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

:root {
    --primary-color: #4285f4;
    --primary-light: #e8f0fe;
    --primary-dark: #1a73e8;
    --secondary-color: #34a853;
    --accent-color: #ea4335;
    --warning-color: #fbbc04;
    --text-primary: #202124;
    --text-secondary: #5f6368;
    --text-tertiary: #80868b;
    --surface-color: #ffffff;
    --surface-secondary: #f8f9fa;
    --border-color: #dadce0;
    --shadow-1: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
    --shadow-2: 0 3px 6px rgba(0,0,0,0.16), 0 3px 6px rgba(0,0,0,0.23);
    --shadow-3: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);
    --border-radius: 8px;
    --border-radius-large: 12px;
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Google Sans', 'Roboto', 'Segoe UI', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 14px;
}

.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 顶部导航栏 */
.top-nav {
    background: var(--surface-color);
    box-shadow: var(--shadow-1);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
}

.nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-left .logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 500;
    color: var(--primary-color);
}

.nav-left .logo i {
    font-size: 24px;
}

.language-switcher {
    display: flex;
    background: var(--surface-secondary);
    border-radius: 20px;
    padding: 4px;
    border: 1px solid var(--border-color);
}

.lang-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: 16px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: var(--transition);
    font-family: inherit;
}

.lang-btn.active {
    background: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-1);
}

.lang-btn:hover:not(.active) {
    background: rgba(66, 133, 244, 0.1);
    color: var(--primary-color);
}

/* 主要内容区域 */
.main-content {
    flex: 1;
    padding: 24px;
}

.content-wrapper {
    max-width: 1200px;
    margin: 0 auto;
}

/* 欢迎区域 */
.hero-section {
    text-align: center;
    margin-bottom: 48px;
    color: white;
}

.hero-content h1 {
    font-size: 48px;
    font-weight: 400;
    margin-bottom: 16px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.hero-content p {
    font-size: 18px;
    margin-bottom: 32px;
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: 32px;
    flex-wrap: wrap;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.1);
    padding: 12px 20px;
    border-radius: 24px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.feature-item i {
    font-size: 16px;
    color: var(--warning-color);
}

/* 卡片样式 */
.upload-card, .settings-card, .preview-card {
    background: var(--surface-color);
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-2);
    margin-bottom: 24px;
    overflow: hidden;
    transition: var(--transition);
}

.upload-card:hover, .settings-card:hover, .preview-card:hover {
    box-shadow: var(--shadow-3);
}

/* 上传区域 */
.upload-section {
    margin-bottom: 24px;
}

.upload-area {
    padding: 48px 24px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.upload-area::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(66, 133, 244, 0.1), transparent);
    transition: left 0.6s;
}

.upload-area:hover::before {
    left: 100%;
}

.upload-area:hover {
    background: var(--primary-light);
}

.upload-area.dragover {
    background: var(--primary-light);
    transform: scale(1.02);
}

.upload-content {
    position: relative;
    z-index: 1;
}

.upload-icon {
    font-size: 48px;
    margin-bottom: 16px;
    color: var(--primary-color);
    opacity: 0.8;
}

.upload-area h3 {
    font-size: 24px;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-weight: 500;
}

.upload-area p {
    font-size: 16px;
    margin-bottom: 8px;
    color: var(--text-secondary);
}

.upload-hint {
    font-size: 14px;
    color: var(--text-tertiary);
    margin-bottom: 24px;
}

.upload-button {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--primary-color);
    color: white;
    padding: 12px 24px;
    border-radius: 24px;
    font-weight: 500;
    transition: var(--transition);
    box-shadow: var(--shadow-1);
}

.upload-button:hover {
    background: var(--primary-dark);
    box-shadow: var(--shadow-2);
    transform: translateY(-1px);
}

/* 设置区域 */
.settings-section {
    margin-bottom: 24px;
}

.card-header {
    padding: 24px 24px 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
}

.card-header h2 {
    font-size: 20px;
    font-weight: 500;
    color: var(--text-primary);
    margin: 0;
}

.settings-tabs {
    display: flex;
    background: var(--surface-secondary);
    border-radius: var(--border-radius);
    padding: 4px;
    border: 1px solid var(--border-color);
}

.tab-btn {
    background: transparent;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 14px;
}

.tab-btn.active {
    background: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-1);
}

.tab-btn:hover:not(.active) {
    background: rgba(66, 133, 244, 0.1);
    color: var(--primary-color);
}

.settings-content {
    padding: 24px;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.setting-group {
    margin-bottom: 24px;
}

.setting-group label {
    display: block;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-size: 14px;
}

/* 选择框样式 */
.select-wrapper {
    position: relative;
    display: inline-block;
    width: 100%;
}

.select-wrapper select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 14px;
    background: var(--surface-color);
    transition: var(--transition);
    appearance: none;
    font-family: inherit;
}

.select-wrapper select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(66, 133, 244, 0.2);
}

.select-wrapper i {
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-tertiary);
    pointer-events: none;
}

/* 颜色选择器 */
.color-options {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.color-option {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    padding: 8px 12px;
    border-radius: var(--border-radius);
    transition: var(--transition);
    border: 2px solid transparent;
    background: var(--surface-secondary);
}

.color-option:hover {
    background: var(--primary-light);
    border-color: var(--primary-color);
}

.color-option.selected {
    background: var(--primary-light);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.color-preview {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
}

.color-preview.white {
    background: #ffffff;
}

.color-preview.blue {
    background: #4285f4;
}

.color-preview.red {
    background: #ea4335;
}

/* 滑块样式 */
.slider-container {
    display: flex;
    align-items: center;
    gap: 16px;
}

.slider {
    flex: 1;
    height: 4px;
    border-radius: 2px;
    background: var(--border-color);
    outline: none;
    -webkit-appearance: none;
    min-width: 150px;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    box-shadow: var(--shadow-1);
}

.slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
    box-shadow: var(--shadow-1);
}

.slider-value {
    min-width: 50px;
    text-align: center;
    font-weight: 500;
    color: var(--primary-color);
    font-size: 14px;
}

/* 预览区域 */
.preview-section {
    margin-bottom: 24px;
}

.preview-controls {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.preview-container {
    padding: 24px;
    display: flex;
    justify-content: center;
}

#previewCanvas {
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    max-width: 100%;
    box-shadow: var(--shadow-1);
    background: white;
}

.preview-info {
    padding: 0 24px 24px;
}

.info-item {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 14px;
}

.info-item i {
    color: var(--primary-color);
}

/* 按钮样式 */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-family: inherit;
    box-shadow: var(--shadow-1);
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    box-shadow: var(--shadow-2);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--surface-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--border-color);
    box-shadow: var(--shadow-2);
    transform: translateY(-1px);
}

/* 页脚 */
.footer {
    background: var(--surface-color);
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 24px;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
    font-size: 14px;
}

.footer-links a:hover {
    color: var(--primary-color);
}

.footer-content p {
    color: var(--text-tertiary);
    font-size: 12px;
}

/* 消息提示 */
.success-message, .error-message {
    padding: 16px 20px;
    border-radius: var(--border-radius);
    margin: 16px 0;
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 500;
    font-size: 14px;
}

.success-message {
    background: #e6f4ea;
    color: #137333;
    border: 1px solid #34a853;
}

.error-message {
    background: #fce8e6;
    color: #c5221f;
    border: 1px solid #ea4335;
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-top: 2px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-content {
        padding: 0 16px;
    }
    
    .main-content {
        padding: 16px;
    }
    
    .hero-content h1 {
        font-size: 32px;
    }
    
    .hero-content p {
        font-size: 16px;
    }
    
    .hero-features {
        gap: 16px;
    }
    
    .feature-item {
        padding: 8px 16px;
        font-size: 12px;
    }
    
    .upload-area {
        padding: 32px 16px;
    }
    
    .upload-area h3 {
        font-size: 20px;
    }
    
    .card-header {
        padding: 16px 16px 0;
        flex-direction: column;
        align-items: flex-start;
    }
    
    .settings-content {
        padding: 16px;
    }
    
    .preview-container {
        padding: 16px;
    }
    
    .preview-controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .color-options {
        justify-content: center;
    }
    
    .footer-content {
        padding: 16px;
    }
    
    .footer-links {
        gap: 16px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.settings-section, .preview-section {
    animation: fadeIn 0.3s ease-out;
}

/* 页面加载动画 */
.app-container {
    opacity: 0;
    animation: fadeIn 0.5s ease-out forwards;
}