:root {
    /* ========================================
       现代化配色系统
       ======================================== */
    
    /* 主色调 - 深蓝紫渐变系 */
    --color-primary: #4F46E5;
    --color-primary-light: #6366F1;
    --color-primary-dark: #3730A3;
    --color-primary-soft: #EEF2FF;
    
    /* 辅助色 - 温暖珊瑚色 */
    --color-secondary: #F97316;
    --color-secondary-light: #FB923C;
    --color-secondary-dark: #EA580C;
    --color-secondary-soft: #FFF7ED;
    
    /* 中性色 */
    --color-text: #1F2937;
    --color-text-light: #4B5563;
    --color-text-muted: #9CA3AF;
    --color-text-inverse: #FFFFFF;
    
    /* 背景色 */
    --color-background: #FFFFFF;
    --color-background-alt: #F9FAFB;
    --color-background-warm: #FEF3F2;
    
    /* 边框色 */
    --color-border: #E5E7EB;
    --color-border-light: #F3F4F6;
    --color-border-focus: #4F46E5;
    
    /* 功能色 */
    --color-success: #10B981;
    --color-success-soft: #D1FAE5;
    --color-warning: #F59E0B;
    --color-warning-soft: #FEF3C7;
    --color-error: #EF4444;
    --color-error-soft: #FEE2E2;
    --color-info: #3B82F6;
    --color-info-soft: #DBEAFE;
    
    /* ========================================
       字体系统
       ======================================== */
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
    --font-family-mono: "SF Mono", "Fira Code", "Fira Mono", Menlo, Consolas, monospace;
    --font-size-xs: 12px;
    --font-size-sm: 14px;
    --font-size-base: 16px;
    --font-size-lg: 18px;
    --font-size-xl: 24px;
    --font-size-2xl: 32px;
    --font-size-3xl: 48px;
    
    /* ========================================
       间距系统
       ======================================== */
    --spacing-1: 4px;
    --spacing-2: 8px;
    --spacing-3: 12px;
    --spacing-4: 16px;
    --spacing-5: 20px;
    --spacing-6: 24px;
    --spacing-8: 32px;
    --spacing-10: 40px;
    --spacing-12: 48px;
    --spacing-16: 64px;
    
    /* ========================================
       圆角系统
       ======================================== */
    --border-radius-sm: 6px;
    --border-radius: 10px;
    --border-radius-lg: 16px;
    --border-radius-xl: 24px;
    --border-radius-full: 9999px;
    
    /* ========================================
       阴影系统
       ======================================== */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px 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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.05);
    
    /* ========================================
       过渡系统
       ======================================== */
    --transition-fast: 150ms ease;
    --transition: 300ms ease;
    --transition-slow: 500ms ease;
    
    /* ========================================
       布局系统
       ======================================== */
    --navbar-height: 72px;
    --sidebar-width: 260px;
    --container-max: 1200px;
    --container-narrow: 800px;
    --container-wide: 1400px;
}

/* ========================================
   深色主题
   ======================================== */
[data-theme="dark"] {
    --color-primary: #6366F1;
    --color-primary-light: #818CF8;
    --color-primary-dark: #4F46E5;
    --color-primary-soft: #1E1B4B;
    
    --color-secondary: #FB923C;
    --color-secondary-light: #FDBA74;
    --color-secondary-dark: #F97316;
    --color-secondary-soft: #431407;
    
    --color-text: #F3F4F6;
    --color-text-light: #D1D5DB;
    --color-text-muted: #9CA3AF;
    --color-text-inverse: #1F2937;
    
    --color-background: #0F172A;
    --color-background-alt: #1E293B;
    --color-background-warm: #2A1A15;
    
    --color-border: #374151;
    --color-border-light: #1F2937;
    --color-border-focus: #6366F1;
    
    --color-success: #34D399;
    --color-success-soft: #064E3B;
    --color-warning: #FBBF24;
    --color-warning-soft: #78350F;
    --color-error: #F87171;
    --color-error-soft: #7F1D1D;
    --color-info: #60A5FA;
    --color-info-soft: #1E3A8A;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
}

/* ========================================
   全局微调
   ======================================== */
::selection {
    background-color: var(--color-primary-soft);
    color: var(--color-primary);
}

:focus-visible {
    outline: 2px solid var(--color-border-focus);
    outline-offset: 2px;
}

img {
    max-width: 100%;
    height: auto;
}

hr {
    border: none;
    border-top: 1px solid var(--color-border);
    margin: var(--spacing-6) 0;
}