/* ===== 全局样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #4F46E5;
    --primary-hover: #4338CA;
    --secondary-color: #6B7280;
    --secondary-hover: #4B5563;
    --success-color: #10B981;
    --error-color: #EF4444;
    --bg-color: #F9FAFB;
    --card-bg: #FFFFFF;
    --text-primary: #111827;
    --text-secondary: #6B7280;
    --border-color: #E5E7EB;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
}

/* ===== 头部样式 ===== */
.header {
    background-color: var(--card-bg);
    box-shadow: var(--shadow);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.user-section {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}

.user-name {
    font-weight: 500;
    color: var(--text-primary);
}

/* ===== 按钮样式 ===== */
.btn {
    padding: 0.625rem 1.25rem;
    border: none;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-secondary:hover:not(:disabled) {
    background-color: var(--secondary-hover);
}

/* ===== 主内容区域 ===== */
.main {
    flex: 1;
    padding: 2rem 0;
}

/* ===== 欢迎卡片 ===== */
.welcome-section {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
}

.welcome-card {
    background-color: var(--card-bg);
    border-radius: 1rem;
    padding: 3rem;
    box-shadow: var(--shadow-lg);
    text-align: center;
    max-width: 500px;
}

.welcome-card h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.welcome-card p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.welcome-card .hint {
    margin-top: 1.5rem;
    font-size: 0.875rem;
    color: var(--secondary-color);
}

/* ===== 应用功能区域 ===== */
.app-section {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* ===== 上传卡片 ===== */
.upload-card {
    background-color: var(--card-bg);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
}

.upload-card h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 0.75rem;
    padding: 3rem 2rem;
    text-align: center;
    transition: all 0.3s;
    cursor: pointer;
    position: relative;
    min-height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-color);
}

.upload-area:hover {
    border-color: var(--primary-color);
    background-color: #F3F4F6;
}

.upload-area.dragover {
    border-color: var(--primary-color);
    background-color: #EEF2FF;
}

.upload-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.upload-icon {
    width: 64px;
    height: 64px;
    color: var(--secondary-color);
}

.upload-placeholder p {
    color: var(--text-secondary);
    font-size: 1rem;
}

.upload-hint {
    font-size: 0.875rem;
    color: var(--secondary-color);
}

.preview-image,
.preview-video {
    max-width: 100%;
    max-height: 500px;
    border-radius: 0.5rem;
    object-fit: contain;
}

.upload-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
    justify-content: center;
}

/* ===== 加载状态 ===== */
.loading-card {
    background-color: var(--card-bg);
    border-radius: 1rem;
    padding: 3rem;
    box-shadow: var(--shadow-lg);
    text-align: center;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1.5rem;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.loading-card p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* ===== 结果卡片 ===== */
.result-card {
    background-color: var(--card-bg);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
}

.result-card h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.result-content {
    background-color: var(--bg-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    line-height: 1.8;
    color: var(--text-primary);
    white-space: pre-wrap;
    word-wrap: break-word;
}

.result-content p {
    margin-bottom: 1rem;
}

.result-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* ===== 页脚样式 ===== */
.footer {
    background-color: var(--card-bg);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: auto;
}

.footer .container {
    text-align: center;
}

.copyright {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-top: 1rem;
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        gap: 1rem;
    }

    .logo {
        font-size: 1.25rem;
    }

    .welcome-card {
        padding: 2rem 1.5rem;
    }

    .welcome-card h2 {
        font-size: 1.5rem;
    }

    .upload-card,
    .result-card {
        padding: 1.5rem;
    }

    .upload-area {
        padding: 2rem 1rem;
        min-height: 250px;
    }

    .upload-actions,
    .result-actions {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .user-info {
        flex-wrap: wrap;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .main {
        padding: 1.5rem 0;
    }

    .upload-area {
        min-height: 200px;
    }

    .preview-image,
    .preview-video {
        max-height: 300px;
    }
}