:root {
  color-scheme: light;

  --bg: #f5f7fb;                    
  --surface: #ffffff;               
  --surface-hover: #f0f2f8;         
  --border: #e2e6ef;                
  --border-strong: #c5cde0;         

  --text: #0f1629;                  
  --text-muted: #5a6580;            
  --text-dim: #8892a8;              
  --text-on-accent: #ffffff;        

  --accent: #4d6bfe;                
  --accent-hover: #3b54e0;          
  --accent-pressed: #3348c9;        
  --accent-light: #edf0ff;          
  --accent-strong: #1a2b4a;         

  --warning: #f59e0b;               
  --warning-light: #fef4e2;
  --low: #6b7280;                   
  --mid: #4d6bfe;                   
  --high: #002fa7;                  

  --success: #12a150;               
  --success-light: #e8f7ef;
  --danger: #e5484d;                
  --danger-light: #fdeeee;

  --nav-bg: rgba(255, 255, 255, 0.85);  
  --overlay: rgba(15, 22, 41, 0.4);     
  --scrollbar: rgba(15, 22, 41, 0.2);

  
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto,
          "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI",
          "Microsoft YaHei", Arial, sans-serif;
  --font-display: "SF Pro Display", -apple-system, BlinkMacSystemFont, "Segoe UI",
          Roboto, "PingFang SC", "Microsoft YaHei UI", "Microsoft YaHei",
          "Helvetica Neue", Arial, sans-serif;
  --mono: "SF Mono", SFMono-Regular, ui-monospace, Menlo, Consolas, monospace;

  --fs-caption: 0.75rem;   
  --fs-body: 0.9rem;       
  --fs-subtitle: 1.2rem;   
  --fs-title: 1.5rem;      
  --fs-title-lg: 1.9rem;   

  --lh-caption: 1.4;
  --lh-body: 1.55;
  --lh-subtitle: 1.4;
  --lh-title: 1.25;
  --lh-tight: 1.05;        

  --fw-regular: 400;
  --fw-medium: 500;
  --fw-semibold: 600;
  --fw-bold: 700;
  --fw-heavy: 800;         

  --fs-hero: clamp(1.9rem, 4.5vw, 2.75rem);   
  --fs-page-title: clamp(1.4rem, 3vw, 1.75rem);
  --fs-stat: clamp(1.6rem, 3.5vw, 2.1rem);    

  --sp-1: 4px;
  --sp-1-5: 6px;
  --sp-2: 8px;
  --sp-2-5: 10px;
  --sp-3: 12px;
  --sp-3-5: 14px;
  --sp-4: 16px;
  --sp-4-5: 18px;
  --sp-5: 20px;
  --sp-6: 24px;
  --sp-7: 28px;
  --sp-8: 32px;
  --sp-9: 36px;
  --sp-10: 40px;
  --sp-12: 48px;
  --sp-14: 56px;

  --card-pad: var(--sp-7);      
  --section-y: var(--sp-9);     
  --gutter: var(--sp-12);       

  --r-control: 10px;       
  --r-card: 14px;          
  --r-full: 999px;         

  
  --shadow-card: 0 1px 3px rgba(15, 22, 41, 0.06),
                 0 4px 12px rgba(15, 22, 41, 0.06);
  --shadow-card-hover: 0 2px 6px rgba(15, 22, 41, 0.07),
                       0 8px 24px rgba(15, 22, 41, 0.08);
  --shadow-flyout: 0 4px 16px rgba(15, 22, 41, 0.10),
                   0 12px 40px rgba(15, 22, 41, 0.08);
  --shadow-dialog: 0 8px 32px rgba(15, 22, 41, 0.14),
                   0 24px 64px rgba(15, 22, 41, 0.12);

  --control-h: 38px;       
  --control-h-sm: 30px;
  --control-h-lg: 46px;
  --nav-h: 64px;           
  --sidebar-w: 232px;

  --container: 1120px;

  --dur-fast: 0.15s;       
  --dur-normal: 0.2s;      
  --dur-slow: 0.3s;        
  --dur-slower: 0.5s;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  --ease-in: cubic-bezier(0.4, 0, 1, 1);

  --z-nav: 50;
  --z-dropdown: 100;
  --z-modal: 200;
  --z-toast: 300;

  
  --divider: var(--border);
  --surface-stroke: transparent;        
  --subtle: rgba(15, 22, 41, 0.04);     
  --subtle-hover: var(--surface-hover);
  --subtle-pressed: rgba(15, 22, 41, 0.06);

  --control: var(--surface);
  --control-hover: var(--surface-hover);
  --control-pressed: rgba(15, 22, 41, 0.08);
  --control-disabled: #f2f4fa;
  --control-stroke: var(--border);
  --control-stroke-strong: var(--border-strong);

  --text-disabled: var(--text-dim);

  --neutral: var(--text-muted);
  --neutral-tint: rgba(15, 22, 41, 0.05);

  --critical: var(--danger);
  --critical-hover: #cf3b40;
  --critical-tint: var(--danger-light);

  --status-todo: var(--border-strong);
  --status-in-progress: var(--accent);
  --status-completed: var(--success);

  --focus-outer: var(--accent);
  --focus-inner: #ffffff;

  --surface-solid: var(--surface);
  --accent-tint: var(--accent-light);
  --accent-tint-strong: rgba(77, 107, 254, 0.16);
  --success-tint: var(--success-light);
  --caution: var(--warning);
  --caution-tint: var(--warning-light);

  --ease-decel: var(--ease-out);
  --ease-accel: var(--ease-in);
  --lh-title-lg: var(--lh-tight);
  --fs-display: clamp(2.4rem, 7vw, 3.6rem);   
  --sp-16: 64px;
}

html[data-theme="dark"] {
  color-scheme: dark;

  --bg: #12141c;
  --surface: #1c1f2b;
  --surface-hover: #232736;
  --border: #2c3142;
  --border-strong: #3d4356;

  --text: #eef0f6;
  --text-muted: #a3abc2;
  --text-dim: #767f97;
  --text-on-accent: #ffffff;

  --accent: #7b93ff;
  --accent-hover: #93a7ff;
  --accent-pressed: #a9b9ff;
  --accent-light: rgba(123, 147, 255, 0.14);
  --accent-strong: #dfe4f5;      

  --warning: #fbbf24;
  --warning-light: rgba(251, 191, 36, 0.14);
  --low: #8b93a8;
  --mid: #7b93ff;
  --high: #b9c6ff;

  --success: #3dd68c;
  --success-light: rgba(61, 214, 140, 0.14);
  --danger: #ff6b6f;
  --danger-light: rgba(255, 107, 111, 0.14);

  --nav-bg: rgba(18, 20, 28, 0.85);
  --overlay: rgba(0, 0, 0, 0.6);
  --scrollbar: rgba(255, 255, 255, 0.22);

  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.4), 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-card-hover: 0 2px 6px rgba(0, 0, 0, 0.45), 0 8px 24px rgba(0, 0, 0, 0.35);
  --shadow-flyout: 0 4px 16px rgba(0, 0, 0, 0.5), 0 12px 40px rgba(0, 0, 0, 0.4);
  --shadow-dialog: 0 8px 32px rgba(0, 0, 0, 0.6), 0 24px 64px rgba(0, 0, 0, 0.5);

  --subtle: rgba(255, 255, 255, 0.05);
  --subtle-pressed: rgba(255, 255, 255, 0.07);
  --control-pressed: rgba(255, 255, 255, 0.10);
  --control-disabled: rgba(255, 255, 255, 0.04);
  --neutral-tint: rgba(255, 255, 255, 0.07);
  --critical-hover: #ff8386;
  --focus-inner: #12141c;
  --accent-tint-strong: rgba(123, 147, 255, 0.22);
}