:root {
    --primary: #4F46E5;
    --primary-hover: #4338CA;
    --bg: #F3F4F6;
    --surface: #FFFFFF;
    --text: #1F2937;
    --text-light: #6B7280;
    --border: #E5E7EB;
    --disabled: #D1D5DB;
    --error: #EF4444;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
        Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.5;
    margin: 0;
    padding: 0;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    background: var(--surface);
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

h1 {
    font-size: 1.5rem;
    margin-top: 0;
    margin-bottom: 8px;
    text-align: center;
}

.subtitle {
    color: var(--text-light);
    text-align: center;
    font-size: 0.9rem;
    margin-bottom: 24px;
}

/* 上传区 */
.upload-area {
    border: 2px dashed var(--border);
    border-radius: 8px;
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    position: relative;
}

.upload-area:hover {
    border-color: var(--primary);
    background-color: #F8FAFC;
}

.upload-area.disabled {
    opacity: 0.6;
    cursor: not-allowed;
    pointer-events: none;
}

.upload-area input[type="file"] {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    opacity: 0;
    cursor: pointer;
}

/* 视频信息 */
.video-info {
    background: #F9FAFB;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
    margin-top: 20px;
    display: none;
    font-size: 0.9rem;
}

.video-info p {
    margin: 4px 0;
}

.video-info strong {
    color: var(--text);
}

/* 分辨率选项 */
.options {
    margin-top: 24px;
    display: none;
}

.options h3 {
    font-size: 1rem;
    margin-bottom: 12px;
}

.radio-group {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.radio-label {
    display: flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
}

.radio-label.disabled {
    color: var(--disabled);
    cursor: not-allowed;
}

/* 按钮 */
.action-area {
    margin-top: 30px;
    text-align: center;
}

button {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 12px 32px;
    font-size: 1rem;
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.2s;
    width: 100%;
    font-weight: 600;
}

button:hover:not(:disabled) {
    background-color: var(--primary-hover);
}

button:disabled {
    background-color: var(--disabled);
    cursor: not-allowed;
}

/* 进度 */
.progress-container {
    margin-top: 20px;
    display: none;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--border);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 8px;
}

.progress-fill {
    height: 100%;
    background-color: var(--primary);
    width: 0%;
    transition: width 0.3s ease;
}

.status-text {
    font-size: 0.85rem;
    color: var(--text-light);
    text-align: center;
}

#downloadArea {
    margin-top: 20px;
    display: none;
}

.error-text {
    color: var(--error);
}

.file-limit {
    font-size: 0.85rem;
    color: #6B7280;
    margin-top: 4px;
}