb;
}

.result-filename {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.result-status {
    margin: 0 12px;
    font-size: 13px;
}

.result-item.success .result-status {
    color: #28a745;
}

.result-item.error .result-status {
    color: #dc3545;
}

.btn-download {
    background: #28a745;
    color: #fff;
    padding: 6px 16px;
    border-radius: 4px;
    text-decoration: none;
    font-size: 13px;
    white-space: nowrap;
    transition: background 0.3s;
}

.btn-download:hover {
    background: #218838;
}

.btn-reset {
    display: block;
    width: 100%;
    padding: 12px;
    background: #6c757d;
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    margin-top: 16px;
    transition: background 0.3s;
}

.btn-reset:hover {
    background: #5a6268;
}

/* Responsive */
@media (max-width: 480px) {
    .container {
        padding: 24px;
    }

    h1 {
        font-size: 20px;
    }

    .upload-area {
        padding: 24px 16px;
    }
}