:root {
    /* 颜色系统 - 浅色主题 */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #1a1a1a;
    --text-secondary: #6c757d;
    --text-tertiary: #adb5bd;
    
    /* 品牌色 */
    --color-primary: #6366f1;
    --color-primary-hover: #4f46e5;
    --color-success: #10b981;
    --color-success-hover: #059669;
    --color-danger: #ef4444;
    --color-warning: #f59e0b;
    
    /* 边框和阴影 */
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    /* 渐变 */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-success: linear-gradient(135deg, #10b981 0%, #059669 100%);
    
    /* 间距 */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* 圆角 */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* 字体 */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Consolas', monospace;
    
    /* 过渡 */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* 深色主题 */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-tertiary: #3d3d3d;
    --text-primary: #f8f9fa;
    --text-secondary: #adb5bd;
    --text-tertiary: #6c757d;
    --border-color: #404040;
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background var(--transition-base), color var(--transition-base);
}

/* 容器 */
.container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 头部 */
.header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-lg) var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.header-content {
    max-width: 1600px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-icon {
    font-size: 2rem;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

.header-actions {
    display: flex;
    gap: var(--spacing-sm);
}

/* 工具栏 */
.toolbar {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    transition: all var(--transition-base);
}

.toolbar-left,
.toolbar-right {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
    font-weight: 500;
    font-family: var(--font-sans);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    box-shadow: var(--shadow-sm);
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn:active {
    transform: translateY(0);
}

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

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

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

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

.btn-icon {
    background: transparent;
    border: 1px solid var(--border-color);
    padding: 0.5rem;
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

.btn-icon:hover {
    background: var(--bg-tertiary);
}

/* 工作区 */
.workspace {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 4px 1fr;
    gap: 0;
    max-width: 1600px;
    width: 100%;
    margin: 0 auto;
    padding: var(--spacing-lg);
    overflow: hidden;
}

/* 面板 */
.editor-panel,
.preview-panel {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: all var(--transition-base);
}

.panel-header {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--bg-secondary);
}

.panel-title {
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

.panel-badge {
    font-size: 0.75rem;
    padding: 0.25rem 0.625rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
}

/* 编辑器 */
.editor-wrapper {
    flex: 1;
    position: relative;
    overflow: hidden;
}

.markdown-editor {
    width: 100%;
    height: 100%;
    padding: var(--spacing-lg);
    font-family: var(--font-mono);
    font-size: 0.9375rem;
    line-height: 1.7;
    background: var(--bg-primary);
    color: var(--text-primary);
    border: none;
    outline: none;
    resize: none;
    transition: all var(--transition-base);
}

.markdown-editor::placeholder {
    color: var(--text-tertiary);
}

/* 拖拽区域 */
.drop-zone {
    position: absolute;
    inset: 0;
    background: rgba(99, 102, 241, 0.05);
    border: 2px dashed var(--color-primary);
    border-radius: var(--radius-md);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 10;
    pointer-events: none;
}

.drop-zone.active {
    display: flex;
}

.drop-zone-content {
    text-align: center;
}

.drop-zone-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: var(--spacing-sm);
}

.drop-zone-text {
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--color-primary);
}

/* 预览区 */
.preview-wrapper {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
}

.markdown-preview {
    padding: var(--spacing-xl);
    min-height: 100%;
}

/* 预览占位符 */
.preview-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    min-height: 400px;
    color: var(--text-tertiary);
}

.placeholder-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.5;
}

.placeholder-text {
    font-size: 1.25rem;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
}

.placeholder-hint {
    font-size: 0.875rem;
}

/* 分隔条 */
.divider {
    width: 4px;
    background: var(--border-color);
    cursor: col-resize;
    transition: background var(--transition-fast);
}

.divider:hover {
    background: var(--color-primary);
}

/* Markdown 预览样式 */
.markdown-preview h1,
.markdown-preview h2,
.markdown-preview h3,
.markdown-preview h4,
.markdown-preview h5,
.markdown-preview h6 {
    margin-top: 1.5em;
    margin-bottom: 0.75em;
    font-weight: 600;
    line-height: 1.3;
}

.markdown-preview h1 { font-size: 2em; border-bottom: 2px solid var(--border-color); padding-bottom: 0.3em; }
.markdown-preview h2 { font-size: 1.5em; border-bottom: 1px solid var(--border-color); padding-bottom: 0.3em; }
.markdown-preview h3 { font-size: 1.25em; }
.markdown-preview h4 { font-size: 1.1em; }

.markdown-preview p {
    margin-bottom: 1em;
}

.markdown-preview code {
    background: var(--bg-secondary);
    padding: 0.2em 0.4em;
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.875em;
}

.markdown-preview pre {
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: 1em 0;
}

.markdown-preview pre code {
    background: none;
    padding: 0;
}

.markdown-preview blockquote {
    border-left: 4px solid var(--color-primary);
    padding-left: var(--spacing-md);
    margin: 1em 0;
    color: var(--text-secondary);
}

.markdown-preview ul,
.markdown-preview ol {
    margin: 1em 0;
    padding-left: 2em;
}

.markdown-preview table {
    width: 100%;
    border-collapse: collapse;
    margin: 1em 0;
}

.markdown-preview th,
.markdown-preview td {
    border: 1px solid var(--border-color);
    padding: 0.5em 1em;
    text-align: left;
}

.markdown-preview th {
    background: var(--bg-secondary);
    font-weight: 600;
}

.markdown-preview img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
}

.markdown-preview a {
    color: var(--color-primary);
    text-decoration: none;
}

.markdown-preview a:hover {
    text-decoration: underline;
}

/* 页脚 */
.footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-lg);
    text-align: center;
}

.footer-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.footer-divider {
    margin: 0 var(--spacing-sm);
    color: var(--border-color);
}

/* 加载遮罩 */
.loading-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    transition: opacity var(--transition-base);
}

.loading-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.loading-spinner {
    width: 48px;
    height: 48px;
    border: 4px solid rgba(255, 255, 255, 0.2);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.loading-text {
    margin-top: var(--spacing-lg);
    color: white;
    font-size: 1.125rem;
    font-weight: 500;
}

/* Toast 提示 */
.toast {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    background: var(--bg-primary);
    color: var(--text-primary);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-color);
    z-index: 1001;
    transform: translateY(0);
    transition: all var(--transition-base);
}

.toast.hidden {
    transform: translateY(calc(100% + var(--spacing-xl)));
    opacity: 0;
}

.toast.success {
    border-left: 4px solid var(--color-success);
}

.toast.error {
    border-left: 4px solid var(--color-danger);
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .workspace {
        grid-template-columns: 1fr;
        grid-template-rows: 1fr 1fr;
    }
    
    .divider {
        display: none;
    }
}

@media (max-width: 768px) {
    .header {
        padding: var(--spacing-md);
    }
    
    .logo {
        font-size: 1.25rem;
    }
    
    .toolbar {
        padding: var(--spacing-sm) var(--spacing-md);
    }
    
    .workspace {
        padding: var(--spacing-md);
    }
    
    .btn {
        padding: 0.5rem 1rem;
        font-size: 0.8125rem;
    }
    
    .btn-icon span {
        font-size: 1.125rem;
    }
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-tertiary);
}